Photographic silver halide material

Details Photographic silver halide material Photographic silver halide material

2001-07-26

2002-12-24

Letscher, Geraldine (Department: 1752)

Radiation imagery chemistry: process, composition, or product th

Radiation sensitive product

Silver compound sensitizer containing

C430S566000, C430S567000, C430S570000, C430S572000, C430S607000, C430S613000, C430S614000

Reexamination Certificate

active

06498003

ABSTRACT:

The invention relates to a photographic material comprising a support and at least one layer which comprises at least one spectrally sensitised silver halide emulsion.
It is known that spectrally sensitised emulsions can be supersensitised by depositing compounds apart from sensitisers, particularly additional dyes, on the surface of the silver halide crystals, which compounds are capable of increasing the spectrally sensitised sensitivity. Ascorbic acid is a typical example of such compounds. Other suitable compounds are disclosed in U.S. Pat. Nos. 2,945,762, 3,695,888, 3,809,561 and 4,011,083. The supersensitisation of silver halide emulsions with catechol sulphonic acids is also known. The aforementioned compounds do have a supersensitising effect, but result in an unwanted increase in fogging.
U.S. Pat. No. 5,457,022 describes supersensitisation by metallocenes. These are aromatic transition metal complexes of cyclopentadiene and derivatives thereof which have a characteristic “sandwich structure” without a direct metal-carbon &sgr; bond. The best known of these compounds are bis-(cyclopentadienyl)iron (ferrocene) and derivatives thereof. One disadvantage is that supersensitisation with ferrocenes results either in an unsatisfactory increase in sensitivity or is associated with an increase in fogging, during storage at the latest, due to which any increase in sensitivity is lost again.
With these known measures, however, no success has been achieved in obtaining photographic materials such as those which are required nowadays and which comprise a very high spectral sensitivity together with reduced fogging and a good shelf life, particularly when they are stored under humid climatic conditions.
The underlying object of the present invention is thus to identify photographic materials of increased spectral sensitivity which furthermore are distinguished by a high sensitivity/fogging ratio and by a good shelf life, particularly when stored under humid climatic conditions.
It has surprisingly been found that this object can be achieved by the addition of certain amino(1,2,4)-triazole compounds.
The present invention therefore relates to a photographic material comprising a support and at least one layer which comprises at least one spectrally sensitised silver halide emulsion layer, characterised in that the material contains at least one compound of formulae
and/or
wherein
R
1
denotes H, alkyl, aryl, aralkyl, alkenyl, heterocyclyl,
R
2
denotes OH, NH
2
, NHR
7
, NR
8
R
9
or
R
1
together with R
2
, denotes the atoms necessary for the completion of a heteroaliphatic ring,
R
3
denotes OH, NH
2
, NHR
7
, NR
8
R
9
,
R
4
denotes H, alkyl, aryl, aralkyl, alkenyl, heterocyclyl,
R
5
, R
6
independently of each other, denote OH, NH
2
, NHR
10
, NR
11
R
12
, or
R
4
together with R
5
, or R
4
together with R
6
, denote the atoms necessary for the completion of a heteroaliphatic ring, and the R
5
or R
6
radical, which is not part of a ring, denotes OH, NH
2
, NHR
10
or NR
11
R
12
,
R
7
, R
10
denote alkyl, aryl, aralkyl, heterocyclyl,
R
8
, R
9
independently of each other, denote alkyl, aryl, aralkyl, heterocyclyl, or
R
8
together with R
9
, denotes the atoms necessary for the completion of a heteroaliphatic ring, and
R
11
, R
12
independently of each other, denote alkyl, aryl, aralkyl, heterocyclyl, or
R
11
together with R
12
, denotes the atoms necessary for the completion of a heterocyclic ring, and
wherein only one of the radicals R
2
and R
3
and only one of the radicals R
5
and R
6
can denote OH or NH
2
.
Of the possible rings formed from the radicals R
8
with R
9
, R
11
with R
12
, R
1
with R
2
and R
4
with R
5
or with R
6
