Cyanine dyes

Details Cyanine dyes Cyanine dyes

1999-09-10

2001-07-10

Chea, Thorl (Department: 1752)

Radiation imagery chemistry: process, composition, or product th

Radiation sensitive product

Silver compound sensitizer containing

C430S543000, C430S585000

Reexamination Certificate

active

06258523

ABSTRACT:

This invention relates to cyanine dyes according to the formula (I), and to a colour photographic material which contains cyanine dyes of the formula (I) and to the use of compounds of the formula (I) as spectral sensitisers.
Improving the spectral sensitivity of photographic materials is a constant challenge. By using polymethine dyes, it is possible to extend sensitivity beyond the intrinsic sensitivity range. Cyanines are particularly suitable for this purpose. DE 1 053 309 discloses spectral sensitisers having a thienyl substituent on the benzene ring, which give rise to good spectral sensitivities on silver halide emulsions.
There is, however, a requirement for spectral sensitisers which have increased spectral sensitivity, especially when used in tab-grain emulsions.
The object of the present invention is to provide cyanine dyes which are distinguished by particularly elevated spectral sensitivity and simultaneously by good storage stability, in particular under tropical conditions.
It has surprisingly been found that cyanine dyes of the formula (I), in which at least one of the substituents R
1
, R
2
or R
3
denotes benzothienyl, have excellent spectral sensitivity accompanied by good storage stability, in particular under tropical conditions.
The present application provides cyanine dyes of the formula (I)
in which
R
1
, R
2
, R
3
, R
4
, R
5
, R
6
mutually independently mean H, a substituent or R
5
together with R
6
or R
4
together with R
5
mean the remaining members to complete an optionally substituted fused benzo ring or naphtho ring system, providing that at least one of the substituents R
1
, R
2
or R
3
is a benzothienyl substituent,
X denotes O, S, Se, CH=CH, C(CH
3
)
2
or NR
7
(R
7
=optionally substituted alkyl),
S
1
, S
2
mutually independently mean alkyl, sulfoalkyl, carboxyalkyl, —(CH
2
)
1
—SO
2
—Y—SO
2
-alkyl, —(CH
2
)
1
—SO
2
—Y—CO-alkyl, —(CH
2
)
1
—CO—Y—SO
2
-alkyl, —(CH
2
)
1
NHSO
−
3
, —(CH
2
)
1
N(alkyl)SO
−
3,
—(CH
2
)
1
N(aryl)SO
−
3
, —(CH
2
)
1
—CO—Y—CO-alkyl, providing that 1 means 1 to 6 and Y means NH or N
−
,
n means 3, 5 or7,
L denotes substituted or unsubstituted methine groups, which may be constituents of one or more carbocyclic rings, and
M denotes a counterion optionally necessary to equalise charges.
The benzothienyl residue may be attached to the benzo ring via position 2, 3, 4, 5, 6 or 7.
For the purposes of the present application, unless otherwise defined, a substituent should be taken to mean halogen, in particular fluorine, chlorine or bromine, alkyl, alkoxy, aryl, aryloxy, hetaryl and alkenyl substituents as well as CF
3
, CN or, where X=S, a benzothienyl substituent, which is attached via position 2, 3, 4, 5, 6 or 7 to the benzo ring.
For the purposes of the present application, alkyl should be taken to mean linear or branched, cyclic or linear, substituted or unsubstituted hydrocarbon groups, preferably alkyl groups having 1 to 20 C. atoms, in particular 1 to 6 C. atoms; open-chain alkyl groups which may be considered are in particular methyl, ethyl, n-propyl, n-butyl and n-pentyl while branched alkyl residues which may be considered are in particular methyl- or ethyl-branched.
For the purposes of the present invention, alkenyl should be taken to mean linear or branched, cyclic or linear, substituted or unsubstituted unsaturated hydrocarbon residues, such as for example ethenyl, 2-propenyl.
For the purposes of the present application, aryl should be taken to mean aromatic hydrocarbon groups, wherein they preferably comprise 5- or 6-membered ring systems, which may be in the form of monocyclic or also fused ring systems. These may comprise both substituted and unsubstituted ring systems. Phenyl and naphthyl groups are, for example, particularly preferred.
For the purposes of the present application, unless otherwise defined, hetaryl should be taken to mean aromatic systems which contain at least one heteroatom. These may comprise both substituted and unsubstituted ring systems. Typical examples are pyridine, pyridazine, pyrimidine, pyrazines, oxazole, isoxazole, thiazoles, 3,4-oxadiazole, 1,2,4-oxadiazole, imidazole, indole, 1,2,3-triazole, 1,2,4-triazole; particularly preferred heterocyclic substituents are 2-furanyl, 3-furanyl, pyrrolyl, 2-thienyl, 3-thienyl and indolyl.
For the purposes of the present application, alkoxy should be taken to mean substituents of the formula OR in which the R denotes an alkyl residue having the meaning stated above. Such substituents comprise, for example, methoxy, ethoxy, propoxy or butoxy substituents.
For the purposes of the present application, aryloxy should be taken to mean substituents of the formula OR, in which the R denotes an aryl residue having the meaning stated above. Such substituents comprise, for example, phenoxy or naphthoxy substituents.
For the purposes of the present invention, unless otherwise defined, counterions M which may be considered, depending upon the substituents and thus charge relationships, are for example the following compounds: tosylate, I
−
, Br
−
, Cl
−
, preferably diazabicyclooctane-H
+
(DABCOH
+
) or diazabicycloundecane-H
+
(DBUH
+
), in particular Na
+
, Li
+
, K
+
and particularly preferably Et
3
N
+
H.
n denotes 7, preferably 5, in particular 3,
L may, for example, denote=C− or, as a constituent of a ring system
The following combinations may arise from the above:
for
for
or perferably
or
For n=
5

