Reactions of ground state Cr + with C 2H 6, C 2H 4, cyclo-C 3H 6, and cyclo-C 2H 4O: bond energies for CrCH +n ( n = 1–3)

Abstract

The reaction of ground state chromium ions with ethane, ethene, cyclopropane and ethylene oxide has been studied using guided ion beam mass spectrometry. A predominant process in all these reactions is CC bond cleavage to form CrCH + n . Modeling of the translational energy dependence of endothermic reactions yields the bond energies D 0(Cr +−CH) = 75±8, D 0(Cr +−CH 2) = 53.8±1.9, and D 0(Cr +−CH 3) = 30.2±2.3 kcal mol −1. These values provide a direct comparison between experiment and theoretical calculations suggesting that Cr + forms a single, double, and triple bond with the ligands CH 3, CH 2, and CH, respectively. Bond energies for CrO, CrO +, CrC 2H + 2, CrC 2H + 4, and CrCO + are also evaluated.