KR100809430B1 - Compounds for molecular electronic device having asymmetric disulfide anchoring group, synthesis of the same, and molecular electronic devices having molecular active layer obtained from the compounds - Google Patents

Abstract

A compound for a molecular electronic device, a method for preparing the compound, and a molecular electronic device using the compound are provided to improve the coverage of a self-assembled molecular monolayer and to allow the thickness of a molecular active layer. A compound for a molecular electronic device comprises a ruthenium-terpyridine disulfide complex represented by the formula 2, wherein R1 and R2 are a C1-C20 saturated or unsaturated hydrocarbon group substituted or unsubstituted with F, respectively. A molecular electronic device comprises a first electrode; a second electrode; and a molecular active layer which is interposed between the two electrodes and has a structure formed by the self-assembling of the compound of the formula 2 on the first electrode.

Description

Compounds for molecular electronic devices having an asymmetric disulfide fixing group, and a method of manufacturing the same, and a molecular electronic device having a molecular active layer obtained from the compound (Compounds for molecular electronic device having asymmetric disulfide anchoring group, synthesis of the same, and molecular electronic devices having molecular active layer obtained from the compounds}

1 is a diagram illustrating a structure in which a compound for molecular electronic devices according to the present invention is self-assembled on an electrode surface to form a monomolecular film.

2 is a schematic layout of an exemplary molecular electronic device in accordance with the present invention.

3 is a cross-sectional view taken along the line III-III 'of FIG. 2.

Figure 4 is a schematic diagram showing the structure before and after the self-assembled compound for a molecular electronic device according to the present invention.

5 is a hysteresis graph showing switching characteristics of a molecular electronic device according to the present invention.

6 is a graph showing memory characteristics of the molecular electronic device according to the present invention.

<Explanation of symbols for the main parts of the drawings>

10: electrode, 20: monomolecular film, 100: molecular electronic device, 102: substrate, 110: lower electrode, 120: molecular active layer, 130: upper electrode.

The present invention relates to a compound having a functional group capable of providing electrical properties, a method for producing the same, and a molecular electronic device obtained from the compound, and in particular, a compound for a molecular electronic device having a disulfide fixing group, a method for producing the same, and a compound obtained from the compound. A molecular electronic device having a molecular active layer.

With the development of the informatization industry, computer chips that play the most important role in storing information are becoming highly integrated. Current semiconductor devices are reaching the limits of performance improvement by integrated technology due to physical limitations and increased production costs. As one way to overcome this problem, considerable efforts have been made to implement devices using molecules.

In order to apply molecules to electronic devices, molecules must be used to form a monomolecular film on an electrode. Until now, molecular self-assembly and Langmuir-Blodgett methods are known as methods for forming molecules into monomolecular films. Among them, in order to use the molecular self-assembly method, it is essential to include a thiol group or a functional group having a reactivity similar to a thiol group at the terminal of the molecule for reaction with a gold electrode which is commonly used. In addition, it is essential to introduce electroactive functional groups to implement molecular electronic devices. However, steric hindrance occurs due to the introduction of electroactive functional groups, and when the molecular active layer is formed on the electrode using these active materials, the coverage characteristic of the molecular active layer is due to the steric hindrance as described above. This is not good and causes a short circuit.

In order to solve the above problems, many studies have been conducted so far. In particular, techniques for forming a mixed self-sssembled monolayer are known. This technique is largely classified in four ways. First, a monomolecular film is formed by adjusting the mole ratio of bulky molecules having functional groups and molecules having good coverage properties (primarily alkane thiols) (e.g. Adv. Mater . 1996, 8 (9), 719; Thin solid film, 1996, 273, 54). Second, a monomolecular film is first formed on the electrode using bulky molecules, and then a molecule capable of easily forming a monomolecular film is inserted into the electrode surface exposed through the obtained monomolecular film (eg, Ann. NY Acad. Sci). , 1998, 852 , 349). Third, the self-assembly method and the Langmoore-Blockt method are used simultaneously to form a monomolecular film using an alkyl halide silane compound (eg Langmuir, 1995, 11, 1341). Fourth, a monomolecular film is formed by introducing a functional group (for example, -OH group) to a terminal group (eg, Langmuir, 1998, 14, 3545; Lanmuir, 1993, 9, 141) by hydrogen bonding or the like.

However, when the monomolecular film is formed in solution by the above methods, there is a problem in that phase segregation occurs and a uniform monomolecular film cannot be formed. The phase separation phenomenon may be caused by structural differences between two molecules to form a monolayer, for example, a length difference between molecules, a dipole difference between molecules, and a lattice constant difference between molecules.

In order to overcome the above phase separation phenomenon, a method of controlling the temperature of the mixed solution when forming a monomolecular film has been proposed ( Lanmuir , 2000, 16 , 9287). However, it is not easy to form a monomolecular film without phase separation for every molecule.

According to the recent trend of competitive device development for the commercialization of tens of nanometer fine micro-integrated semiconductor products, the ultra-thin and finer molecular electronic devices have excellent performance according to the device function without causing short circuit problems. In order to provide device characteristics, it is required to develop a material for molecular electronic devices having a new structure capable of improving the coverage characteristics of the molecular active layer.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above problems in the prior art, and to provide compounds for molecular electronic devices having a novel structure that can be suitably applied to implement fine molecular electronic devices on the order of tens of nanometers.

Another object of the present invention is to provide a method for preparing compounds for molecular electronic devices having a novel structure that can be suitably applied to realize microscopic molecular electronic devices on the order of tens of nanometers.

It is still another object of the present invention to provide a molecular electronic device in which a molecular active layer composed of a monomolecular film interposed between two metal electrodes is self-assembled on an electrode with excellent coverage characteristics.

In order to achieve the above object, the compound for molecular electronic device according to the present invention consists of a disulfide derivative of the asymmetric structure represented by the following formula.

