Stereomutation at an Octahedral Transition-Metal Center: Energetics of Hydride Transit between Syn and Anti Faces of the Bis(diphenylphosphinopropyl)(methyl)silyl (biPSi) Complex RuH(biPSi)(CO)<sub>2</sub>
作者:Xiaobing (“Joe”) Zhou、Stephen R. Stobart
DOI:10.1021/om0100939
日期:2001.5.1
Reaction of SiH(Me)(CH2CH2CH2PPh2)(2), "bi-PSiH", with Ru(PPh3)(2)(CO)(3) affords quantitatively the phosphinoalkylsilyl complex RuH(biPSi)(CO)(2), as a mixture of the crystallographically characterized syn diastereomer 3-s and its anti correspondent 3-a; subsequent treatment with CCl4 then (LiAlH4)-H-2 provides access to the deuterioisotopomer (RuH)-H-2(biPSi)(CO)(2), 3-d(1). Slow stereomutation of pure 3-s to art equilibrium mixture 3-a/3-a (4.5:1, 295 K) occurs with DeltaG(295)(double dagger), 102(5) kJ mol(-1); DeltaH(295)(double dagger), 113(7) kJ mol(-1); DeltaS(295)(double dagger), 37(2) J K-1 mol(-1); this is not accompanied by incorporation of external (CO)-C-13, shores only a minor isotope effect us 3-d(1), and is concluded to be nondissociative.