Luminescent Properties of Mercury-taining Diethynylfluorene Derivatives

Excited state structures and spectroscopic properties of mercury(II) complexes, Hg-TFT( 1 ) and its electron-withdrawing substituents Hg-TFOT ( 2 ), Hg-TFCNT ( 3 ), where TFT = diethynylfluorenyl, TFOT = diethynyl-fluorenone, and TFCNT = diethynyl-[9-(dicyanomethylene) fluorene], were studied using singlet excitation configuration interaction (CIS) and time-dependent density functional theory(TDDFT) methods. The results of the theoretical calculations indicate that the electron-withdrawing substitutions lead to a significant decrease in the energy gap between the ground state and the first excited states. In the case of Hg-TFCNT, the second singlet excited state (S 2 ) may contribute to the luminescence because of its large S 1 - S 2 separation.