U.S. patent application number 12/630285 was filed with the patent office on 2010-04-01 for optical recording medium.
This patent application is currently assigned to ADEKA CORPORATION. Invention is credited to Koichi SHIGENO, Toru YANO.
Application Number | 20100080947 12/630285 |
Document ID | / |
Family ID | 35786060 |
Filed Date | 2010-04-01 |
United States Patent
Application |
20100080947 |
Kind Code |
A1 |
YANO; Toru ; et al. |
April 1, 2010 |
OPTICAL RECORDING MEDIUM
Abstract
An optical recording material for use in an optical recording
layer of an optical recording medium comprising the optical
recording layer provided on a substrate, the optical recording
material comprising a cyanine compound represented by general
formula (I): ##STR00001## wherein rings A and B each represent a
substituted or unsubstituted benzene or naphthalene ring; X
represents O, S, Se, CR.sup.3R.sup.4 or NY; one of R.sup.1 and
R.sup.2 represents a specific group of formula (II) or (III), with
the other representing a C1 to C30 organic group; R.sup.3 and
R.sup.4 each represent a C1 to C30 organic group; Y, Y.sup.1, and
Y.sup.2 each represent a hydrogen atom or a C1 to C30 organic
group; Z represents a hydrogen atom, a halogen atom or a cyano
group; An.sup.m-1 represents an m-valent anion; m represents an
integer of 1 or 2; and p represents a coefficient maintaining
charge neutrality.
Inventors: |
YANO; Toru; (Tokyo, JP)
; SHIGENO; Koichi; (Tokyo, JP) |
Correspondence
Address: |
YOUNG & THOMPSON
209 Madison Street, Suite 500
Alexandria
VA
22314
US
|
Assignee: |
ADEKA CORPORATION
Tokyo
JP
|
Family ID: |
35786060 |
Appl. No.: |
12/630285 |
Filed: |
December 3, 2009 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
11632643 |
Jan 16, 2007 |
|
|
|
PCT/JP2005/010391 |
Jul 29, 2004 |
|
|
|
12630285 |
|
|
|
|
Current U.S.
Class: |
428/64.4 |
Current CPC
Class: |
G11B 7/246 20130101;
G11B 7/2495 20130101; G11B 7/2478 20130101; G11B 7/2535 20130101;
C09B 23/06 20130101; Y10S 430/146 20130101; G11B 7/2533 20130101;
G11B 7/2467 20130101; G11B 7/245 20130101; G11B 7/2472 20130101;
G11B 7/2534 20130101; G11B 7/248 20130101; G11B 7/2531
20130101 |
Class at
Publication: |
428/64.4 |
International
Class: |
B32B 3/02 20060101
B32B003/02 |
Foreign Application Data
Date |
Code |
Application Number |
Jul 29, 2004 |
JP |
2004-222239 |
Claims
1. An optical recording medium comprising: a substrate, and a thin
film of an optical recording material on the substrate, wherein the
optical recording material comprises a cyanine compound represented
by general formula (I): ##STR00024## wherein ring A and ring B each
represent a benzene ring optionally having a substituent or a
naphthalene ring optionally having a substituent; X represents O,
S, Se, CR.sup.3R.sup.4 or NY; one of R.sup.1 and R.sup.2 represents
a group represented by general formula (II) or (III) below, with
the other representing an organic group having 1 to 30 carbon
atoms; R.sup.3 and R.sup.4 each represent an organic group having 1
to 30 carbon atoms; Y, Y.sup.1, and Y.sup.2 each represent a
hydrogen atom or an organic group having 1 to 30 carbon atoms; Z
represents a hydrogen atom, a halogen atom or a cyano group;
An.sup.m-1 represents an m-valent anion; m represents an integer of
1 or 2; and p represents a coefficient maintaining charge
neutrality, wherein the bond between E and G is a double bond or a
triple bond; E represents a carbon atom; G represents a carbon
atom, an oxygen atom or a nitrogen atom; x, y, and z each
independently represent 0 or 1; R.sup.5 represents a hydrogen atom,
a halogen atom, an alkyl group having 1 to 4 carbon atoms and
optionally substituted with a halogen atom or an alkoxy group
having 1 to 4 carbon atoms and optionally substituted with a
halogen atom; R.sup.6, R.sup.7, and R.sup.8 each independently
represent a hydrogen atom, a halogen atom or an alkyl group having
1 to 4 ##STR00025## carbon atoms and optionally substituted with a
halogen atom; R.sup.6 and R.sup.8 may be connected to each other to
form a cyclic structure. ##STR00026## wherein the bond between E'
and G' is a double bond; E' represents a carbon atom; G' represents
a carbon atom, an oxygen atom or a nitrogen atom; the ring
containing E' and G' is a 5-membered ring optionally containing a
hetero atom, a heterocyclic 6-membered ring, a naphthalene ring, a
quinoline ring, an isoquinoline ring, an anthracene ring or an
anthraquinone ring; the ring containing E' and G' may be
substituted with at least one substituent selected from the group
consisting of a halogen atom, a nitro group, a cyano group, an
alkyl group, and an alkoxy group.
Description
TECHNICAL FIELD
[0001] This invention relates to an optical recording material
containing a specific cyanine compound and an optical recording
medium having a thin film of the optical recording material as an
optical recording layer.
BACKGROUND ART
[0002] Compounds having a large absorption in a range of from 550
to 620 nm, particularly those having a maximum absorption
(.lamda..sub.max) in a range of from 550 to 620 nm are used as an
optical recording material forming an optical recording layer of
optical recording media, such as DVD-Rs.
