Molecules 2006, 11(4), 298-308; doi:10.3390/11040298
Article

Catalytic Properties of the Dioxomolybdenum Siloxide MoO2(OSiPh3)2 and its 2,2'-Bipyridine Adduct MoO2(OSiPh3)2(bpy)

Department of Chemistry, CICECO, University of Aveiro, 3810-193 Aveiro, Portugal
* Author to whom correspondence should be addressed.
Received: 31 March 2006; in revised form: 10 April 2006 / Accepted: 10 April 2006 / Published: 12 April 2006
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Abstract: The tetrahedral triphenylsiloxy complex MoO2(OSiPh3)2 (1) and its Lewis baseadduct with 2,2'-bipyridine, MoO2(OSiPh3)2(bpy) (2), were prepared and characterised byIR/Raman spectroscopy, and thermogravimetric analysis. Both compounds catalyse theepoxidation of cis-cyclooctene at 55 oC using tert-butylhydroperoxide (t-BuOOH) isdecane as the oxidant, giving 1,2-epoxycyclooctane as the only product. The best resultswere obtained in the absence of a co-solvent (other than the decane) or in the presence of1,2-dichloroethane, while much lower activities were obtained when hexane oracetonitrile were added. With no co-solvent, catalyst 1 (initial activity 272 mol·molMo-1·h-1for a catalyst:substrate: oxidant molar ratio of 1:100:150) is much more active than 2(initial activity 12 mol·molMo–1·h–1). The initial reaction rates showed first orderdependence with respect to the initial concentration of olefin. With respect to the initialamount of oxidant, the rate order dependence for 1 (1.9) was higher than that for 2 (1.6).The dependence of the initial reaction rate on reaction temperature and initial amount ofcatalyst was also studied for both catalysts. The lower apparent activation energy of 1 (11kcal·mol–1) as compared with 2 (20 kcal·mol–1) is in accordance with the higher activity ofthe former.
Keywords: Dioxomolybdenum(VI) complexes; siloxide ligands; Lewis base adducts; 2; 2'-bipyridine; olefin epoxidation.

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MDPI and ACS Style

Bruno, S.M.; Monteiro, B.; Balula, M.S.; Lourenço, C.; Valente, A.A.; Pillinger, M.; Ribeiro-Claro, P.; Gonçalves, I.S. Catalytic Properties of the Dioxomolybdenum Siloxide MoO2(OSiPh3)2 and its 2,2'-Bipyridine Adduct MoO2(OSiPh3)2(bpy). Molecules 2006, 11, 298-308.

AMA Style

Bruno SM, Monteiro B, Balula MS, Lourenço C, Valente AA, Pillinger M, Ribeiro-Claro P, Gonçalves IS. Catalytic Properties of the Dioxomolybdenum Siloxide MoO2(OSiPh3)2 and its 2,2'-Bipyridine Adduct MoO2(OSiPh3)2(bpy). Molecules. 2006; 11(4):298-308.

Chicago/Turabian Style

Bruno, Sofia M.; Monteiro, Bernardo; Balula, Maria S.; Lourenço, Catarina; Valente, Anabela A.; Pillinger, Martyn; Ribeiro-Claro, Paulo; Gonçalves, Isabel S. 2006. "Catalytic Properties of the Dioxomolybdenum Siloxide MoO2(OSiPh3)2 and its 2,2'-Bipyridine Adduct MoO2(OSiPh3)2(bpy)." Molecules 11, no. 4: 298-308.

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