JPWO2019093395A1 - Molecular design methods, programs, host materials, luminescent molecules and organic luminescent devices - Google Patents

Abstract

The off-diagonal electrokinetic interaction constants for the reference vibration mode α between the first electronic state n in the molecule and the second electronic state m whose energy is lower than that of the first electronic state n are Vmn, α. Then, based on the correlation between the sum of squares V2 of Vmn and α represented by the following equation (1) and the non-radiation transition rate constant knr of internal conversion from the first electronic state n to the second electronic state m. By performing the molecular design, it is possible to perform the molecular design in which the non-radiation transition of the molecule is accurately controlled while suppressing the calculation cost. Ψn is the electron wave function of the first electronic state n, Ψm is the electron wave function of the second electronic state m, x is the spatial and spin coordinates of N electrons contained in the molecule, and r is the N contained in the molecule. Spatial coordinates of one electron, R is the spatial coordinate of M nuclei contained in the molecule, H (r, R) is the molecular Hamiltonian, R0 is the reference nucleus arrangement, Qα is the mass-weighted reference vibration coordinate of the reference vibration mode α. Represent.

Description

The present invention relates to a molecular design method and program capable of performing molecular design in which a non-radiative transition of a molecule is controlled, a host material in which a non-radiative transition is controlled, a luminescent molecule, and an organic light emitting device using any of them.

As one of the fundamental interactions in a molecule, an off-diagonal electrokinetic interaction, which is an interaction between the vibration of an atomic nucleus and an electronic state, is known, which causes an internal conversion between two electronic states and the lifetime of the excited state. It is regarded as important because it is related to the quantum yield.
For example, in order to efficiently utilize the electron energy in the excited state for light emission, charge separation, and reaction in optical functional materials such as fluorescent materials, host materials, other organic electroluminescence element materials, solar cell materials, and photocatalysts. It is necessary to suppress the off-diagonal fluorescence interaction between the excited states, which is related to the lifetime of the excited states. On the other hand, there are some materials such as an ultraviolet absorbing material in which the lifetime of the excited state is desirable, and in this case, it is desirable that the off-diagonal electrokinetic interaction is large. In any case, controlling off-diagonal oscillating interactions is an important issue in the development of optical functional materials.
Taking a fluorescent material as a specific example, the fluorescence quantum yield Φ _PL is given by the following formula (4).

In the formula (4), _{k r} denotes the radiative transition rate _{constant, k nr} represents a non-radiative transition rate constant.
From the equation (4), it is shown that in order to improve the fluorescence quantum yield Φ _PL , it is necessary that the non-radiation transition rate constant k _nr is smaller than the radiation transition rate constant k _r . The non-radiative transition is divided into internal conversion due to off-diagonal electrokinetic interaction and intersystem intersection due to spin orbital interaction. In the following, non-radiative transition as internal conversion is particularly referred to as "non-radiative transition (internal conversion)". The non-radiation transition rate constant in the internal conversion process is called "non-radiation transition (internal conversion) rate constant k _nr ".
Here, at the temperature T, the non-radiation transition (internal conversion) rate constant k _nrn ^{→ m} (T) in the process of internal conversion from the electronic state n to the electronic state m is expressed by the following equation (5) (non-radiation transition). See Patent Document 1).

Here, the off-diagonal oscillating interaction constants V _{mn and α} that determine the non-radiation transition (internal conversion) rate constant k _nrn ^{→ m} are defined by the following equation (2).

In equation (2), Ψ _n represents the electron wave function of the electronic state n, Ψ _m represents the electron wave function of the electronic state m, and x represents the spatial coordinates and spin coordinates of N electrons contained in the molecule. , R represent the spatial coordinates of N electrons contained in the molecule, R represents the spatial coordinates of the M nuclei contained in the molecule, and H (r, R) represents the molecular Hamiltonian. R ₀ represents the reference nucleus arrangement and corresponds to the optimized structure of the electronic state n as the excited state. Q _α represents the mass-weighted reference vibration coordinates of the reference vibration mode α.

On the other hand, the overlapping density (transition density) [rho (r _i) between the electron state n and electronic m is defined by the following formula (6).

In equation (6), Ψ _n represents the electron wave function of the electronic state n, Ψ _m represents the electron wave function of the electronic state m, and x represents the spatial coordinates and spin coordinates of N electrons contained in the molecule. , R represent the spatial coordinates of N electrons contained in the molecule, R represents the spatial coordinates of the M nuclei contained in the molecule, and R ₀ represents the reference nucleus arrangement.
Here, the overlapping density (transition density) [rho (r _i) and unpaired Tsunofuri electrostatic interaction constants V _mn, relationship of the following equation (7) between the _α holds.

In the formula _{(7), ν α (r} i) represents a potential derivative of the reference oscillation mode alpha.
Thus, the off-diagonal oscillating interaction constants V _{mn, α} and the off-diagonal oscillating interaction density (the integrand on the right side in equation (7)) depend on both the electronic state and the oscillating state. In order to perform molecular design that controls the non-radiation transition (internal conversion) of, it is necessary to calculate and design considering both the electronic state and the vibration state.

Phys. Chem. Chem.Phys. 16, 14244-14256 (2014)

As described above, the non-radiation transition (internal conversion) rate constant k _nr ^{n → m} of the molecule is obtained by using the off-diagonal oscillating interaction constants V _{mn, α} . Here, the off-diagonal oscillating interaction constants V _{mn and α} should be calculated by performing vibration analysis of the electronic state m which is the excited state, but it is very large for the vibration analysis of the excited state. Computational resources are needed. For this reason, it is usual to substitute the optimized structure R ₀ of the excited state n by performing vibration analysis for the basal electronic state. However, unpaired Tsunofuri electrostatic interaction constants V _mn obtained in the ground state vibration _{analysis, alpha} is unpaired Tsunofuri electrostatic interaction constants V _mn obtained in the excited state vibration _{analysis, might alpha} value is shifted, thereby There was a problem in reliability of the required non-radiation transition (internal conversion) rate constant k _nrn ^{→ m} .
In addition, so far, the off-diagonal oscillating interaction constant has been obtained for each reference vibration mode, and the unpaired whole molecule is based on the off-diagonal oscillating interaction constant | V | _max , which has the maximum absolute value. We are discussing the magnitude of the angular vibration-electric interaction. However, | V | _max tends to be smaller when the molecular size becomes large and the overlap of electronic states is delocalized, so the off-diagonal electrokinetic interaction between molecules with different molecular sizes is compared. It was inappropriate as an index to do.

Therefore, in order to solve the problems of the prior art, the present inventors provide a molecular design method and a program capable of performing a molecular design in which the non-radiation transition of the molecule is accurately controlled while suppressing the calculation cost. We proceeded with the study for the purpose of doing so. Furthermore, we proceeded with studies for the purpose of providing luminescent molecules / host materials with controlled non-radiation transitions and organic luminescent devices with high luminous efficiency.

Result of intensive studies to solve the above problems, the present inventors have unpaired Tsunofuri electrostatic interaction constants V _mn, non-radiative transitions square sum V ² of _alpha (internal conversion) rate constant k _nr ^{n → It} was found that it has a high correlation with ^m, and that the overlap indexes η ⁰ , η ^N , and η ^M obtained only from the electronic state calculation have a correlation with the sum of squares V ² . Then, by using these indexes, the magnitude of the non-radiation transition (internal conversion) rate constant k _nrn ^{→ m} can be grasped by a simple calculation, and the molecular design can be performed by accurately controlling the non-radiation transition of the molecule. I came to the conclusion of. The present invention has been proposed based on these findings, and specifically has the following configuration.

[1] The off-diagonal oscillating interaction constant for the reference vibration mode α between the first electronic state n in the molecule and the second electronic state m whose energy is lower than that of the first electronic state n is V _{mn. , Α} , the norm || V _mn || of the vector V _mn = (V _{mn, α} ) whose components are V _{mn, α} represented by the following equation (2), and the first electronic state n A molecular design method for performing molecular design based on the correlation of the non-radiation transition rate constant k _nr of internal conversion from the second electronic state to the second electronic state m.

[2] The norm || _{V mn} using p- norm || _{V mn} || _p represented by the following formula as a ||, the a p- norm || _{V mn} || _p, the first electronic state The molecular design method according to [1], wherein the molecular design is performed based on the correlation of the non-radiation transition rate constant k _nr of the internal conversion from n to the second electronic state m.

[In the equation, p represents a real number of 1 ≦ p ≦ ∞. ]
[3] P-norm || V _mn || _p with p = 2 || V _mn || ₂ squared V _{mn, α} sum of squares V represented by the following equation (1) ^{Using 2} , the molecular design is performed based on the correlation between the sum of squares V ² and the non-radiation transition rate constant k _nr of the internal conversion from the first electronic state n to the second electronic state m. The molecular design method according to [1].

[In the equation (1), V _{mn and α} are the off-diagonal oscillating interaction constants represented by the equation (2). ]
[4]


[5]

[6]
The molecular design method according to [4], wherein the molecular design is performed based on the correlation between the first electronic state n and the non-radiation transition rate constant k _nr of the internal conversion from the second electronic state m. ..
[7] A molecular design method for designing a molecule by using at least one of the overlap indexes η ⁰ , η ^N, and η ^M defined by the following equation for controlling the non-radiation transition of the molecule.


[8] The decrease in the overlap density between the electronic states due to the localization of the molecular orbital due to the static Jahn-Teller effect that occurs when the electronic state of the molecule is degenerate is used to control the non-radiation transition of the molecule. Molecular design method for molecular design.
[9] The off-diagonal oscillating interaction constant for the reference vibration mode α between the first electronic state n in the molecule and the second electronic state m whose energy is lower than that of the first electronic state n is V _{mn. , Α} , the numerator by controlling the sum of squares V ² of V _{mn and α} represented by the above formula (1) using at least one of the overlap indexes η ⁰ , η ^N and η ^M. The molecular design method according to [7], which controls the non-radiation transition of.
[10] The decrease in the overlap density between the electronic states due to the localization of the molecular orbital due to the static Jahn-Teller effect that occurs when the electronic state of the molecule is degenerate is described by the overlap indexes η ⁰ , η ^N , and so on. The molecular design method according to [7] or [9], which is used for controlling η ^M.
[11] The item according to any one of [7], [9], and [10], wherein I in the overlap indexes η ⁰ , η ^N , and η ^M is I _p represented by the following formula (3). Molecular design method.

