Zeromethine merocyanine dyes useful as spectral sensitizers in photographic elements

Abstract

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: ##STR1## wherein: R.sup.1, R.sup.2, R.sup.3, and R.sup.4 each independently represents H; halogen; alkyl of 1-6 carbons; aryl of 6-24 carbons; alkoxy of 1-6 carbons; carbonyl; or sulfonate; or R.sup.1 and R.sup.2, R.sup.2 and R.sup.3, or R.sup.3 and R.sup.4 taken together represent the atoms necessary to complete a six-membered carbocylic ring; R.sup.5 represents hydrogen, alkyl of 1-6 carbons or aryl of 6-24 carbons; R.sup.6, R.sup.7, and R.sup.8 independently represent alkyl 1-6 carbons; aryl of 6-24 carbons; or any pair of R.sup.6, R.sup.7 and R.sup.8 taken together represent a five- or six-member heterocyclic ring; X represents O, S, CH.dbd.CH, Se, Te or N--R.sup.10 ; Y represents O, S, or N--R.sup.9 ; Z represents O, S or Se; R.sup.9 represents alkyl of 1-6 carbons; or an aryl of 6-24 carbons; R.sup.10 represents alkyl of 1-6 carbons; n is an integer of 1-6; and Q represents a counterion.

Dependencies are inferred from the claim text.