AB INITIO STUDIES ON RH(I)- AND IR(I)-PHENYLACETYLENE COMPLEXES

The structures and energies for the intramolecular rearrangement in (HC≡CPh), M=Rh and Ir, complexes were studied by ab initio method at the Hartree-Fock and MP2 levels of theory. Three transition states in two pathways were optimized and characterized by frequency calculations. The activation energies for the process of π-type complex 1 to hydrido-alkynyl 2 have been computed to be relatively low 6.97 and 21.33 kcal/mol at MP2 level for Rh and Ir metals, respectively. However, the activation energies for a 1,2-hydrogen shift via t.s.3 have been computed to be high 50.83 and 60.05 kcal/mol for Rh and Ir metals.