Zeromethine merocyanine dyes useful as spectral sensitizers in photographic elements

摘要

The present invention is directed to a dye suitable for spectral sensitization of a photographic element. Specifically, the dye is a compound having the structure: wherein: R1, R2, R3, and R4 each independently represents H; halogen; alkyl of 1-6 carbons; aryl of 6-24 carbons; alkoxy of 1-6 carbons; carbonyl; or sulfonate; or R1 and R2, R2 and R3, or R3 and R4 taken together represent the atoms necessary to complete a six-membered carbocylic ring; R5 represents hydrogen, alkyl of 1-6 carbons or aryl of 6-24 carbons; R6, R7, and R8 independently represent alkyl 1-6 carbons; aryl of 6-24 carbons; or any pair of R6, R7 and R8 taken together represent a five- or six-member heterocyclic ring; X represents O, S, CH=CH, Se, Te or N-R10; Y represents O, S, or N-R9; Z represents O, S or Se; R9 represents alkyl of 1-6 carbons; or an aryl of 6-24 carbons; R10 represents alkyl of 1-6 carbons; n is an integer of 1-6; and Q represents a counterion.