Cyanine dyes

Details Cyanine dyes Cyanine dyes

1999-09-29

2001-04-24

Chea, Thorl (Department: 1752)

Radiation imagery chemistry: process, composition, or product th

Radiation sensitive product

Silver compound sensitizer containing

C430S574000, C430S584000, C430S585000, C430S592000

Reexamination Certificate

active

06221574

ABSTRACT:

This invention relates to cyanine dyes of 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. It is known to use polymethine dyes, to extend sensitivity beyond the intrinsic sensitivity range of the silver halide used. Cyanine dyes are particularly suitable for this purpose.
Cyanines containing benzoxazole comprise one group of cyanine dyes which has been thoroughly investigated. Numerous different cyanines containing benzoxazole are known and are conventionally used in colour photographic materials.
EP 0 599 383 discloses cyanine dyes which, as a constituent of silver halide emulsion layers, in particular avoid the formation of colour spots after processing when tab-grain emulsions are used. These comprise cyanine dyes, the benzo ring of which is linked with a furanyl or pyrrolyl substituent.
There is thus a requirement for cyanine dyes which both have increased spectral sensitivity, especially when used in tab-grain emulsions, and have good storage stability, especially after storage at elevated temperature and elevated humidity.
The object of the present invention is to provide cyanine dyes which are distinguished by particularly elevated spectral sensitivity and simultaneously by good long term storage stability, in particular under tropical conditions.
It has surprisingly been found that cyanine dyes containing benzoxazole according to the formula (I) and having at least one indolyl substituent have outstanding spectral sensitivity combined with good storage stability, in particular under tropical conditions. It has additionally proved possible distinctly to increase the spectral sensitivity of tab-grain emulsions.
The present application provides cyanine dyes of the formula (I)
in which
R
1
, R
2
, R
3
, R
4
, R
5
and R
6
mutually independently denote a substituent, providing that at least one of the residues R
1
, R
2
, R
3
denotes an indolyl substituent,
X denotes O, S, Se, NR
9
, CH═CH or C(CH
3
)
2
, wherein R
9
denotes a optionally substituted alkyl residue,
R
7
, R
8
mutually independently denote 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
—CO—Y—O—alkyl or —(CH
2
)
1
—NH—SO
3
—, —(CH
2
)
1
—N(alkyl)—SO
3
— or —(CH
2
)
1
—N(aryl)—SO
3
—, providing that l=1 to 6 and Y means NH or N
−
,
n means 1, 3, 5, 7,
L denotes a substituted or unsubstituted methine group, which may be a constituent of one or more carbocyclic rings, and
M denotes a counterion optionally necessary to equalise charges.
For the purposes of the present application, unless more specifically defined, a substituent should be taken to mean, for example, H, halogen, preferably F, Cl or Br, aryl, hetaryl, alkyl, alkenyl, OR
10
, wherein R
10
denotes C
1
, to C
6
alkyl, in particular methyl, ethyl and propyl. A substituent may, however, furthermore comprise fused ring systems, which are optionally substituted. For example, a fused ring system may be formed by R
6
with R
5
or R
5
with R
4
. Fused ring systems should preferably be taken to mean benzo or naphtho ring systems.
For the purposes of the present application, alkyl should be taken to mean linear or branched, cyclic or straight-chain, 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. Alkyl may moreover comprise partially or completely halogenated alkyl groups as substituents, such as in particular CF
3
or —CH
2
CF
2
CF
2
H.
For the purposes of the present invention, alkenyl should be taken to mean linear or branched, cyclic, substituted or unsubstituted unsaturated hydrocarbon residues, such as for example ethenyl, 2-propenyl.
For the purposes of the present application, unless otherwise defined, 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. Substituents which may be considered are the compounds already mentioned, preferably halogen, alkyl and OR
10
with the above-stated meaning.
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, 1,2,3-triazole, 1,2,4-triazole; particularly preferred heterocyclic substituents are 2-furanyl, 3-furanyl, N-pyrrolyl, 2-pyrrolyl, 3-pyrrolyl, 2-thienyl, 3-thienyl and N-indolyl.
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 1 or 3.
L may, for example, denote ═C— or, as a constituent of a ring system
The following combinations for
may arise from the above: for n=1, ═C— is preferred, for n=3
or preferably
wherein R and R′ preferably denote H or alkyl and R″ denotes H, halogen, N(alkyl)
2
, N(aryl)
2
, 5-membered nitrogenous heterocyclics, such as pyrrole or pyrrolidine or S-alkyl. For n=7
residues R, R′ and R″ are defined as already stated above.
Particularly preferred compounds of the formula (I) are the compounds of the formulae (Ia), (Ib) and (Ic) listed below:
in which
X
a
, X
b
and X
c
denote O, S, Se, NR
9
, CH═CH or C(CH
3
)
2
, wherein R
9
denotes an optionally substituted alkyl residue; preferably, X
a
denotes S, O, X
b
denotes O, S, N—C
2
H
5
, Se and X
c
denotes S, Se or O,
R
11
to R
16
and R
18
R
20
denote a substituent, preferably H, halogen, in particular F, Cl or Br, a substituted or unsubstituted 1-, 2- or 3-pyrrolyl, 2- or 3-thienyl, N-indolyl, phenyl or 2- or 3-furanyl residue, alkyl, preferably having 1 to 6 C atoms, in particular methyl, ethyl or propyl,
R
11
and R
12
or R
12
and R
13
or R
14
and R
15
or R
15
and R
16
or R
18
and R
19
or R
19
and R
20
may be a constituent of a fused benzo or naphtho ring,
R
17
denotes H, CH
3
or C
2
H
5
R
21
preferably denotes halogen, in particular Cl, as well as N(alkyl)
2
, N-piperidinyl, N-pyrrolidinyl, N-pyrrolyl, as well as S-alkyl, in particular SCH
3
or S(CH
2
)
m
COOH, providing that m denotes 1, 2, 3, 4, 5 or 6,
R
22
and R
23
denote H or alkyl, in particular methyl, or carboxylic acid or carboxylic acid ester residues,
R
7
and R
8
have the above-stated meaning and mutually independently preferably denote ethyl, sulfoethyl, sulfopropyl, sulfobutyl, 3-methylsulfopropyl and
M may, where required, denote a counterion, preferably Na
+
, EtN
+
H, tosylate and I
−
.
A typical list of particularly preferred compounds according to the present invention is shown below:
In the formulae I-1 to I-15, “Et” means C
2
H
5
and “Ph” means phenyl.
The cyanine dyes according to the invention may be synthesised in an analogous manner to production processes known from the literature:
Synthesis of Dye (I)-16
3 was synthesised from 1 and 2 in an analogous manner to the method described in
J. Chem. Soc., Perkin Trans.,
1989, 240

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