[0003] There have been many reports on cyanine compounds having an
indole ring because of their high sensitivity and capability of
coping with increasing recording speeds in the above-described
applications as an optical recording material. For example, cyanine
compounds having a specific organic group introduced at the
3-position of the indole ring to cope with high-speed recording are
reported in Patent Document 1 and Patent Document 2. Patent
Document 1 discloses a cyanine compound having spiroalkane at the
3-position, and Patent Document 2 discloses a cyanine compound with
benzyl at the 3-position.
[0004] Optical recording media have ever been required to achieve
further increase in recording speed, and optical recording
materials are also required to exhibit performance in response to
such requirement.
Patent Document 1: JP 2002-52829A
Patent Document 2: JP 2003-231359A
DISCLOSURE OF THE INVENTION
Problems to be Solved by the Invention
[0005] An object of the present invention is to provide an optical
recording material and medium exhibiting performance adequate for
high-speed optical recording applications.
Means for Solving the Problems
[0006] As a result of extensive investigations, the present
inventors have found that a cyanine compound having a group
containing a multiple bond incorporated at a specific position
thereof is suitable for use as an optical recording material.
[0007] The present invention has been completed based on the above
finding. The invention provides an optical recording material for
use in an optical recording layer of an optical recording medium
comprising the optical recording layer provided on a substrate,
[0008] the optical recording material comprising a cyanine compound
represented by general formula (I) shown below. The invention also
provides an optical recording medium having a substrate and a thin
film formed of the optical recording material.
##STR00002##
wherein ring A and ring B each represent a benzene ring optionally
having a substituent or a naphthalene ring optionally having a
substituent; X represents O, S, Se, CR.sup.3R.sup.4 or NY; one of
R.sup.1 and R.sup.2 represents a group represented by general
formula (II) or (III) shown below, with the other representing an
organic group having 1 to 30 carbon atoms; R.sup.3 and R.sup.4 each
represent an organic group having 1 to 30 carbon atoms; Y, Y.sup.1,
and Y.sup.2 each represent a hydrogen atom or an organic group
having 1 to 30 carbon atoms; Z represents a hydrogen atom, a
halogen atom or a cyano group; An.sup.m-1 represents an m-valent
anion; m represents an integer of 1 or 2; and p represents a
coefficient maintaining charge neutrality
##STR00003##
wherein the bond between E and G is a double bond or a triple bond;
E represents a carbon atom; G represents a carbon atom, an oxygen
atom or a nitrogen atom; x, y, and z each independently represent 0
or 1; R.sup.5 represents a hydrogen atom, a halogen atom, an alkyl
group having 1 to 4 carbon atoms and optionally substituted with a
halogen atom or an alkoxy group having 1 to 4 carbon atoms and
optionally substituted with a halogen atom; R.sup.6, R.sup.7, and
R.sup.8 each independently represent a hydrogen atom, a halogen
atom or an alkyl group having 1 to 4 carbon atoms and optionally
substituted with a halogen atom; R.sup.6 and R.sup.8 may be
connected to each other to form a cyclic structure.
##STR00004##
wherein the bond between E' and G' is a double bond; E' represents
a carbon atom; G' represents a carbon atom, an oxygen atom or a
nitrogen atom; the ring containing E' and G' is a 5-membered ring
optionally containing a hetero atom, a heterocyclic 6-membered
ring, a naphthalene ring, a quinoline ring, an isoquinoline ring,
an anthracene ring or an anthraquinone ring; the ring containing E'
and G' may be substituted with at least one substituent selected
from the group consisting of a halogen atom, a nitro group, a cyano
group, an alkyl group, and an alkoxy group.
BRIEF DESCRIPTION OF THE DRAWING
[0009] FIG. 1 shows a .sup.1H-NMR spectrum of the optical recording
material obtained in Example 1 (hexafluorophosphate of compound No.
4).
[0010] FIG. 2 shows a .sup.1H-NMR spectrum of the optical recording
material obtained in Example 2 (hexafluorophosphate of compound No.
5).
[0011] FIG. 3 shows a .sup.1H-NMR spectrum of the optical recording
material obtained in Example 3 (hexafluorophosphate of compound No.
14).
[0012] FIG. 4 shows a .sup.1H-NMR spectrum of the optical recording
material obtained in Example 4 (hexafluorophosphate of compound No.
19).
[0013] FIG. 5 shows a .sup.1H-NMR spectrum of the optical recording
material obtained in Example 5 (hexafluorophosphate of compound No.
40).
[0014] FIG. 6 shows a .sup.1H-NMR spectrum of the optical recording
material obtained in Example 6 (hexafluorophosphate of compound No.
41).
[0015] FIG. 7 shows a .sup.1H-NMR spectrum of the optical recording
material obtained in Example 7 (hexafluorophosphate of compound No.
48).
BEST MODE FOR CARRYING OUT THE INVENTION
[0016] The cyanine compound of the invention represented by general
formula (I) is a compound characterized by having a specific
structure group at the 3-position of the indole skeleton. The
compound is characterized by its higher ability to respond to high
speed recording than conventional cyanine compounds used in optical
recording materials for DVD-R application.
[0017] In general formula (I), examples of the substituent of the
substituted benzene or naphthalene ring represented by rings A and
B include a halogen atom such as fluorine, chlorine, bromine or
iodine; an alkyl group which may be substituted with a halogen
atom, such as methyl, ethyl, propyl, isopropyl, butyl, sec-butyl,
tert-butyl, isobutyl, amyl, isoamyl, tert-amyl, hexyl, cyclohexyl,
heptyl, isoheptyl, tert-heptyl, n-octyl, isooctyl, tert-octyl,
2-ethylhexyl or trifluoromethyl; an aryl group, such as phenyl,
naphthyl, 2-methylphenyl, 3-methylphenyl, 4-methylphenyl,
4-vinylphenyl or 3-isopropylphenyl; an alkoxy group which may be
substituted with a halogen atom, such as methoxy, ethoxy, propoxy,
isopropoxy, butoxy, sec-butoxy, tert-butoxy or trifluoromethoxy; an
alkylthio group, such as methylthio, ethylthio, propylthio,
isopropylthio, butylthio, sec-butylthio, tert-butylthio or
trifluoromethylthio; a nitro group; and a cyano group.