[In equation (3), ρ represents the overlap density between the first electronic state n and the second electronic state m whose energy is lower than that of the first electronic state n, and p is 1 ≦ p ≦ ∞. Represents a real number of. ]
[12] The molecule for which the molecular design is performed is a luminescent molecule that emits light due to the radiation transition of the singlet state generated by the crossover between the inverse triplet states T _n from the higher triplet state T _n, and the higher triplet state T _n and the above. At least one of the overlap indices η ⁰ , η ^N and η ^{M with} the lower triplet state T _p (n> p), which has a lower energy than the higher triplet state T _n , is set between these triplet states. The molecular design method according to [9], wherein the molecular design is performed so that the non-radiation transition is suppressed by using the control of the sum of squares V2 of the off-diagonal oscillating interaction constants between the ^two .
[13] The decrease in the overlap density between the electronic states due to the localization of the molecular orbital due to the static Jahn-Teller effect that occurs when the electronic state of the molecule is degenerate is described by the overlap indexes η ⁰ , η ^N , and so on. The molecular design method according to [12], which is used for controlling η ^M.
[14] [3], [6], [9], [12], used in the molecular design method according to any one of [13], the program having the step of calculating the square sum ^{V 2.}
[15] It is used in the molecular design method according to any one of [7] and [9] to [13], and has a step of calculating at least one of the overlap indexes η ⁰ , η ^N , and η ^M. program.
[16] The off-diagonal oscillating interaction constant for the reference vibration mode α between the first electronic state n in the molecule and the second electronic state m whose energy is lower than that of the first electronic state n is V _{mn. , Α} , a program having a step of calculating the sum of squares V ² of V _{mn and α} represented by the above equation (1).
[17] The higher excited states E _n in the numerator and the first electronic state n, the low-order excited state E _p energy is lower than the higher excited states E _n the second electronic state m, these electronic states when the unpaired Tsunofuri electrostatic interaction constants for normal modes alpha between each other and with the V _{mn, alpha,} V _mn represented by the formula _(1), the square sum V ² of _alpha, the higher-order excitation inhibiting molecules of the non-radiation transition process which is less 5.0 × 10 ^-6 au between state E _n and the higher excited states E _n all lower order excited state E _p is less energy than.
[18] The higher triplet state T _n in the molecule is _defined as the first electronic state n, and the lower triplet state T _p whose energy is lower than that of the higher triplet state T _n is _defined as the second electronic state m. the unpaired Tsunofuri electrostatic interaction constants for normal modes alpha V _mn between these electronic states _each other when the _alpha, V _mn represented by the formula _(1), the square sum V ² of _alpha, the Between the higher triplet state T _n and all lower triplet states T _p whose energy is lower than the higher triplet state T _n, it is 5.0 × 10 ^-6 au or less, in [17]. The molecule in which the non-radiation transition process described is suppressed.
[19] A light-emitting molecule emits light by radiative transition of singlet state produced by reverse inter-system crossing from higher triplet state T _n, the higher triplet state T _n is set as a first electronic state n The lower triplet state T _p, which has a lower energy than the higher triplet state T _n , is set as the second electronic state m, and the off-diagonal triplet interaction constant for the reference vibration mode α between these electronic states. when was the _{V mn, alpha, V mn} represented by the formula _(1), square sum ^{V 2} of _alpha is, the higher triplet state _{T n} and energy than the higher-order triplet state _{T n} is A luminescent molecule that is 5.0 × ^10-6 au or less with all lower triplet electronic states T _p .
[20] The molecule in which the non-radiation transition process is suppressed according to [17] or [18], which has a symmetric molecular structure having three or more axes of symmetry (rotation axis or reflection axis).
[21] The luminescent molecule according to [19], which has a symmetric molecular structure having three or more axes of symmetry (rotation axis or reflection axis).
[22] The molecule in which the non-radiation transition process is suppressed according to [20], which has a rotationally symmetric structure having a three-fold rotation axis.
[23] The luminescent molecule according to [21], which has a rotationally symmetric structure having a rotation axis three times.
[24] The molecule in which the non-radiation transition process is suppressed according to [20] or [22], wherein the structure containing the center of symmetry is a triphenylamine structure.
[25] The luminescent molecule according to [21] or [23], wherein the structure including the center of symmetry is a triphenylamine structure.
[26] The molecule in which the non-radiation transition process is suppressed according to [24], which has a structure in which an indole ring or a pyrrole ring is bonded to each phenyl group having a triphenylamine structure.
[27] The luminescent molecule according to [25], which has a structure in which an indole ring or a pyrrole ring is bonded to each phenyl group having a triphenylamine structure.
[28] The molecule in which the non-radiation transition process according to [17] is suppressed, which comprises a compound represented by the following general formula (1).

[In the general formula (1), R ¹ represents a hydrogen atom, a substituted or unsubstituted alkyl group, or a substituted or unsubstituted aryl group, and R ^{2 to} R ⁸ are independently hydrogen atoms, substituted or unsubstituted, respectively. Represents an alkyl group or a halogen atom. ]
[29] The luminescent molecule according to [19], which comprises the compound represented by the general formula (1).
[30] The molecule containing the suppressed molecule of the non-radiation transition process according to any one of [17], [18], [20], [22], [24], [26], and [28]. Host material.
[31] An organic light emitting device containing the molecule according to any one of [17] to [29] in the light emitting layer.
[32] The organic light emitting device according to [31], which is an organic electroluminescence device.

According to the present invention, it is possible to design a molecule in which the non-radiation transition of the molecule is accurately controlled while suppressing the calculation cost.

It is a schematic diagram which shows the potential curved surface and the molecular orbital of the molecule which expresses a static Jahn-Teller effect. The radiative transition of singlet state caused by reverse intersystem crossing system from higher triplet state T _n is an energy level diagram of a light-emitting molecule emits light. It is a molecular orbital chart obtained by the off-diagonal oscillating interaction density analysis of D _2h -ethylene and C _2h -butadiene. Radiationless transitions square sum V ² is a scatter diagram showing a correlation between (internal conversion) rate constant k _nr. It is a scatter diagram which shows the correlation of the overlap index η _∞ ⁰ and the sum of squares V ² . It is a scatter diagram which shows the correlation of the overlap index η _∞ ^N and the sum of squares V ² . It is a scatter diagram which shows the correlation of the overlap index η _∞ ^M and the sum of squares V ² . It is a scatter diagram which shows the correlation of the overlap index η ₁ ^N and the sum of squares V ² . It is a scatter diagram showing the correlation between the overlap index η ₁ ^M and the sum of squares V ² . Overlap index eta ₁ ⁰ Compound 1 as a scatter diagram showing a correlation between the square sum V ^2. Overlap index eta _∞ ⁰ Compound 1 as a scatter diagram showing a correlation between the square sum V ^2. Compound 1 of the overlap index eta ₁ ⁰ and | V | is a scatter diagram showing a correlation between _max. It is a scatter diagram which shows the correlation of the overlap index η _∞ ⁰ of compound 1 and | V | _max . It is a scatter diagram which shows the correlation of the overlap index η ₁ ^N of compound 1 and the sum of squares V ² . It is a scatter diagram which shows the correlation of the overlap index η _∞ ^N of compound 1 and the sum of squares V ² . It is a scatter diagram which shows the correlation of the overlap index η ₁ ^N of compound 1 and | V | _max . It is a scatter diagram which shows the correlation of the overlap index η _∞ ^N of compound 1 and | V | _max . It is a scatter diagram which shows the correlation of the overlap index η ₁ ^M of compound 1 and the sum of squares V ² . It is a scatter diagram which shows the correlation of the overlap index η _∞ ^M of compound 1 and the sum of squares V ² . It is a scatter diagram which shows the correlation of the overlap index η ₁ ^M of compound 1 and | V | _max . It is a scatter diagram which shows the correlation of the overlap index η _∞ ^M of compound 1 and | V | _max . It is a molecular orbital diagram of the optimized structure of the triplet state T ₅ of the compound 12. It is a molecular orbital diagram which shows the overlap density between the electronic states of compound 12 and comparative compound 1. It is a scatter diagram which shows the correlation of the overlap index η ₁ ^M of compound 12 and the sum of squares V ² . It is a scatter diagram which shows the correlation of the overlap index η _∞ ^M of compound 12 and the sum of squares V ² . It is a light absorption spectrum and an emission spectrum of the dichloromethane solution of compound 1. It is a light absorption spectrum and an emission spectrum of the hexane solution of compound 1. It is a light absorption spectrum and an emission spectrum of the toluene solution of compound 1. It is a light absorption spectrum and an emission spectrum of the tetrahydrofuran solution of compound 1. It is a light absorption spectrum and an emission spectrum of the acetonitrile solution of compound 1. It is a light absorption spectrum and an emission spectrum of the dichloromethane solution of the comparative compound 1. It is a cyclic voltammogram of a dichloromethane solution of compound 1. It is a graph which shows the result of the photoelectron yield spectroscopic measurement of the single film of compound 1. It is a light absorption spectrum of a single film of compound 1. It is an emission spectrum of a single film and a doped film of compound 1. It is a transient attenuation curve of the light emission of the doping film of compound 1. It is an emission spectrum of the EL element 1 using the compound 1. It is a graph which shows the external quantum efficiency η _EQE -current density characteristic of the EL element 1 using compound 1. It is an emission spectrum of EL elements 2 and 3 using compound 1. It is a graph which shows the external quantum efficiency η _EQE -current density characteristic of EL elements 2 and 3 using compound 1.

Hereinafter, the present invention will be described in detail. The description of the constituent elements described below may be based on typical embodiments or specific examples, but the present invention is not limited to such embodiments. In this specification, the numerical range represented by using "~" means a range including the numerical values before and after "~" as the lower limit value and the upper limit value.
Further, the "first electronic state n" and the "second electronic state m" in the following description do not mean a specific electronic state, and the energy of the first electronic state n is the second electronic state. It is intended to include all combinations of electronic states that have a relationship higher than the energy of m.
Further, the non-radiant transition is divided into a non-radiant transition as an internal conversion and a non-radiated transition as an intersystem intersection. In the present specification, the non-radiated transition as an internal conversion is referred to as a “non-radiated transition”. "Internal conversion)", and the non-radiation transition rate constant in the internal conversion process is called "non-radiation transition (internal conversion) rate constant k _nr ".

<First molecular design method>
The first molecular design method of the present invention is unpaired for a reference vibration mode α between a first electronic state n in a molecule and a second electronic state m whose energy is lower than that of the first electronic state n. When the angular vibration electric interaction constants are V _{mn, α} , the norm of the vector V _mn = (V _{mn, α} ) whose component is V _{mn, α} represented by the following equation (2) || V _mn || This is a method of molecular design based on the correlation of the non-radiation transition rate constant k _nr of internal conversion from the first electronic state n to the second electronic state m.

