Th e Development of New Methods of Electrochemical Generation and Activation of Highly Effi cient Catalysts Based on Complexes of Group VIII 3d-Metals and α-Diphenylphosphinoglycines for the Oligomerization of Ethylene

This study is focused on the development of highly efficient and environmentally friendly methods for production of new catalysts based on complexes of group VIII 3d-metals (cobalt and nickel) bearing α-diphenylphosphinoglycines in the coordination sphere for the processes of homogeneous ethylene oligomerization and polymerization. Novel α-diphenylphosphinoglycines were synthesized by the threecomponent condensation reaction using diphenylphosphine, the primary amine, and glyoxylic acid monohydrate and characterized by various physicochemical methods. Their electrochemical properties and reactivity have been studied in the presence of neutral and doubly charged complexes of group VIII 3d metals (cobalt and nickel). Quantum-chemical calculations have been performed to rationalize the influence of the substituents at amino group in N-derivatives of α-diphenylphosphinoglycines on the molecular weight distribution of the formed α-olefin products. It was established that the difference in catalytic performance of L/Ni systems, where L – N-aryl-diphenylphosphinoglycines, is mainly due to the steric effects influencing the relative thermodynamic stability of various conformations of the catalyst as well as the thermodynamic and kinetic parameters of various competing catalytic transformations. The obtained results can serve as the basis for the future rational design of new catalytically active systems with desired properties.