Dinickel complexes with anthyridine-based ligands

Abstract

Two new dinickel complexes with anthyridine-based ligands, 5-phenyl-2,8-bis(2-pyridinyl)-1,9,10-anthyridine (L₂) and 5-phenyl-2,8-bis(6′-bipyridinyl)-1,9,10-anthyridine (L₃), are reported. Complexation of Ni(OAc)₂ with L₂ and L₃ in trifluoroacetic acid provided the corresponding dinickel complexes [{Ni₂(L₂)(H₂O)₆(CF₃COO)₂}(CF₃COO)₂] (2) and [Ni₂(L₃)(CF₃COO)₄(H₂O)] (3), respectively. Both complexes were characterized by spectroscopic methods and further confirmed by X-ray crystallography. Structural analyses of 2 and 3 revealed the Ni⋯Ni distances in the complexes to be 5.4086(6) and 5.0138(7) Å, respectively. The catalytic activities of complexes 2 and 3 toward the reduction of carboxylic acids were evaluated. It appears that complex 3 shows a good catalytic activity toward the reduction of carboxylates into the corresponding alcohols by diphenylsilane.