In equation (2), Ψ _n represents the electron wave function of the first electronic state n, Ψ _m represents the electron wave function of the second electronic state m, and x is the space of N electrons contained in the molecule. Represents coordinates and spin coordinates, r represents the spatial coordinates of N electrons contained in the molecule, R represents the spatial coordinates of M nuclei contained in the molecule, and H (r, R) represents the molecular Hamiltonian. , R ₀ represents the reference nucleus arrangement, and Q _α represents the mass-weighted reference vibration coordinates of the reference vibration mode α.
x is specifically coordinates _{(r 1, s 1, ···} , r i, s i, ··· r N, s N) is, where _{r i} is the spatial coordinates of the electron i, s _i is the spin coordinate of the electron i.
Ψ _n , Ψ _m , R ₀ , and Q _α in the equation (2) can be obtained as follows when the molecular Hamiltonian H (r, R) is given. The reference nucleus arrangement R ₀ is obtained by structural optimization of the electronic state n of the molecular Hamiltonian H (r, R). The mass-weighted reference vibration coordinate Q _α of the reference vibration mode α is determined by the vibration analysis at the reference nucleus arrangement R ₀ . Ψ _n and Ψ _m are obtained by calculating the electronic states of the electronic states n and m at the reference nucleus arrangement R ₀ , respectively.
For a specific analysis method, the description in the section of Examples can be referred to.

As the norm || V _mn ||, it is preferable to use the _p -norm || V _mn || _p represented by the following formula.

[In the equation, p represents a real number of 1 ≦ p ≦ ∞. ]

Further, p-norm || V _mn || _p with p = 2 || V _mn || ₂ squared V _{mn, α} squared sum V ² represented by the following equation (1) It is more preferable to use it.

[In the equation (1), V _{mn and α} are the off-diagonal oscillating interaction constants represented by the above equation (2). ]

It is derived from the following equation (5) that the sum of squares V ^{2 of the off} -diagonal oscillating interaction constants V _{mn and α} correlates with the non-radiative transition (internal conversion) rate constant k _nr . The following equation (5) represents a non-radiation transition (internal conversion) rate constant k _nrn ^{→ m} (T) in the process of internal conversion from the first electronic state n to the second electronic state m at the temperature T. It is an equation and represents a case where a plurality of reference vibration modes α and β are involved in the internal conversion process.

Here, the part containing the product of the off-diagonal oscillating interaction constants V _{mn, α} , V _{mn, β} for different reference vibration modes α, β and the Franck-Condon factor (the part including the overlapping integral of the vibration wave function). Assuming that the difference due to the vibration mode can be ignored, the equation (5) is expressed by the approximate equation shown in the following equation (8), and is unpaired from the equation (8) with the non-radiation transition (internal conversion) velocity constant k _nr ^{n → m} . It is shown that the sum of squares V ^{2 of the} angular vibration electric interaction constants V _{mn and α} are in a proportional relationship.

Then, when V = (V _{mn, α} ) _{α = 1, ..., 3N-6, or 3N-5} is regarded as a vector, V ² = | V | ² , which is for unitary transformation. It is an invariant amount. Further, the vibration mode in which the vibration analysis is performed on the excited electronic state in the excited state optimized structure and the vibration mode in which the vibration analysis is performed on the ground electronic state in order to save the calculation cost are connected to each other by unitary transformation. Therefore, V ² is invariant regardless of which method is used.

As described above, the non-radiation transition (internal conversion) velocity constant k _nrn ^{→ m} and the sum of squares V ² of the off-diagonal oscillating interaction constants V _{mn and α} have a proportional relationship. Therefore, it is possible to grasp the magnitude relationship of k _nrn ^{→ m using} the magnitude relationship of the sum of squares V ² as an index. In addition, the sum of squares V ² is the same value in the excited state vibration analysis and the ground state vibration analysis, and by using the sum of squares V ² as an index, even when the ground state vibration analysis that does not require a calculation cost is used, the excited state vibration It is possible to grasp the magnitude relationship of the non-radiation transition (internal conversion) velocity constant k _nrn ^{→ m} with the same accuracy as when using the analysis. In addition, in the conventional molecular design focusing on the reference vibration mode in which the absolute value of the off-diagonal oscillating interaction constant is maximized, the magnitude of the off-diagonal oscillating interaction of the entire molecule is determined between molecules having different molecular sizes. There was a problem that it could not be compared. However, according to the method using the sum of squares V ² as an index, it is possible to compare the magnitude of the off-diagonal electrokinetic interaction between molecules of different molecular sizes. Therefore, according to the first molecular design method of the present invention, it is possible to perform molecular design by accurately controlling the non-radiation transition while suppressing the calculation cost.
Specifically, the control of non-radiation transition is, for example, squared when trying to obtain a molecule having a small non-radiation transition (internal conversion) rate constant k _nrn ^{→ m} , that is, a molecule in which radiation transition occurs preferentially. By designing the structure of the molecule so that the sum V ² becomes small, and designing the structure of the molecule so that the sum of squares V ² becomes large when trying to obtain a molecule in which the non-radiation transition occurs preferentially. It can be carried out. The factors that determine the sum of squares V ^{2 of the} molecule are the electronic state and vibration state of equation (2) that defines the off-diagonal electrokinetic interaction constants V _{mn and α} , and the overlap index used in the <third molecular design method> described later. It is an electronic state represented by η ⁰ , η ^N , and η ^M , and the sum of squares V ² can be controlled accurately by appropriately selecting and combining these.

<Second molecular design method>
Next, the second molecular design method of the present invention will be described.
The second molecular design method of the present invention is a method of designing a molecule by using the sum of squares obtained without performing any vibration analysis for controlling the non-radiation transition of the molecule. Here, VCC is calculated for the displacement in the Cartesian coordinate direction, the sum of squares is calculated, and the translation mode and the rotation mode are corrected.
Since no vibration analysis is required, the calculation cost can be significantly saved.

<Third molecular design method>
Next, the third molecular design method of the present invention will be described.
The third molecular design method of the present invention is a method of designing a molecule by using at least one of the overlap indexes η ⁰ , η ^N and η ^M defined by the following formulas for controlling the non-radiation transition of the molecule.

In each equation, N represents the number of electrons contained in the molecule, and M represents the number of reference vibration modes of the molecule or the number of atoms contained in the molecule. I represents the norm || ρ || of the function when the overlap density between the first electronic state n and the second electronic state m is ρ.

In equation (6), Ψ _n represents the electron wave function of the first electronic state n, Ψ _m represents the electron wave function of the second electronic state m, and x is the space of N electrons contained in the molecule. Represents coordinates and spin coordinates, r represents the spatial coordinates of N electrons contained in the molecule, R represents the spatial coordinates of M nuclei contained in the molecule, and R ₀ represents the reference nucleus arrangement.

^M in η ^M may be the number of vibrational modes in which the vibronic interaction is active, where a selection rule exists for highly symmetric molecules. Here, the vibronic interaction active vibration mode refers to a vibration mode in which the vibronic interaction constant of Eq. (2) does not necessarily become zero due to symmetry.
Further, it is preferable that I of each equation representing the overlap index η ⁰ , η ^N and η ^M is I _p represented by the following equation (3).

[In the formula (3), [rho is an expression function represented by _{(6) ρ (r i)} , p represents a real number of 1 ≦ p ≦ ∞. ]

That is, it is preferable that the overlap indexes η ⁰ , η ^N and η ^M are the following η _p ⁰ , η _p ^N and η _p ^M , respectively.

The theory that led to these overlap indices η ⁰ , η ^N , and η ^M will be described below.
First, the driving force of the non-radiative transition (internal conversion) between the first electronic state n and the second electronic state m by the reference vibration mode α is the off-diagonal electric interaction, and the off-diagonal electric interaction. The constants V _{mn and α} are given by the following equation (10).

In the formula (10), [rho (r _i) represents the overlap Density (transition density) of the first electronic state n and a second electronic state m, ν _α (r _i) the potential derivative of the normal modes alpha Represents.
In general, for the square integrable functions f and g, the mathematical relational expression of Cauchy-Schwartz's inequality in the following equation (11) holds.

Here, assuming that the equation (11) can be applied to the above equation (10), when the value of I represented by the following equation (12) is sufficiently small, it is mathematical that V _{mn and α} are small. Can lead to.

However, since ν _α in equation (10) is not square-integrable, Cauchy-Schwartz's inequality cannot be applied. Therefore, it is not obvious whether the proposition expressed by the following equation (13) holds.

Therefore, the present inventors have derived the overlap indexes η _p ⁰ , η _p ^N , and η _p ^M that can be calculated only from the above electronic states as follows. Then, as shown in the examples below, these overlap indexes are comprehensively calculated for molecules known as reference materials for fluorescence quantum yield measurement, and these overlap indexes and off-diagonal electrokinetic interactions are generated. We found that they correlate and that these overlapping indicators can be used to control non-radiative transitions (internal conversion).

There are many things that can be taken in the norm. For example, || ρ || ₁ expressed by the following equation is a norm because it satisfies axioms 1-3.

By generalizing this equation, the p-norm || ρ || _p expressed by the following equation can be defined.

The ∞-norm || ρ || _∞ is defined as follows.

An index that adopts these norms is defined as the following formula.

Since the overlap density is the electron density when the first electronic state n = the second electronic state m, the integral gives the number of electrons N. Therefore, in order to compare systems with different electron numbers N, it is necessary to normalize with N. The index standardized by N is defined by the following formula.

Here, the index to be obtained predicts the non-radiation transition (internal conversion) rate constant k _nr . Since k _nr is roughly proportional to the sum of squares V ² of the off-diagonal oscillating interaction constants V _{mn and α} , the index standardized by N should be squared. Furthermore, since the sum is taken for the vibration mode, the index should depend on the number M of the vibration mode. The index multiplied by the squared mode number M is defined as the following equation.

The overlap indexes η ⁰ , η ^N , and η ^M in the third molecular design method of the present invention are the above overlap indexes η ₁₀ ⁰ , η ₁ ^N , η ₁ ^M , η _p ⁰ , η _p ^N , η _p ^M , It is assumed that η _∞ ⁰ , η _∞ ^N , and η _∞ ^M are all included. For ^M in η ₁ ^M , η _p ^M , and η _∞ ^M, it is preferable to take the number of vibronic active modes in consideration of the selection rule of vibronic interaction for highly symmetric molecules.

The overlap indexes η ⁰ , η ^N , and η ^M as described above are the sum of squares V ² which is proportional to the non-radiation transition (internal conversion) rate constant k _nr described in the section of the first molecular design method described above. , Has a high correlation. Therefore, according to the third molecular design method of the present invention, the non-radiation rate constant from the values of the overlap indexes η ⁰ , η ^N , and η ^M , which can be calculated only from the result of the electronic state calculation, via the sum of squares V ^2. (Internal conversion) It is possible to grasp the magnitude of the vibronic interaction that determines the k _nr and the quantum yield Φ _PL . This makes it possible to perform molecular design in which the non-radiation transition of the molecule is accurately controlled at a lower calculation cost. Specifically, molecular design aimed at improving the efficiency of functional materials that need to suppress internal conversion and efficiently use excited state energy, such as organic electroluminescence devices and organic thin-film solar cells, is designed in a vibronic state. It is possible without performing the calculation related to and the vibrational interaction calculation. If this index is used in molecular design for suppressing off-diagonal oscillating interactions, the factors that must be considered are reduced, and the design becomes easier.