[0018] The organic groups having 1 to 30 carbon atoms as
represented by R.sup.1, R.sup.2, R.sup.3R.sup.4, Y, Y.sup.1 or
Y.sup.2 include, but are not limited to, an alkyl group, e.g.,
methyl, ethyl, propyl, isopropyl, butyl, sec-butyl, tert-butyl,
isobutyl, amyl, isoamyl tert-amyl, hexyl, cyclohexyl,
cyclohexylmethyl, 2-cyclohexylethyl, heptyl, isoheptyl, t-heptyl,
n-octyl, isooctyl, t-octyl, 2-ethylhexyl, nonyl, isononyl, decyl,
dodecyl, tridecyl, tetradecyl, pentadecyl, hexadeyl, heptadecyl or
octadecyl; an alkenyl group, e.g., vinyl, 1-propenyl
(2-methylethenyl), 2-propenyl (allyl), isopropenyl
(1-methylethenyl), butenyl (e.g., 1-butenyl, 2-butenyl, 3-butenyl
or isobutenyl), pentenyl, hexenyl, heptenyl, octenyl, decenyl,
pentadecenyl or 1-phenylpropen-3-yl; phenyl, naphthyl; an alkylaryl
group, e.g., 2-methylphenyl, 3-methylphenyl, 4-methylphenyl,
4-vinylphenyl, 3-isopropylphenyl, 4-isopropylphenyl, 4-butylphenyl,
4-isobutylphenyl, 4-t-butylphenyl, 4-hexylphenyl,
4-cyclohexylphenyl, 4-octylphenyl, 4-(2-ethylhexyl)phenyl,
4-stearylphenyl, 2,3-dimethylphenyl, 2,4-dimethylphenyl,
2,5-dimethylphenyl, 2,6-dimethylphenyl, 3,4-dimethylphenyl,
3,5-dimethylphenyl, 2,4-di-t-butylphenyl or cyclohexylphenyl; and
an arylalkyl group, e.g., benzyl, phenethyl, 2-phenylpropan-2-yl,
diphenylmethyl, triphenylmethyl, styryl or cinnamyl. Further
included are the above-recited hydrocarbon groups which are
interrupted by an ether linkage and/or a thioether linkage, such as
2-methoxyethyl, 3-methoxypropyl, 4-methoxybutyl, 2-butoxyethyl,
methoxyethoxyethyl, methoxyethoxyethoxyethyl, 3-methoxybutyl,
2-phenoxyethyl, 2-methylthioethyl, and 2-phenylthioethyl. These
organic groups may further be substituted with an alkoxy group, an
alkenyl group, a nitro group, a cyano group, a halogen atom,
etc.
[0019] When R.sup.1, R.sup.2, R.sup.3 or R.sup.4 is a C1 to C30
organic group other than the groups of general formulae (II) and
(III), if the organic group is bulky, such a bulky substituent
reduces the molar absorptivity of the cyanine compound and can
affect the sensitivity. Moreover, steric hindrance can occur to
markedly reduce the efficiency of producing the cyanine compound.
Accordingly, it is preferred that R.sup.1 to R.sup.4 each represent
any of the following groups.
[0020] Alkyl groups, particularly those having 1 to 4 carbon atoms,
such as methyl, ethyl, propyl, isopropyl, butyl, sec-butyl,
tert-butyl, and isobutyl.
[0021] Substituted or unsubstituted benzyl groups, the substituents
including a hydroxyl group; a halogen atom, e.g., fluorine,
chlorine, bromine or iodine; a cyano group; a nitro group; an alkyl
group with 1 to 4 carbon atoms, e.g., methyl, ethyl, propyl,
isopropyl, butyl, sec-butyl, tert-butyl or isobutyl; a
halogen-substituted alkyl group with 1 to 4 carbon atoms, e.g.,
chloromethyl, dichloromethyl, trichloromethyl, bromomethyl,
dibromomethyl, tribromomethyl, fluoromethyl, difluoromethyl,
trifluoromethyl, 2,2,2-trifluoroethyl, perfluoroethyl,
perfluoropropyl or perfluorobutyl; an alkoxy group with 1 to 4
carbon atoms, e.g., methoxy, ethoxy, propoxy, isopropoxy, butoxy,
sec-butoxy or tert-butoxy; and a halogen-substituted alkoxy group,
e.g., chloromethoxy, dichloromethoxy, trichloromethoxy,
bromomethoxy, dibromomethoxy, tribromomethoxy, fluoromethoxy,
difluoromethoxy, trifluoromethoxy, 2,2,2-trifluoroethoxy,
perfluoroethoxy, perfluoropropoxy or perfluorobutoxy.
[0022] It is also preferred that R.sup.3 and R.sup.4 are taken
together to represent a group forming a 3- to 6-membered ring.
Examples of the group forming a 3- to 6-membered ring include
cyclopropane-1,1-diyl, cyclobutane-1,1-diyl,
2,4-dimethylcyclobutane-1,1-diyl, 3-dimethylcyclobutane-1,1-diyl,
cyclopentane-1,1-diyl, cyclohexane-1,1-diyl,
tetrahydropyran-4,4-diyl, thiane-4,4-diyl, piperidine-4,4-diyl,
N-substituted piperidine-4,4-diyl, morpholine-2,2-diyl, morpholine
3,3-diyl, N-substituted morpholine-2,2-diyl, and N-substituted
morpholine-3,3-diyl, in which the N-substituent may be selected
from the substituents that may be present on rings A and B.
