Application of the copper(II)-aminosilane catalysts in the oxidative polymerization of 2,6-dimethylphenol

Abstract

The aim of this work was to examine the aminosilane ligands for the copper(II) salts and their application as catalysts for the oxidative polymerization of 2,6-dimethylphenol leading to poly(2,6-dimethyl-1,4-phenylene ether) (PPE) [also known as poly(phenylene oxide) (PPO)] formation. As aminosilane ligands, silane derivatives containing primary and/or secondary amino groups were tested. Among aminosilanes used, PPE was only obtained when N-methylaminopropyltrimetoxysilane (MAPTMS) as a ligand for copper(II) was used. CuCl 2 and CuBr 2 were compared as catalyst precursors for 2,6-dimethylphenol polymerization and influence of N/Cu molar ratio in the range from 80 to 160 on PPE yield and its M w was tested. It was observed, that with increasing N/Cu molar ratio from 80 to 120, both PPE yield and M w increased. PPE with the highest M w was obtained when CuBr 2 -MAPTMS as a catalyst was used. At N/Cu molar ratio equal to 160, a decrease in PPE M w obtained with use of both precursors and decrease in PPE yield for CuCl 2 -MAPTMS catalyst were noticed. The condensed nanoorganosilicon particles of spherical shape well dispersed in PPE were determined in the polymer matrix. The UV-Vis studies showed that, strong ligand field of the aminosilane ligand easier electron transfer from monomer to Cu(II) and thus polymerization facilitate.

New Optically Active tert-Butylarylthiophosphinic Acids and Their Selenium Analogues as the Potential Synthons of Supramolecular Organometallic Complexes: Syntheses and Crystallographic Structure Determination

“…The crystal structure investigations of the enantiomeric forms of thioacids (1) and selenoacids (2) (Scheme 1), by using the X-ray method, were performed to obtain the critical and important information connected with their future application as ligands in organometallic catalysts. Thus, for example, after complexation with the copper-containing compounds, those chiral complexes could be used as the catalysts in the reactions in which copper acetate is routinely used as a catalyst (a "standard" asymmetric Henry reaction [22][23][24][25][26], the modified Ullmann [27,28], or Sonogashira [29] coupling reactions) and the reactions of oxidative polymerization [30]. Therefore, the newly proposed complexes of our enantiomerically pure chiral thio-and seleno-acids with metals could eliminate the use of extra chiral ligands in chemical reactions.…”