THE THERMAL-ENERGY GAS-PHASE REACTION BETWEEN D2CC- AND O-2

Rate constants and product branching ratios for the reaction between vinylidene anion, D2CC-, and molecular oxygen have been determined at 90 and 297 K. The overall measured rate constants are 3.8 × 1010 and 4.5 × 1010 cm3 s-1, respectively. The present study has found the reaction to be more complicated than originally reported in the literature. The ionic products observed, listed in order of decreasing abundance, are O2-, O-, C2D-, C2OD-, and OD-. In addition, a substantial associative electron detachment product channel was detected. The measured efficiency (27% at 90 K) of the charge-transfer channel, which produces O2- + C2D2, suggests that this reaction is driven by the exothermic isomerization of vinylidene (D2CC) to acetylene (DCCD) within the complex. This charge-transfer reaction would be endothermic if the neutral product were vinylidene but is exothermic for production of neutral acetylene. © 1990 American Chemical Society.