JPH03127791A - Porphyrin compound and optical recording material using same - Google Patents

Abstract

NEW MATERIAL:Tetra(9-phenanthrenyl)porphyrin of the formula. USE:Optical recording dyestuffs utilizing photochemical hole burning effect. PREPARATION:Phenanthrene-9-carboxaldehyde is reacted with pyrrole under heating.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a porphyrin compound and an optical recording material using the same. The present invention relates to a porphyrin compound useful as an optical recording dye and an optical recording material using the same.

[Prior art and problems to be solved by the invention] A wavelength multiplexing optical recording method based on photochemical hole burning (PHB) or non-photochemical hole burning (NPHB) is
It is attracting attention as a means to achieve high-density, high-speed recording, which will be necessary as computer processing power improves in the future.

Conventionally, as substances exhibiting PHB or NPHB, metal-free phthalocyanine exhibiting a phototautomeric reaction, quinizarine exhibiting hydrogen transfer, and various ionic dyes are known.

However, when hole burning recording is performed using these, the problem of destructive readout always accompanies since the hole burning reaction is a one-photon reaction.

In other words, the writing wavelength and the reading wavelength are the same for the hole corresponding to one bit, and the hole burning efficiency is the same during writing and reading, so reading is repeated even if the reading light is weakened. In this case, there is a problem in that the hole gradually becomes shallower due to the sweep of the readout light and bits are lost. Moreover, when reading -
・It is necessary to ensure a S/N ratio of "2" for reading, or to increase the S/N ratio, the intensity of the read light must be increased, so there is a problem that only destructive readout becomes noticeable. be.

On the other hand, some research attempts to solve the above problem by controlling hole burning efficiency using light or an electric field.

For example, there is a known method that uses a substance that exhibits a two-photon hole-burning reaction and uses the second photon as control light to increase the hole-burning efficiency only during writing [Carter, T., P.; Brauchei
, G:,; Lee, V., Y.; Manavi, M.
; Moerner, W.

E,,, Opt, Let, t,, 1987.12 (
5), 370].

Additionally, a method has been proposed in which the hole burning efficiency is increased only when an electric field is applied (Japanese Patent Laid-Open No. 62-20
0546, JP-A-62-74688).

However, the former method has the disadvantage that the write-erase cycle is not easy because the reverse reaction to the hole burning reaction is difficult, and the latter method has the disadvantage that the hole width widens due to the Stark effect caused by the electric field, or Since the wavelength of the hole shifts, there are problems in that the hole shape and wavelength position differ between writing and reading, or that the recording density decreases.

Furthermore, the method described in Japanese Unexamined Patent Publication No. 62-200546 has the disadvantage that the holes disappear in a short time when the electric field is turned off.

The present invention has been made in view of the above circumstances.

The object of the present invention is to provide a dye compound for optical recording that exhibits a high writing speed by controlling light irradiation during PHB recording and enables high non-destructive readability by extinguishing the control light during reading, and optical recording using the same. The aim is to provide materials for

[Means for Solving the Problems] In order to solve the above-mentioned problems, the present inventors have conducted intensive research on a new optical recording material that uses photochemical hole burning and an optical recording material that uses it. .

In tetraphenylporphyrin, it is already known that the hole-burning quantum efficiency of tetraphenylporphyrin increases or decreases when an electron-withdrawing or electron-donating group is introduced into the phenyl group (Ni1sii, N,; Asai,
N,; Kawasaki, N; Tamura, S
,; 5eto.

J., Appl, Phys., Lett., 19
88.52(1), 16). At present, the details of whether the hole-burning quantum efficiency increases or decreases due to fIII when an electron-withdrawing or electron-donating group is introduced are not well understood.

However, based on this fact, the present inventors deduced that if the electronic state (energy level or electron density) of porphyrin is changed, its hole burning quantum efficiency will change. Furthermore, he realized that if such a change in electronic state could be brought about through photoexcitation of the introduced substituent, it would be possible to optically control the hole-burning quantum efficiency.

Therefore, the present inventors introduced a substituent into a compound exhibiting PHB that can be photoexcited by control light having a wavelength different from that of the writing light that activates PHB in the compound to form a complex. , only when the substituent is photoexcited by controlled light irradiation, a change in the electronic state of the substituent is caused to affect the PHB active body, and as a result, a change is caused in the PHB quantum efficiency of the PHB active body. I thought it might be possible. Based mainly on this idea, the present inventors conducted extensive research in order to find a system in which the PHB quantum efficiency of the complex is significantly different when the substituent is excited with control light and when it is not. .

