Ruthenium(II) complexes of Schiff base derived from cycloalkylamines as pre-catalysts for ROMP of norbornene and ATRP of methyl methacrylate

Author(s)

Afonso, Maria Beatriz A. ^[1] ; Cruz, Thais R. ^[1] ; Silva, Yan F. ^[1] ; Pereira, Joao Clecio A. ^[2] ; Machado, Antonio E. H. ^[3] ; Goi, Beatriz E. ^[1] ; Lima-Neto, Benedito S. ^[2] ; Carvalho-, Jr., Valdemiro P. ^[1]

Affiliation

^[1] UNESP Univ Estadual Paulista, 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, BR-38400902 Uberlandia, MG - Brazil

• Document type: Journal article
• Source: JOURNAL OF ORGANOMETALLIC CHEMISTRY; v. 851, p. 225-234, NOV 15 2017.
• Web of Science Citations: 3

Abstract

Ruthenium(II) complexes of Schiff base derived from cycloalkylamines (cycloalkyl = cyclopentyl (1a), cyclohexyl (1b), cycloheptyl (1c), and cyclooctyl) (1d) were synthesized: {[}RuCl(CyPen-Salen)(PPh3) 2] (2a), {[}RuCl(CyHex-Salen)(PPh3)(2)] (2b), {[}RuCl(CyHep-Salen)(PPh3)(2)] (2c), and {[}RuCl(CyOct-Salen)(PPh3) 2] (2d). The Schiff base-RuII complexes 2a-d were characterized by elemental analysis, FTIR, UV-Vis, 1H-, 13C and 31pNMR, and cyclic voltammetry. The complexes 2a-d were evaluated as catalytic precursors for ROMpof norbornene (NBE) and for ATRpof methyl methacrylate (MMA). The syntheses of polynorbornene (polyNBE) via ROMpwith complexes 2a-d as pre-catalysts were evaluated under different reaction conditions ({[}HCl]/{[}Ru], {[}EDA]/{[}Ru], {[}NBE]/{[}Ru], and temperature). The highest yields of polyNBE were obtained with {[}NBE]/{[}HCl]/{[}Ru] = 5000/25/1 M ratio in the presence of 5 mL of EDA for 60 min at 50 degrees C. MMA polymerization via ATRpwas conducted using the complexes 2a-d in the presence of ethyla- 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 85 degrees C. The linear correlation of ln({[}MMA](0)/{[}MMA]) and time indicates that the concentration of radicals remains constant during the polymerization and that the ATRpof MMA mediated by 2a-d proceeds in a controlled manner. Molecular weights increased linearly with conversion, however, the experimental molecular weights were higher than the theoretical ones. (C) 2017 Elsevier B.V. All rights reserved. (AU)

• FAPESP's process: 13/10002-0 - Development of ruthenium complexes as dual catalytic systems in simultaneous polymerization ROMP/ATRP
• Grantee: Valdemiro Pereira de Carvalho Júnior
• Support Opportunities: Research Grants - Young Investigators Grants