THEORETICAL-STUDY OF THE ACTIVATION OF C-C BONDS BY TRANSITION-METAL ATOMS

Quantum chemical model studies have been performed for the transition metal activation of C-C bonds in ethane, cyclopropane, and cyclobutane. Both the ethane and cyclobutane reactions have been studied for the entire second row of transition metal atoms, for both equilibrium states and transition states. For cyclobutane the first transition metal series has also been studied. The cyclopropane reaction has only been fully studied for rhodium and palladium. The quantum chemical calculations include a size-consistent treatment of electron correlation of all the valence electrons with fairly large basis sets including f functions on the metal. The geometries have been fully optimized. Palladium is found to have the smallest barriers for the C-C bond breaking reaction, and the C-C bond in cyclopropane is easiest to break, in line with general experimental experience for transition metal complexes.