Abstract: Provided are novel ligands for transition metal complexes which exhibit high coordination power with respect to metals by being free of substituents at the positions ortho to phosphorus or arsenic and which have electron-withdrawing power comparable to the highest level known in conventional ligands. One ligand includes a compound represented by General Formula (1): R1R2R3A or General Formula (2): R1R2A-Y-AR3R4 and having a total of 15 to 110 carbon atoms. In the formulae, A is phosphorus or arsenic; R1, R2, R3 and R4 are each independently a substituted pyridyl group having optionally different electron-withdrawing groups bonded to the positions meta to the atom A as well as hydrogen atoms bonded to the positions ortho to the atom A; and Y is a divalent group derived from a C2-20, optionally substituted and optionally heteroatom-containing, aliphatic, alicyclic or aromatic compound or from ferrocene.

Abstract: The invention provides novel ligands for transition metal complexes which exhibit high coordination power with respect to metals by being free of substituents at the positions ortho to phosphorus or arsenic and which have electron-withdrawing power comparable to the highest level known in conventional ligands. A ligand of the invention includes a compound represented by General Formula (1): R1R2R3A or General Formula (2): R1R2A-Y-AR3R4 and having a total of 15 to 110 carbon atoms. In the formulae, A is phosphorus or arsenic; R1, R2, R3 and R4 are each independently a substituted pyridyl group having optionally different electron-withdrawing groups bonded to the positions meta to the atom A as well as hydrogen atoms bonded to the positions ortho to the atom A; and Y is a divalent group derived from a C2-20, optionally substituted and optionally heteroatom-containing, aliphatic, alicyclic or aromatic compound or from ferrocene.