Vibronic activation of the CO molecule in transition-metal clusters in the one-parameter approximation

Abstract

VIBRONIC ACTIVATION OF THE CO MOLECULE IN TRANSITION-METAL CLUSTERS IN THE ONE-PARAMETER APPROXIMATION A. P. Svitin, S. S. Budnikov, I. B. Bersuker, and D. V. Korol'kov UDC 539.193+541.128 In order to study the high catalytic activity of transition-metal clusters in reactions involving carbon monoxide, we have investigated the vibronic activation of CO molecules in mononuclear [Mo(CO)6], binuclear [Co2(CO),, Mn~(CO) xo], trinuc!ear [Os,(CO) I~], and hexa- nuclear [Rh6(CO):6] complexes. In doing this, use was made of the vibronic theory of the elementary act of catalytic action, approved in [1-5]. In the present work the greatest amount of attention has been paid to a consideration of the nature of the changes in the activation energies of reactions involving the participation of CO (regardless of the actual nature of the reaction) as a function of the mode of coordination of the CO groups in the clusters. Therefore, first of all, we considered the vibronic destabilization of a CO mole- cule upon its coordination to one or several (two-three) M atoms in mono- and polynuclear carbonyl complexes. According to [i-5], the change in the energy of activation AD of a coordinated molecule is related to the energy of activation D of the same process but without the participation of a catalyst by the equation