Cyclic amines homobimetallic ruthenium pre-catalysts bearing bidentate phosphine and their dual catalytic activity for the ring-opening metathesis and atom-radical polymerizations

Author(s)

Gois, Patrik D. S. ^[1] ; Cruz, Thais R. ^[1] ; Martins, Daniele M. ^[2] ; Machado, Antonio E. H. ^{[3, 4]} ; Bogado, Andre L. ^[5] ; Lima-Neto, Benedito S. ^[2] ; Goi, Beatriz E. ^[1] ; Carvalho Jr, Valdemiro P.

Affiliation

^[1] Univ Estadual Paulista, UNESP, Fac Ciencias & Tecnol, BR-19060900 Presidente Prudente, SP - Brazil

^[2] Univ Sao Paulo, Inst Quim Sao Carlos, BR-13560970 Sao Carlos, SP - Brazil

^[3] Univ Fed Uberlandia, Inst Quim, POB 593, BR-38400089 Uberlandia, MG - Brazil

^[4] Univ Fed Goias, Programa Posgrad Ciencia & Tecnol, Catalao, Go - Brazil

^[5] Univ Fed Uberlandia, Inst Ciencias Exatas & Nat Pontal, Rua Vinte 1600, BR-38304402 Ituiutaba, MG - Brazil

• Document type: Journal article
• Source: Journal of Molecular Structure; v. 1198, DEC 15 2019.
• Web of Science Citations: 0

Abstract

A series of {[}RuCl(dppb)(mu-Cl)(3)Ru(dppb)(amine)] complexes, where amine is pyrrolidine (1), piperidine (2) or perhydroazepine (3), were synthesized and characterized by elemental analysis, FTIR, UV-Vis, and H-1, C-13[H-1] and P-31[H-1] NMR spectroscopy. The electrochemistry properties of the complexes 1-3 were investigated by cyclic voltammetry and exhibited two successive single-electron oxidation processes. The presence of two redox pairs suggests the formation of a dimeric species in which two different fragments, [Ru(amine)(dppb)] and [RuCl(dppb)], were connected via three mu-chloro bridges. The complexes 1-3 were evaluated as catalytic precursors for ROMP of norbornene (NBE) and norbornadiene (NBD), as well as for ATRP of methyl methacrylate (MMA). The polynorbornene (polyNBE) syntheses via ROMP using the complexes 1-3 as pre-catalysts were assessed under reaction conditions of {[}EDA]/{[}Ru] = 28 (5 mu L) and {[}NBE]/{[}Ru] = 5000 as a function of time at 25 or 50 degrees C. Polymerization of MMA via ATRP was conducted using the complexes 1-3 in the presence of ethyl 2-bromoisobutyrate (EBiB) as initiator. Differences in the catalytic activities and polymerization controls were observed in the order 3 > 2 > 1 for both reactions. The activities were discussed considering the steric hindrance and electronic characteristics of the amines as ancillary ligands in the metal center using cyclic voltammetry and NMR studies. (C) 2019 Elsevier B.V. All rights reserved. (AU)

• 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
• 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