TD-DFT Calculation on UV-Vis Spectra of the Complex 8-((Trimethoxysilyl)methylthio)quinoline⋅ZnCl2

ArticleinJournal of Solution Chemistry 40(1):147-153 · January 2011with35 Reads
Impact Factor: 1.18 · DOI: 10.1007/s10953-010-9630-x

    Abstract

    The electronic structure and absorption spectra properties of the complex 8-((trimethoxysilyl)methylthio)quinoline⋅ZnCl2 in the gas phase and in acetonitrile (MeCN) have been investigated by means of DFT/TD-DFT calculations. Calculation results
    indicate that the broad and weak experimentally observed absorption bands of the complex in MeCN at 335.6nm originates from
    spin-forbidden singlet-triplet transitions, but the other experimentally observed absorption bands at 318.5nm, 310.6nm and
    237.5nm arise from spin-allowed singlet-singlet transitions. Inclusion of MeCN as solvent leads to dramatic changes in the
    electronic structures and energy levels of the frontier molecular orbitals of the complex, and hence transition mechanisms
    of the absorption bands are also changed. For the complex, whether in the gas phase or in MeCN, the metal Zn does not participate
    in the transitions involved, in the gas phase the calculated lowest-energy absorption band of the complex comes from π→π
    ∗ mixed with n→π
    ∗ transitions with LLCT (ligand-to-ligand charge transfer) character, while in MeCN, the calculated lowest-energy absorption
    band is of LLCT/ILCT (intra-ligand charge transfer) character.

    Keywords8-((Trimethoxysilyl)methylthio)quinoline⋅ZnCl2
    -TD-DFT-Solvent effect-Transition mechanism