Cy- (R ₁ ) -SS- (R ₂ )

Wherein Cy is an electroactive functional group containing a cyclic compound, and R ₁ and R ₂ are each a C ₁ to C ₂₀ saturated or unsaturated hydrocarbon group unsubstituted or substituted with F.

The disulfide derivatives of the asymmetric structure according to the present invention include ruthenium-terpyridine disulfide complexes, silole disulfide compounds, ferrocene disulfide compounds, o- carborane disulfide compounds, or porphyrine It may consist of a disulfide compound.

In order to achieve the above another object, in the method for producing a compound for molecular electronic device according to the first aspect of the present invention, a compound having a structure represented by Cy-R ₁ -Br (Cy and R ₁ are as defined above) the synthetic intermediates represented by ^- sodium thiosulfate pentahydrate react with Cy-R ₁ -S-SO ₃ by. The intermediate product is then reacted with a compound represented by R ₂ -SH (R ₂ is as defined above) to synthesize a disulfide derivative represented by Cy-R ₁ -SSR ₂ .

In addition, in order to achieve the above another object, in the method for producing a compound for molecular electronic device according to the second aspect of the present invention has a structure represented by H-CO-R ₁ -Br (R ₁ is as defined above) The compound is reacted in turn with a compound represented by sodium thiosulfate pentahydrate and R ₂ -SH (R ₂ is as defined above) to synthesize a compound represented by H-CO-R ₁ -SSR ₂ . The compound represented by H-CO-R ₁ -SSR ₂ is condensed with pyrrole and R-aldehyde (R is pentyl or paratoyl). The product obtained as a result of the condensation reaction is oxidized using DDQ (2,3-dichloro-5,6-dicyano-1,4-benzoquione).

In order to achieve the above another object, the molecular electronic device according to the present invention is a molecular active layer interposed between the first electrode, the second electrode formed on the first electrode, and the first electrode and the second electrode It includes. The molecular active layer has a structure in which a compound composed of a disulfide derivative having an asymmetric structure represented by the following formula is self-assembled in the first electrode.

Cy- (R ₁ ) -SS- (R ₂ )

Wherein Cy, R ₁ and R ₂ are as defined above.

The molecular active layer may be formed of a monomolecular layer including -SR ₁ -Cy group and -SR ₂ group self-assembled to the first electrode, respectively.

Alternatively, the molecular active layer is a -S- (CH ₂ ) m-Cy group (m is an integer of 1 to 20) and -S- (CH ₂ ) n-CH ₃ groups (self-assembled to the first electrode, respectively) n may be composed of a single molecule layer containing an integer of 1 to 19.

Cy may be any one group selected from the group consisting of ruthenium terpyridine, cyrrole, ferrocene, ortho carborane and porphyrin.

The molecular active layer may constitute a switch device that is switchable between an on state and an off state according to a voltage applied between the first electrode and the second electrode.

Alternatively, the molecular active layer may constitute a memory device that stores a predetermined electrical signal according to a voltage applied between the first electrode and the second electrode.

In the compound for a molecular electronic device according to the present invention, -R ₁ -Cy groups and -R ₂ groups bonded to both ends of the disulfide group (-SS-), respectively, contribute to the formation of a monomolecular film on the electrode surface. Therefore, it is possible to form a monomolecular film having a dense structure having excellent coverage in forming a monomolecular film containing bulky electroactive functional groups on the electrode surface, thus short-circuit phenomenon which may be caused by poor coverage in molecular electronic devices. It can prevent.

Next, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

The present invention provides compounds for molecular electronic devices comprising asymmetric disulfide derivatives having functional functional groups suitable for application to molecular electronic devices, methods for their preparation, and molecular electronic devices including a molecular active layer comprising the asymmetric disulfide derivatives.

Compounds for molecular electronic devices according to the present invention consists of a disulfide derivative having an asymmetric structure represented by the formula (1).

Cy- (R ₁ ) -SS- (R ₂ )

In Formula 1, Cy is an electroactive functional group containing a cyclic compound. And R ₁ and R ₂ are each a C ₁ to C ₂₀ saturated or unsaturated hydrocarbon group unsubstituted or substituted with F.

Exemplary disulfide derivatives constituting the compound for molecular electronic device according to the present invention may be composed of a ruthenium-terpyridine disulfide complex represented by the formula (2) having redox activity.

In formula (2), R ₁ and R ₂ are each a C ₁ to C ₂₀ saturated or unsaturated hydrocarbon group unsubstituted or substituted with F.

Exemplary other disulfide derivatives constituting the compound for molecular electronic device according to the present invention may be made of a silole disulfide compound represented by the formula (3) which is an electron transporting material.

In formula (3), R ₁ and R ₂ are each a C ₁ to C ₂₀ saturated or unsaturated hydrocarbon group unsubstituted or substituted with F, and R is a methyl, ethyl or phenyl group.

Another exemplary disulfide derivative constituting the compound for molecular electronic devices according to the present invention may be composed of a ferrocene disulfide compound represented by the formula (4) having redox activity.

In formula (4), R ₁ and R ₂ are each a C ₁ to C ₂₀ saturated or unsaturated hydrocarbon group unsubstituted or substituted with F.

Another exemplary disulfide derivative constituting the compound for molecular electronic devices according to the present invention is ortho carborane ( o -carborane: o -C ₂ H ₁₂ B in which carbon (C) and boron (B) are bonded to a polyhedron) ₁₀ ) may be composed of an ortho carborane disulfide compound represented by the formula (5).

In formula (5), R ₁ and R ₂ are each a C ₁ to C ₂₀ saturated or unsaturated hydrocarbon group unsubstituted or substituted with F. In the cage structure of Formula 5,? Is C, and the unmarked vertex is BH.

Another exemplary disulfide derivative constituting the compound for molecular electronic devices according to the present invention may be made of a porphyrine disulfide compound represented by Chemical Formula 6.