As a result, the PHB quantum efficiency of a specific complex formed by introducing a specific substituent into a compound exhibiting a specific PHB is higher than that of the compound without the substituent. We have discovered an extremely important phenomenon in that the substituent group is low in non-photoexcited Samurai, and can be increased only when the substituent is photoexcited with control light.

That is, if an optical recording material containing a specific optical recording dye compound called a specific complex containing this specific substituent is used as a recording medium, in wavelength multiplexed optical recording based on PHH, the substituent The control light is a light that excites the PHB and has a wavelength different from that of the writing light.When writing, the control light is used as an illuminant in addition to the writing light to write with high PHB quantum efficiency.When reading, the control light is used as an illuminant. It becomes possible to expose the readout light under conditions of low quantum efficiency without irradiating. This makes it possible to improve non-destructive read performance while maintaining a high write speed.

The present inventors have completed the present invention based on these findings.

That is, the first invention of the present application is a porphyrin compound represented by the following formula;
The invention is an optical recording material characterized in that the porphyrin compound represented by the formula [I] is dispersed in a medium through which control light, writing light, and reading light can pass.

The compound represented by the formula [I] of the present invention, that is, tetra(9-phenanthrenyl)porphyrin, can be produced without any particular limitation, and conventional synthesis techniques and separation/purification techniques may be used as appropriate. It can be manufactured using

This tetra(9-phenanthrenyl)porphyrin is
For example, it can be obtained by heat-reacting phenanthrene-9-carboxaldehyde and pyrrole.

The compound represented by the above formula [I] of the present invention is useful as a PH8 dye.

When the compound represented by the formula [I] of the present invention is used as a PH8 dye to form the optical recording material of the present invention, it is dispersed in a solid medium (matrix) to form the desired recording medium. What is necessary is just to form|mold it into the shape suitably.

Note that, if desired, other optical recording substances and various additives may be mixed in this medium within a range that does not impede the purpose of the present invention.

As the medium (matrix), various materials can be used as long as they are transparent in the wavelength range used.

Specifically, for example, organic polymers such as polymethyl methacrylate and polystyrene (JP-A-64-040391
The organic polymer medium described in the above publication can also be used. ) or their compositions, or those obtained by cooling and solidifying organic low molecules such as methanol, and silica glass prepared by the sol-gel method (for example,
Inorganic polymers such as silica glass (described in Japanese Patent No. 1989) and alumina glass can be suitably used.

The concentration of the compound represented by the formula [I] (that is, the optical recording dye compound of the present invention; hereinafter, this may be simply referred to as a dye) dispersed in the medium depends on the medium used. Although it cannot be specified uniformly because it varies depending on the type and other conditions such as the type and amount of other additives added if desired, it is usually 10-1 to 106 mol based on the volume of the medium (matrix). It is appropriate to set it within the range of 100%.

If the concentration of this dye is too low, the hole detection S/
On the other hand, if the N ratio is too high, problems such as a decrease in the ability to form holes due to intermolecular interactions of the dye may occur.

Further, a more desirable range or value of this concentration is further determined by the extinction coefficient in the writing wavelength range, writing conditions, reading conditions, etc.

Dispersion of the dye into a medium (matrix) and further shaping into a recording medium are carried out using known methods (for example, Japanese Patent Laid-Open No. 6
The method described in Publication No. 4-040391, Japanese Patent Publication No. 62-1
It can be carried out by various methods such as the method described in Japanese Patent No. 989, etc.) or a method analogous thereto.

For example, a given dye is dispersed or dissolved in a solution of a medium (matrix) such as an organic polymer in a suitable solvent, along with other additives and other components as necessary, and then this is cast or spun. A method of forming using the cord method,
A method in which a specified dye is dispersed or dissolved in a liquid medium (matrix) such as an organic low molecule, along with other components such as additives as necessary, and then cooled and solidified, or an inorganic sol-gel method. It is also possible to suitably use a method in which a raw material for a medium (matrix) material such as an organic crosslinkable polymer, a predetermined pigment, or other components such as a pigment or the like are mixed, reacted, and solidified.

