Cyanine derivatives, fluorescent conjugates containing same and use thereof

A cyanine derivative of formula:

• in which the dotted lines represent the atoms necessary for the formation of one or two fused aromatic rings, each ring comprising 5 or 6 carbon atoms;
• R1, R2, R3 and R4 represent, independently of one another:
• a hydrogen atom;
• a substituted or unsubstituted C1-C15 alkyl group;
• a C1-C6 alkoxy group;
• a (C2-C12) dialkylamino group;
• a C1-C6 alkoxycarbonyl group;
• a (C2-C12) dialkylamido group;
• a substituted or unsubstituted aryl, arylalkyl or aryloxy group;
• a halogen atom;
• a nitro group;
• a group chosen from:
• L1-W, L2-M, L2-A or L2-G;
• R5 and R6 represent, independently of one another:
• a substituted or unsubstituted C1-C15 alkyl group;
• a substituted or unsubstituted aryl or arylalkyl group;
• a group chosen from:
• L1-W, L2-M, L2-A or L2-G;
• X is chosen from:
• O, S or CR7R8;
• Y is chosen from:
• O, S or CR9R10;
• R7, R8, R9 and R10 independently represent:
• a substituted or unsubstituted C1-C15 alkyl group;
• a substituted or unsubstituted aryl, arylalkyl or aryloxy group;
• a group chosen from:
• L1-W, L2-M, L2-A or L2-G;
• R7 and R8 and/or R9 and R10 can also together form a ring comprising 5 or 6 atoms or a heterocycle comprising 4 to 5 carbon atoms and an oxygen atom;
• B represents a polymethine bridge comprising 1 to 5 methines, in which the methine groups are individually unsubstituted or substituted by a group chosen from:
• a substituted or unsubstituted C1-C15 alkyl group;
• a substituted or unsubstituted aryl, arylalkyl or aryloxy group;
• a nitro group;
• a group chosen from:
• L1-W, L2-M, L2-A or L2-G;
• or else two substituents of adjacent methines can together form a saturated or unsaturated hydrocarbon ring comprising 4, 5 or 6 atoms which is optionally substituted one or more times by a group chosen from:
• a substituted or unsubstituted C1-C15 alkyl group;
• a substituted or unsubstituted aryl, arylalkyl or aryloxy group;
• a halogen atom;
• a nitro group;
• a group chosen from:
• L1-W, L2-M, L2-A or L2-G;
• L1 and L2 are connecting arms;
• G is a reactive group;
• A is a coupling agent;
• M is a conjugated molecule;
• W is a phosphate or phosphonate ester chosen from:
• in which:
• R11 and R12 are identical or different and are chosen from:
• a hydrogen atom;
• an unsubstituted C1-C5 alkyl group;
• R13 and R14 are identical or different and are chosen from:
• a hydrogen atom;
• an unsubstituted C1-C15 alkyl group;
• a C1-C6 alkoxycarbonyl group;
• a C1-C6 alkylcarboxyl group;
• an N,N—(C2-C12)dialkylamido group;
• an amido group;
• a group of formula —C—S—CO-Alk, Alk being an unsubstituted linear or branched C1-C4 alkyl;
• R11 and R12 and/or R13 and R14 can also together form a phthalidyl group of formula:
• with the proviso that the cyanine derivative comprises one or two L1-W groups and one or two groups chosen from L2-A, L2-G and L2-M.