In formula (6), R ₁ and R ₂ are each a C ₁ to C ₂₀ saturated or unsaturated hydrocarbon group unsubstituted or substituted with F, and R ', R'', and R''' are each pentyl (-). C ₅ H ₁₁ ) or paratoyl ( p -toyl: p -CH ₃ C ₆ H _5- ) and M is Zn or Mg.

As exemplified above, the compounds for molecular electronic devices according to the present invention are bulky, such as molecules capable of transferring redox activity or charge at one of the bonding positions at both ends of the disulfide group (-SS-). (Bulky) electroactive functional groups are bonded, and in another position, a saturated or unsaturated hydrocarbon group substituted or unsubstituted with F having a structure which is not affected by steric hindrance caused by the electroactive functional groups is bonded, thus, the present invention In the self-assembly of compounds for molecular electronic devices according to the present invention, when the disulfide group (-SS-) is used as a fixing unit to form a monomolecular film on the electrode surface, a more compact structure can be obtained on the electrode surface.

1 is a diagram illustrating a structure in which a compound for molecular electronic devices according to the present invention represented by Chemical Formula 1 is self-assembled on a surface of an electrode 10 to form a monomolecular film 20.

As can be seen from the structure of FIG. 1, when the compound for molecular electronic device according to the present invention is self-assembled on the surface of the electrode 10, it is self-assembled on the electrode 10 using the disulfide group (-SS-) as a fixing unit. In addition, -R ₁ -Cy groups and -R ₂ groups bonded to both ends of the disulfide group, respectively, contribute to the formation of the monomolecular film 20 on the surface of the electrode 10.

Therefore, in forming the monomolecular film 20 including bulky electroactive functional groups on the surface of the electrode 10, a coverage failure phenomenon that may occur when there is only one thiol group in one compound is eliminated. By improving, it is possible to form the monomolecular film 20 which provides excellent coverage. Therefore, it is possible to prevent a short circuit phenomenon which may be caused by poor coverage in the molecular electronic device.

Next, the manufacturing process of the compounds for molecular electronic devices according to the preferred embodiment of the present invention will be described in detail.

Scheme 1 shows the main reaction processes (Ia) and (Ib) of the manufacturing process of the compound for molecular electronic device according to an embodiment of the present invention.

In Scheme 1, Cy, R ₁ and R ₂ are as defined in Formula 1.

In the process for producing a compound for molecular electronic devices according to the present invention shown in Scheme 1, a compound having a structure represented by Cy-R ₁ -Br is reacted with sodium thiosulfate pentahydrate to form Cy-R ₁ -S-SO _3- ^. Reaction process (Ia) for synthesizing intermediate product represented by &lt; RTI ID = 0.0 &gt; and &lt; / RTI &gt; reaction process (Ib) for synthesizing disulfide derivative represented by Cy-R ₁ -SSR ₂ by reacting the intermediate product with compound represented by R ₂ -SH. It includes.

Scheme 2 shows main reaction processes (IIa) and (IIb) in the process of preparing a compound for molecular electronic device according to another embodiment of the present invention.

In Scheme 2, Cy, R ₁ and R ₂ are as defined in Formula 1.

In the process for preparing a compound for molecular electronic device according to the present invention shown in Scheme 1, a compound having a structure represented by H-CO-R ₁ -Br is sequentially added to a compound represented by sodium thiosulfate pentahydrate and R ₂ -SH. Reaction process (IIa) for synthesizing a compound represented by H-CO-R ₁ -SSR ₂ by reaction, and represented by Cy-R ₁ -SSR ₂ from the compound represented by H-CO-R ₁ -SSR ₂ Reaction process (IIb) to synthesize disulfide derivatives. The reaction process (IIb) is a step of condensation reaction of the compound represented by H-CO-R ₁ -SSR ₂ with pyrrole and R-aldehyde (R is pentyl or paratoyl), and the product obtained as a result of the condensation reaction Oxidizing with DDQ (2,3-dichloro-5,6-dicyano-1,4-benzoquione).

Next, a method of manufacturing the molecular electronic device according to the present invention illustrated in Scheme 1 and Scheme 2 will be described in detail.

Scheme 3 illustrates the preparation of ruthenium terpyridine disulfide complex (IIId) as illustrated in formula (2).

In Reaction Scheme 3, m is an integer of 1 to 20, n is an integer of 1 to 19.

The preparation process of ruthenium terpyridine disulfide complex (IIId) shown in Scheme 3 consists of three steps. The first step is to prepare a bromoalkyl terpyridine compound (IIIb) from a tetramethylpiperidyllithium compound and a compound (IIIa). The second step is the synthesis of disulfide terpyridine compound (IIIc) using sodium thiosulfate pentahydrate and alkanthiol from bromoalkyl terpyridine compound (IIIb). The third step is to prepare a ruthenium terpyridine disulfide complex (IIId) by reacting a disulfide terpyridine compound (IIIc) with a ruthenium terpyridine trichloride complex. In particular, in the first process, the reaction conditions are sensitive to water and air, so care should be taken, and when adding the dibromo alkanes compound, it should be added slowly at low temperature (below -70 ℃) to increase the yield of the reaction.

Scheme 4 illustrates the preparation of a cyclol disulfide compound (IVe) illustrated in Formula 3.

In Reaction Scheme 4, m is an integer of 1-20, n is an integer of 1-19. And R is a methyl, ethyl or phenyl group.

The manufacturing process of the cyclool disulfide compound (IVe) shown in Scheme 4 is largely composed of three processes. The first step is to react diphenylacetylene (IVa) with lithium metal to form reaction intermediate (IVb) of dimerization, and then react the reaction intermediate (IVb) with alkyltrichlorosilane (RSiCl ₃ ). It is a process of preparing a roll compound (IVc). The second step is the reaction of xylol compound (IVc) with butyllithium for lithiation, followed by dibromoalkanes to synthesize bromoalkylcylol ((IVd)). The third process for obtaining compound (IVe) is similar to the second process in Scheme 3. In Scheme 4, the overall yield is determined in the first and second processes and is very sensitive to moisture and air, so lithium metal is particularly important. It also reacts easily with moisture in the air and should be handled in a glove box.