[0023] When Y, Y.sup.1, and Y.sup.2 in general formula (I) are
bulky, such bulky substituents reduce the molar absorptivity of the
cyanine compound and can affect the sensitivity. Therefore,
hydrocarbon groups having 1 to 8 carbon atoms, particularly alkyl
groups having 1 to 8 carbon atoms are preferred.
[0024] Examples of the halogen atom as represented by Z in general
formula (I) include fluorine, chlorine, bromine, and iodine.
[0025] Of the anions represented by An.sup.m-1 in general formula
(I), monovalent ones include halide anions, e.g., chloride,
bromide, iodide and fluoride anions; inorganic anions, such as
perchlorate, chlorate, thiocyanate, hexafluorophosphate,
hexafluoroantimonate, and tetrafluoroborate anions; organic
sulfonate anions, such as benzenesulfonate, toluenesulfonate,
trifluoromethanesulfonate, diphenylamine-4-sulfonate,
2-amino-4-methyl-5-chlorobenzenesulfonate, and
2-amino-5-nitrobenzenesulfonate anions; and organophosphate anions,
such as octylphosphate, dodecylphosphate, octadecylphosphate,
phenylphosphate, nonylphenylphosphate, and
2,2'-methylenebis(4,6-di-tert-butylphenyl)phosphonate anions.
Divalent ones include benzenedisulfonate and naphthalenedisulfonate
anions. If desired, a quencher anion capable of deexcitation
(quenching) an active molecule in an excited state, a metallocene
compound anion of, for example, a ferrocene or ruthenocene compound
having an anionic group (e.g., carboxyl, phosphonic or sulfonic
group) on the cyclopentadienyl ring, and the like can be used.
[0026] Examples of the quencher anion include anions represented by
general formulae (A) and (B) shown below and those described in JP
60-234892A, JP 5-43814A, JP 6-239028A, JP 9-309886A, and JP
10-45767A.
##STR00005##
wherein M represents a nickel atom or a copper atom; R.sup.10 and
R.sup.11 each represent a halogen atom, an alkyl group having 1 to
8 carbon atoms, an aryl group having 6 to 30 carbon atoms or
--SO.sub.2--Z; Z represents an alkyl group, an aryl group, a
halogen-substituted aryl group, a dialkylamino group, a diarylamino
group, a piperidino group or a morpholino group; a and b each
represent an integer of 0 to 4; and R.sup.12, R.sup.13, R.sup.14,
and R.sup.15 each independently represent an alkyl group, an
alkylphenyl group, an alkoxyphenyl group or a halogen-substituted
phenyl group.
[0027] In general formula (II), examples of the halogen atom
represented by R.sup.5, R.sup.6, R.sup.7 or R.sup.8 are fluorine,
chlorine, bromine, and iodine. Examples of the C1 to C4 alkyl group
that may be substituted with a halogen atom include methyl, ethyl,
propyl, isopropyl, butyl, sec-butyl, tert-butyl, isobutyl,
chloromethyl, dichloromethyl, trichloromethyl, bromomethyl,
dibromomethyl, tribromomethyl, fluoromethyl, difluoromethyl,
trifluoromethyl, 2,2,2-trifluoroethyl, perfluoroethyl,
perfluoropropyl, and perfluorobutyl. Examples of the C1 to C4
alkoxy group that may be substituted with a halogen atom include
methoxy, ethoxy, propoxy, isopropoxy, butoxy, sec-butoxy,
tert-butoxy, and trifluoromethoxy. Examples of the cyclic structure
formed by connecting R.sup.6 and R.sup.8 include cyclobutene,
cyclopentene, cyclohexene, pyrrole, dihydropyrrole, and pyridine
rings.
[0028] In general formula (III), examples of the 5-membered ring
containing E' and G' and optionally containing a hetero atom
include cyclopentene, cyclopentadiene, pyrrole, imidazole,
pyrazole, triazole, thiophene, furan, thiazole, isothiazole,
oxazole, isoxazole, dihydropyrrole, dihydroimidwole,
dihydropyrazole, triazole, dihydrothiophene, dihydrofuran,
dihydrothiazole, dihydroisothiazole, dihydrooxazole, and
dihydroisoxazole rings. Examples of the heterocyclic 6-membered
ring containing E' and G' include pyridine, pyrazine, pyrimidine,
pyridazine, pyran, and thiopyran rings. The rings containing E' and
G' may be substituted with a halogen atom, e.g., fluorine,
chlorine, bromine or iodine; a nitro group; a cyano group; an alkyl
group, e.g., methyl, ethyl, propyl, isopropyl, butyl, isobutyl,
tert-butyl or trifluoromethyl; or an alkoxy group, e.g., methoxy,
ethoxy, propoxy, isopropoxy, butoxy, sec-butoxy, tert-butoxy or
trifluoromethoxy.
[0029] Specific examples of the cyanine compound represented by
general formula (I) according to the present invention include
compound Nos. 1 through 72 below. The formulae shown are cation
moieties of the cyanine compounds.
##STR00006## ##STR00007## ##STR00008## ##STR00009## ##STR00010##
##STR00011## ##STR00012## ##STR00013## ##STR00014## ##STR00015##
##STR00016## ##STR00017## ##STR00018##
[0030] Of the cyanine compounds described above preferred are those
of general formula (I) in which X is CR.sup.3R.sup.4 (e.g.,
compound Nos. 1 to 48 and 61 to 69) because of their good light
resistance and those in which the ring constructing the indole
skeleton to which the group of general formula (II) or (III) is
bonded (i.e., the ring A and/or the ring B in the general formula
(I)) is a naphthalene ring (e.g., compound Nos. 1 to 12, 19 to 24,
26, 29, 31 to 36, 38 to 57, 60, 62, 63, 65, 66, and 68 to 72)
because of their good thermal behavior as an optical recording
material, particularly those in which the indole ring has a benzene
ring fused to its [e] face (e.g., compound Nos. 1, 4 to 12, 19, 22
to 24, 31, 32, 34, 38, 40 to 57, 60, 62, 63, 65, 66, and 68 to
72).
