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Synthesis of [2-(pyridin-2′-yl)phenyl]-mercury(II) arylthiosemicarbazonates: An unusual coordination mode of a deprotonated 2-formyl-(2-hydroxy-benzene)-thiosemicarbazone

1998; Elsevier BV; Volume: 17; Issue: 21 Linguagem: Inglês

10.1016/s0277-5387(98)00165-x

1873-3719

Tarlok S. Lobana, A. Sánchez, José S. Casas, A. Castiñeiras, J. Sordo, M.S. Garcı́a-Tasende,

Organometallic Compounds Synthesis and Characterization

The reactions of [2-(pyridin-2′-yl)phenyl]mercury(II) acetate with 2-formyl-benzene-(Hbtsc), 2-formyl-(2-hydroxybenzene)-(H2stsc) and 2-formyl-(4-methoxybenzene)-(Hmbtsc) thiosemicarbazones in ethanol in 1:1 ratio at room temperature formed [Hg(C6H4C5H4N)L] (L=btsc, 1; Hstsc, 2; mbtsc, 3). The derivative [Hg(C6H4C5H4N)L] 2 crystallises in the triclinic space group P\1 (n. 2), Z=2, R=0.0353 and V=906.8(3)Å3. Mercury is bonded strongly only to sulphur atom of thiosemicarbazonate anion [Hg–S, 2,357(2)Å] and Hg...N(3) distance of 3.126(6)Å, slightly less than the sum of the van der Waals radii (3.28 Å) shows a weak interaction. The pyridyl nitrogen binds strongly to Hg [Hg–N(4), 2.575(6)Å] with a short C(9)HgN(4) bite angle of 74.6(2)°, but Hg retains near linearity in CPhHgS bond angle [177.8(2)°]. 1H and 19;Hg NMR spectra in CDCl3 solution reveal two isomers (A and B) for each of 1–3 and probably also a third isomer (C) for 2. The similarity of 1H and 19;Hg data of B isomers (minor for 1 and 3; major for 2) clearly support that thiosemicarbazones are unidentate S-donors as established for crystallized B isomer of 2 (major) by X-ray study, with pyridyl nitrogen of 2-pyridylphenyl coordinating to Hg. The A isomers (major for 1 and 3; minor for 2) have presumably N3,S-coordinated thiosemicarbazonates with weak Hg–N(pyridyl) interaction and the Hg atom formally tetracoordinated.