Scheme 5 illustrates the preparation of the ferrocene disulfide compound (Vc) illustrated in Formula 4.

In Scheme 5, m is an integer of 1-20, n is an integer of 1-19.

The process for producing the ferrocene disulfide compound (Vc) shown in Scheme 5 is largely composed of two processes. In the first process, ferrocene (V) is mono-lithiated with tertiary butyllithium and then reacted with dibromo alkanes to synthesize bromoalkyl ferrocene (Vb). The second step to obtain the final product ferrocene disulfide compound (Vc) is similar to the second step in Scheme 3. The first thing to notice in Scheme 5 is the first step. In this process, only one of the two pentadienes is activated by the active cycle. For this purpose, the reaction temperature and the reaction solvent should be well selected. Specific experimental examples relating to this will be described later.

Scheme 6 illustrates the manufacturing process of ortho carborane (o -carborane) disulfide compound (VIc) which are illustrated in formula (5).

In Scheme 6, m is an integer of 1-20, n is an integer of 1-19.

The manufacturing process of ortho carborane disulfide compound (VIc) shown in Scheme 6 is largely composed of two processes. The first process is to synthesize bromoalkyl carborane (VIb) by orthocarborane (VIa) by monolithizing with n-butyllithium and then reacting with dibromo alkanes. The second step to obtain the final product, ortho carborane disulfide compound (VIc), is similar to the second step in Scheme 3. The first thing to notice in Scheme 6 is the first step. In this process, only one of the two C positions of the activated Ortho Caboran should be retired. For this purpose, the reaction temperature and the reaction solvent should be well selected. Specific experimental examples relating to this will be described later.

Scheme 7 illustrates the preparation of the porphyrin disulfide compound (VIIf) illustrated in Formula 6.

In Scheme 7, m is an integer of 1-20, n is an integer of 1-19. And R is pentyl (-C ₅ H ₁₁ ) or paratoyl ( p -CH ₃ C ₆ H _5- ) and M is Zn or Mg.

The preparation process of the porphyrin disulfide compound (VIIf) shown in Scheme 7 consists of three steps. The first step is the synthesis of disulfide aldehyde compounds (VIIb) using sodium thiosulfate pentahydrate and alkanthiol from bromoalkyl aldehydes (VIIa). The second step is to condense the synthesized disulfide aldehyde compound (VIIb) with pyrrole (VIIc) and R-aldehyde (VIId) and DDQ (2,3-dichloro-5,6-dicyano-1,4-benzoquione) Oxidation to obtain the intermediate product (VIIe). The third step is to synthesize the porphyrin disulfide compound (VIIf) by reacting the intermediate product (VIIe) with metal acetate (metal is Zn or Mg).

In addition, the present invention provides a molecular electronic device obtained by immobilizing the above compounds according to the present invention by a self-assembly method on the lower electrode to form a molecular active layer consisting of a single molecular layer, and depositing the upper electrode thereon. In the molecular electronic device according to the present invention, the molecular active layer serves as a buffer for trapping charges according to a voltage applied between a pair of electrodes.

2 is a schematic layout of an exemplary molecular electronic device 100 in accordance with the present invention. 2 illustrates an example of the molecular electronic device 100 in which the lower electrode 110 and the upper electrode 130 are arranged in a 3 × 3 array. 3 is a cross-sectional view taken along the line III-III 'of FIG. 2.

2 and 3, the molecular electronic device 100 according to the present invention extends in a direction orthogonal to each other such that the lower electrode 110 and the upper electrode 130 intersect at predetermined positions on the substrate 102, respectively. It is. The lower electrode 110 and the upper electrode 130 may be made of gold, platinum, silver, or chromium, respectively.

The molecular active layer 120 is interposed between the lower electrode 110 and the upper electrode 130. The molecular active layer 120 is a layer formed by self-assembly of the compound for molecular electronic device according to the present invention represented by the formula (1) on the surface of the lower electrode (110). In the compound according to the present invention, the disulfide group (-S-S-) serves as a functional group capable of self-assembling on the lower electrode 110. That is, the compound according to the present invention is selectively bonded to the lower electrode 110 by self-assembly by using a disulfide group as a fixing unit to form a single molecular layer on the lower electrode 110.

4 is a schematic diagram showing the structure before and after the self-assembled compound for a molecular electronic device according to the present invention on the lower electrode (110).

In FIG. 4, a ruthenium terpyridine disulfide compound, which can be obtained through a reaction similar to the preparation process of ruthenium terpyridine disulfide compound (IIId) in Scheme 3, is self-assembled on the lower electrode 110 (see FIG. 3). The molecular active layer 120 is formed.

The ruthenium terpyridine disulfide compound shown in FIG. 4 has m = 8 in-(CH ₂ ) m- and a t-butylheptyl group instead of-(CH ₂ ) n-CH ₃ is bonded, which is obtained in Scheme 3 It has a structure similar to that of nium terpyridine disulfide compound (IIId).

The molecular layer constituting the molecular active layer 120 is determined by determining the chain length of the hydrocarbon compound in the compound constituting the molecular layer, that is, the length of R ₁ and R ₂ in Chemical Formula 1, or in Schemes 3 to 7. In compounds IIId, IVe, Vc, VIc, and VIIf of the illustrated structure, it is possible to control their thickness by determining the m and n values to appropriate levels.

