title: Geometry and Electronic Structure of Titanabenzene and Its Valence Isomers.
abstract: Potentially aromatic metallocycles are of interest due to their possible use as experimental catalytic materials and to their assistance in developing theoretical understanding of metal-carbon bonds. Ab initio analysis of titanabenzene and its valence isomers reveals the lack of aromatic stability for the planar, heterosubstituted benzene molecule. The planar molecule is in fact a transition state on the potential energy surface. Due to a pseudo-Jahn-Teller effect, the planar titanabenzene molecule is predicted to be less stable than the Dewar-titanabenzene molecule by 25.9 kcal/mol. However, the most stable structural isomer of HTiC5H5is found to be the open-sandwich (η5-cyclopentadienyl)titanium(II) hydride structure that is a ground-state triplet and 50.3 kcal/mol lower in energy than Dewar-titanabenzene. Electronic structures and bonding within these valence isomers are presented from analysis of the population bond order density matrices based on the novel oriented valence quasi-atomic molecular orbitals (QUAOs) obtained from TCSCF wave functions.
authors.affiliation: Department of Chemistry, University of St. Thomas , St. Paul, Minnesota 55105, United States.
authors.forename: John R
authors.initials: JR
authors.lastname: Kummer
authors.affiliation: Department of Chemistry, University of St. Thomas , St. Paul, Minnesota 55105, United States.
authors.forename: Joseph M
authors.identifier: http://orcid.org/0000-0003-3818-9040
authors.initials: JM
authors.lastname: Brom