Abstract

The metal carbonyl clusters have been recognized as one of the most successful organometallic complexes with extensive catalytic applications. In this paper, we carried out a DFT study of the stability, electronic structure and thermodynamic properties of the intermediates [M-3(CO)(11)] and [M-3(CO)(10)] in the synthesis of [M-3(2,3-bpp)(CO)(10)] (M=Ru and Os). CO binding energy analysis revealed that [M-3(CO)(10)(mu-CO)], [Ru-3(CO)(8)(mu-CO)(2)] and [Os-3(CO)(6)(mu(3)-CO)(2)(mu-CO)(2)] are the most stables compounds due to the presence of bridge carbonyls which favor a covalent interaction. Sigma donation from the carbonyl to metal d orbital is the most significant contribution. Moreover, spectroscopic and computational studies indicated that [Ru-3(2,3-bpp)(CO)(10)] is in good agreement with the analogues osmium complex. Regarding the pathway associated to the formation of [M-3(2,3-bpp)(CO)(10)] we have found that the determinant step is the dissociation of a second CO axial into [M-3(CO)(10)(mu-CO)]. Thus, unsaturated metal carbonyl intermediates exert a thermodynamic and kinetically control as consequence of the orbital reorganization.