[0031] The cyanine compound of the invention represented by general
formula (I) is not restricted by the process of preparation. The
cyanine compound is obtainable by, for example, linking two
intermediate compounds, 2-methylindole quaternary salt derivatives,
using a bridging agent, such as N,N'-diphenylformamidine. The group
having a multiple bond represented by general formula (II) or (DI)
can be introduced in the course of preparing the 2-methylindole
quaternary salt derivative. For example, an arylhydrazine
derivative as a starting material is allowed to react with a
2-butanone derivative having the multiple bond group of general
formula (II) or (DI) to form an indole ring, or a halogenated
derivative is allowed to react on an indole ring. Y, Y.sup.1, and
Y.sup.2 can be introduced by using Y-D, Y.sup.1-D, and Y.sup.2-D,
respectively (wherein D is a halogen group, e.g., chlorine, bromine
or iodine, or a sulfonyloxy group, e.g., phenylsulfonyloxy,
4-methylphenylsulfonyloxy or 4-chlorophenylsulfonyloxy) reactive
with NH of an arylamine derivative or an indole ring. The
2-butanone derivative having the multiple bond group represented by
general formula (II) or (III) can be obtained by the reaction
between acetone and benzaldehyde having a corresponding
substituent
[0032] The "optical recording material" according to the present
invention includes the cyanine compound represented by general
formula (I) per se and a mixture of the cyanine compound and an
organic solvent and/or other compounds hereinafter described. The
optical recording medium according to the invention has a substrate
and an optical recording layer formed on the substrate in a thin
film form using the optical recording material of the
invention.
[0033] The method of forming an optical recording layer of an
optical recording media using the optical recording material of the
invention is not particularly limited. A wet coating technique is
generally used, in which a solution of the cyanine compound and, if
necessary, various compounds described later in an organic solvent
is applied to a substrate by spin coating, spray coating, dipping
or a like method. Examples of the organic solvent include lower
alcohols, such as methanol and ethanol; ether alcohols, such as
methyl cellosolve, ethyl cellosolve, butyl cellosolve, and butyl
diglycol; ketones, such as acetone, methyl ethyl ketone, methyl
isobutyl ketone, cyclohexanone, and diacetone alcohol; esters, such
as ethyl acetate, butyl acetate, and methoxyethyl acetate; acrylic
esters, such as ethyl acrylate and butyl acrylate; fluoroalcohols,
such as 2,2,2-trifluoroethanol, perfluoroethanol,
2,2,3,3-tetrafluoro-1-propanol, and perfluoropropanol;
hydrocarbons, such as benzene, toluene, and xylene; and chlorinated
hydrocarbons, such as methylene dichloride, dichloroethane, and
chloroform. The optical recording layer may also be formed by
vacuum evaporation, sputtering or a like technique.
[0034] The thickness of the optical recording layer is usually
0.001 to 10 .mu.m, preferably 0.01 to 5 .mu.m.
[0035] When the optical recording material of the invention is used
to form an optical recording layer of an optical recording medium,
the content of the cyanine compound of the general formula (I) in
the optical recording layer is preferably 25% to 100% by mass.
Accordingly, the optical recording material of the invention
preferably contains 25% to 100% by mass of the cyanine compound of
the general formula (I) on a solid basis to give the above-recited
cyanine compound content in the optical recording layer.
[0036] Where necessary, the optical recording layer may contain
color compounds commonly employed in an optical recording layer,
such as cyanine compounds other than those of the invention, azo
compounds, phthalocyanine compounds, oxonol compounds, squarylium
compounds, styryl compounds, and porphin compounds, in addition to
the cyanine compound of general formula (I). The optical recording
layer may further contain resins, such as polyethylene, polyester,
polystyrene, and polycarbonate; surface active agents; antistatic
agents; lubricants; flame retardants; radical scavengers, e.g.,
hindered amines; pit formation accelerators, e.g., ferrocene
derivatives; dispersants; antioxidants; crosslinking agents; light
resistance imparting agents; and so forth. The optical recording
layer may furthermore contain an aromatic nitroso compound, an
aluminum compound, an iminium compound, a bisiminium compound, a
transition metal chelate compound, and the like as a quencher for
singlet oxygen, etc. These various compounds are preferably used in
the optical recording layer in an amount of up to 75% by mass.
Accordingly, the content of these compounds in the optical
recording material of the invention is preferably up to 75% by mass
on a solid basis.
[0037] Materials of the substrate on which the optical recording
layer is provided is not particularly limited as long as it is
substantially transparent to writing (recording) light and reading
(reproducing) light and include resins, such as polymethyl
methacrylate, polyethylene terephthalate, and polycarbonate, and
glass. The substrate can have an arbitrary form, including a tape,
a drum, a belt, and a disk.
[0038] A reflective layer of gold, silver, aluminum, copper, etc.
may be formed on the optical recording layer by vacuum evaporation
or sputtering. A protective layer of an acrylic resin, an
ultraviolet cured resin, etc. may be provided on the optical
recording layer.
[0039] The optical recording material of the invention is suitable
to optical recording media using a semiconductor laser for writing
and reading, especially high-speed recording type optical disks
such as DVD-Rs.
EXAMPLES
[0040] The present invention will now be illustrated in greater
detail with reference to Examples and Evaluation Example, but it
should be understood that the invention is not construed as being
limited thereto.
[0041] Examples 1 to 7 show working examples of the optical
recording material of the present invention. In Evaluation Example,
the optical recording materials of the invention prepared in
Examples and the optical recording materials containing comparative
compounds were evaluated for high speed recording performance.
