The position of the sulfur atom in the thienyl group of 6-(thienyl)-2-(imino)pyridine ligands strongly affects the catalytic activity of the corresponding tetrahedral high-spin dihalide Co-II complexes in the oligomerization of ethylene to alpha-olefins upon activation with methylaluminoxane (MAO). Complexes with the sulfur atom in the 3-position of the thienyl ring catalyze the selective conversion of ethylene to 1-butene, while catalysts containing thien-2-yl groups give C-4-C-14 alpha-olefins. In situ EPR experiments showed the occurrence of a spin state changeover with the formation of low-spin Co-II species upon activation of the catalyst precursors by MAO. DFT calculations suggest that only thien-2-yl rings allow for the coordination of the sulfur atom to the cobalt center in the MAO-activated systems.

Electronic influence of the thienyl sulfur atom on the oligomerization of the ethylene by cobalt, pyridine catalysis / C. Bianchini; D. Gatteschi; G. Giambastiani; I.G. Rios; A. Ienco; F. Laschi; C. Mealli; A. Meli; L. Sorace; A. Toti; F. Vizza. - In: ORGANOMETALLICS. - ISSN 0276-7333. - STAMPA. - 26:(2007), pp. 726-739. [10.1021/om0609665]

Electronic influence of the thienyl sulfur atom on the oligomerization of the ethylene by cobalt, pyridine catalysis

BIANCHINI, CLAUDIO;GATTESCHI, DANTE;G. Giambastiani;SORACE, LORENZO;
2007

Abstract

The position of the sulfur atom in the thienyl group of 6-(thienyl)-2-(imino)pyridine ligands strongly affects the catalytic activity of the corresponding tetrahedral high-spin dihalide Co-II complexes in the oligomerization of ethylene to alpha-olefins upon activation with methylaluminoxane (MAO). Complexes with the sulfur atom in the 3-position of the thienyl ring catalyze the selective conversion of ethylene to 1-butene, while catalysts containing thien-2-yl groups give C-4-C-14 alpha-olefins. In situ EPR experiments showed the occurrence of a spin state changeover with the formation of low-spin Co-II species upon activation of the catalyst precursors by MAO. DFT calculations suggest that only thien-2-yl rings allow for the coordination of the sulfur atom to the cobalt center in the MAO-activated systems.
2007
26
726
739
C. Bianchini; D. Gatteschi; G. Giambastiani; I.G. Rios; A. Ienco; F. Laschi; C. Mealli; A. Meli; L. Sorace; A. Toti; F. Vizza
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Utilizza questo identificatore per citare o creare un link a questa risorsa: https://hdl.handle.net/2158/314340
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