Cyanine compound and optical filter and optical recording material containing same

An optical filter comprising at least one cyanine compound of general formula (VI):

• wherein R3 each represents an optionally substituted alkyl group having 1 to 10 carbon atoms, or an optionally substituted arylalkyl group having 7 to 30 carbon atoms
• R1 and R2, and R5 and R6, together form a a benzene or naphthalene ring;
• X1 represents an oxygen atom, or —CR7R8—
• R7 and R8 in X1 each independently represent an optionally substituted alkyl group having 1 to 10 carbon atoms, or an optionally substituted arylalkyl group having 7 to 30 carbon atoms;
• Y1 and Y2 each independently represent an optionally substituted alkyl group having 1 to 10 carbon atoms, or an anchor group represented by general formula (IX)
• -L-COOH (IX)
• wherein L represents a single bond or a divalent hydrocarbon group having 1 to 12 carbon atoms, with the proviso that at least one of Y1 and Y2 is an anchor group;
• -Q- represents a linking group comprising a polymethine chain optionally containing a cyclic structure, the polymethine chain may have its hydrogen atom replaced by a halogen atom, a cyano group, a hydroxyl group, an alkyl group, an alkoxy group, or an aryl group, of which the alkyl, alkoxy or aryl group may further be substituted with a halogen atom, a cyano group, a hydroxyl group, an alkyl group, an alkoxy group, or an aryl group;
• Anq− represents a q-valent anion;
• a represents a number of 0 to 4;
• q represents 1 or 2;
• and
• p represents a number necessary to neutralize the electric charge;
• R13, each of which may be the same or different, represents a cyano group, a carboxyl group, or
• adjacent R13s may be connected to each other to form a benzene ring;
• and
• m represents a number of 0 to 5.