Computational studies rhodium catalysis

One computational study see Molecular Orbital Theory) has appeared using RhCl(PH3)2 to model the rhodium-catalyzed hydroboration of ethylene see Hydroboration Catalysis). Both associative and dissociative pathways were examined (equation 47). In the associative path, three possible... 

The ability to harness alkynes as effective precursors of reactive metal vinylidenes in catalysis depends on rapid alkyne-to-vinylidene interconversion [1]. This process has been studied experimentally and computationally for [MC1(PR3)2] (M = Rh, Ir, Scheme 9.1) [2]. Starting from the 7t-alkyne complex 1, oxidative addition is proposed to give a transient hydridoacetylide complex (3) vhich can undergo intramolecular 1,3-H-shift to provide a vinylidene complex (S). Main-group atoms presumably migrate via a similar mechanism. For iridium, intermediates of type 3 have been directly observed [3]. Section 9.3 describes the use of an alternate alkylative approach for the formation of rhodium vinylidene intermediates bearing two carbon-substituents (alkenylidenes). 

In this chapter, we have highlighted the important new developments within computational chemistry over the last decade or so, which have enabled near-quantitative description of transition metal-catalyzed reactions. We have also introduced some of the most popular experimental mechanistic tools such as determination of KlEs and Hammett substituent effects. The level of accuracy that can be expected is highlighted through a series of case studies performed over the last 5 years and includes catalysis performed by rhodium, iridium, palladium, and ruthenium. The combined use of experimental and theoretical methods have in all cases led to additional insights that would not have been possible using either of the two separately. The inclusion of experimental results... 

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