Theoretical investigation of ground- and excited-state properties of fluorenone-alkynyl Hg(II) complexes: The tuning of electronic spectroscopy

The electronic properties of RCCH (1), [RCCHgCH3] (2), [CH3HgCCRCCHgCH3] (3) and [RCCHgCCR] (4) (R = fluoren-9-one) in the ground and singlet/triplet excited states were explored theoretically. Calculations indicate that geometry parameters of 1-4 change slightly on going from ground state to excited state. Experimental spectra were well reproduced by the combined TD-DFT (time-dependent density functional theory) and PCM (Polarized-Continuum Model) calculations. With increasing methylmercury and/or fluorenone groups, the featured absorption and emission bands of complexes are redshifted. The investigation reveals such a variation can tune excitation energies but not change transition nature.