Design of an Asymmetric PCN Pincer Nickel(II) Complex Based on 2,3,4,5-Tetraphenyl-1-monophosphole

Abstract

A new asymmetric PCN pincer ligand, N-ethyl-N-[3-((2,3,4,5-tetraphenyl-1H-phosphol-1-yl)methyl)benzyl]ethanamine, combining different donor groups (amino and phosphole), has been synthesized. The ligand was obtained in four steps with a good overall yield (49%) from commercially available reagents. Based on this ligand, the design of an asymmetric nickel(II) pincer complex was proposed. Quantum chemical calculations of the molecular structure of the complex indicate the formation of weak Ni–P bonds and reveal a weak trans influence of the phosphole group relative to the amino group, which distinguishes this complex from its analogs, PCN complexes based on dialkylphosphines.