Atom transfer radical polymerization by [RuCl2(PPh3)2(amine)] catalysts: Cyclic amines as tuner of reactivity

Abstract

Atom transfer radical polymerizations (ATRP) of styrene (St) and methyl methacrylate (MMA) mediated by [RuCl 2 (PPh 3) 2 (amine)] complexes, with amine = pyrrolidine (1), piperidine (2), or perhydroazepine (3), were investigated as a function of time, temperature, and concentrations of monomers and 2-bromoisobutyrate as initiator. The plots of ln([M] 0 /[M]) vs. time and molecular weights vs. monomer conversion were linear and the dispersity indexes decreased with increasing monomer conversions. The complexes 1, 2, and 3 were able to mediate the polymerizations with acceptable rate and level of control. Differences in the rate and control of polymerization were observed in the order 3 > 2 > 1 for both monomers. The activities were discussed considering the steric hindrance and electronic characteristics of the amines as ancillary ligands in the metal centres, considering studies by cyclic voltammetry and NMR.

Monometallic and heterobimetallic ruthenium (II) and palladium (II) complexes based on a pyridine‐hydrazone ligand as bifunctional catalysts for ROMP of norbornene and ethylene polymerization

“…[17][18][19] Since Grubbs and Schrock discovered systems capable of polymerizing cyclic olefins by ROMP, complexes containing Ru (II), Mo (II), Rh (II), and W (II) have been the subject of extensive studies that aimed to obtain well-defined polyolefins. [20][21][22][23][24][25][26] Our research group has been interested in complexes of the type [Ru (arene)(amine)Cl 2 ], which have exhibited good activity in the metathesis of norbornene (NBE) and present the possibility of addition of functionalized groups. [25,26] In a recent progress, we reported the synthesis, full characterization, and application of a Ru-Ni heterobimetallic complex as catalyst for both ROMP and ethylene polymerization.…”

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

“…In our research group, noncarbene ruthenium-based complexes have been studied for ROMP and ATRP. [22][23][24][25][26][27][28][29][30][31][32][33][34][35][36][37][38][39][40] Many of these compounds have exhibited good activity, forming polymers and copolymers in high yields, with different thermal and morphological characteristics. Among these precatalysts, ruthenium amine compounds have produced polymers from norbornene (NBE) and norbornadiene (NBD) by ROMP and controlled methyl methacrylate (MMA) and styrene (St) polymerization via ATRP.…”

“…Ruthenium complexes bearing p ‐cymene with different types of ligands such as phosphines, Schiff bases, and N ‐heterocyclic carbenes with a general formula of [RuCl 2 ( p ‐cymene)(L)] have been investigated as ROMP or ATRP catalysts. In our research group, noncarbene ruthenium‐based complexes have been studied for ROMP and ATRP . Many of these compounds have exhibited good activity, forming polymers and copolymers in high yields, with different thermal and morphological characteristics.…”