Merocyanine dyes useful as photographic red sensitisers without discoloration

摘要

Merocyanine dyes of formula (I) are new; X, Y, z = S or Se; R1, R2, R3 = sulphoalkyl, sulphoaryl, carboxyalkyl or carboxyaryl and R2, R3 may also = H; R4 = H, (substd.) alkyl, (substd.) aryl or heteroaryl; R = (substd.) alkyl, alkoxy, (substd.) aryl, aryloxy, NH2, mono- or di-alkylamino or halogen; n = 0-4; -CR-CR- may = a benzene or naphthalene ring; only one of R2, R3, R4 may have an acid gp.. Also claimed is photographic material contg. cpd(s). (I).