Novel mercury(II) complexes of 1,3-dithiole-2-thiones containing the 2-pyridyl moiety: syntheses, X-ray crystal structures and solution behavior

Abstract The mercury(II) complexes of 5-pyridin-2-yl-5,6-dihydro-[1,3]dithiolo[4,5- b ][1,4]dithiin-2-thione (2PyEDT-DTT: 1 ), [Hg(2PyEDT-DTT)X 2 ] (X=Cl ( 2a ), Br ( 2b ) and I ( 2c )) were obtained from the reaction of HgX 2 and 2PyEDT-DTT. These complexes adopt a dimeric arrangement of [Hg(2PyEDT-DTT)X 2 ] 2 through intermolecular Hg⋯N and Hg⋯S interactions. According to the FT-IR/UV–Vis/NMR spectroscopy data, these intermolecular interactions are cleaved in media containing trace H 2 O. [Hg(2PyDT-DTT) 2 ] ( 3 ; 2PyDT-DTT: 5-(1-pyridin-2-yl-vinylsulfanyl)-2-thioxo-[1,3]dithiole-4-thiolate) was isolated from the filtrate of 2 . The Hg(II) ion is located in a center of symmetry and adopts a distorted octahedral geometry with four sulfur atoms (two from the thiolate groups and two from the sulfide groups) and two nitrogen atoms from the pyridyl group. The time-dependent solution UV–Vis and 1 H NMR measurements showed the transformation of 2PyDT-DTT to 2PyEDT-DTT caused by trace H 2 O in organic solvents.