Squarylium compounds and optical recording media using the same

A squarylium compound represented by the general formula (Ia):

• wherein, R1a and R2a are taken together with an adjacent nitrogen atom to form a carbazole ring optionally having a substituent;
• and R3 represents the general formula (II):
• wherein, R4 and R5 are the same or different, and represent a hydrogen atom or an alkyl group, or R4 and R5 may be taken together with an adjacent nitrogen atom to form a heterocycle;
• and R6, R7, R8 and R9 are the same or different, and represent a hydrogen atom, an alkyl group optionally having a substituent or an alkoxy group optionally having a substituent, a hydroxyl group or a halogen atom, or R4 and R6 or R5 and R7 may be taken together with adjacent N—C—C to form a heterocycle, wherein the heterocycle may have a substituent;
• or R3 represents the general formula (III):
• wherein, R10 represents a carbon or nitrogen atom;
• R11 and R12 are the same or different, and represent a hydrogen atom, an alkyl group optionally having a substituent, an aryl group optionally having a substituent, an aralkyl group optionally having a substituent or a hydroxyl group (provided that, when R10 is a nitrogen atom, then R12 is not present);
• R13 represents a hydrogen atom, an alkyl group optionally having a substituent, an aryl group optionally having a substituent or an aralkyl group optionally having a substituent;
• and R14 and R15 are the same or different, and represent a hydrogen atom, an alkyl group optionally having a substituent, an alkoxy group or a halogen atom, or R14 and R15 may be taken together with two adjacent carbon atoms to form an alicyclic hydrocarbon ring, an aromatic ring optionally having a substituent or a heterocycle optionally having a substituent.

A squarylium compound represented by the general formula (Ib):

• wherein, R1b represents a hydrogen atom, and R2b represents an aryl group substituted with —R16═R17—Ar(R16 and R17 are the same, and represent N or CH, and Ar represents an aryl group optionally substituted with a substituent selected from the group consisting of a hydroxyl group, a carboxyl group, a nitro group, an alkoxy group, an alkyl group optionally substituted with a halogen group, or a cyano group and a halogen atom);
• and R3 represents the general formula (II):
• wherein, R4 and R5 are the same or different, and represent a hydrogen atom or an alkyl group, or R4 and R5 may be taken together with an adjacent nitrogen atom to form a heterocycle;
• and R6, R7, R8 and R9 are the same or different, and represent a hydrogen atom, an alkyl group optionally having a substituent or an alkoxy group optionally having a substituent, a hydroxyl group or a halogen atom, or R4 and R6 or R5 and R7 may be taken together with adjacent N—C—C to form a heterocycle, wherein the heterocycle may have a substituent;
• or R3 represents the general formula (III):
• wherein, R10 represents a carbon or nitrogen atom;
• R11 and R12 are the same or different, and represent a hydrogen atom, an alkyl group optionally having a substituent, an aryl group optionally having a substituent, an aralkyl group optionally having a substituent or a hydroxyl group (provided that, when R10 is a nitrogen atom, then R12 is not present);
• R13 represents a hydrogen atom, an alkyl group optionally having a substituent, an aryl group optionally having a substituent or an aralkyl group optionally having a substituent;
• and R14 and R15 are the same or different, and represent a hydrogen atom, an alkyl group optionally having a substituent, an alkoxy group or a halogen atom, or R14 and R15 may be taken together with two adjacent carbon atoms to form an alicyclic hydrocarbon ring, an aromatic ring optionally having a substituent or a heterocycle optionally having a substituent.

A squarylium compound represented by the general formula (Ic):

• wherein, R1 and R2 are the same or different, and represent a hydrogen atom, an alkyl group optionally having a substituent, an aralkyl group optionally having a substituent, an aryl group optionally having a substituent or a heterocyclic group optionally having a substituent, or R1 and R2 may be taken together with an adjacent nitrogen atom to form a heterocycle, wherein the heterocycle may have a substituent;
• and R3c represents the general formula (III):
• wherein, R10 represents a carbon or nitrogen atom;
• R11 and R12 are the same or different, and represent a hydrogen atom, an alkyl group optionally having a substituent, an aryl group optionally having a substituent, an aralkyl group optionally having a substituent or a hydroxyl group (provided that, when R10 is a nitrogen atom, then R12 is not present);
• R13 represents a hydrogen atom, an alkyl group optionally having a substituent, an aryl group optionally having a substituent or an aralkyl group optionally having a substituent;
• and R14 and R15 are the same or different, and represent a hydrogen atom, an alkyl group optionally having a substituent, an alkoxy group or a halogen atom, or R14 and R15 may be taken together with two adjacent carbon atoms to form an alicyclic hydrocarbon ring, an aromatic ring optionally having a substituent or a heterocycle optionally having a substituent.