Laura K. Stultz, M. Huynh, R. Binstead
Jun 10, 2000
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0
Influential Citations
53
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Journal
Journal of the American Chemical Society
Abstract
The kinetics of oxidation of cyclohexene, cyclohexen-1-ol, and indene by cis-[RuIV(bpy)2(py)(O)]2+ (bpy = 2,2‘-bipyridine and py = pyridine) have been studied in CH3CN. The reactions are first-order in both RuIV=O2+ and substrate in an initial, rapid stage in which Ru(IV) is reduced to Ru(III). The rate constants are 0.16 ± 0.01, 1.10 ± 0.02, and 5.74 ± 0.74 M-1 s-1 for cyclohexene, cyclohexen-1-ol, and indene, respectively. A k(α,α‘-H4)/k(α,α‘-D4) kinetic isotope effect of 21 ± 1 is observed for the oxidation of cyclohexene. At a 2:1 ratio of RuIVO2+ to olefin, the reactions of RuIVO2+ with either cyclohexene or indene give RuII−NCCH32+ and the 4-electron ketone products, 2-cyclohexen-1-one and indenone, respectively, as identified by GC−MS. As the ratio of cyclohexene to RuIVO2+ is increased, cyclohexen-1-ol becomes an increasingly competitive product. The mechanisms of these reactions are highly complex. They involve two distinct stages and the formation and subsequent reactions of RuIII-substrate boun...