Rodriguez J, Boudjelel M, Mueller LJ, Schrock RR, Conley MP. Ring Contraction of a Tungstacyclopentane Supported on Silica: Direct Conversion of Ethylene to Propylene.
J Am Chem Soc 2022;
144:18761-18765. [PMID:
36197795 DOI:
10.1021/jacs.2c07934]
[Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The reaction of W(NAr)(13C4H8)(OSiPh3)2 (1) (NAr = 2,6-diisopropylphenylimido) with silica partially dehydroxylated at 700 °C (SiO2-700) is highly dependent on the reaction conditions. The primary product of this reaction is W(NAr)(13C4H8)(OSiPh3)(OSi(O-)3) (2) when the reaction is carried out in the dark. Grafting 1 onto SiO2-700 in ambient lab light results in the formation of 2, W(NAr)(13CH213CH2)(OSiPh3)(OSi(O-)3) (4), and one isomer of square-pyramidal W(NAr)(13CH213CH(13Me)13CH2)(OSiPh3)(OSi(O-)3) (3). Heating 2 to 85 °C for 6 h results in the formation of 3, 4, W(NAr)(13CH(13Me)13CH213CH2)(OSiPh3)(OSi(O-)3) (5), and W(NAr)((13CH2)213CH(13Me)(13CH2)2)(OSiPh3)(OSi(O-)3) (6). Photolysis of 2 with blue LEDs (λmax = 450 nm) produces 4, both isomers of 3, 5, and free ethylene. In the presence of excess ethylene and blue LED irradiation at 85 °C, 1/SiO2-700 catalyzes the direct conversion of ethylene to propylene.
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