PM3(tm) Analysis of Transition-Metal Complexes

Transition-metal complexes with prototypical ligands were studied using the PM3(tm) semiempirical method. The calculated complexes in this paper include 35 halides, 7 aqua complexes, 7 tris(ethylenediamine) complexes, 27 multiply bonded complexes, and 19 organometallics. PM3(tm)-predicted geometries were compared with the experimental data from 1200 crystal structures. For multiply bonded complexes, a comparison was also made between PM3(tm) and higher level calculations employing effective core potentials and MP2 wave functions. In general, PM3(tm) was quite successful in predicting the geometries of transition-metal complexes, especially those incorporating metals from the left-hand side of the transition series.