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

A new unsymmetrical PCN pincer ligand, -ethyl--(3-((2,3,4,5-tetraphenyl-1-phosphol-1-yl))methyl) benzylpethanamine, combining different donors (amine and phosphole groups), has been synthesized. The ligand was obtained in four steps with a good overall yield (49%), using commercially available reagents as starting materials. Based on the obtained ligand, a design of an unsymmetrical nickel(II) pincer complex was proposed. Quantum-chemical calculations of the molecular structure of the complex show the formation of weak Ni–P bonds and the manifestation of a weak -influence of the phosphole group with respect to the amine group, which distinguishes this complex from its analogs, PCN complexes based on dialkylphosphines.