Photographic element containing a coupler capable of releasing a photographically useful group

Abstract

A photographic element comprising a support having situated thereon at least one silver halide emulsion layer, the layer containing a photographic coupler represented by the formula COUP--T.sup.1 --T.sup.2 --(T.sup.3).sub.b --PUG wherein COUP is a coupler moiety having a coupling site to which T.sup.1 is attached; T.sup.1 is a timing or linking group which releases from COUP during processing and which functions by electron transfer down a conjugated or unconjugated chain, or by nucleophilic displacement reaction, to release T.sup.2, T.sup.2 being an indazole timing or linking group which, after release from T.sup.1, functions by electron transfer down a conjugated chain to release T.sup.3 or PUG, and which is represented by the formula: ##STR1## wherein ** denotes the point of attachment to T.sup.1 and *** denotes the point of attachment to T.sup.3 or PUG; R.sup.1 and R.sup.2 are independently selected from hydrogen, or an aliphatic, carbocyclic, or heterocyclic group, or may be bonded together to form a 5, 6, or 7 membered ring; V is independently selected from the group consisting of an alkyl, carbocyclic, heterocyclic, halo, carbamoyl, sulfamoyl, carbonamido, sulfonamido, keto, sulfo, nitro, hydroxyl, carboxyl, amino, alkoxy, alkoxycarbonyl, aryloxy, or arylthio group; q is 0, 1, 2, 3 or 4; T.sup.3 is a timing or linking group attached to T.sup.2 which is released therefrom after T.sup.2 releases from T.sup.1, and which functions by electron transfer down a conjugated or unconjugated chain, or by nucleophilic displacement reaction, to release PUG; b is 0 or 1; and PUG is a photographically useful group.

Dependencies are inferred from the claim text.