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): R
1
R
2
R
3
A or General Formula (2): R
1
R
2
A-Y-AR
3
R
4
and having a total of 15 to 110 carbon atoms. In the formulae, A is phosphorus or arsenic; R
1
, R
2
, R
3
and R
4
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 C
2-20
, optionally substituted and optionally heteroatom-containing, aliphatic, alicyclic or aromatic compound or from ferrocene.
该发明提供了过渡
金属配合物的新型
配体,这些
配体在与
金属的配位能力方面表现出很高的能力,因为它们在
磷或
砷的邻位位置上没有取代基,并且具有与传统
配体中已知的最高
水平相当的电子吸引力。该发明的
配体包括由通用式(1)表示的化合物:R1R2R3A或通用式(2):R1R2A-Y-AR3R4,并且总共含有15至110个碳原子。在上述公式中,A代表
磷或
砷;R1、R2、R3和R4分别独立地是取代
吡啶基,在位置与原子A的间位上带有可选择的不同电子吸引基团,以及在位置与原子A的邻位上带有氢原子;Y是从C2-20、可选择取代且可含有杂原子的脂肪、脂环或芳香族化合物或
二茂铁中得到的二价基团。