| 摘要 |
Disclosed is a novel near-infrared absorbing dye of formula: <IMAGE> wherein X1, X2 independently represents -CR8R9-, -S-, -Se-, -NR10-, -CH=CH- or -O-; n is an integer of 2 or 3; R1 and R2 independently represent alkyl of 1 to 10 carbons or substituted alkyl of 1 to 10 carbons; R3 represents a ring chosen from a set consisting of aryl, substituted aryl, and a heterocyclic ring of a type present in photographic emulsions; R4, R5, R6 and R7 independently represent hydrogen, alkyl of 1-10 carbons, substituted alkyl of 1-10 carbons, R4 and R5 taken together or R6 and R7 taken together can represent atoms necessary to form a 5 or 6-membered aliphatic ring, an aromatic six-membered ring, an aromatic 10-membered ring, a substituted aromatic six-member ring or a substituted aromatic 10-member ring; R8, R9 independently represent alkyl of 1-10 carbons, substituted alkyl of 1-10 carbons, aryl of 6-10 carbons, or substituted aryl of 6-10 carbons; and R10 represents an alkyl of 1-10 carbons, substituted alkyl of 1-10 carbons, aryl of 6-10 carbons, or substituted aryl of 6-10 carbons; with the proviso that when R3 is phenyl or substituted phenyl and n=3, R1 or R2 is not an unsubstituted alkyl.
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