Reactivity of electrophilic Cp∗Ru(NO) complex towards alcohols
Treatment of the complex 1 Cp∗Ru(NO)(OTf) (OTf = OSO CF , Cp∗= η -C(CH ) ) with neat 2-propanol results in the rapid quantitative formation of the Ru(0) complex [Cp∗Ru(μ-NO)] and (CH ) C=O. Formation of H and CHDCl is detected when the reaction between 1 and 2-propanol occurs in CDCl , indicating possible formation of a short-lived metal hydride species. Similar results are observed upon treatment of 1 with ethanol and methanol, with formation of acetaldehyde and formaldehyde, respectively. The kinetics of the oxidation of 2-propanol by complex 1 is studied by H NMR spectroscopy in CH Cl at variable temperatures and the reaction is found to be first-order in complex 1 and in 2-propanol. The kinetic isotope effect for the reaction of 1 with (CD ) CD-OD at -11 °C is determined to be k /k = 2.0 (3). A mechanism for alcohol oxidation by electrophilic ruthenium (II) complexes via a β-hydrogen elimination step is proposed. The pre-equilibrium exchange step between complex Cp∗Ru(NO)(OTf) (1) and alcohol-coordinated species is examined by F and H NMR spectroscopy in CH Cl solution, where triflate substitution is found to be exothermic and entropically unfavorable. The synthesis and solid state structure of the chelate-stabilized complex diol salt [Cp∗Ru(NO)(HO-CH CH -OH)][2OTf] are discussed. 2 2 3 3 5 2 3 2 2 2 3 2 2 3 2 H D 2 2 2 2 2 5 1 19 1
Diaz, Jason; Rich, Kellee; Munie, Semeret; Zoch, Christopher R.; Hubbard, John L.; and Larsen, Anna S., "Reactivity of electrophilic Cp∗Ru(NO) complex towards alcohols" (2016). Faculty Articles Indexed in Scopus. 731.