By the way, the optical recording dye compound of the present invention mainly has a wavelength absorption band related to its porphyrin ring (hereinafter, this may be referred to as a recording wavelength absorption band).

) and a wavelength absorption band mainly related to the substituent, that is, the 9-phenanthrenyl group (hereinafter, this may be referred to as a control wavelength absorption band).

When a recording medium made of the optical recording material of the present invention is used for PI (B recording), the following optical recording method may be used.

That is, bit writing by PHH is performed in the recording wavelength absorption band. At this time, control light having a wavelength corresponding to somewhere in the control wavelength absorption band is irradiated onto a recording area of the recording medium that is the same as or includes the irradiation spot of the write light. This control light irradiation can be performed at any time during writing, but it is usually effective to perform it simultaneously with, immediately before, or after the write light irradiation. That is, it is effective to irradiate the control light at any time or period from immediately before to immediately after the irradiation of the write light.

Note that although it is usually sufficient to irradiate the control light once, it may be irradiated multiple times intermittently as necessary.

The writing light and control light may be continuous light or pulsed light. However, since the writing light is required to have high resolution and selectivity, highly monochromatic light, that is, laser light, is used. The light source for this laser light can be appropriately selected from various wavelength tunable sources.

On the other hand, control light usually does not require the high monochromaticity of writing light, so in addition to laser light, light from an incoherent light source, such as a xenon lamp or mercury lamp, can be used as it is, or by using an optical filter or spectrometer. It can also be used through a container.

However, in order to increase the writing speed sufficiently,
It is also desirable to use laser light, which has excellent intensity, operability, etc., as the control light.

Note that hole embedding may occur depending on the wavelength of the control light. This embedding depends on the wavelength of the control light and can be easily avoided by appropriately selecting the wavelength.

As described above, the PHB quantum efficiency when the control light is irradiated in addition to the writing light can be significantly improved compared to the case where the control light is not irradiated.

Only when control light is irradiated in addition to writing light in this way, the details of the mechanism by which the quantum efficiency improves (P) (B) are not necessarily clear; 9- in the optical recording dye compound
The phenanthrenyl group is photoexcited, and through this photoexcitation, the electronic state of the porphyrin ring in the optical recording dye compound undergoes some change, and the quantum efficiency of P) (B) to the wavelength absorption band related to the porphyrin ring It can be estimated that this is improved compared to the case without irradiation.

On the other hand, when reading information recorded in this way,
Reading is performed by irradiating only normal read light without irradiating (or using) control light according to the conventional method.

That is, according to the PHB recording method using the optical recording dye compound or optical recording material of the present invention, bits can be written with high quantum efficiency by using control light during writing, while controlling light is used during reading. Information can be read by exposing to read light under conditions of low quantum efficiency without irradiating (using) light. Therefore, the non-destructive reading performance of recorded information can be significantly improved while maintaining a high writing speed.

[Example] (Example 1) Tetra(9-phenanthrenyl)porphyrin was synthesized as follows.

In a round bottom flask equipped with a reflux condenser and a stirrer, add 5.9 g of phenanthrene-9-carboxaldehyde.
g, and 200 ml of propionic acid were added and heated to gently reflux. After the start of reflux, 1.9 g of pea roll immediately after distillation was added to the mixture, and the mixture was heated and refluxed for 18 hours to react. After the reaction product mixture was allowed to cool, the liquid part was removed by decantation, the solid part was washed three times with 50 ml of dichloromethane, and the soluble part was separated and collected as a dichloromethane solution. This dichloromethane solution was washed with a saturated aqueous sodium bicarbonate solution and water, and purified by silica gel column chromatography.
mg, was obtained.

The structure was confirmed by nuclear magnetic resonance spectroscopy, elemental analysis, etc.

The data is shown below.

Mass spectrometry spectrum (see Figure 1) Nuclear magnetic resonance spectrum data (see below and Figure 2) 6 δ (CDCI+) knee 2.1 (2H, br, s), 7
．． 2 ~ 7.25 (8H, m), 7.6 (4H, t),
7.75 (4H, s), 7.85 (4H, t), 8.0
5 (4H, d), 8.55 (41-1, m), 8.6 (
8H, br.

s), 8.95 (88, t) Elemental analysis data calculation value C: 89.9, H: 4.6, N: 5.
5 Measured values C: 90.4, H: 4.5, N: 5
．． 1st, tetra(9-phenanthrenyl) obtained above
A sample in which porphyrin was dispersed in polymethyl methacrylate (PMMA) having a number average molecular weight of approximately 300,000 was prepared as follows.

