Asymmetric cyanine dye
A compound represented by the general formula (I) or a salt thereof [wherein R 1 , R 2 , R 4 , and R 5 represent an alkyl group or an aryl group, and R 1 and R 2 and/or R 4 and R 5 may bind to each other to form a ring; R 3 represents hydrogen atom or sulfo group; R 6 , R 7 , R 8 , and R 9 represent hydrogen atom, a halogen atom, an alkyl group, an alkoxyl group, an amino group, nitro group or cyano group; X 1 and X 2 represent an alkyl group or an aryl group; m 1 to m 3 represents 0 or 1; L 1 to L 7 represent a methine group, and when two or more of methine groups among the aforementioned methine groups have a substituent, the substituents may bind to each other to form a ring; M represents hydrogen atom, a metal or a quaternary ammonium salt; and n represents an integer of 1 to 7 required to neutralize a charge]. The compound can be utilized as a novel cyanine dye useful as an infrared photosensitive dye that give no bad influence on photographic characteristics of a photographic emulsion and gives reduced residual color after development.
1 . A compound represented by the following general formula (I) or a salt thereof:
wherein R 1 , R 2 , R 4 , and R 5 independently represent a substituted or unsubstituted alkyl group having 1 to 10 carbon atoms or a substituted or unsubstituted aryl group, and R 1 and R 2 and/or R 4 and R 5 may bind to each other to form a ring; R 3 represents a hydrogen atom or a sulfo group; R 6 , R 7 , R 8 , and R 9 each independently represents a hydrogen atom, a halogen atom, a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted alkoxyl group having 1 to 6 carbon atoms, a substituted or unsubstituted amino group, nitro group or cyano group, and two of adjacent groups selected from the group consisting of R 6 , R 7 , R 8 , and R 9 may bind to each other to form a ring; X 1 and X 2 each independently represents a substituted or unsubstituted alkyl group having 1 to 10 carbon atoms or a substituted or unsubstituted aryl group; m 1 represents 0 or 1; m 2 represents 0 or 1; m 3 represents 0 or 1; L 1 , L 2 , L 3 , L 4 , L 5 , L 6 , and L 7 each independently represents a substituted or unsubstituted methine group, and when two or more of methine groups among the aforementioned methine groups have a substituent, the substituents may bind to each other to form a ring; M represents a hydrogen atom, a metal or a quaternary ammonium salt; and n represents an integer of 1 to 7 required to neutralize a charge.
2 . The compound or a salt according to claim 1 , wherein m 1 , m 2 , and m 3 all represent 1.
3 . The compound or a salt according to claim 1 or 2 , wherein R 3 is a sulfo group.
4 . The compound or a salt according to claim 1 or 2 , wherein at least one of L 1 , L 2 , L 3 , L 4 , L 5 , L 6 , and L 7 is a methine group having a substituent.
5 . The compound or a salt according to claim 3 , wherein at least one of L 1 , L 2 , L 3 , L 4 , L 5 , L 6 , and L 7 is a methine group having a substituent.