<Fourth molecular design method>
The fourth molecular design method of the present invention is an overlap between electronic states derived from the localization of molecular orbitals due to the static Jahn-Teller effect, which is expressed when the basal electronic state or excited electronic state of a molecule is degenerated. This is a method of molecular design using degeneracy control of non-radiation transition.
Non-linear molecules with degenerate electronic states are unstable to structural deformation, reduce the symmetry of the molecular structure, and stabilize to solve the degeneracy. This phenomenon is called the "static yarn teller effect".
FIG. 1A shows a potential energy surface in which vibrations in a Jahn-Teller molecule having a degenerate electronic state having a three-fold axis of symmetry are plotted against reference coordinates. FIG. 1 (b) shows the molecular orbital of this Jahn-Teller molecule before the static Jahn-Teller effect is exhibited, and FIG. 1 (c) shows the orbital of the yarn-teller molecule due to the degeneracy caused by the static Jahn-Teller effect. The molecular orbital of the Jahn-Teller molecule is shown.
As shown in FIG. 1 (a), on this potential surface, there are three minimum points and three transition states derived from the three-fold axis of symmetry around the conical intersection. It can be seen that the degeneracy of the electronic state is observed at the conical intersection with high symmetry, but the symmetry is reduced at other points (including the minimum point) and the degeneracy is solved.

The decrease in the overlap density between the electronic states due to the static Jahn-Teller effect of the molecule having the degenerate electronic state as described above works in the direction of suppressing the non-radiative transition. Therefore, by designing the molecule so that the static Jahn-Teller effect works, it is possible to obtain a molecule having a small non-radiation transition (internal conversion) rate constant k _nr and a large quantum yield Φ _PL . The expression of the static Jahn-Teller effect in the molecule can be confirmed by splitting the peak of the ultraviolet-visible absorption spectrum and photoelectron spectroscopy. In addition, by using the overlap indexes η ⁰ , η ^N and η ^M in the fourth molecular design method as indicators of the decrease in the overlap density between electronic states due to the static Jahn-Teller effect, the non-radiation transition of the molecule can be further improved. It becomes possible to control reliably.

<Fifth molecular design method>
Fifth molecular design method of the present invention, molecules that performs molecular design is a light-emitting molecule emits light by radiative transition of singlet state produced by reverse inter-system crossing from higher triplet state T _n, higher At least one of the overlap indices η ⁰ , η ^N and η ^M between the triplet state T _n and the lower triplet state T _p (n> p) having a lower energy than the higher triplet state T _n. using the control of the square sum V ² unpaired Tsunofuri electrostatic interaction constant between between these triplet state, a method for performing molecular design as non-radiative transition is suppressed.
For the explanation of the sum of squares V ² of the off-diagonal oscillating interaction constants, the section <First molecular design method> can be referred to, and for the explanation of the overlap indexes η ⁰ , η ^N and η ^M , < The section of the third molecular design method> can be referred to. As shown in the Examples section below, the overlap indices η ⁰ , η ^N and η ^M have a positive correlation with the sum of squares V ² . Therefore, the electronic states so that the overlap indices η ⁰ , η ^N , and η ^M between the higher triplet state T _n and the lower triplet state T _p become smaller (so that the sum of squares V ² becomes smaller). By controlling the molecular design, it is possible to obtain a luminescent molecule in which the non-radiation transition is suppressed. Specifically, the sum of squares V ² of the vibronic interaction constants between the higher-order triplet state T _n and all triplet electronic states T _p (n> p) with lower energies is 5. it is preferable to perform .0 × 10 ^-6 au molecules designed to be less, and more preferable to carry out molecular design to be less than 3.3 × 10 ^-6 au. As a result, it is possible to obtain a luminescent molecule having a sufficiently low radiation-free transition (internal conversion) rate constant k _{nr and a} high fluorescence quantum yield Φ _PL .

FIG. 2 shows a specific example of a luminescent molecule whose molecule is designed by the fifth molecular design method. The luminescent molecules (a) and (b) shown in FIG. 2 have a basal triplet state S ₀ , a first triplet state S _q, and a second triplet state S _{m in} order from the side with the lowest energy level. 3 of the first triplet state T ₁ , the second triplet state T _p , and the third triplet state T _n , in order from the side with the lowest energy level. It can take two triplet states. Here, the third triplet state T _n correspond to higher triplet state T _n. Further, luminescent molecule (a), the energy level _{E Sm} of the second singlet state _{S m} is high luminescent molecules than the energy level _{E Tn} of higher triplet state _{T n,} i.e. the _{E Sm} and _{E Tn} the difference Delta] E _ST is greater luminescent molecules than 0, luminescent molecule (b), rather than the energy level _{E Tn} energy level _{E Sm} is higher triplet state _{T n} of the second singlet state _{S m} low luminous molecules, i.e. less luminous molecules than the difference Delta] E _ST are 0 _{E Sm} and _{E Tn.} Preferably the absolute value is sufficiently small in any of the luminescent molecules also Delta] E _ST, is preferably 500 meV or less.
In these luminescent molecules, the above-mentioned second singlet state _Sm and higher triplet state _Tn are generated with a probability of 25%: 75% by the recombination of the injected carriers. since at least some of the high-order triplet state T _n crossing between opposite system to the second singlet state S _m, the second singlet state S _m at a greater rate than the results of 25 percent to produce .. Then, the fluorescence emission by the second singlet state S _m is non-radiative transition to the first singlet state S _q, further first singlet state S _q is radiative transition to the ground singlet state S ₀ Occurs. Here, in order to obtain a high fluorescence quantum yield Φ _PL with these luminescent molecules, it is preferable that the radiation transition from the first singlet state S _q to the base singlet state S ₀ occurs preferentially, and these Non-radiative transition that is in parallel with the radiation transition, that is, non-radiation of S _q → S ₀ , S _m → S ₀ , T _n → T _p , T _p → T ₁ , T _n → T ₁ represented by vertical wavy lines. The transition is preferably suppressed. In this case, the overlapping index η ⁰ , η ^N , η ^M is defined with the electronic state on the left side of → as the first electronic state n and the electronic state on the right side of → as the second electronic state m, and these overlapping indexes are By designing the molecule so that it becomes smaller (so that the sum of squares V ² becomes smaller), the non-radiative transition is suppressed, and a luminescent molecule having a high fluorescence quantum yield Φ _PL can be realized.
In the fifth molecular design method, for example, it is preferable to design the luminescent molecule so that the static yarn teller effect is exhibited. This facilitates control in the direction in which the overlap indices η ⁰ , η ^N , and η ^M between the higher triplet state T _n and the lower triplet state T _p become smaller, and the luminescent molecule in which the non-radiation transition is suppressed is suppressed. Can be easily obtained. As a molecular structure that can be expected to exhibit the static Jahn-Teller effect, a symmetric molecular structure having three or more axes of symmetry (rotation axis or reflection axis) can be mentioned. The axis of symmetry of this molecular structure is preferably a rotation axis of 3 to 8 times or a rotation axis, more preferably a rotation axis of 3 to 8 times, and further preferably a rotation axis of 3 times. An XY type ₃ structure can be mentioned as a molecular structure having three-fold symmetry. The XY ₃ type structure, the X portion including the center of symmetry, is a structure bonded to three Y portion satisfies the 3-fold symmetry having the common structure. Examples of the X moiety include a triphenylamine structure, and examples of the Y moiety include a heteroaryl ring. The heteroaryl ring is preferably a heteroaryl ring containing a pyrrole ring structure, and more preferably a pyrrole ring or a fused ring having a structure in which an aromatic hydrocarbon ring is condensed with a pyrrole ring. An indole ring is particularly preferred. Groups Specifically, molecules with XY ₃ type structure, three of the phenyl groups of triphenylamine structure represented by the following formula (a), respectively, represented by at least one of the following formulas (b) It is preferably a compound having a structure substituted with. Further, the bond position of the group represented by the general formula (b) in the phenyl group is preferably the para position with respect to the bond position with the nitrogen atom, and more preferably only the para position.

In formula (a), the hydrogen atom in the phenyl group may be substituted with a substituent. However, at least one of the substitutable positions of the phenyl group is substituted with the group represented by the following general formula (b). Further, the substitution position of the substituent and the chemical structure of the substituent at the corresponding position are the same for the three phenyl groups.
When the triphenylamine structure represented by the formula (a) has a substituent other than the group represented by the general formula (b), the substituent shall be a substituted or unsubstituted alkyl group or a halogen atom. Is preferable. Preferred ranges and their description, specific examples, in R ² to R ⁸ of the general formula (1), a substituted or unsubstituted alkyl group or description and preferred ranges for a halogen atom, referring to the specific example Can be done.

In the general formula (b), R ^1b and R ^{6b to} R ^8b each independently represent a hydrogen atom or a substituent, and R ^6b and R ^7b and R ^7b and R ^8b are bonded to each other to form a cyclic structure. You may. * Represents the bond position to the phenyl group in the formula (a).
The substituent in R ^1b is preferably a substituted or unsubstituted alkyl group or a substituted or unsubstituted aryl group. Preferred ranges and their description, specific examples, see the R ¹ of the following general formula (1), a substituted or unsubstituted alkyl group or description and preferred ranges for the substituted or unsubstituted aryl group, and specific examples can do. Further, the substituents in R ^{6b to} R ^8b are preferably substituted or unsubstituted alkyl groups or halogen atoms. Preferred ranges and their description, specific examples, in R ² to R ⁸ of the general formula (1), a substituted or unsubstituted alkyl group or description and preferred ranges for a halogen atom, referring to the specific example Can be done. The cyclic structure formed by bonding R ^6b and R ^7b and R ^7b and R ^8b to each other is preferably an aromatic hydrocarbon ring that shares one side with the pyrrole ring, and most preferably a benzene ring. Here, the aromatic hydrocarbon ring may be substituted with a substituent. In the group represented by the general formula (b), R ^7b and R ^8b are bonded to each other to form a benzene ring that shares one side with the pyrrole ring, or R ^6b and R ^7b , R ^7b and R ^8b are It is preferable that none of them is bonded to form a cyclic structure. That is, the group represented by the general formula (b) is preferably a substituted or unsubstituted 1H-indole-2-yl group and a substituted or unsubstituted 1H-pyrrole-2-yl group.

Examples of molecules with XY ₃ type structure, the compound represented by the general formula (1) shown in the section <molecules with suppressed non-radiative transition process> The following may be mentioned, compound 1 as a specific example 22 can be mentioned. The compound represented by the general formula (1) is an XY type ₃ molecule in which the triphenylamine structure corresponds to X and the substituted or unsubstituted indole ring corresponds to Y. For example, compound 1 is luminescent and compound 12 can be expected to emit light with higher efficiency, but triphenylamine, methylindole and methylpyrrole are all non-luminescent. The structure that can be adopted for molecular design in the present invention should not be construed as being limited by the compound represented by the general formula (1).

