Pseudo second-order Jahn-Teller effects and symmetry considerations in transition metal polyhydride complexes Academic Article uri icon


  • Pseudo second-order Jahn-Teller distortions are proposed to explain why the equatorial hydride ligands in a series of cyclopentadienyl metal polyhydrides (Cp*ReH6, Cp*OsH5, Cp*IrH4) bend away from the Cp ring at such large angles. Restricted Hartree-Fock (RHF) geometry optimizations on models of these complexes where the Cp* ring has been replaced by a hydride reproduce these large distortions. Walsh diagrams and Mulliken populations have been used to show that the stability provided by distortion results from maximizing the overlap population between the hydride s orbitals and the metal d orbitals. This study also includes a comparison of previous work on the structures of d0 MH6 complexes with our work on d0 MH6 complexes. We found that an occupied d orbital has a significant effect on the geometry of this type of molecule due to the change in hybridization on the metal from sd5 to spd4. Symmetry arguments are demonstrated as a means to predict the low energy geometries of these complexes.

author list (cited authors)

  • Bayse, C. A., & Hall, M. B.

citation count

  • 8

publication date

  • June 1997