New bis(azolylcarbonyl)pyridine chromium(III) complexes as initiators for ethylene polymerization
Loading...
Date
2011
Journal Title
Journal ISSN
Volume Title
Publisher
ELSEVIER SCIENCE SA
Abstract
Reaction of 2,6-pyridinedicarbonyl dichloride with 3,5-dimethylpyrazole and 1H-indazole, respectively, yield the tridentate ligands 2,6-bis(3,5-dimethylpyrazol-1-ylcarbonyl)pyridine (1) and 2,6-bis(indazol-1-ylcarbonyl)pyridine (2). The molecular structure of the new compound (2) was determined by single-crystal X-ray diffraction. These ligands react with CrCl3(THF)(3) in THF to form neutral complexes of general formula [CrCl3{2,6-bis(azolylcarbonyl)pyridine-N,N,N}] (3, 4) which were isolated in high yield as air stable green solids and characterized by elemental analysis, magnetic moment, IR, and mass spectroscopies. Theoretical calculations predict that the thermodynamically preferred structure of the complexes is the fac configuration. After reaction with methylaluminoxane (MAO) the chromium(III) complexes are active for the polymerization of ethylene. (C) 2011 Elsevier B.V. All rights reserved.
Description
Keywords
Chromium, Tridentate ligands, Theoretical studies, Ethylene polymerization, X-RAY STRUCTURES, COPPER(II) COMPLEXES, TRIDENTATE LIGANDS, METAL-COMPLEXES, CATALYSTS, OLIGOMERIZATION, IRON, ENERGY, APPROXIMATION, BEHAVIOR