Synthesis, characterisation and study of mercury(II) chloride complexes with triphenylphosphine and heterocyclic thiones. The crystal structures of [(benzothiazole-2-thionato)(benzothiazole-2-thione)(bis-triphenylphosphine) chloro mercury(II)] and [(μ 2-dichloro){(bis-pyrimidine-2-thionato)mercury(II)}{(bis-triphenylphosphine)mercury(II)}] at 100 K

Abstract

Direct reaction of mercury(II) chloride with triphenylphosphine (PPh 3) and benzothiazole-2-thione (bzthtH) in the molar ratio of 1:1:2 results in the formation of the [Hg(PPh 3)(bzthztH)(bzthzt)Cl] ( 1) (bzthzt=the anion of benzothiazole-2-thione) while the reaction of mercury(II) chloride with triphenylphosphine (PPh 3) and pyrimidine-2-thione (pmtH) in the molar ratio of 1:1:1 gives [Hg 2Cl 2(PPh 3) 2(pmt) 2] ( 2) (pmt=the anion of pyrimidine-2-thione). The complexes have been characterised by their elemental analyses, melting points and their FTIR, far-IR spectroscopic data. The crystal structure of complex 1 which has been determined by single-crystal X-ray crystallography at r.t. reveals that the molecule is monomeric with tetrahedral geometry around the metal ion. A benzothiazole-2-thione molecule and a benzothiazole-2-thionato anion are coordinated, via sulfur atoms, to the mercury(II) ion [HgS(2A)=2.726(2) and HgS(2)=2.419(2) Å]. A triphenylphosphine molecule is also coordinated through a phosphorus atom to the metal ion [HgP=2.453(2) Å] while the tetrahedral geometry around the mercury is completed by a chlorine atom [HgCl=2.633(2) Å]. The complex is covalent in the solid state. The crystal structure of complex 2 which has also been established by single-crystal X-ray crystallography at 100(1) K shows that the molecule is binuclear and consists of two different moieties with tetrahedral geometry around each mercury(II) ion. One moiety consists of a mercury(II) ion with two phosphorus atoms from phosphine ligands and two bridging chlorine atoms, while the other consists of a mercury(II) ion and two sulfur atoms of pyrimidine-2-thionato ligands. The entire complex is covalent in the solid state. The two Hg(2)S(42) bond lengths are 2.3513(11) Å while the two Hg(1)P(1) bond lengths are 2.4826(9) Å. The two parts of the molecule are linked to each other by two chlorine atoms with Hg(1)Cl(1) and Hg(2)Cl(1) bond distances of 2.5310(10) and 3.0472(10) Å, respectively.