Example 1
Preparation of Hexafluorophosphate of Compound No. 4
[0042] In a reaction flask were put 0.050 mol of
1,2,3-trimethylbenzindole, 0.090 mol of 3-bromopentene, and 16.5 g
of ethanol and allowed to react at 62.degree. C. for 10 hours. The
reaction mixture was cooled to room temperature, and 40 ml of ethyl
acetate was slowly added thereto. The crystals thus precipitated
were collected by filtration and dried in vacuo at 80.degree. C.
for 2 hours to give an intermediate,
1,2,3-trimethyl-3-propenylbenzindolenium bromide, as white crystals
in a yield of 70.9%.
[0043] In a reaction flask were put 0.008 mol of indole derivative
A represented by formula shown below, 0.16 mol of pyridine, and
0.024 mol of acetic anhydride and stirred until the mixture became
uniform. To the mixture was added 0.008 mol of the intermediate
obtained above (1,2,3-trimethyl-3-propenylbenzindolenium bromide),
followed by stirring at room temperature for 17 hours. Fifty grams
of chloroform and a solution of 0.024 mol of potassium
hexafluorophosphate in 50 g of water were added to the reaction
mixture, followed by stirring at 50.degree. C. for 30 minutes to
effect salt exchange. The aqueous phase was discarded, and a
solution of 0.012 mol of potassium hexafluorophosphate in 50 g of
water was added to the organic phase, followed by stirring at
50.degree. C. for 30 minutes. The aqueous phase was discharged, and
a solution of 0.012 mol of potassium hexafluorophosphate in 50 g of
water was added, followed by stirring at 50.degree. C. for 30
minutes to complete salt exchange. The aqueous phase was removed,
and the residual organic phase was washed with four 50 g portions
of water and concentrated to give a residue. While heating the
residue, 100 g of methanol was added thereto to conduct
crystallization. The crystals were collected by filtration, washed
successively with methanol, 60.degree. C. water, and methanol, and
dried in vacuo at 110.degree. C. for 2 hours to give green crystals
in a yield of 43.1%. As a result of analyses, the resulting green
crystals were identified to be the title compound,
hexafluorophosphate of compound No. 4. The results of the analyses
are shown below.
##STR00019##
[0044] Optical characteristics (chloroform; 4.13.times.10 mol/l):
.lamda..sub.max598 nm; .epsilon.=1.20.times.10.sup.5
[0045] Molecular weight (TOF-mass spectrum): 628.6
[0046] .sup.1H-NMR (DMSO): FIG. 1
Example 2
Preparation of Hexafluorophosphate of Compound No. 5
[0047] In a reaction flask were put 0.02 mol of the intermediate
prepared in the same manner as in Example 1 (i.e.,
1,2,3-trimethyl-3-propenylbenzindolenium bromide), 0.01 mol of
N,N'-diphenylamidine, 0.2 mol of pyridine, and 0.03 mol of acetic
anhydride and stirred at 50.degree. C. for 10 hours. To the
reaction mixture were added 15.8 g of chloroform, 55 g of water,
and 0.03 mol of potassium hexafluorophosphate, followed by stirring
at 50.degree. C. for 0.5 hours to effect salt exchange. The aqueous
phase was discarded, and a solution of 0.014 mol of potassium
hexafluorophosphate in 50 g of water was again added to the organic
phase, followed by stirring at 50.degree. C. for 0.5 hours to
complete salt exchange. The aqueous phase was removed, and the
residual organic phase was washed with three 50 g portions of water
and concentrated to give a residue. While heating the residue, 15.8
g of methanol was added thereto to conduct crystallization. The
crystals were collected by filtration, washed successively with
methanol and 60.degree. C. water, and dried in vacuo at 120.degree.
C. for 3 hours to give green crystals in a yield of 58.0%. As a
result of analyses, the resulting green crystals were identified to
be the title compound, hexafluorophosphate of compound No. 5. The
results of the analyses are shown below.
[0048] Optical characteristics (chloroform; 6.11.times.10.sup.-6
mol/l): nm; .epsilon.=1.24.times.10.sup.5
[0049] Molecular weight (TOF-mass spectrum): 654.7
[0050] .sup.1H-NMR (DMSO): FIG. 2
Example 3
Preparation of Hexafluorophosphate of Compound No. 14
[0051] In a reaction flask were put 0.050 mol of
1,2,3-trimethylindole, 0.058 mol of 2-bromocyclohexene, and 16.0 g
of ethanol and caused to react at room temperature for 21 hours.
The reaction mixture was concentrated, and 30 ml of acetone was
slowly added to the residue. The crystals thus precipitated were
collected by filtration and dried in vacuo at 80.degree. C. for 2.5
hours to afford an intermediate,
1,2,3-trimethyl-3-cyclohexenylindolenium bromide, as white crystals
in a yield of 47.2%.
[0052] In a reaction flask were put 0.005 mol of indole derivative
A, 0.05 mol of pyridine, and 0.007 mol of acetic anhydride and
stirred until the mixture became uniform. To the mixture was added
0.005 mol of the intermediate obtained above
(1,2,3-trimethyl-3-cyclohexenylindolenium bromide), followed by
stirring at 50.degree. C. for 1 hour. Eight grams of chloroform was
added to the reaction mixture, and the resulting organic solution
was washed with 8 g of water. A solution of 0.0075 mol of potassium
hexafluorophosphate in 8 g of water was added thereto, followed by
stirring at 50.degree. C. for 0.5 hours to effect salt exchange.
The aqueous phase was discarded, and a solution of 0.0005 mol of
potassium hexafluorophosphate in 8 g of water was added to the
organic phase, followed by stirring at 50.degree. C. for 0.5 hours
to complete salt exchange. The aqueous phase was removed, and the
residual organic phase was washed with two 8 g portions of water
and concentrated. The resulting residue was dissolved in 4 g of
pyridine while hot, and 8 g of methanol was added thereto to
conduct crystallization. The crystals collected by filtration were
again dissolved in pyridine while hot and recrystallized from
methanol and dried in vacuo at 140.degree. C. for 2 hours to give
green crystals in a yield of 27.8%. As a result of analyses, the
resulting green crystals were identified to be the title compound,
hexafluorophosphate of compound No. 14. The results of the analyses
are shown below.