<Program>
Next, the program of the present invention will be described.
Program of the present invention has a step of calculating the square sum V ² unpaired Tsunofuri electrostatic interaction constant.
Further, another program of the present invention is a program used in the molecular design method of the present invention, in which the sum of squares V ^{2 of} the off-diagonal oscillating interaction constant and the overlap index η ⁰ , η ^N , η ^M are at least one. It has a step of calculating one.
For the explanation of the sum of squares V ² of the off-diagonal oscillating interaction constants, the section <First molecular design method> can be referred to, and for the explanation of the overlap indexes η ⁰ , η ^N and η ^M , < The section of the third molecular design method> can be referred to.
As described above, the calculation process of the sum of squares V ² of the off-diagonal radiant interaction constants and the overlap indices η ⁰ , η ^N , and η ^M is simple. Therefore, by using the program of the present invention, the calculation cost can be suppressed. , It becomes possible to perform molecular design in which the non-radiation transition of the molecule is accurately controlled.

<Molecules with suppressed non-radiation transition process>
Next, the molecule in which the non-radiation transition process of the present invention is suppressed will be described.
Molecules with suppressed nonradiative transition process of the present invention, unpaired for normal modes α between the low-order excited state E _p energy is lower than the higher excited states E _n and higher excited states E _n square sum V ² of Tsunofuri electrostatic interaction constant, higher excited state and E _n, 5.0 × 10 ^-6 between all lower order excited state E _p is lower energy than higher excited state E _n It is au or less, and preferably 3.3 × ^10-6 au or less. Here square sum V ² of the higher excited states E _n the first electronic state n, the low-order excited state E _p energy is lower than the higher excited states E _n the second electronic state m, The off-diagonal oscillating interaction constants for the reference vibration mode α between these electronic states are set to V _{mn and α} , and are obtained by the equation (1) used in the first molecular design method. The molecules square sum V ² is defined as above between the high-order excited state E _n and Low-Order excited state E _p, non-radiative transition from the higher excited states E _n to the low-order excited state E _p process is suppressed, thereby energy is high-order excited state E _n, intersystem crossing and inverse inter-system crossing to the other systems, possible movement of the excitation energy to other molecules. Therefore, for example, when a molecule in which the non-radiation transition process is suppressed is used as the host material of the light emitting layer, the high excitation energy can be supplied from the host material to the light emitting molecule, so that deep blue or the like can be obtained. It can effectively function as a host material for a light emitting layer that emits short wavelength light. Here, when the molecule of the present invention is used as a host material, the luminescent molecule to be combined with the molecule is not particularly limited, and in addition to a normal fluorescent luminescent molecule and a normal phosphorescent luminescent molecule, a thermoactive delayed fluorescent luminescent molecule and a higher-order triplet. It may be a luminescent molecule by a fluorescence (FvHT) mechanism via a term. Here, J. Comput. Chem. Jpn. 14, 189-192 (2015), Sci.Rep.7, 4820 1- for explanation of luminescent molecules by the higher-order triplet fluorescence (FvHT) mechanism and examples of compounds. 9 (2017) can be referred to.
The molecule in which the non-radiation transition process of the present invention is suppressed may be one in which any non-radiation transition process is suppressed. For example, it may be a molecule that non-radiative decay process is suppressed from the higher excited triplet state T _n to the lower order excited triplet state T _p, lower order excited singlet from higher excited singlet state S _n may be a molecule that non-radiative decay process is suppressed to the excited state S _p, it may be a molecule that non-radiative transition process of both is suppressed. Further, in inhibiting molecules of the non-radiation transition process of the present invention, the order of higher excited states E _n where radiationless transition to the low-order excited state E _p is suppressed are not particularly limited, 1 to 20 It is preferably 1 to 10, more preferably 1 to 5, and even more preferably 1 to 5.
Thus, molecules of the present invention, since the non-radiative transition from the higher excited states E _n to the low-order excited state E _p is suppressed, in addition to the host material be used for a variety of applications It can be used effectively, especially as a luminescent molecule. For a description of the case where the molecule in which the non-radiation transition process of the present invention is suppressed is a luminescent molecule, the description in the <luminescent molecule> section below can be referred to.
Examples of the molecule in which the non-radiation transition process of the present invention is suppressed include a compound having a symmetric molecular structure having three or more axes of symmetry (rotation axis or reflection axis), and having three rotation axes. is preferably XY ₃ type molecules having a rotation symmetry structure. Here, the preferred range of the axis of symmetry of the molecule, for a description of XY ₃ type molecule, can be referred to the light-emitting molecules in the section <Fifth molecular design method>.
Further, the molecule in which the non-radiation transition process of the present invention is suppressed is preferably a compound represented by the following general formula (1).

In the general formula (1), R ¹ represents a hydrogen atom, a substituted or unsubstituted alkyl group, or a substituted or unsubstituted aryl group.
The alkyl group in R ¹ may be linear, branched or cyclic. The number of carbon atoms is preferably 1 to 20, more preferably 1 to 10, and even more preferably 1 to 6. For example, a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group, a tert-butyl group, a hexyl group and the like can be exemplified and may be a methyl group. preferable.
Aromatic ring constituting the aryl group in R ¹ can be a single ring may be a condensed ring in which two or more aromatic rings are condensed, the linking ring structures in which two or more aromatic rings are linked by a single bond You may have. The aromatic ring constituting the aryl group preferably has 6 to 18 carbon atoms, more preferably 6 to 14 carbon atoms, and particularly preferably 6 to 10 carbon atoms. Specific examples of the aryl group include a phenyl group, a naphthalenyl group, a biphenyl group, a tolyl group, a benzyl group, a xsilyl group and the like, and a phenyl group is preferable.
R ^{2 to} R ⁸ independently represent a hydrogen atom, a substituted or unsubstituted alkyl group, or a halogen atom.
For the description and preferred range of the alkyl group in R ^{2 to} R ⁸ and specific examples, the description and preferred range of the alkyl group in R ¹ and specific examples can be referred to.
As the halogen atom in R ² to R ^8, fluorine atom, chlorine atom, bromine atom, and an iodine atom.
Among R ² to R ^8, the number of those which are hydrogen atoms is preferably 2 or more, more preferably all are hydrogen atoms.
The alkyl group in R ^{1 to} R ^{8 and} the aryl group in R ¹ may be substituted with a substituent. Examples of the substituent of the alkyl group include an aryl group and a halogen atom, and examples of the substituent of the aryl group include an alkyl group and a halogen atom. The alkyl group and aryl group as substituents may be further substituted with an alkyl group, an aryl group, or a halogen atom.
R ⁶ and R ⁷ may be coupled to each other to form an annular structure, and R ⁷ and R ⁸ may be coupled to each other to form an annular structure. The cyclic structure referred to here is preferably an aromatic ring, and more preferably a benzene ring. Further, the aromatic ring and the benzene ring may be substituted, or may have a condensed ring structure. As a preferable group of compounds represented by the general formula (1), a group of compounds in which R ⁷ and R ⁸ are bonded to each other to form a substituted or unsubstituted benzene ring can be mentioned.
In the compound represented by the general formula (1), R ^{1 to} R ⁸ may be the same or different. Further, the three ^R 1, three ^R 2, three ^R 3, three ^R 4, three ^R 5, three ^R 6, three ^R 7, three ^{R 8} are each identical to one another.
Since the compound represented by the general formula (1) has a three-fold symmetric structure, the static Jahn-Teller effect is likely to be exhibited, and the non-radiation transition process is effectively suppressed by the expression.
Specific examples of the compound represented by the general formula (1) include the following compounds 1 to 22. In the following formula, t-Bu represents a tert-butyl group. However, the molecule in which the non-radiation transition process of the present invention is suppressed should not be construed in a limited manner by this specific example.

The compound represented by the general formula (1) can be synthesized by combining known synthetic reactions, and for detailed synthetic conditions, the synthetic example in the section of Examples can be referred to.

<Luminous molecule>
Next, the luminescent molecule of the present invention will be described.
Luminescent molecules of the present invention is a light-emitting molecule emits light by radiative transition of singlet state produced by reverse inter-system crossing from higher triplet state T _n, higher triplet state T _n and higher triplet The sum of squares V ² of the off-diagonal oscillating interaction constants for the reference vibration mode α between the lower triplet state T _p, which has a lower energy than the state T _n, is the higher triplet state T _n and the higher triplet. It must be 5.0 × ^10-6 au or less and 3.3 × ^10-6 au or less with all lower triplet electronic states T _p whose energy is lower than the term state T _n. Is preferable. Here, the sum of squares V ² has a higher-order triplet state T _n as the first electronic state n and a lower-order triplet electronic state T _p as the second electronic state m, and is a reference between these electronic states. The off-diagonal oscillating interaction constants for the vibration mode α are set to V _{mn and α} , and are obtained by the equation (1) used in the first molecular design method. The luminescent molecule in which the sum of squares V ² between the higher-order triple-term state T _n and the lower-order triple-term state T _p is defined as described above has a sufficiently low non-radiation transition (internal conversion) rate constant k _nr. , High fluorescence quantum yield Φ _PL can be obtained. For the specific luminescence mechanism of the luminescent molecule of the present invention, the description in the section <Fifth Molecular Design Method> can be referred to. Here, radiative transition in the light-emitting molecules of the present invention may be a radiative transition from the singlet state caused directly by reverse inter-system crossing from higher triplet state T _n, free from the singlet state It may be a radiation transition from a low-order single term state that has undergone a radiation transition.
As such light-emitting molecules, there may be mentioned a compound having a symmetric molecular structure having three or more symmetry axis (rotation axis or times Utsujiku) in XY ₃ type molecules having a rotationally symmetrical structure with a 3-fold axis It is preferable to have. Here, the preferred range of the axis of symmetry of the light emitting molecule, for a description of XY ₃ type molecule, can be referred to the section <Fifth molecular design method>.
Further, the luminescent molecule of the present invention is preferably a compound represented by the above general formula (1). For a description of the compound represented by the general formula (1), a preferable range, and specific examples, the above section <Molecules in which the non-radiation transition process is suppressed> can be referred to. Since the compound represented by the general formula (1) has a three-fold symmetric structure, the static Jahn-Teller effect is likely to be exhibited, non-radiation transition is suppressed, and a high fluorescence quantum yield Φ _PL can be obtained. ..

