Cyanine dyes

A compound represented by the following formula (I) or a salt thereof:

• wherein R1 and R2 each independently represent a substituted or unsubstituted alkyl group having 1 to 10 carbon atoms or a substituted or unsubstituted aryl group, and R1 and R2 may bind to each other to form a ring:
• R3, R4, R5 and R6 each independently represent hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted aryl group, a substituted or unsubstituted heteroaryl group, a halogen atom, cyano group, carboxyl group or sulfo group, and two of adjacent groups selected from the group consisting of R3, R4, R5 and R6 may bind to each other to form a ring:
• X1 and X2 each independently represent a substituted or unsubstituted alkyl group having 1 to 15 carbon atoms or a substituted or unsubstituted aryl group, and the total number of carboxyl groups existing in X1 and X2 is 4 or less, provided when the total number of carboxyl groups existing in X1 and X2 is 0 or 1, X1 and X2 each independently represent a carboxyalkyl group having 1 to 5 carbon atoms or a sulfoalkyl group having 1 to 5 carbon atoms, and at least one of R3, R4, R5 and R6 represents a substituted or unsubstituted aryl group or a substituted or unsubstituted heteroaryl group;
• m1 represents 0 or 1;
• m2 represents 0 or 1;
• m3 represents 0 or 1;
• L1, L2, L3, L4, L5, L6 and L7 each independently represent a substituted or unsubstituted methine group, and when two or more methine groups among the methine groups have a substituent, these substituents may bind to each other to form a ring, provided when X1 and X2 each have one carboxyl group, at least one methine group selected from the group consisting of L1, L2, L3, L4, L5, L6 and L7 represents a substituted methine group, and R4 represents a sulfo group;
• M represents a hydrogen atom, a metal or a quaternary ammonium salt;
• Y represents nonmetallic elements required to form a 5- to 10-membered heterocyclic ring wherein said heterocyclic ring may be a condensed ring;
• and n represents an integer of 1 to 7 required to neutralize charge,
• wherein X1 is a group represented by the following formula (i):
• wherein Y1 and Y2 each independently represent a substituted or unsubstituted divalent bridging group.

A compound represented by the following formula (II) or a salt thereof:

• wherein R1, R2, R7 and R8 each independently represent a substituted or unsubstituted alkyl group having 1 to 10 carbon atoms or a substituted or unsubstituted aryl group, and R1 and R2 and/or R7 and R8 may bind to each other to form a ring;
• R3, R4, R5, R6, R9, R10, R11 and R12 each independently represent a hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted aryl group, a substituted or unsubstituted heteroaryl group, a halogen atom, cyano group, carboxyl group or sulfo group, and R3, R4, R5, R6, R9, R10, R11 and R12 may bind to each other to form a ring;
• X1 and X2 each independently represent a substituted or unsubstituted alkyl group having 1 to 15 carbon atoms or a substituted or unsubstituted aryl group, and the total number of carboxyl groups existing in X1 and X2 is four or less, provided when the total number of carboxyl groups existing in X1 and X2 is 0 or 1, X1 and X2 each independently represent a carboxyalkyl group having 1 to 5 carbon atoms or a sulfoalkyl group having 1 to 5 carbon atoms, and at least one R3, R4, R5, R6, R9, R10, R11 and R12 represents a substituted or unsubstituted aryl group or a substituted or unsubstituted heteroaryl group;
• L1, L2, L3, L4, L5, L6 and L7 each independently represent a substituted or unsubstituted methine group, and when two or more methine groups among the methine groups have a substituent, these substituents may bind to each other to form a ring, provided when X1 and X2 each have one carboxyl group, at least one methine group selected from the group consisting of L1, L2, L3, L4, L5, L6 and L7 is a substituted methine group, and R4 and R10 each represents a sulfo group;
• M represents a hydrogen atom, a metal or a quaternary ammonium salt;
• and n represents an integer of 1 to 7 required to neutralize charge,
• wherein m1, m2 and m3 all represent 1.

A compound represented by the following formula (II) or a salt thereof:

• wherein R1, R2, R7 and R8 each independently represent a substituted or unsubstituted alkyl group having 1 to 10 carbon atoms or a substituted or unsubstituted aryl group, and R1 and R2 and/or R7 and R8 may bind to each other to form a ring;
• R3, R4, R5, R6, R9, R10, R11 and R12 each independently represent hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted aryl group, a substituted or unsubstituted heteroaryl group, a halogen atom, cyano group, carboxyl group or sulfo group, and R3, R4, R5, R6, R9, R10, R11 and R12 may bind to each other to form a ring;
• X1 and X2 each independently represent a substituted or unsubstituted alkyl group having 1 to 15 carbon atoms or a substituted or unsubstituted aryl group, and the total number of carboxyl groups existing in X1 and X2 is four or less, provided when the total number of carboxyl groups existing in X1 and X2 is 0 or 1, X1 and X2 each independently represent a carboxyalkyl group having 1 to 5 carbon atoms or a sulfoalkyl group having 1 to 5 carbon atoms, and at least one of R3, R4, R5, R6, R9, R10, R11 and R12 represents a substituted or unsubstituted aryl group or a substituted or unsubstituted heteroaryl group:
• m1 represents 0 or 1;
• m2 represents 0 or 1;
• m3 represents 0 or 1;
• L1, L2, L3, L4, L5, L6 and L7 each independently represent a substituted or unsubstituted methine group, and when two or more methine groups among the methine groups have a substituent, these substituents may bind to each other to form a ring, provided when X1 and X2 each have one carboxyl group, at least one methine group selected from the group consisting of L1, L2, L3, L4, L5, L6 and L7 is a substituted methine group, and R4 and R10 each represents a sulfo group;
• M represents a hydrogen atom, a metal or a quaternary ammonium salt;
• and n represents an integer of 1 to 7 required to neutralize charge,
• wherein X1 a group represented by the following formula (i):
• wherein Y1 and Y2 each independently represent a substituted or unsubstituted divalent bridging group.

