Organometallic complex catalyst

A ligand which comprises a nitrogen-containing heterocyclic carbene structure represented by the following formula (2) and is a structural material of an organometallic complex catalyst for use in a cross-coupling reaction having a structure represented by the following formula (1).

• wherein, in the formulae (1) and (2),
• M is a coordination center and represents any one of metal atoms selected from the group consisting of Pd, Pt, Rh, Ru and Cu, or an ion thereof;
• R1, R2 and R3 is optionally the same or different, and each represents at least one substituent selected from the group consisting of a hydrogen atom, an alkyl group, an alkoxy group, alkenyl group, an alkynyl group and an aryl group;
• R4, R5, R6 and R7 is optionally the same or different, and each represents at least one substituent selected from a hydrogen atom, a halogen atom, an alkyl group, an alkoxy group, an alkenyl group, an alkynyl group, an aryl group, a hydroxy group, hydroxylate group, a thiocarboxyl group, a dithiocarboxyl group, a sulfo group, a sulfino group, an oxycarbonyl group, a carbamoyl group, a hydrazinocarbonyl group, an amidino group, a cyano group, an isocyano group, a cyanato group, an isocyanato group, a thiocyanato group, an isothiocyanato group, a formyl group, an oxo group, a thioformyl group, a thioxo group, a mercapto group, an amino group, an imino group, a hydrazino group, an aryloxy group, a sulfide group, a nitro group and a silyl group;
• X represents a halogen atom which is capable of coordinating to the coordination center M;
• R8 represents a substituent having a π bond and 3 to 20 carbon atoms which is capable of coordinating to the coordination center M;
• provided that, with regard to electron-donating property with respect to the coordination center M, R1, R2, R3, R4, R5, R6 and R7 are so combined and arranged that a TEP value (Tolman electronic parameter) [cm−1] obtained by an infrared spectroscopy of a ligand having a nitrogen-containing heterocyclic carbene structure represented by the following formula (2) which contains R1 to R7, sifts toward a low frequency side compared to the TEP value [cm−1] of a ligand represented by the formula (2-1).
• wherein, in the formula (2-1), R4, R5, R6 and R7 represent the same substituents as R4, R5, R6 and R7 in the formula (1).