<Organic light emitting element>
Next, the organic light emitting device of the present invention will be described.
The organic light emitting device of the present invention is characterized by containing the molecule of the present invention as a light emitting molecule or a host material in the light emitting layer. Since the molecule of the present invention has a sufficiently low radiation-free transition (internal conversion) rate constant k _{nr and} has a high fluorescence quantum yield Φ _PL as a light emitting molecule, it is possible to realize an organic light emitting element having high luminous efficiency. .. In particular, an organic light emitting device containing compound 1 in the light emitting layer can obtain deep blue light emission derived from compound 1 and can realize high exciton utilization efficiency.
The organic light emitting device of the present invention may be an organic photoluminescence device or an organic electroluminescence device, but is preferably an organic electroluminescence device. Other configurations of the organic light emitting device are not particularly limited, and known configurations can be adopted. For example, the light emitting layer may be composed of only light emitting molecules, or may be composed of a combination of light emitting molecules and a host material. In addition to the light emitting layer, the organic electroluminescence element is provided with a hole transport layer, a hole injection layer, an electron blocking layer, a hole blocking layer, an electron injection layer, an electron transport layer, an exciton blocking layer, and the like. May be good. As the material for these layers, a known material can be selected and used.

The features of the present invention will be described in more detail with reference to Examples and Comparative Examples. The materials, amounts used, ratios, treatment contents, treatment procedures, etc. shown in the following examples can be appropriately changed as long as they do not deviate from the gist of the present invention. Therefore, the scope of the present invention should not be construed as limiting by the specific examples shown below. Further, in the examples shown below, the structural optimization and vibration analysis of the ground state are performed by the density functional theory (DFT) method using the functional mPW1PW91, and the structural optimization and vibration analysis of the excited state are performed by mPW1PW91 / 6. It was performed by the time-dependent density functional theory (TD-DFT) method at the -31G (d, p) level. For the initial state of the transition, the electronic state in the structure optimized for the excited state was used. The electronic state is calculated using the Gaussian09 Rev.D01 package, and the overlap density is calculated, the numerical integration using the cube file, and the I _∞ calculation of the cube file are performed using the program created for the calculation. It was.

[1] Examination of control of non-radiation transition (internal exchange) rate constant k _nr (Experimental example 1) Analysis of ethylene (D _2h -ethylene) having a D _2h structure and butadiene (C _2h -butadiene) having a C _2h structure D _{2h -} for ethylene, performed ground state vibration analysis and excited state vibration analysis, respectively, excited singlet state and between the ground singlet state (hereinafter, referred to as "S between ₁ -S _0") vibronic interaction activity examine the Do vibration mode, and calculates the square sum V ^2. Table 1 shows the results and the calculation time required for each analysis.

As shown in Table 1, as a result of performing ground state vibration analysis and excited state vibration analysis for D _2h -ethylene, two vibration modes (mode 7 and mode 9) were detected, respectively. Then, in each analysis method, a difference was observed in the off-diagonal oscillating interaction constant V, but the values of the sum of squares V ² were the same. On the other hand, the calculation time required for the excited state vibration analysis to be 7.6 times that for the ground state vibration analysis. According to the second molecular design method of the present invention, the calculation time is zero because these vibration analyzes are not performed. The value of the square sum V ² calculated in accordance with the second molecular design method were consistent with the values in Table 1.
Next, for D _2h -ethylene and C _2h -butadiene, ground state vibration analysis is performed, and the absolute value of the off-diagonal oscillating interaction constant between S _{1 and} S ₀ becomes the maximum | V | _max. The interaction mode) was investigated. The maximum off-diagonal oscillating interaction constant | V | _max is shown in Table 2. _{Further, D 2h} - ethylene and _{C 2h} - for _butadiene, shows the results of unpaired Tsunofuri electrostatic interaction Density Analysis between S 1 -S ₀ in FIG.

The maximum interaction mode of D _2h -ethylene is C = C expansion and contraction mode (mode 7), the maximum interaction mode of C _2h -butadiene is CH expansion and contraction mode (mode 22), and | V | of C _2h -butadiene. _The value of _max was clearly smaller than that of | V | _max of D _2h -ethylene. The off-diagonal interaction constant of butadiene vibration mode (mode 13) corresponding to the maximum interaction mode of D _2h -ethylene was 0.00153564267 au, which was even smaller. From this, it was found that as the molecular size increases, | V | _max tends to decrease. This is because when the molecular size increases and the overlap between electronic states is delocalized, the absolute values of the vibronic interaction densities η _{mn and α} for each vibration mode decrease, and the integral value of the vibronic interaction This is thought to be because the constant becomes smaller.

(Experimental Example 2) unpaired Tsunofuri conductive non-radiative transitions square sum V ² interaction constant (internal conversion) Study compound of correlation between the rate constant _{k nr 1 (TPA-MeIndole)} , compound 12 (TPA-MePyrrole) and using physical values of various compounds was investigated the correlation between the S ₁ → S ₀ nonradiative decay and square sum V ² unpaired Tsunofuri electrostatic interaction constants between (internal conversion) rate constant k _nr.
The table below shows the maximum emission wavelength λ _em at 77K, the fluorescence quantum yield Φ _F , the natural radiation rate constant k _{F in the} singlet state S ₁ , and the non-radiation transition rate constant k _NR between S ₁ → S ₀ of each of the following compounds. Shown in 3. "N" described below each structural formula below represents the number of electrons of each compound, and "M" represents the number of reference vibration modes of each compound. The non-radiation transition rate constant k _NR is a non-radiation transition rate constant for the entire molecule. The number of electrons N of each of the above compounds, the number M of the reference vibration mode, and the numerical values shown in Table 3 are quoted from the values described in J. Photochem. Photobio. A Chem. 194,67 (2008). It was done.

In addition to the above compounds, J. Luminescence 195,252 (2018); J. Photochem. Photobiol. A: Chem. 83, 7 (1994); J. Photochem. Photobiol. A: Chem. 110 , 123 (1997); Cryst. Growth Des.DOI: 10.1021 / acs.cgd.8b00509. Tables 4 and 5 show the off-diagonal oscillating interactions of these compounds, compound 1 (TPA-MeIndole), and compound 12 (TPA-MePyrrole), and the calculation results of the overlap index, respectively. Cubeint Rev.7 was used for the calculation of I ₁ , and cubemax Rev.4 was used for the calculation of I _∞ .

FIG. 4 shows the relationship between the sum of squares V ² of the off-diagonal oscillating interaction constants between S _{1 and} S ₀ of each of these compounds and the non-radiative transition (internal conversion) rate constant k _nr . As shown from FIG. 4, two square sum V ² and nonradiative decay rate constant k _nr of vibronic interaction constants had a positive correlation. Therefore, the magnitude relationship between the square sum V ^2, it was found that can grasp the magnitude of nonradiative decay rate constant k _nr.

(Experimental Example 3) Examination of the correlation between the overlap indexes η ⁰ , η ^N , η ^M and the sum of squares V ² of the off-diagonal oscillating interaction constants S ₁ → S using the physical property values of the following compounds S1 to S15. index eta _∞ ⁰ overlap between _{^{0, η ∞ N, η ∞}} M, η 1 N, was examined the correlation between the square sum ^{V 2} of eta ₁ ^M and vibronic interaction constants. The results are shown in FIGS. 5-9. The compounds S1 to S15 are used as standard substances for measuring the fluorescence quantum yield, and the number of electrons N and the number M of the reference vibration mode described below each structural formula are Pure Appl. Chem. 83. , 2213 (2011).

The maximum unpaired Tsunofuri electrostatic interaction constants of each compound | shows a square sum V ² of _max and unpaired Tsunofuri electrostatic interaction constants in Table 6 | V.

As shown in FIGS. 5 to 9, the overlap indexes η _∞ ⁰ , η _∞ ^N , η _∞ ^M , η ₁ ^N , and η ₁ ^M are positive with the sum of squares V ² of the off-diagonal oscillating interaction constants. Had a correlation of. Therefore, these overlapping indicators can control two multiplication sum V ^2, nonradiative decay (internal conversion) rate constant k _nr having a proportional relationship with the square sum V ² also was able to be controlled simultaneously.

(Experimental Example 4) Examination example 1 of the correlation between the overlap index η ⁰ , η ^N , η ^M and the sum of squares V ² of compounds expressing the static Jahn-Teller effect
In this experimental example, the following compound 1 was used as a luminescent molecule expected to have a static Jahn-Teller effect.

Moreover, as a comparison, the following comparative compound 1 was used. In the following structural formula, Me represents a methyl group. Comparative compound 1 is a non-luminescent molecule.

The excited electronic states that Compound 1 can take, the excitation energy required to generate the excited electronic states, the oscillator strength f, the main electronic configurations that make up the excited electronic states, and the CI (configuration interaction) coefficient were calculated. As a result of the calculation, it was found that the triplet states T ₈ and T ₉ are energetically close to the singlet state S ₃ . Here, the energy difference Delta] E _ST between singlet state _{S 3} and a triplet state _{T 8} is 94MeV, energy difference Delta] E _ST between singlet state _{S 3} and a triplet state _{T 9} was -154meV .. Therefore, compound 1 is likely to cause an inverse intersystem crossover from the triplet states T ₈ and T ₉ to the single term state S _3, and the basis of S ₁ caused by the non-radiative transition from its single term state S _3. it was found that it is capable of emitting light by radiative transition to the singlet state S _0.

When the overlap density of the molecular orbitals of the triplet state T ₉ of compound 1 and the other triplet states was calculated, the overlap density of the triplet states T ₉ and T ₈ of compound 1 with the other triplet states was small. It turned out to be localized. This suggests that the overlap indices η ⁰ , η ^N , η ^M and the sum of squares V ^{2 of} T ₉ and T ₈ and other triplet states are small values.
| V | _max between each electronic state of compound 1 and comparative compound 1, sum of squares of off-diagonal electrokinetic interaction constant V ² , overlap index η _∞ ⁰ , η ₁₀ ⁰ , η _∞ ^N , η ₁ ^N , η Table 7 shows _∞ ^M and η ₁ ^M. Here, the calculation for the compound 1 was performed with the number of electrons N as 334 and the number of atoms M as 85, and the calculation for the comparative compound 1 was performed with the number of electrons N as 178 and the number of atoms M as 46.
Overlap index eta ₁ ⁰ Compound 1 and a scatter plot of the square sum ^{V 2} shown in FIG. 10, the overlap index eta _∞ ⁰ a scatter plot of the square sum ^{V 2} shown in FIG. 11, the overlap index eta ₁ ⁰ and | V | A scatter plot of _max is shown in FIG. 12, a scatter plot of the overlap index η _∞ ⁰ and | V | _max is shown in FIG. 13, and a scatter plot of the overlap index η ₁ ^N and the sum of squares V ² is shown in FIG. A scatter plot of η _∞ ^N and the sum of squares V ² is shown in FIG. 15, a scatter plot of the overlap index η ₁ ^N and | V | _max is shown in FIG. 16, and a scatter plot of the overlap index η _∞ ^N and | V | _max is shown. FIG. 17 shows a scatter plot of the overlap index η ₁ ^M and the sum of squares V ^2, a scatter plot of the overlap index η _∞ ^M and the sum of squares V ² is shown in FIG. 19, and the overlap index η ₁ ^M and | A scatter plot of V | _max is shown in FIG. 20, and a scatter plot of the overlap index η _∞ ^M and | V | _max is shown in FIG.