A compound represented by the following formula (II) or a salt thereof:

• wherein R1, R2, R7 and R8 each independently represent a substituted or unsubstituted alkyl group having 1 to 10 carbon atoms or a substituted or unsubstituted aryl group, and R1 and R2 and/or R7 and R8 may bind to each other to form a ring;
• R3, R4, R5, R6, R9, R10, R11 and R12 each independently represent hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted aryl group, a substituted or unsubstituted heteroaryl group, a halogen atom, cyano group, carboxyl group or sulfo group, and R3, R4, R5, R6, R9, R10, R11 and R12 may bind to each other to form a ring;
• X1 and X2 each independently represent a substituted or unsubstituted alkyl group having 1 to 15 carbon atoms or a substituted or unsubstituted aryl group, and the total number of carboxyl groups existing in X1 and X2 is four or less, provided when the total number of carboxyl groups existing in X1 and X2 is 0 or 1, X1 and X2 each independently represent a carboxyalkyl group having 1 to 5 carbon atoms or a sulfoalkyl group having 1 to 5 carbon atoms, and at least one of R3, R4, R5, R6, R9, R10, R11 and R12 represents a substituted or unsubstituted aryl group or a substituted or unsubstituted heteroaryl group;
• m1 represents 0 or 1;
• m2 represents 0 or 1;
• m3 represents 0 or 1:
• L1, L2, L3, L4, L5, L6 and L7 each independently represent a substituted or unsubstituted methine group, and when two or more methine groups among the methine groups have a substituent, these substituents may bind to each other to form a ring, provided when X1 and X2 each have one carboxyl group, at least one methine group selected from the group consisting of L1, L2, L3, L4, L5, L6 and L7 is a substituted methine group, and R4 and R10 each represents a sulfo group;
• M represents a hydrogen atom, a metal or a quaternary ammonium salt;
• and n represents an integer of 1 to 7 required to neutralize charge,
• wherein X1 and X2 each independently represent a group represented by the following formula (i):
• wherein Y1 and Y2 each independently represent a substituted or unsubstituted divalent bridging group.

A compound represented by the following formula (II) or a salt thereof:

• wherein R1, R2, R7 and R8 each independently represent a substituted or unsubstituted alkyl group having 1 to 10 carbon atoms or a substituted or unsubstituted aryl group, and R1 and R2 and/or R7 and R8 may bind to each other to form a ring;
• R3, R4, R5, R6, R9, R10, R11 and R12 each independently represent a hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted aryl group, a substituted or unsubstituted heteroaryl group, a halogen atom, cyano group, carboxyl groin or sulfo group, and R3, R4, R5, R6, R9, R10, R11 and R12 may bind to each other to form a ring;
• X1 and X2 each independently represent a substituted or unsubstituted alkyl group having 1 to 15 carbon atoms or a substituted or unsubstituted aryl group, and the total number of carboxyl groups existing in X1 and X2 is four or less, provided when the total number of carboxyl groups existing in X1 and X2 is 0 or 1, X1 and X2 each independently represent a carboxyalkyl group having 1 to 5 carbon atoms or a sulfoalkyl group having 1 to 5 carbon atoms, and at least one of R3, R4, R5, R6, R9, R10, R11 and R12 represents a substituted or unsubstituted aryl group or a substituted or unsubstituted heteroaryl group;
• m1 represents 0 or 1;
• m2 represents 0 or 1;
• m3 represents 0 or 1;
• L1, L2, L3, L4, L5, L6 and L7 each independently represent a substituted or unsubstituted methine group, and when two or more methine groups among the methine groups have a substituent, these substituents may bind to each other to form a ring, provided when X1 and X2 each have one carboxyl group, at least one methine group selected from the group consisting of L1, L2, L3, L4, L5, L6 and L7 is a substituted methine group, and R4 and R10 each represents a sulfo group;
• M represents a hydrogen atom, a metal or a quaternary ammonium salt;
• and n represents an integer of 1 to 7 required to neutralize charge,
• wherein X1 and X2 each independently represent a group represented by the following formula:
• wherein Y3 represents a hydrocarbon group having 1 to 10 carbon atoms, at least one methine group selected from the group consisting of L1, L2, L3, L4, L5, L6 and L7 is a substituted methine group, and R4 and R10 each represents a sulfo group.