Mercury(II) Complexes with Heterocyclic Thiones − Preparation and Characterization of the 1:1 and 1:2 Mercury(II) Complexes with Benzo-1,3-imidazole-2-thione

Abstract

A series of complexes HgX2(bzimtH2) and HgX2(bzimtH2)2 (X = Cl−, Br−, I−, SCN−; bzimtH2 = benzo‐1,3‐imidazole‐2‐thione) was obtained by reaction of the mercury(II) salts with benzo‐1,3‐imidazole‐2‐thione in the appropriate molar ratio (1:1 or 1:2). Hg(bzimtH)2 was obtained by the deprotonation of bzimtH2 with mercury(II) acetate (irrespective of the molar ratio of the reactants). The complexes were characterised by chemical and thermal analysis, IR, 1H, and 13C NMR spectroscopy, and some [HgX2(bzimtH2), X = I− and HgX2(bzimtH2)2, X = I− and SCN−] by X‐ray single crystal diffractometry. 1H and 13C NMR spectroscopic measurements in dimethyl sulphoxide revealed that the sulphur atom is coordinated to the mercury centre. The greatest complexation effects on the chemical shifts were observed for the thione carbon atom and thioamide proton. The crystal structures of HgI2(bzimtH2)2 and Hg(SCN)2(bzimtH2)2·C2H5OH consist of discrete monomeric molecules with halide or pseudohalide donor atoms and thione sulphur atoms tetrahedrally coordinated to the mercury atom. The structure of HgI2(bzimtH2) is polymeric with a trigonal bipyramidal 3 + 2 coordination geometry around the mercury atom. Polymerisation occurs through Hg···I interactions with neighbouring molecules. The distribution of the π‐electron density in bzimtH2 corresponds to the thioketo tautomeric form in the solid state, and also in the DMSO solution of the complexes. Intermolecular hydrogen bonds of the type N−H···N, N−H···S and N−H···I are observed.

Crystal structures of [Hg(N-ethylthiourea)2(CN)2] and [Hg(N-propylthiourea)2(CN)2]

“…The thiourea ligands behave as Sdonors and bind in a terminal mode although the bridging mode has also been observed in some other metal-thioureas systems [33]. The Hg-S and Hg-C bond distances and most of the bond angle values are in agreement with those observed in the other reported complexes [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20]34]. The Hg-C distance in 1 (2.065(6) Å) is found to be somewhat longer than that in 2 (2.055(14) Å and 2.062(15) Å).…”

Homoleptic Group 12 Metal Bis(mercaptoimidazolyl)borate Complexes M(BmR)2 (M = Zn, Cd, Hg)

“…Likewise, downfield shifts of up to 6.8 ppm for the imidazolyl carbons in their 13 C NMR spectra were measured upon complexation to the metals. However, upfield chemical shifts of between 3.8 and 10.4 ppm were found for the thione carbons, a phenomenon also verified for the tris(mercaptoimidazolyl)borate derivatives [Tm tBu ]MBr (M = Zn, Cd, Hg) 5 and various other group 12 metal thione complexes …”

Solution and Solid-State Study of Heteroleptic Hg(II)-Thiolates: Crystal Structures of [Hg4I4(SCH2CH2NH2)4] and [Hg4I8(SCH2CH2NH3)2]n·nH2O

“…The NH···S distances observed in 1 (avg 3.442 Å) are in the lower range of those observed for tetrahedral Hg(II) complexes with similar interactions (3.398−3.733 Å). , It is quite interesting to observe that only N2 is involved with S, whereas N1 is involved with only I. This might be due to the orientation of the molecules in the packing structure.…”