As shown in Table 7, in each of the triplet states T _{7 to} T ₁ of the compound 1, the sum of squares V ² between the higher order triple term states T ₅₉ and T ₈ is 5.0 × ^10-6 or less. there were.
Further, from FIGS. 10 to 21, the overlap indexes η _∞ ⁰ , η ₁₀ ⁰ , η _∞ ^N , η ₁ ^N , η _∞ ^M , and η ₁ ^M correlate better with the sum of squares V ² than | V | _max. In particular, a high correlation was observed between the sum of squares V ² and η _∞ ^M and η ₁ ^M.

(Experimental Example 5) Examination example 2 of the correlation between the overlap index η ⁰ , η ^N , η ^M and the sum of squares V ² of compounds expressing the static Jahn-Teller effect.
In this experimental example, the following compound 12 was used as a luminescent molecule expected to have a static Jahn-Teller effect. Moreover, as a comparison, the above-mentioned comparative compound 1 was used.

Excited electronic states that compound 12 can take, the excited energy required to generate the excited electronic states, the oscillator strength f, the main electron configurations that make up the excited electronic states, and the CI (configuration interaction) coefficient (in parentheses). Is shown in Table 8.

Of the electronic state shown in Table 8, singlet state S ₁ is a light emitting state. This is _{S 1,} are close triplet state _{T 5} is the most energy difference Delta] E _ST between singlet state _{S 1} and a triplet state _{T 5} was 30 meV. Therefore, compound 12 is likely to cause an intersystem crossing from the triplet state T ₅ to the singlet state S ₁ , and the resulting radiative transition from the singlet state S ₁ to the base singlet state S ₀ . It was found that it can emit light. Moreover, compound 12 is expected to internal conversion of _{S 1} → _{S 0} is suppressed, since a smaller and Delta] E _ST also 30 meV, highly efficient light emission can be expected.
The frontier orbital in the optimized structure of the triplet state T ₅ of the compound 12 shown in FIG. 22.
From FIG. 22, the localization of molecular orbitals due to the static Jahn-Teller effect was observed in MO126, MO127, MO129, MO130, MO132, and MO133 of the molecular orbitals.

Next, the overlap density between the excited states of compound 12 was examined.
Overlap density ρ (Ψ _1, Ψ ₂₎ between the two wave functions [psi ₁ and [psi ₂ and represents the one-electron excitation arrangement from occupied orbitals [psi _i to an empty orbital character [psi _r to be expressed as [Phi _i ^r To do. T ₅ following electron excitation arrangement of triplet state is represented as follows.

The overlap density of the triplet state T ₅ and another triplet state is represented as follows.

The overlap density of molecular orbital triplet state T ₅ and another triplet state of the compound 12 shown in FIG. 23 (a) ~ (d) , the molecules of singlet state S ₁ and a ground singlet state S ₀ of Compound 12 the overlap density trajectory shown in FIG. 23 (e), shown in FIG. 23 (f) the overlapping density of molecular orbital singlet state S ₁ and a ground singlet state S ₀ of the comparative compound 1.
From Figure 23, the compound 12, the molecular orbitals are localized, it has been found overlapping density of the triplet state T ₅ and another triplet state is small in each triplet state. This suggests that the overlap index η ⁰ , η ^N , η ^M and the sum of squares V ² are small values.
| V | _max between each electronic state of compound 12 and comparative compound 1, sum of squares of off-diagonal oscillating interaction constants V ² , overlap index η _∞ ⁰ , η ₁₀ ⁰ , η _∞ ^N , η ₁ ^N , η Table 9 shows _∞ ^M and η ₁ ^M. A scatter plot of the overlap index η ₁ ^M and the sum of squares V ² of compound 12 is shown in FIG. 24, and a scatter plot of the overlap index η _∞ ^M and the sum of squares V ² is shown in FIG.

As shown in Table 9, the triplet states T ₄ , T ₃ , T ₂ and T ₁ of the compound 12 all have a sum of squares V ² with the higher order triple term state T ₅ of 3.3 × 10 ^−. It was ⁶ or less.
Further, from FIGS. 24 and 25, it was shown that the overlap indexes η ₁ ^M and η _∞ ^M of the compound 12 have a high correlation with the sum of squares V ² of the off-diagonal oscillating interaction constants.

[2] Evaluation of Emission Characteristics of Compound Obtained by Molecular Design (Synthesis Example 1) Synthesis of Compound 1 The synthesis scheme of Compound 1 is shown below.

According to this synthesis scheme, compound 1 was synthesized by the following procedure.

2-Br-1-H-indole (0.508 g, 2.6 mmol) and sodium hydride (160 mg, 4 mmol) were stirred in N, N-dimethylformamide (15 mL) at 0 ° C. for 30 minutes. Iodomethane (0.25 mL, 4 mmol) was added dropwise to this mixture, the temperature was returned to room temperature, and the mixture was stirred overnight. Water was added to the reaction mixture to separate the aqueous layer, and ethyl acetate was further added to the aqueous layer to separate the organic layer. The obtained organic layer was dried with sodium sulfate, and then the organic solvent was volatilized to obtain a non-volatile component. This non-volatile component was purified by silica gel column chromatography using a mixed solvent of ethyl acetate: n-hexane = 9: 1 as a developing solvent. By the above steps, Intermediate 1, which is a pale yellow solid, was obtained in a yield of 0.313 g and a yield of 57.3%. The melting point of Intermediate 1 was 66 ° C.

Intermediate 1 (0.252 g, 1.2 mmol), Tris- (4-pinaborylphenyl) amine (0.250 g, 0.4 mmol), Tetrakis (triphenylphosphine) palladium (O) (0.048 g, 0) .04 mmol) and sodium tert-butoxide (0.144 g, 1.5 mmol) were stirred in toluene for 24 hours. After washing the reaction mixture with brine, the organic layer was separated and dried over sodium sulfate. The organic solvent was volatilized from this organic layer, and the obtained non-volatile component was purified by silica gel column chromatography using a mixed solvent of ethyl acetate: n-hexane = 9: 1 as a developing solvent. By the above steps, the target compound 1 was obtained as a white solid in a yield of 0.172 g and a yield of 48.3%. The melting point of the obtained compound 1 was 139 ° C.
^{1 1} H-NMR (400 MHz, CD ₂ Cl ₂ ) δ7.60 (d, J = 7.8 Hz, 3H), 7.49 (d, J = 7.6 Hz, 6H), 7.38 (d, J = 8.0Hz, 6H), 7.32 (d, J = 8.0Hz, 6H), 7.22 (t, 8.0Hz, 3H), 7.10 (t, 8.0Hz, 3H), 6. 56 (s, 3H), 3.80 (s, 9H); ¹³ C-NMR (100MHz, CD ₂ Cl ₂ ): δ147,6,142.0,139.2,130.9,128.8,128 .2,124.8,122.1,120.8,120.3,110.1,101.7,31.7; APCI HRMS: m / z calcd for C ₄₅ H ₃₆ N ₄ : 633.3013 [ M + H] ⁺ ; found 633.3004.

(Example 1) Evaluation of physical properties of compound 1 solution A dichloromethane solution of compound 1 (concentration 0.01 mM) was prepared in a glove box in an Ar atmosphere.
Further, a solution of Compound 1 was prepared in the same manner except that hexane, toluene, tetrahydrofuran, acetonitrile or 2-methyl tetrahydrofuran was used instead of dichloromethane.

(Comparative Example 1) Evaluation of Physical Properties of Solution of Comparative Compound 1 A dichloromethane solution of Comparative Compound 1 was prepared in the same manner as in Example 1 except that Comparative Compound 1 was used instead of Compound 1.

For each solution of Compound 1, the light absorption spectrum measured at room temperature and the emission spectrum by 350 nm excitation light are shown in FIGS. 26 to 30, and for the dichloromethane solution of Comparative Compound 1, the light absorption spectrum measured at room temperature and the emission spectrum by 350 nm excitation light are shown. The spectrum is shown in FIG. Table 10 shows the optical property values of each solution of Compound 1 and Comparative Compound 1. In Table 10, the optical property values of the 2-methyltetrafuran solution of Compound 1 were measured at 77K, and the optical property values of the other solutions were measured at room temperature.

As shown in Table 10, Compound 1 had a significantly higher fluorescence quantum yield than Comparative Compound 1.
In addition, the cyclic voltammogram of Compound 1 in dichloromethane is shown in FIG. From FIG. 32, it was confirmed that Compound 1 has good redox properties and can realize a good device life.

(Example 2) Fabrication and evaluation of organic photoluminescence element using compound 1 A thin film (single film) of compound 1 under the condition of a vacuum degree of 3 to 5 × ^10-5 Pa by a vacuum deposition method on a quartz substrate. Was formed to have a thickness of 50 nm to obtain an organic photoluminescence element.
Separately, compound 1 and PPF are deposited on a quartz substrate by a vacuum vapor deposition method under the conditions of 3 to 5 × ^10-5 Pa from different vapor deposition sources, and the concentration of compound 1 is 13% by weight. A thin film (doped film) was formed to a thickness of 50 nm to obtain an organic photoluminescence device.
The result of photoelectron yield spectroscopic measurement of the single film of Compound 1 is shown in FIG. 33, and the light absorption spectrum is shown in FIG. 34. The emission spectra of the single film and the doped film of Compound 1 by the 280 nm excitation light are shown in FIG. 35, and the transient attenuation curve of the emission by the 365 nm excitation light or the 280 nm excitation light is shown in FIG. The ionization potential Ip of Compound 1 was 5.67 eV, and the electron affinity Ea was 2.7 eV. The photoluminescence quantum yield was 22.0% for the single film of compound 1 and 34.1% for the doped film of compound 1.

