Reaction of antimony trichloride with thiamine chloride (TCl, vitamin B-1): Synthesis and crystal structure of the new thiaminium chloroantimonate(III) (HT)(2)[Sb4Cl16].2CH(3)CN

The title compound was isolated from the mother liquor resulting from react ion of thiamine chloride monohydrate (TCl.H2O) with antimony trichloride in acetonitrile. Its crystal structure was solved by X-ray diffraction (cryst al data: triclinic, space group P(-)1 (No. 2), a = 10.6060(10) Angstrom, b = 10.8010(10) Angstrom, c = 13.2720(10) Angstrom, alpha = 110.780(10)degree s, beta = 92.62(2)degrees, gamma = 101.65(2)degrees, V = 1380.7(2) Angstrom (3), and Z = 2). The compound is formed by thiaminium [(HT)(2+)] cations an d [Sb4Cl16](4-) anions. The four Sb atoms of this chloroantimonate anion ar e linked in a chain by pairs of bridging Cl ligands. Further Cl ligands mak e the coordination number of the central [Sb(1)] and terminal [Sb(2)] atoms up two six and five respectively. Very weak Sb(2)-Cl...Sb(2) interactions [Cl...Sb(2) = 3.860 A] interconnect the anions in a pseudopolymeric arrange ment. Thiaminium adopts its S conformation and forms a strong hydrogen bond with a mu-Cl ligand, distorting the double bridges between Sb(1) and Sb(2) .