[0053] Optical characteristics (chloroform; 1.22.times.10.sup.-5
mol/l): .lamda..sub.max=578 nm; .epsilon.=1.26.times.10.sup.5
[0054] Molecular weight (TOF-mass spectrum): 618.7
[0055] .sup.1H-NMR (DMSO): FIG. 3
Example 4
Preparation of Hexafluorophosphate of Compound No. 19
[0056] In a reaction flask were put 0.150 mol of
1,2,3-trimethylbenzindole, 0.195 mol of 4-bromo-2-butene, and 103 g
of ethanol and allowed to react at 48.degree. C. for 2 hours. The
reaction mixture was concentrated. The residue was dissolved in 10
ml of methanol, and 100 g of ethyl acetate was added thereto to
precipitate crude crystals, which were collected by filtration and
dissolved in 19 g of methanol and recrystallized by the addition of
50 g of ethyl acetate. The crystals were dried in vacuo at
80.degree. C. for 2.5 hours to give an intermediate,
1,2,3-trimethyl-3-butenylbenzindolenium bromide, as white crystals
in a yield of 34.1%.
[0057] In a reaction flask were put 0.0094 mol of indole derivative
B represented by formula shown below, 0.1 mol of pyridine, and
0.014 mol of acetic anhydride and stirred until the mixture became
uniform. To the mixture was added 0.01 mol of the intermediate
obtained above (1,2,3-trimethyl-3-butenylbenzindolenium bromide),
followed by stirring at 40.degree. C. for 2.5 hours. Ten grams of
chloroform was added to the reaction mixture, and the resulting
organic solution was washed with 10 g of water. A solution of
0.0025 mol of potassium hexafluorophosphate in 10 g of water was
added to the solution, followed by stirring at 40.degree. C. for
0.5 hours to effect salt exchange. The aqueous phase was discarded,
and the organic phase was again washed with two 10 g portions of
water and concentrated to give a residue. The residue was heated,
and 16 g of ethyl acetate was added thereto to conduct
crystallization. The crystals were collected by filtration and
dried in vacuo at 120.degree. C. for 2 hours to give green crystals
in a yield of 48.8%. As a result of analyses, the resulting green
crystals were identified to be the title compound,
hexafluorophosphate of compound No. 19. The results of the analyses
are shown below.
##STR00020##
[0058] Optical characteristics (chloroform; 7.64.times.10 mol/l):
.lamda..sub.max=583 nm; .epsilon.=1.34.times.10.sup.5
[0059] Molecular weight (TOF-mass spectrum): 634.7
[0060] .sup.1H-NMR (DMSO): FIG. 4
Example 5
Preparation of Hexafluorophosphate of Compound No. 40
[0061] In a reaction flask were put 0.080 mol of
1,2,3-trimethylbenzindole, 0.080 mol of bromomethylnaphthalene, and
68.9 g of ethanol and caused to react at 30.degree. C. for 3 hours.
The reaction mixture was filtered, and the filtrate was
concentrated. The residue was dissolved in 10 ml of methanol while
hot, and 50 g of ethyl acetate was added thereto to precipitate
crude crystals. The crude crystals were dissolved in 83 g of
methanol, the solution heated, and 62 g of ethyl acetate added to
perform crystallization. The resulting crude crystals were again
recrystallized using methanol and ethyl acetate in the same manner
as above. The crystals were dried in vacuo at 80.degree. C. for 2
hours to furnish an intermediate,
1,2,3-trimethyl-3-naphthylmethylbenzindolenium bromide, as white
crystals in a yield of 35.8%.
[0062] In a reaction flask were put 0.004 mol of indole derivative
B, 0.08 mol of pyridine, and 0.0056 mol of acetic anhydride and
stirred at 50.degree. C. until the mixture became uniform. To the
mixture was added 0.004 mol of the intermediate obtained above
(1,2,3-trimethyl-3-naphthylmethylbenzindolenium bromide), followed
by stirring at 50.degree. C. for 2 hours. To the reaction mixture
was added 6.3 g of chloroform, and the resulting organic solution
was washed with 12.6 g of water. A solution of 0.012 mol of
potassium hexafluorophosphate in 15 g of water was added to the
solution, followed by stirring at 50.degree. C. for 1.5 hours to
effect salt exchange. The reaction mixture was filtered, and the
collected crystals were dried in vacuo at 180.degree. C. for 2
hours to give green crystals in a yield of 51.7%. As a result of
analyses, the resulting green crystals were identified to be the
title compound, hexafluorophosphate of compound No. 40. The results
of the analyses are shown below.
[0063] Optical characteristics (chloroform; 4.09.times.10.sup.-6
mol/l): .lamda..sub.max=602 nm; .epsilon.=1.21.times.10.sup.5
[0064] Molecular weight (TOF-mass spectrum): 728.8
[0065] .sup.1H-NMR (DMSO): FIG. 5
Example 6
Preparation of Hexafluorophosphate of Compound No. 41
[0066] In a reaction flask were put 0.01 mol of
1,2,3-trimethyl-3-naphthylmethylbenzindolenium bromide obtained in
the same manner as in Example 5, 0.006 mol of N,N'-diphenylamidine,
and 0.10 mol of pyridine and stirred at 90.degree. C. for 4 hours.
