Mercury-sulphur stretching frequencies, synthesis and x-ray crystal structure of catena-μ-(3-dimethylammonio-1-propanethiolato)dichloromercury(II)

The crystal structure of the title compound has been determined. Crystals of HgC1₂{μ-S(CH₂)₃NH(CH₃)₂}] are monoclinic, space group P2₁/n, with a = 10.136(2), b = 6.519(1), c = 15.940(6) Å and β = 97.20(3)°. The structure consists of (---Hg---S---)_n helicoidal chains linked by hydrogen bonding, which give rise to chemically unconnected layers along the ( 02) planes. Each mercury is tetrahedrally coordinated to two terminal chlorine atoms and two bridging sulphur atoms. Assignments of ν_as(SHgS) and ν_s(SHgS) for this complex and its isostructural bromine analogue, and of ν_s(C1HgC1) and ν_s(BrHgBr) from IR and Raman spectroscopy are reported. Comparison of Hg---S frequencies with those reported for closely related compounds as well as correlation with Hg---S bond distances are made.