Theoretical study of the rhenium–alkane interaction in transition metal–alkane -complexes

Metal–alkane binding energies have been calculated for [CpRe(CO)2](alkane) and [(CO)2M(C5H4)C'C(C5H4)M(CO)2](alkane), where M Re or Mn. Calculated binding energies were found to increase with the number of metal–alkane interaction sites. In all cases examined, the manganese–alkane binding energies were predicted to be significantly lower than those for the analogous rhenium–alkane complexes. The metal (Mn or Re)–alkane interaction was predicted to be primarily one of charge transfer, both from the alkane to the metal complex (70–80% of total charge transfer) and from the metal complex to the alkane (20–30% of the total charge transfer).