In order to manufacture the molecular electronic device according to the present invention illustrated in FIGS. 2 and 3, first, a lower electrode 110 formed of a plurality of line patterns may be formed on the substrate 102. The lower electrode 110 may be formed using, for example, nanoimprint technology. In order to form a molecular layer made of a compound according to the present invention on the surface of the lower electrode 110, an immobilization technique by a self-assembly method may be used. To this end, a method of dipping the substrate 102 on which the lower electrode 110 is formed in a solvent in which the compound is dissolved may be used. Here, anhydrous and oxygen free DMF (N, N-dimethylformamide) can be used as a representative solvent suitable for use in dissolving the compound. In an exemplary method, the lower electrode 110 is formed by self-assembly by dipping the substrate 102 on which the lower electrode 110 is formed in a solution in which the compound according to the present invention is dissolved at a concentration of 1 mmol in a DMF solvent for about 24 hours. A molecular active layer 120 consisting of a single molecular layer can be formed on the surface. Thereafter, the resultant having the molecular active layer 120 formed on the surface of the lower electrode 110 may be washed and dried in a vacuum, and the upper electrode 130 may be deposited thereon.

As described above, the molecular electronic device according to the present invention may constitute a switch device that is switchable between an ON state and an OFF state. In addition, the molecular electronic device according to the present invention may constitute a memory device for storing a predetermined electrical signal according to a voltage applied between the lower electrode 10 and the upper electrode 30.

The structures shown in FIGS. 2 and 3 and the related descriptions thereof are merely exemplary configurations provided to aid the understanding of the present invention, and the present invention is not limited thereto. Various modifications and variations are possible in the structure of the molecular electronic device and its manufacturing method within the spirit and scope of the present invention.

Hereinafter, specific synthesis examples of the compounds for molecular electronic devices according to the present invention will be described in detail. The following synthesis examples are merely illustrated to aid understanding of the compounds according to the present invention and their synthesis process, and the scope of the present invention is not limited to the following synthesis examples.

Example 1

Synthesis of Lucerium-terpyridine disulfide complex

Synthesis of Compound (IIId) of Scheme 3 (m = 7, n = 11)

In order to prepare starting material 4'-methyl-2,2 '; 6,2' '-terpyridine, a reaction procedure as shown in Scheme 8 was performed.

For the reaction of Scheme 8, 0.74 g (1.13 mmol) of bistriphenylphosphinonickel dichloride was added to a 250 mL two-necked flask and 20 mL of anhydrous THF (tetrahydrofuran) was used as a syringe. To this was added 5.8 mL (17.3 mmol, 3.0 M solution in ether) of methylmagnesium bromide dropwise using a syringe. After stirring for 15 minutes at room temperature, 2.0 g (7.14 mmol) of 4'-thiomethyl-2,2 ';6,2''-terpyridine (VIIIa) dissolved in 40 mL of anhydrous THF was added using a cannula. . After heating and stirring at 40 ° C. for 48 hours, the solution was poured into saturated ammonium chloride solution (conc-NH ₄ Cl) and extracted with 200 mL of chloroform (CHCl ₃ ). The solution was dried over Na ₂ SO ₄ , a drying agent, and distilled under reduced pressure. Then, the mixture was purified by column chromatography (developing agent: THF / normal hexane = 1/10) to give 4'-methyl-2,2 in 60% yield. ';6,2''-terpyridine (VIIIb) was obtained. The ¹ H-nuclear magnetic resonance spectrum analysis of 4'-methyl-2,2 ';6,2''-terpyridine (VIIIb) was as follows.

¹ H NMR (400 MHz, CDCl ₃ , δ, ppm); 8.68 (m, 2H), 8.60 (d, 2H, J = 7.9 Hz), 8.27 (s, 2H), 7.82 (dd, 2H, J = 7.8, 1.7 Hz), 7.30-7.24 (m, 2H), 2.50 (s, 3 H). MS: m / z (M ⁺ ) = 279.

4 '-(7-bromoheptyl) -2,2'; 6 ', 2''-ter from 4'-methyl-2,2'; 6,2 ''-terpyridine (VIIIb) obtained in Scheme 8 To synthesize pyridine (Compound IIIb of Scheme 3), the following procedure was followed. First, 0.5 mL (3 mmol) of tetramethylpiperidine and 20 mL of anhydrous THF were added to a 100 mL Schlenk flask and stirred well. After cooling to −78 ° C. using liquid nitrogen and ethyl acetate, 1.88 mL (3 mmol, 1.6 M hexane solution) of normal butyllithium was slowly added dropwise using a syringe. Here, a solution of 0.5 g (2 mmol) of 4'-methyl-2,2 ';6,2''-terpyridine (VIIIb) synthesized as in Scheme 8 with 15 mL of THF was added using a syringe. It was put at ℃. After stirring for 30 minutes at this temperature, the solution was slowly added dropwise at -78 ° C using cannula to a solution of 1 mL (4 mmol) of 1,6-dibromohexane diluted in 50 mL of THF. . After stirring at this temperature for 12 hours, the mixture was distilled under reduced pressure to obtain a saturated solution. Then purified using column chromatography (developing agent: THF / normal hexane = 1/3) to yield compound 4 '-(7-bromoheptyl) -2,2'; 6 ', 2' in 76% yield. '-Terpyridine (compound IIIb of Scheme 3) was obtained. The ¹ H-nuclear magnetic resonance spectrum analysis of 4 '-(7-bromoheptyl) -2,2'; 6 ', 2''-terpyridine (IIIb) was as follows.

¹ H NMR (400 MHz, CDCl ₃ , δ, ppm): 8.69-8.67 (m, 2H), 8.61-8.58 (m, 2H), 8.27 (s, 2H), 7.82 (dd, 2H, J = 11, 5.8 Hz), 7.32-7.29 (m, 2H), 3.37 (t, 2H, J = 6.8 Hz), 2.77 (t, 2H, J = 7.6 Hz), 1.84-1.71 (m, 4H), 1.42-1.33 (m , 6H). MS: m / z (M ⁺ ) = 411.

