The mechanisms on the model reaction of [(Ind)Rh(CO)(2)Me]BF4 with nbd have been studied using density functional theory. Two pathways are proposed due to the rotation of indenyl group. Our results of calculations predict that the methyl migration is the rate-determining step, and that the rotation of indenyl group around the Rh-indenyl axis plays an important role in lowering the reaction barrier. Theoretical studies also reveal that this kind of reaction is favorable thermodynamically as a result of the relief of ring strain as nbd coordinating to the metal center and the chelation effect arisen from the cyclometallation. (c) 2006 Elsevier B.V. All rights reserved.