Heat development of elements containing methine-dye releasing couplers

A heat-developable photographic color diffusion transfer element comprising a dimensionally stable support and one or more layers comprising radiation sensitive silver halide, an organic silver salt oxidizing agent, a reducing agent, a methine-dye releasing compound, a thermal solvent for facilitating the thermal diffusion of methine-dye through hydrophilic binder, and a hydrophilic binder, wherein said methine-dye is heat diffusible in said binder and thermal solvent, and wherein said methine-dye releasing compound is of the structure

• Cp--L--M (I)
• where
• Cp is a coupler radical substituted in the coupling position with a divalent linking group, L;
• M is a methine-dye radical exhibiting selective absorption in the visible spectrum;
• and where the --L--M group couples off upon reaction of said coupler radical with the oxidation product of a primary amine developing agent;
• and
• where
• said methine-dye radical M is given by structure (II):
• ##STR28## wherein R.sup.1 is hydrogen or a substituted or unsubstituted alkyl, aryl, or heteroaryl group;
• A is a substituted or unsubstituted aryl or heteroaryl ring;
• each R.sup.2 is independently a substituted or unsubstituted alkyl group which may form a ring with Z' or Z when n=O;
• p is an integer from 0 to 3;
• each Z, Z', and Y' is independently hydrogen or a substituent;
• Y is an electron withdrawing group;
• n is 0, 1, or 2;
• and
• B is a heterocycle having the formula (III):
• ##STR29## wherein:
• X is O, S, or N(R.sup.5) where R.sup.5 is hydrogen or alkyl;
• W is N or C(R.sup.4) where R.sup.4 is hydrogen or a substituent;
• R.sup.3 is a substituent linked to the heterocycle by a carbon or nitrogen atom of the substituent;
• provided that R.sup.3 and R.sup.4 may be linked to form a ring.

A heat-developable photographic color diffusion transfer element comprising a dimensionally stable support and one or more layers comprising radiation sensitive silver halide, an organic silver salt oxidizing agent, a reducing agent, a methine-dye releasing compound, a thermal solvent for facilitating the thermal diffusion of methine-dye through hydrophilic binder, and a hydrophilic binder, wherein said methine-dye is heat diffusible in said binder and thermal solvent, and wherein said methine-dye releasing compound is of the structure

• Cp--L--M (I)
• where
• Cp is a coupler radical substituted in the coupling position with a divalent linking group, L;
• M is a methine-dye radical exhibiting selective absorption in the visible spectrum;
• and where the --L--M group couples off upon reaction of said coupler radical with the oxidation product of a primary amine developing agent, and where said methine-dye radical M is released from said --L--M group subsequent to the coupling off of said --L--M group;
• and
• where
• said linking group L comprises at least one of L-2, L-3, L-4, L-5, L-6, L-7, L-8, L-9, L-10, L-11, L-12, L-13, and L-14:
• ##STR30## where n is 0 or 1;
• ##STR31## where n is 0 or 1;
• ##STR32## wherein Z.sub.1 is ##STR33## where X is a substituent;
• Z.sub.2 is ##STR34## Z.sub.3 is ##STR35## where X is a substituent;
• R.sub.1 is hydrogen, alkyl of 1 to 20 carbon atoms, or aryl of 6 to 30 carbon atoms;
• each R.sub.2 independently is hydrogen, alkyl of 1 to 25 carbon atoms, cycloalkyl, substituted cycloalkyl, or aryl of 6 to 30 carbon atoms;
• X.sub.1 is hydrogen, cyano, fluoro, chloro, bromo, iodo, nitro, alkyl of 1 to 20 carbon atoms, aryloxy, alkoxycarbonyl, hydroxy, sulfonyl, acyl, alkoxy, sulfo, --OR.sub.2, --COOR.sub.2, --CONHR.sub.2, --NHCOR.sub.2, --NHSO.sub.2 R.sub.2, --SO.sub.2 NHR.sub.2, or --SO.sub.2 R.sub.2.