or perferably
for n=
7

or perferably
R and R′ preferably denote H, aryl or alkyl and R″ denotes H, halogen, N-tetrahydro-pyrrolyl, N-piperidinyl, N-(alkyl)
2
, N-(aryl)
2
or S-alkyl.
Sensitisers which are preferably to be used according to the present invention are listed below:
In the formulae I-1 to I-26, “Me” means methyl, “Et” means ethyl, “Ph” means phenyl and “TosO
−
” means toluenesulfonate.
Synthesis of dye I-11
6 was synthesised in a similar manner to the methods described in
J Heterocyclic Chem.,
25, 1437 (1988). Catalytic hydrogenation to yield
7
proceeded in an autoclave with Ra-Ni as catalyst.
8
was formed from
7
in a similar manner to a method described in
Chem. Ber.,
36, 3121 (1903). Saponification of
8
with aqueous alkali and subsequent acetylation gives rise to the diacetyl compound
9
, which is thermally cyclised at 180-200° C. to yield the thiazole base
10
.
Synthesis of the quaternary salt 11
1.41 g (5 mmol) of 10 and 0.61 g (5 mmol) of 1,3-propanesultone are stirred for 8 hours at 150° C. in 4 ml of dichlorobenzene. After cooling to room temperature, 20 ml of acetone is added, the mixture is briefly brought to boiling, is suction filtered once cool and thoroughly rewashed with acetone. The residue is decocted in 20 ml of methanol.
Yield: 1.63 g (81% of theoretical)
Synthesis of dye I-11
1.61 g (4 mmol) of 11 are dissolved in 10 ml of m-cresol with heating and, at an internal temperature of approx. 100° C., combined with 5.29 g (30 mmol) of ortho-propionic acid triethyl ester and stirred for 30 minutes at 95° C. After cooling to room temperature, a solution of 1.61 g (4 mmol) of 11, dissolved in 10 ml of m-cresol, is added and 1.78 ml (12.8 mmol) of triethylamine are apportioned at room temperature within 5 minutes. After 2 hours' stirring at 90° C., the mixture is allowed to cool to room temperature and stirring is continued for a further 2 hours. The dye solution is introduced into 75 ml of acetone within 45 minutes. The dye solution is left to crystallise overnight, suction filtered and thoroughly rewashed with acetone. The crude dye is dissolved in 60 ml m-cresol with heating, hot-filtered and combined with 180 ml of acetone. The dye is left to crystallise overnight, is suction filtered and thoroughly washed with acetone. After drying to constant weight under a vacuum at 50° C., 1.55 g (41% of theoretical) of dye is obtained.
The cyanines according to the invention may also be produced by using the synthesis methods which are described in “

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