A polymer solution was prepared by dissolving 5 g of PMMA in 20 mJl of dichloromethane.

On the other hand, in order to set the dispersion concentration of tetra(9-phenanthrenyl)porphyrin in the obtained optical recording medium to 10-3 mol/view, 4 mg of tetra(9-phenanthrenyl)porphyrin was dissolved in 10 ml of dichloromethane. . After adding this dye solution to the polymer solution and mixing thoroughly, it was spread on a glass petri dish and kept at room temperature for 12 hours.
Air dry for an hour. Thereafter, it was dried under reduced pressure for 12 hours in a vacuum dryer heated to 80°C.

This dried material was sandwiched between two glass plates on a hot plate heated to about 300° C. to form a thin film of about 0.5 mm, and then left to cool and used as a target sample.

This sample was placed in a cryostat using liquid helium as a cryogen, and burned pulsed light (wavelength: 650 nm) using excimer laser-excited dye laser light at a temperature of 6°C.
m, intensity per pulse approximately 17 JLJ/cm2
) and control pulse light (wavelength 308 nm, intensity per pulse approximately 101 LJ/cm") at 20 Hz, and the hole burning quantum efficiency (G) when the control light is irradiated is determined from the literature (Moerner, W. E, ;G
ehrtz, M.; Huston, A.L., J.

Phys, Chem, 1984.88.6459)
It was measured according to the method described in . On the other hand, the hole burning quantum efficiency (Kl) when the control light was not irradiated was measured in the same manner, and the control performance was investigated by comparing these measured values.

The results are shown in Table 1. Note that when determining the G value, the amount of hole filling caused by the control light was subtracted.

(Comparative Example 1) The hole burning quantum efficiency (K2) of a sample in which tetraphenylporphyrin was dispersed in PMMA in place of tetra(9-phenanthrenyl)porphyrin at a dispersion concentration of 10 −3 mol/gram was measured.

The results are shown in Table 1.

3xlO-' to 12xlO""25xlO-' As shown in Table 1, when using the optical recording medium containing the porphyrin compound of the present invention, compared to the usual method as in Comparative Example 1, Therefore, when the control light is not irradiated, the hole burning quantum efficiency (K1) is about two orders of magnitude lower. This indicates that the read performance has been improved by at least 100 times in terms of the number of reads. On the other hand, when the control light is irradiated, the efficiency is recovered by about one order of magnitude, so that a sufficient writing speed is ensured.

[Effects of the Invention] According to the present invention, the advantages of wavelength multiplexing optical recording using PHB, such as high density of recorded information and high speed of writing, can be maintained at a practical level, and moreover, It is possible to significantly change the PHB quantum efficiency during writing (for example, when irradiating control light, the writing speed increases by 15 times compared to when not irradiating), and therefore, irradiating control light The difference between the PHB quantum efficiency during writing and the PHB quantum efficiency during reading without irradiation with control light can be significantly increased, and as a result, the nondestructive readability can be significantly improved (for example, when using conventional dyes, It is possible to provide a dye compound for optical recording which can be improved by two orders of magnitude compared to the present invention, and an optical recording material using the same.

[Brief explanation of the drawing]

FIG. 1 is a chart showing an example of a mass spectrometry spectrum of the optical recording dye compound of the present invention. The horizontal axis of Figure 1 and the numbers in the figure indicate the mass/charge ratio (ta
le), and the vertical axis shows the relative spectral intensity. FIG. 2 is a chart showing an example of the nuclear magnetic resonance spectrum of the optical recording dye compound of the present invention, and the partially enlarged spectrum and measurement conditions are also shown in the figure. The horizontal axis of FIG. 2 and its partially enlarged spectrum shows the chemical shift δ (in ppm), and the vertical axis shows the spectral intensity.

Claims (2)

[Claims] (1) The following formula ▲There are mathematical formulas, chemical formulas, tables, etc.▼［I］ A porphyrin compound represented by (2) An optical recording material, characterized in that the porphyrin compound according to claim 1 is dispersed in a medium through which control light, writing light, and reading light can pass.