, 5- and 6-membered ring are preferred, particularly six-membered rings which also contain an oxygen or sulphur atom in the ring, as well as five-membered rings which also contain a condensed-on aromatic compound. In one particularly advantageous embodiment, the ring formed from these radicals is a pyrrolidine, piperidine, perhydroazepine, piperazine, morpholine or thiomorpholine ring.
The alkyl, aralkyl and alkenyl radicals in the sense of the present invention can be straight chain, branched or cyclic radicals. The alkyl and alkenyl radicals can be substituted by aryl, heterocyclyl, hydroxy, carboxy, halogen, alkoxy, aryloxy, heterocyclyloxy, alkylthio, arylthio, heterocyclylthio, alkylseleno, arylseleno, heterocyclylseleno, acyl, acyloxy, acylamino, cyano, nitro, amino, thione or mercapto groups, and the aryl, aralkyl, and heterocyclyl radicals can be substituted by alkyl, aryl, heterocyclyl, hydroxy, carboxy, halogen, alkoxy, aryloxy, heterocyclyloxy, alkylthio, arylthio, heterocyclylthio, alkylseleno, arylseleno, heterocyclylseleno, acyl, acyloxy, acylamino, cyano, nitro, amino, thione or mercapto groups, wherein the term “heterocyclyl” represents a saturated, unsaturated or aromatic heterocycle and the term “acyl” represents the radical of an aliphatic, olefinic or aromatic carboxylic, carbamic, carbonic, sulphonic, amidosulphonic, phosphoric, phosphonic, phosphorous phosphinic or sulphinic acid.
In addition to the preferred possibility of its forming a ring together with R
2
, R
1
can also preferably be H or alkyl, particularly H or methyl, and particularly advantageously is H.
In another particularly preferred embodiment, R
5
denotes NHR
10
and R
10
forms an heteroaliphatic ring, particularly a 5- or 6-membered ring, with R
4
.
In another advantageous embodiment, R
2
or R
3
, or R
5
or R
6
, preferably denotes H or NH
2
.
In a further preferred embodiment, R
8
and R
9
or R
11
and R
12
are identical alkyl radicals, and in particular denote methyl.
Compounds of formula Ia are preferred to those of formula Ib.
Compounds of formula I (compounds I) are hereinafter to be understood to include both those of formula Ia and those of formula Ib.
Examples of preferred compounds of formula I are given below:
Compounds I-3 to I-9 as well as compound I-31, are particularly preferred.
The production of aminotriazole compounds I has been extensively described, for example by the replacement of halogen atoms by amino groups as described in DDR Patent 59 288, or by the replacement of hetero atoms, particularly O or S atoms, via ring opening, as described by Oliver, Chang, Brown et al., in J. Med. Chem. 15, 315-320 [1972]. One typical method for the production of diaminotriazoles which are only substituted on one side with amino groups is described by Ried, Broft, Bats; Chem. Ber. 116, 1547-1563 [1983]. A review of the existing options is given in “The Chemistry of Heterocyclic Compounds—A Series of Monographs” (A. Weissberger, E. C. Taylor, Eds., John Wiley & Sons, New York 1981; Volume 37, Triazoles 1,2,4, pages 205-224, and an early source is the article by E. Fromm and A. Weller in Liebigs Ann. Chem. 361, 304-319.
The compounds of formula I can be hydrophobic, or, in the presence of anionisable groups, for example, can be hydrophilic. Moreover, in one preferred embodiment they can contain specific groups which improve their adsorption on silver halides, e.g. thioether, selenoether, thione, thiol or amine radicals.
The preferred compounds of formula I are characterised in that their redox potential in aqueous solution within the pH range between 5 and 7 differs by no more than +/−100 mV from the standard potential of the hydrogen electrode. The redox potential of a compound I can generally readily be determined by cyclic voltammetry.
Compounds I can be added to the material at any point, in a preferred amount of 10
−6
to 10
−2
mol, particularly 10
−5
to 10
−2
mol per mol of total silver halide. This applies in particular to substances of low molecular weight which are capable of migrating within the layer composite. Compound I is preferably used in an amount of 10
−6
to 10
−2
mol, particularly 10
−5
to 10
−3
mol, per mol of layer silver halide, in the same layer which also contains the spectrally sensitised silver halide emulsion. Compound I is m

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