Dual catalytic performance of arene-ruthenium amine complexes for norbornene ring-opening metathesis and methyl methacrylate atom-transfer radical polymerizations

Author(s)

Cruz, Thais R. ; Silva, Eliada A. ; Oliveira, Douglas P. ; Martins, Daniele M. ; Gois, Patrik D. S. ; Machado, Antonio E. H. ; Maia, Pedro Ivo S. ; Goi, Beatriz E. ; Lima-Neto, Benedito S. ; Carvalho-Jr, Valdemiro P.

• Document type: Journal article
• Source: APPLIED ORGANOMETALLIC CHEMISTRY; v. 34, n. 5, p. 12-pg., 2020-02-20.

Abstract

Arene ruthenium(II) complexes bearing the cyclic amines RuCl2(eta(6)-p-cymene)(pyrrolidine)] (1), [RuCl2(eta(6)-p-cymene)(piperidine)] (2), and [RuCl2(eta(6)-p-cymene)(peridroazepine)] (3) were successfully synthesized. Complexes 1-3 were fully characterized by means of Fourier transform infrared, UV-visible, and NMR spectroscopy, elemental analysis, cyclic voltammetry, computational methods, and one of the complexes was further studied by single crystal X-ray crystallography. These compounds were evaluated as catalytic precursors for ring-opening metathesis polymerization (ROMP) of norbornene (NBE) and atom-transfer radical polymerization (ATRP) of methyl methacrylate (MMA). NBE polymerization via ROMP was evaluated using complexes 1-3 as precatalysts in the presence of ethyl diazoacetate (EDA) under different [NBE]/[EDA]/[Ru] ratios, temperatures (25 and 50 degrees C), and reaction times (5-60 min). The highest yields of polyNBE were obtained with [NBE]/[EDA]/[Ru] = 5000/28/1 for 60 min at 50 degrees C. MMA polymerization via ATRP was conducted using 1-3 as catalysts in the presence of ethyl-alpha-bromoisobutyrate (EBiB) as initiator. The catalytic tests were evaluated as a function of the reaction time using the initial molar ratio of [MMA]/[EBiB]/[Ru] = 1000/2/1 at 95 degrees C. The increase in molecular weight as function of time indicates that complexes 1-3 were able to mediate the MMA polymerization with an acceptable rate and some level of control. Differences in the rate of polymerization were observed in the order 3 > 2 > 1 for the ROMP and ATRP. (AU)

• FAPESP's process: 17/06329-5 - Development of ruthenium complexes with ammines as ancillary ligands for homogeneous catalysis of ring opening metathesis polymerization of cyclic olefins
• Grantee: Benedito dos Santos Lima Neto
• Support Opportunities: Regular Research Grants
• FAPESP's process: 18/06340-1 - Bimetallic complexes of ruthenium(II) and nickel(II): coupling of mechanistically-incompatible reactions using multifunctional catalysts via tandem catalysis
• Grantee: Valdemiro Pereira de Carvalho Júnior
• Support Opportunities: Regular Research Grants