Syntheses, crystal and molecular structures, and properties of some new phenylmercury(ii) dithiolate complexes

Abstract

A series of new phenylmercury(II) dithio complexes [PhHg(Buⁿ₂dtc)] (1; Buⁿ₂dtc⁻ = di-n-butyldithiocarbamate), [PhHg(morphdtc)] (2; morphdtc⁻ = morpholinedithiocarbamate), [PhHg(Bz₂dtc)] (3; Bz₂dtc⁻ = dibenzyldithiocarbamate), [PhHg(methoxethxant)] (4; methoxethxant⁻ = 2-methoxyethylxanthate) [(PhHg)₂NED] (5; NED²⁻ = 1-nitroethylene-2,2-dithiolate) and [(PhHg)₂CDC] (6; CDC²⁻ = cyanodithioimidocarbonate) have been prepared and characterized by elemental analysis, UV-Vis, IR, ¹H and ¹³C NMR spectra and mass spectrometry. The crystal structures of 1, 2 and 3 showed a linear Hg(II) core at the center of the molecules. The weak intra- and intermolecular Hg⋯S interactions provide a molecular chain framework. The reaction of PhHgO₂CCH₃ with Buⁿ₂dtcH gave the known dimeric complex Hg(Buⁿ₂dtc)₂ while the Ni(O₂CCH₃)₂ mediated reaction gave 1 instead of the expected heterobimetallic complex [PhHgNi(Buⁿ₂CS₂)₂]O₂CCH₃ which has been corroborated by natural charges at each atom obtained at the density functional level (DFT) of theory. Upon excitation at 358 nm 3 exhibited a medium strong photoluminescence emission at 420 nm as a consequence of intraligand π → π* transitions. The electronic absorption bands of 3 were assigned from time dependent density functional theory (TD-DFT) calculations. Geometrical configurations of 4, 5 and 6 have been optimized using the DFT method. All of the complexes are weakly conducting (σ_rt ∼ 10⁻¹² S cm⁻¹). However 2 and 6 exhibited semiconductivity with band gaps of 0.39 and 0.94 eV respectively.