Ultraviolet spectrum and molecular orbital studies of bis(4-R-1,2-diphenylcyclo-pentadienylzirconium(IV) dichlorides complexes (RZH, Me, Ph)

The ultraviolet spectrum was determined by experiment for the titled compounds. Their molecular orbits were calculated with the methods of DFT, and the ultraviolet spectra are calculated by TD-DFT method. The results show that the main composition of LUMO for the titled compounds is the D-orbit of zirconium, P-orbits of chlorine and p-orbit of cyclopentadienyl ring. The main composition of HOMO is the D-orbit of zirconium, P-orbits of chlorine and p-orbit of phenyl ring, without p-orbit of cyclopentadienyl ligand, because the p-orbit energy level of cyclopentadienyl ring becomes lower due to the interaction between the D-orbit of zirconium and p-orbit of cyclopentadienyl ligand. The UV spectra are the electron transition from HOMOK1, HOMOK2 and HOMOK3 to LUMOC1, LUMOC2, not from HOMO to LUMO. The molecular orbits of interaction between zirconium and cyclopentadienyl ligand are HOMOK4, HOMOK3 HOMOK2 and HOMOK1 which are lower than HOMO in energy level. q 2004 Elsevier B.V. All rights reserved.