Sodium thiosulfate pentahydrate 0.9 in a solution of 1 g (2.44 mmol) of 4 '-(7-bromoheptyl) -2,2'; 6 ', 2' '-terpyridine (IIIb) dissolved in 50 mL of dimethylformamide. g (3.66 mmol, 1.5 equiv) was dissolved in 10 mL of distilled water, and then reacted at 60 ° C. for 6 hours and cooled at room temperature. Then, 0.54 g (2.68 mmol, 1.1 equiv) of dodecanethiol, methanol, and 0.12 g (2.93 mmol) of sodium hydroxide were dissolved in 2 mL of distilled water, and a solution was stirred for 1 hour. The solution cooled to room temperature was slowly added dropwise to the solution using a syringe, followed by stirring at room temperature for 3 hours. 200 mL of ethyl acetate was poured out and washed three times with 200 mL of distilled water using a separatory funnel. The combined organic layers were distilled under reduced pressure to form a saturated solution, which was then separated using column chromatography (eluent: ethyl acetate: hexane = 3: 1) to obtain pale yellow terpyridine disulfide compound (IIIc). Could.

To 0.25 g (0.45 mmol) of the synthesized terpyridine disulfide compound (IIIc), 0.2 g of terpyridine ruthenium trichloride, and (0.45 mmol) were added 40 mL of ethanol / distilled water (3/1), followed by heating and stirring for 5 hours. After cooling to room temperature, a solution of 2.93 g (18 mmol) of ammonium hexafluorophosphate was dissolved in 2 mL of distilled water. After stirring for 10 minutes at room temperature, the mixture was separated using a sintering funnel. After washing several times with distilled water and ethanol and then several times with ether, the insoluble solid was dried to obtain ruthenium terpyridine disulfide complex (IIId). (Yield 64%)

^It was confirmed that the product obtained by the ¹ H-nuclear magnetic resonance spectrum and the mass spectrometry spectrum was ruthenium terpyridine disulfide complex (IIId).

¹ H NMR (400 MHz, CDCl ₃ , δ, ppm): 8.70-8.66 (m, 2H), 8.62-8.58 (m, 2H), 8.26 (s, 2H), 7.83-7.81 (m, 2H), 7.31- 7.27 (m, 2H), 2.75 (t, 2H), 2.70 (t, 4H), 1.68-1.66 (m, 4H), 1.54-1.48 (m, 2H), 1.18-1.44 (m, 24H), 0.87 ( t, 3H).

MS: m / z (M ⁺ ) = 599.

Example 2

Synthesis of Cyrrole-Disulfide Compounds

Synthesis of Compound (IVe) of Scheme 4 (m = 6, n = 11, R = -CH ₃ )

The starting material, cyclol compound (IVc), was synthesized according to the known method ( Chem. Mater. 2003, 15 , 1535). 1 g (2.30 mmol) of the synthesized 1-methyl-1-chloro-2,3,4,5-tetramethyl xylol (IVc) was dissolved in 25 mL of tetrahydrofuran. After the solution was cooled to -75 ° C, 1.72 mL (2.78 mmol, 1.6 M solution in hexane) of n-butyllithium was added thereto, followed by stirring at room temperature for 4 hours. 0.56 g (2.30 mmol) of 1,6-dibrohexane was added thereto, stirred at room temperature for 12 hours, and 200 mL of tetrahydrofuran was added thereto. This solution was washed three times with distilled water (200 mL) using a separatory funnel. Thereafter, the resulting mixture was distilled under reduced pressure to give a saturated solution, which was then separated by column chromatography (tetrahydrofuran: hexane = 3: 1).

In a similar manner to the method used to obtain compound (IIIc) in Example 1, the reaction of 1-methyl-1-bromohexyl-cyrrole compound (IVd) with sodium thiosulfate pentahydrate and dodecanethiol To prepare a xyrol disulfide compound (IVe). (Yield 71%)

^It was confirmed that the product obtained by the ¹ H-nuclear magnetic resonance spectrum and the mass spectrometry spectrum was a cyclol disulfide compound (IVe).

¹ H NMR (400 MHz, CDCl ₃ , δ, ppm): 7.38-6.72 (m, 20H), 2.70 (t, 4H), 1.70-1.66 (m, 4H), 1.30-1.64 (m, 26H), 0.89 ( t, 3H), 0.46 (s, 3H, Si- CH ₃ ).

MS: m / z (M ⁺ ) = 716.

Example 3

Synthesis of Ferrocene-disulfide Compound

Synthesis of Compound (Vc) of Scheme 5 (m = 6, n = 11)

The previously reported method ( J. Orgmet. Chem . 2002, 656 , 71) was used for the monothiation of ferrocene (compound (V) in Scheme 5). 1 g (5.38 mmol) of ferrocene was dissolved in 20 mL of tetrahydrofuran, and 4.3 mL (6.45 mmol, 1.5 M solution in C ₅ H ₁₂ ) of tert-butyllithium was added at 0 ° C., and the mixture was stirred at room temperature for 6 hours. 1.31 g (5.38 mmol) of 1,6-dibromohexane was added thereto, stirred at room temperature for 12 hours, and then 200 mL of tetrahydrofuran was added thereto. This solution was washed three times with distilled water (200 mL) using a separatory funnel. Thereafter, the resulting mixture was distilled under reduced pressure to give a saturated solution, which was then separated using column chromatography (ethyl acetate: hexane = 10: 1).

In a similar manner to the method used to obtain compound (IIIc) in Example 1, the ferrocene disulfide compound (Vc) was reacted from bromohexyl ferrocene compound (Vb) through reaction with sodium thiosulfate pentahydrate and dodecanethiol. Prepared. (Yield 58%)

^It was confirmed that the product obtained by the ¹ H-nuclear magnetic resonance spectrum and the mass spectrometry spectrum was a ferrocene disulfide compound (Vc).