(Example 3) Fabrication and evaluation of organic electroluminescence element using compound 1 Each thin film is vacuum-deposited on a glass substrate on which an anode made of indium tin oxide (ITO) having a film thickness of 100 nm is formed. , Laminated at a degree of vacuum of 3 to 5 × ^10-5 Pa. First, TAPC was formed on ITO to a thickness of 70 nm, and CDBP was formed on it to a thickness of 10 nm. Next, compound 1 and PPF were co-deposited from different vapor deposition sources to form a layer with a thickness of 20 nm to form a light emitting layer. At this time, the concentration of compound 1 was 12% by weight. Next, PPF was formed to a thickness of 10 nm, and BmPyPhB was formed on the PPF to a thickness of 40 nm. Further, lithium fluoride (LiF) was vapor-deposited to a thickness of 0.8 nm, and then aluminum (Al) was vapor-deposited to a thickness of 80 nm to form a cathode, which was used as an organic electroluminescence element (EL element 1). ..
Separately from this, in the light emitting layer and the layer formed on the light emitting layer, TSPO1 was used instead of PPF, and the concentration of compound 1 in the light emitting layer was set to 5% by weight in the same manner as in the EL element 1. An organic electroluminescence device (EL device 2) was manufactured.
Further, apart from these, an organic electroluminescence device (EL device) is formed in the same manner as the EL device 2 except that the TAPC is formed to a thickness of 70 nm and then the compound 1 is formed to a thickness of 10 nm instead of the CDBP. 3) was prepared.
The emission spectrum of the produced EL element 1 is shown in FIG. 37, and the external quantum efficiency η _EQE − current density characteristic is shown in FIG. 38. The emission spectra of the EL element 2 and the EL element 3 are shown in FIG. 39, and the external quantum efficiency η _EQE − current density characteristic is shown in FIG. 40. Each of the manufactured EL elements had good device characteristics. Further, the CIE color coordinates of the light emitted from the EL element 1 at 50 cdm ^-2 were (x, y) = (0.15, 0.06), which was a good deep blue color. Furthermore, the exciton utilization efficiency of each EL element is estimated to be about 65%, suggesting that light emission via intersystem crossing from the higher triplet state T ₈ or T ₉ to the singlet state was realized. Was done.

According to the molecular design method of the present invention, it is possible to perform molecular design in which the non-radiation transition is accurately controlled while suppressing the calculation cost. Therefore, by using the molecular design method of the present invention, a molecule that functions with high energy efficiency as an optical functional material such as a fluorescent material, a host material, another organic electroluminescence device material, a solar cell material, and a photocatalyst can be realized at low cost. can do. Therefore, the present invention has high industrial applicability.

Claims (32)

The off-diagonal electrokinetic interaction constants for the reference vibration mode α between the first electronic state n in the molecule and the second electronic state m whose energy is lower than that of the first electronic state n are V _{mn, α} . Then, the norm || V _mn || of the vector V _mn = (V _{mn, α} ) having V _{mn, α} as a component represented by the following equation (2) and the first electronic state n to the first. A molecular design method for designing a molecule based on the correlation of the non-radiation transition rate constant k _nr of internal conversion to the electronic state m of 2.

Using the norm || _{V mn} || as p- norm represented by the following formula || _{V mn} || _p, wherein the p- norm || _{V mn} || _p, from the first electronic state n The molecular design method according to claim 1, wherein the molecular design is performed based on the correlation of the non-radiative transition rate constant k _nr of the internal conversion to the second electronic state m.

[In the equation, p represents a real number of 1 ≦ p ≦ ∞. ] The p-norm || V _mn || _p with p = 2 || V _mn || ₂ squared V _{mn, α} squared sum V ² represented by the following equation (1) is used. 1. The molecular design is performed based on the correlation between the sum of squares V ² and the non-radiation transition rate constant k _nr of the internal conversion from the first electronic state n to the second electronic state m. The molecular design method described in.

[In the equation (1), V _{mn and α} are the off-diagonal oscillating interaction constants represented by the equation (2). ]
A molecular design method for designing a molecule by using at least one of the overlap indexes η ⁰ , η ^N, and η ^M defined by the following formula for controlling the non-radiation transition of the molecule.

Molecular design using the decrease in overlap density between electronic states due to the localization of molecular orbitals due to the static yarn teller effect that occurs when the electronic states of the molecule are degenerated, to control the non-radiation transition of the molecule. Molecular design method to do. The off-diagonal oscillating interaction constants for the reference vibration mode α between the first electronic state n in the molecule and the second electronic state m whose energy is lower than that of the first electronic state n are V _{mn, α} . when, V _mn represented by the following formula _(1), the square sum V ² of _alpha, the overlap index eta ^0, by controlling using at least one of the eta ^N and eta ^M, non-radiation of the molecule The molecular design method according to claim 7, wherein the transition is controlled.

[In equation (1), V _{mn and α} are off-diagonal oscillating interaction constants represented by the following equation (2). ]
The decrease in the overlap density between the electronic states due to the localization of the molecular orbital due to the static Jahn-Teller effect that occurs when the electronic state of the molecule is degenerate is described by the overlap indexes η ⁰ , η ^N , and η ^M. The molecular design method according to claim 7 or 9, which is used for control. The molecular design method according to any one of claims 7, 9 and 10, wherein I in the overlap indexes η ⁰ , η ^N , and η ^M is I _p represented by the following formula (3).

[In equation (3), ρ represents the overlap density between the first electronic state n and the second electronic state m whose energy is lower than that of the first electronic state n, and p is 1 ≦ p ≦ ∞. Represents a real number of. ] Molecules performing molecular design is a light-emitting molecule emits light by radiative transition of singlet state produced by reverse inter-system crossing from higher triplet state T _n,
At least the overlap indices η ⁰ , η ^N and η ^M between the higher triplet state T _n and the lower triplet state T _p (n> p), which have lower energies than the higher triplet state T _n. one, used to control the square sum V ² unpaired Tsunofuri electrostatic interaction constant between between these triplet state, the molecules designed to non-radiative transition is suppressed, according to claim 9 Molecular design method. The decrease in the overlap density between the electronic states due to the localization of the molecular orbital due to the static Jahn-Teller effect that occurs when the electronic state of the molecule is degenerate is described by the overlap indexes η ⁰ , η ^N , and η ^M. The molecular design method according to claim 12, which is used for control. It used in the molecular design method according to any one of claims 3,6,9,12,13, program having a step of calculating the square sum ^{V 2.} A program used in the molecular design method according to any one of claims 7 and 9 to 13, comprising a step of calculating at least one of the overlap indexes η ⁰ , η ^N , and η ^M. The off-diagonal oscillating interaction constants for the reference vibration mode α between the first electronic state n in the molecule and the second electronic state m whose energy is lower than that of the first electronic state n are V _{mn, α} . Then, a program having a step of calculating the sum of squares V ² of V _{mn and α} represented by the following equation (1).

[In equation (1), V _{mn and α} are off-diagonal oscillating interaction constants represented by the following equation (2). ]
The higher excited states E _n in the numerator and the first electronic state n, the low-order excited state E _p energy is lower than the higher excited states E _n the second electronic state m, between the electronic states between the unpaired Tsunofuri electrostatic interaction constants V _mn for normal modes alpha _of, when the _alpha, V _mn represented by the following formula _(1), the square sum V ² of _alpha, the higher excited states E _n molecules with suppressed nonradiative decay process is not more than 5.0 × 10 ^-6 au among all the low-order excited state E _p is lower energy than the higher excited states E _n and.

[In equation (1), V _{mn and α} are off-diagonal oscillating interaction constants represented by the following equation (2). ]
The higher-order triple-term state T _n in the molecule is _defined as the first electronic state n, and the lower-order triple-term state T _p having a lower energy than the higher-order triple-term state T _n is _defined as the second electronic state m. when the unpaired Tsunofuri electrostatic interaction constants for normal modes alpha between each other and with the V _{mn, alpha,} the formula (1) represented by V _mn, the square sum V ² of _alpha, the higher order triple ^No. 17 according to claim 17, which is 5.0 × ^10-6 au or less between the term state T _n and all lower triple term states T _p having lower energies than the higher triple term state T _n. A molecule in which the radiation transition process is suppressed. A light-emitting molecule emits light by radiative transition of singlet state caused by reverse intersystem crossing system from higher triplet state T _n,
The higher-order triple-term state T _n is _defined as the first electronic state n, and the lower-order triple-term state T _p having a lower energy than the higher-order triple-term state T _n is _defined as the second electronic state m. normal modes alpha unpaired Tsunofuri electrostatic interaction constant V _{mn for,} when the _alpha, V _mn represented by the following formula _(1), the square sum V ² of _alpha, the higher triplet between A luminescent molecule that is 5.0 × ^10-6 au or less between the state T _n and all lower triplet states T _p that have lower energy than the higher triplet state T _n .

[In equation (1), V _{mn and α} are off-diagonal oscillating interaction constants represented by the following equation (2). ]

[In equation (2), Ψ _n represents the electron wave function of the first electronic state n, Ψ _m represents the electron wave function of the second electronic state m, and x represents the electron wave function of N electrons contained in the molecule. It represents the spatial coordinates and spin coordinates, r represents the spatial coordinates of N electrons contained in the molecule, R represents the spatial coordinates of the M nuclei contained in the molecule, and H (r, R) represents the molecular Hamiltonian. Represented, R ₀ represents the reference nucleus arrangement, and Q _α represents the mass-weighted reference vibration coordinates of the reference vibration mode α. ] The suppressed molecule of the non-radiative transition process according to claim 17 or 18, which has a rotational or improperly symmetric structure having three or more axes of symmetry (rotational or improper axis). The luminescent molecule according to claim 19, which has a rotational or improper rotation symmetry structure having three or more axes of symmetry (rotational axis or reflection axis). The molecule according to claim 20, which has a rotationally symmetric structure having a three-fold rotation axis and in which the non-radiation transition process is suppressed. The luminescent molecule according to claim 21, which has a rotationally symmetric structure having a three-fold rotation axis. The suppressed molecule of the non-radiation transition process according to claim 20 or 22, wherein the structure including the center of symmetry is a triphenylamine structure. The luminescent molecule according to claim 21 or 23, wherein the structure including the center of symmetry is a triphenylamine structure. The molecule in which the non-radiation transition process is suppressed according to claim 24, which has a structure in which an indole ring or a pyrrole ring is bonded to each phenyl group of the triphenylamine structure. The luminescent molecule according to claim 25, which has a structure in which an indole ring or a pyrrole ring is bonded to each phenyl group having the triphenylamine structure. The molecule in which the non-radiation transition process is suppressed according to claim 17, which comprises a compound represented by the following general formula (1).

[In the general formula (1), R ¹ represents a hydrogen atom, a substituted or unsubstituted alkyl group, or a substituted or unsubstituted aryl group, and R ^{2 to} R ⁸ are independently hydrogen atoms, substituted or unsubstituted, respectively. Represents an alkyl group or a halogen atom. ] The luminescent molecule according to claim 19, which comprises a compound represented by the following general formula (1).

[In the general formula (1), R ¹ represents a hydrogen atom, a substituted or unsubstituted alkyl group, or a substituted or unsubstituted aryl group, and R ^{2 to} R ⁸ are independently hydrogen atoms, substituted or unsubstituted, respectively. Represents an alkyl group or a halogen atom. ] A host material comprising a molecule in which the non-radiation transition process of any one of claims 17, 18, 20, 22, 24, 26, 28 is suppressed. An organic light emitting device containing the molecule according to any one of claims 17 to 29 in a light emitting layer. The organic light emitting device according to claim 31, which is an organic electroluminescence device.