| 摘要 |
PROBLEM TO BE SOLVED: To enable the absorption of light at the long-wavelength side more effectively than with a conventional compd. by using, as a photographic sensitizing color, etc., a streptocyanin color compd. of a linked type having a novel structure wherein there are two linking sections each comprising two divalent linking groups. SOLUTION: This compd. is represented by formula I (wherein A1 to A3 are each a streptocyanin color unit; L1 to L4 are each a divalent linking group; and (n) is an integer of 0 or higher) or formula II (wherein R1 to R4 are each an alkyl or aryl; E1 to E9 are each methine; L5 to L8 are each a divalent linking group; m1 to m3, and n2 are each an integer of 0 or higher; and M is a charge-neutralizing ion) and is produced by condensing a pyridinium compd. [e.g. a 1-(2,4-dinitrophenyl)pyridinium compd.] with a diamine compd. (e.g. 1,3- diaminopropane) in a molar ratio of (1:10)-(10:1), e.g. in an alcohol solvent, pref. at 20-100 deg.C, and pref. for 10min to 3hr. |
