Organometallic Reactivity and Applied Quantum Chemistry — Some Aspects of CH-Activation

The rapid development of computational facilities and of increasingly efficient, highly sophisticated quantum chemical methodologies and programs has certainly reached a point now, where ab initio calculations for small molecules, composed of light atoms, appear to provide numerically accurate predictions of structures and energies, comparable or even superior to experimental data. The ultimate goal of molecular quantum chemistry, the reliable a priori prediction of geometry, physical properties and in particular of chemical reactivity in a quantitative sense, based upon “first principles” alone, is, however, still quite far away for organometallic species involving transition metals or heavy main group elements. Even today’s best “state of the art” electronic structure calculations for such systems only represent rather crude approximations to the “truth”, at least as far as molecules of realistic size and of actual relevance to experimental chemists are concerned. On the other hand transition metal organometallics have been playing and obviously will continue to play a vital and important role in synthetic chemistry. This is not only true as far as large scale industrial production through homogeneous (or heterogeneous) catalysis is concerned, but also in the field of stoichiometric, highly selective multistep transformations leading to high value, small scale fine chemicals, or in various other areas of present or future interest to academic and industrial research (Parshall 1987).