¹ H NMR (400 MHz, CDCl ₃ , δ, ppm): 4.08-4.23 (m, 9H, Cp ring ), 2.72 (t, 4H), 2.31 (t, 2H), 1.71-1.66 (m, 4H), 1.30 -1.64 (m, 24H), 0.87 (t, 3H).

MS: m / z (M ⁺ ) = 502.

Example 4

Synthesis of Carborane Disulfide Compounds

Synthesis of Compound VIVI of Scheme 6 (m = 6, n = 11)

For the monothiation of ortho carborane was prepared by the following method. 1 g (6.93 mmol) of ortho carborane was dissolved in 20 mL of diethyl ether, and 5.2 mL (8.32 mmol, 1.6 M solution in hexane) of n-butyllithium was added at 0 ° C., and the mixture was stirred at room temperature for 6 hours. 1.69 g (6.93 mmol) of 1,6-dibromohexane was added thereto, stirred at room temperature for 12 hours, and 200 mL of diethyl ether was added thereto. This solution was washed three times with distilled water (200 mL) using a separatory funnel. Thereafter, the resulting mixture was distilled under reduced pressure to give a saturated solution, which was then separated using column chromatography (ethyl acetate: hexane = 5: 1).

In a manner similar to the method used to obtain compound (IIIc) in Example 1, an ortho carborane disulfide compound through reaction of bromohexyl carborane compound (VIb) with sodium thiosulfate pentahydrate and dodecanethiol (VIc) was prepared. (Yield 62%)

^It was confirmed that the product obtained by the ¹ H-nuclear magnetic resonance spectrum and the mass spectrometry spectrum was an ortho carborane disulfide compound (VIc).

¹ H NMR (400 MHz, CDCl ₃ , δ, ppm): 4.08 (s, 1H, o-carborane ), 3.66-3.55 (m, 2H), 2.73 (t, 4H), 1.68-1.73 (m, 4H), 1.28-1.66 (m, 24H), 0.88 (t, 3H).

MS: m / z (M ⁺ ) = 460.

Example 5

Synthesis of Porphyrin Disulfide Compounds

Synthesis of compound (VIIf) of Scheme 7 (m = 6, n = 11, R = paratoyl, M = Zn)

In a solution of 1 g (5.18 mmol) of 1-bromo-6-aldehyde hexane in 30 mL of dimethylformamide, 1.93 g (7.77 mmol) of sodium thiosulfate pentahydrate was dissolved in 5 mL of distilled water and reacted at 60 ° C. for 6 hours. After cooling to room temperature. Then, 1.15 g (5.70 mmol) of dodecanethiol, methanol, and 0.25 g (6.22 mmol) of sodium hydroxide were dissolved in 2 mL of distilled water, and a solution was stirred for 1 hour. The solution cooled to room temperature was slowly added dropwise to the solution using a syringe, followed by stirring at room temperature for 3 hours. 200 mL of ethyl acetate was poured out and washed three times with distilled water (200 mL) using a separatory funnel. Thereafter, the organic layers were collected, distilled under reduced pressure to obtain a saturated solution, and then separated using a column chromatograph (developing agent: ethyl acetate: hexane = 3: 1) to obtain a pale yellow disulfide aldehyde compound (VIIb).

Synthesis of porphyrin disulfide compound (VIIf) using disulfide aldehyde compound (VIIb) used the previously reported method ( J. Org. Chem . 2000, 65 , 7345). (Yield 45%)

^It was confirmed that the product obtained by the ¹ H-nuclear magnetic resonance spectrum and the mass spectrometry spectrum was the porphyrin disulfide compound (VIIf).

¹ H NMR (400 MHz, THF-d ₈ , δ, ppm): 8.78 (m, 2H), 8.41 (m, 2H), 8.30 (2H), 8.07 (m, 6H), 7.55 (m, 6H), 4.95 (m, 2H), 2.73 (t, 4H), 1.68-1.73 (m, 4H), 1.28-1.66 (m, 24H), 0.88 (t, 3H).

MS: m / z (M ⁺ ) = 960.

Example 6

Manufacturing of Molecular Electronic Devices

The self-assembly method was used to form the molecular active layer by immobilizing the compounds (IIId, IVe, Vc, VIc, VIIe) synthesized in Examples 1 to 5 on the lower electrode (Au electrode) of the molecular electronic device. The lower electrode was formed in three line patterns using a conventionally known compound semiconductor process. Nano imprint process was used to form the lower electrode. Usually, the line width of the lower electrode is appropriately 30 to 100 nm, and in this example, the line width of the lower electrode is formed to be 50 nm and the thickness is 30 nm.

Compounds (IIId, IVe, Vc, VIc, VIIe) synthesized in Examples 1 to 5 are soluble in organic solvents such as chloroform, dichloromethane, THF, DMF and the like. In this example, a 10 mL solution was prepared in which the compounds were each dissolved in a concentration of 1 mmol in a DMF solution. At this time, an oxygen-free, anhydrous DMF solvent was used in a glove box in which an oxygen-free and anhydrous atmosphere was maintained.

As a result, the resultant in which the lower electrode was formed was dipped into the prepared solution for 24 hours to fix the molecular layers respectively obtained from the compounds (IIId, IVe, Vc, VIc, and VIIe) on the lower electrode surface by a self-assembly method. .

The resulting molecular layer formed on the lower electrode surface was washed in the order of DMF, THF, ethanol, distilled water. The washed resultant was placed in a low temperature vacuum oven (40 ° C., 10 ⁻³ Torr) and dried for at least 2 hours.

The upper electrode was formed on the molecular layer using a vacuum equipment of 10 ⁻⁶ Torr and a deposition equipment maintained at a low temperature of −78 ° C. The upper electrode was formed in a Ti / Au stacked structure.