After cooling to room temperature, 0.014 mol of acetic anhydride
was added to the reaction mixture, followed by stirring at
60.degree. C. for 2 hours. To the reaction mixture were added 8.0 g
of chloroform, 16 g of water, and 0.02 mol of potassium
hexafluorophosphate, followed by stirring at 50.degree. C. for 0.5
hours to cause salt exchange. The aqueous phase was discarded, and
a solution of 0.005 mol of potassium hexafluorophosphate in 16 g of
water was added to the organic phase, followed by stirring at
50.degree. C. for 0.5 hours to complete salt exchange. The aqueous
phase was discharged, and the organic phase was washed with two 16
g portions of water and concentrated. The residue was dissolved in
8 g of pyridine while hot, and 16 g of methanol was added thereto
to precipitate crystals, which were collected by filtration and
dissolved in pyridine while hot and recrystallized from methanol.
The crystals were further recrystallized from a mixture of 5 g of
pyridine and 2.5 g of water and dried in vacuo at 175.degree. C.
for 2 hours to give green crystals in a yield of 10.5%. As a result
of analyses, the resulting green crystals were identified to be the
title compound, hexafluorophosphate of compound No. 41. The results
of the analyses are shown below.
[0067] Optical characteristics (chloroform; 4.68.times.10.sup.-6
mol/l): .lamda..sub.max=609 nm; .epsilon.=1.22.times.10.sup.5
[0068] Molecular weight (TOF-mass spectrum): 854.9
[0069] .sup.1H-NMR (DMSO): FIG. 6
Example 7
Preparation of Hexafluorophosphate of Compound No. 48
[0070] In a reaction flask were put 0.020 mol of
1,2,3-trimethylbenzindole, 0.020 mol of 2-nitro-5-bromomethylfuran,
and 17.2 g of ethanol and caused to react at 60.degree. C. for 5
hours. The reaction mixture was concentrated, and 32 g of butyl
acetate was added to the residue, and the mixture was heated to
70.degree. C., followed by cooling. The crystals thus precipitated
were collected by filtration and dried in vacuo at 120.degree. C.
for 2 hours to give an intermediate,
1,2,3-trimethyl-3-(5-nitrofuran-2-ylmethyl)benzindolenium bromide,
as pale yellow crystals in a yield of 76.7%.
[0071] In a reaction flask were put 0.005 mol of indole derivative
A, 0.10 mol of pyridine, and 0.007 mol of acetic anhydride and
stirred at 45.degree. C. until the mixture became uniform. To the
mixture was added 0.005 mol of the intermediate obtained above,
followed by stirring at 45.degree. C. for 4 hours. Eight grams of
chloroform was added to the reaction mixture, and the resulting
organic solution was washed with 15 g of water, and a solution of
0.015 mol of potassium hexafluorophosphate in 15 g of water was
added thereto, followed by stirring at 45.degree. C. for 0.5 hours
to effect salt exchange. The aqueous phase was discarded, and a
solution of 0.005 mol of potassium hexafluorophosphate in 15 g of
water was again added to the organic phase, followed by stirring at
45.degree. C. for 0.5 hours to complete salt exchange. The aqueous
phase was removed, and the residual organic phase was washed with
two 15 g portions of water and concentrated. The resulting residue
was crystallized from 10 g of methanol. The resulting crude
crystals were dissolved in 24 g of pyridine while hot, and 8 g of
water was added. The precipitated solid phase was separated by
filtration. The filtrate was concentrated. The residue was
dissolved in 5 g of pyridine while hot, and 5 g of methanol was
added to cause crystallization. The crystals were collected by
filtration were dried in vacuo at 120.degree. C. for 2.5 hours to
give purple crystals in a yield of 1.4%. As a result of analyses,
the resulting purple crystals were identified to be the title
compound, hexafluorophosphate of compound No. 48. The results of
the analyses are shown below.
[0072] Optical characteristics (chloroform; 5.68.times.10 mol/l):
.lamda..sub.max=600.5 nm; .epsilon.=1.05.times.10.sup.5
[0073] Molecular weight (TOF-mass spectrum): 713.7
[0074] .sup.1H-NMR (DMSO): FIG. 7
Evaluation Example
[0075] Some of the cyanine compounds obtained in the foregoing
Examples and comparative compounds 1 to 3 shown below were
subjected to differential thermal analysis in a nitrogen stream to
measure heat decomposition temperature. The heat decomposition
temperature was expressed by the exothermic peak top temperature of
DTA at a temperature rise of 10.degree. C./min in nitrogen. The
results are shown in Table 1.
TABLE-US-00001 TABLE 1 Comparative Compound 1 ##STR00021##
Comparative Compound 2 ##STR00022## Comparative Compound 3
##STR00023## Cyanine Compound Heat Decomposition Example No. Cation
Anion Temperature (.degree. C.) 2 compound No. 5 PF.sub.6.sup.-
198.9 3 compound No. 14 PF.sub.6.sup.- 200.2 4 compound No. 19
PF.sub.6.sup.- 204.6 5 compound No. 40 PF.sub.6.sup.- 215.3 7
compound No. 48 PF.sub.6.sup.- 203.6 -- comparative compound 1
(anion: 282.5 PF.sub.6.sup.-) -- comparative compound 2 (anion:
292.0 PF.sub.6.sup.-) -- comparative compound 3 (anion: 227.1
PF.sub.6.sup.-)
[0076] It is confirmed from the results in Table 1 that the cyanine
compounds of the invention represented by general formula (I) have
low heat decomposition temperatures. This indicates that the
optical recording material of the invention which contains the
cyanine compound of general formula (I) is suitable for high-speed
recording.
[0077] Optical recording media were fabricated by forming a thin
film on a substrate using each of the compounds prepared in
Examples. As a result, all the optical recording materials were
proved capable of high-speed recording compared with conventional
optical recording media.
INDUSTRIAL APPLICABILITY
[0078] The present invention provides an optical recording material
and an optical recording medium that exhibit performance properties
suited to high-speed optical recording applications.
* * * * *