Example 7

Evaluation of Switching and Memory Characteristics of Molecular Electronic Devices

In order to evaluate the switching characteristics and the memory characteristics of the molecular electronic device obtained in Example 6, the following experiment was conducted. First, in order to exclude degradation such as oxidation of molecules in the molecular electronic device manufactured in Example 6, it was measured by storing in a vacuum chamber maintained at room temperature. The current (I) -voltage (V) characteristics were measured using a semiconductor parameter analyzer (HP 4156C). The switching and memory characteristics of the molecular electronic device according to the present invention were analyzed by the measurement results in two directions. That is, the switching characteristics and the memory characteristics were confirmed from the measurement results of the-voltage at the + voltage and the + voltage at the-voltage. In addition, in the voltage loop, the switching characteristics were confirmed by measuring from 0 → + voltage → − voltage → + voltage.

FIG. 5 is a hysteresis graph showing switching characteristics of a molecular electronic device including a molecular active layer formed using the compound synthesized in Example 1. FIG.

Pulse measurement to implement memory characteristics was performed using a pulse generator unit (HP 41501 expander) and a measurement / pulse select terminal unit (SMU-PGU selector, HP 16440A) that can be interconnected with the measurement apparatus.

FIG. 6 is a measurement result illustrating memory characteristics of a molecular electronic device including a molecular active layer formed using the compound synthesized in Example 1. FIG. In particular, the pulse generating device should be set in consideration of the measurement range of several Hz to several MHz in consideration of the switching characteristics of the molecular memory device. In addition, the rise / fall time of the voltage pulse is to be measured in the time range of 100 ns or less.

As described above, synthesis examples of the compounds for molecular electronic devices and preparation examples of the molecular electronic devices according to the present invention are listed. However, this is only an example to help understand the present invention, and it is obvious to those skilled in the art that various modifications are possible therefrom. Therefore, the true technical protection scope of the present invention will be defined by the technical spirit of the appended claims.

Compounds for molecular electronic devices according to the present invention includes a group containing an electroactive functional group consisting of a oxidizing-reducing active substance or a cyclic compound capable of transporting charges at both ends of the disulfide group (-SS-), Hydrocarbon groups that do not contain electroactive functional groups each have an asymmetric structure to which they are bonded.

From the compounds for molecular electronic devices provided by the present invention, a self-assembly method may be used to form a molecular active layer consisting of a monomolecular film on a metal electrode. In forming the molecular active layer, since the compound for molecular electronic device according to the present invention is self-assembled to the electrode using the disulfide group (-SS-) as a fixing unit, -R ₁ -Cy bonded to both ends of the disulfide group as a center. Groups and -R ₂ groups each contribute to the formation of a monomolecular film on the electrode surface. Therefore, it is possible to form a monomolecular film having a dense structure having excellent coverage in forming a monomolecular film containing bulky electroactive functional groups on the electrode surface, thus short-circuit phenomenon which may be caused by poor coverage in molecular electronic devices. It can prevent.

In addition, the molecular active layer obtained by self-assembly of the compounds according to the present invention can form ultra-thin film of several nanometers. In addition, the compounds according to the present invention may control the thickness of the molecular active layer by controlling the length of the hydrocarbon group included in the compound in the synthesis step.

In the above, the present invention has been described in detail with reference to preferred embodiments, but the present invention is not limited to the above embodiments, and various modifications and changes by those skilled in the art within the spirit and scope of the present invention. This is possible.

Claims (21)

A compound for molecular electronic devices, comprising ruthenium-terpyridine disulfide complex of the following formula:

Food, R ₁ and R ₂ are each a C ₁ to C ₂₀ saturated or unsaturated hydrocarbon group unsubstituted or substituted with F. delete The method of claim 1, The ruthenium-terpyridine disulfide complex compound has a structure represented by the following formula.

Food, m is an integer of 1-20, n is an integer of 1-19. delete delete delete delete delete delete delete delete A tetramethylpiperidyllithium compound, a methyl terpyridine compound and Br (CH ₂ ) _m-1 Br (m is an integer of 1 to 20) to react the bromoalkyl terpyridine compound (alkyl is-(CH ₂ ) _m- ), Sodium thiosulfate pentahydrate and alkanthiol (alkanes are CH ₃ (CH ₂ ) _n- , n is an integer of 1 to 19) from the bromoalkyl terpyridine compound-(CH ₂ ) _m -SS- Synthesizing a disulfide terpyridine compound having a (CH ₂ ) _n CH ₃ group, And reacting the disulfide terpyridine compound with a ruthenium terpyridine trichloride complex to form a ruthenium terpyridine disulfide complex. delete A first electrode, a second electrode formed on the first electrode, and a molecular active layer interposed between the first electrode and the second electrode, The molecular active layer has a structure in which the compound for molecular electronic device according to claim 1 is self-assembled on the first electrode. The method of claim 14, And wherein said molecular active layer is self-assembled on said first electrode using the disulfide group (-S-S-) of said ruthenium-terpyridine disulfide complex as a fixing device. The method of claim 14, The molecular active layer is a -S- (CH ₂ ) _m -Cy group (Cy is a ruthenium terpyridine complex, m is an integer of 1 to 20) self-assembled to the first electrode, respectively, and -S- (CH ₂ A molecular electronic device comprising a monomolecular layer containing _n- CH ₃ group (n is an integer of 1 to 19). delete The method of claim 14, The molecular active layer is a molecular electronic device, characterized in that for constituting a switch element that is switchable between the on and off state according to the voltage applied between the first electrode and the second electrode. The method of claim 14, The molecular active layer is a molecular electronic device, characterized in that for configuring a memory device for storing a predetermined electrical signal in accordance with the voltage applied between the first electrode and the second electrode. delete The method of claim 14, The first electrode and the second electrode is a molecular electronic device, characterized in that each consisting of gold, platinum, silver or chromium.

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