The reaction of cadmium acetate with thiamine chloride hydrochloride in water affords the complex Cd(thiamine) Cl3•0.6H2O, and its structure has been determined by single-crystal X-ray methods. The compound crystallizes with eight molecules in space group C2h 6-C2/c of the monoclinic system in a cell with dimensions at -166 °C of a = 25.86 (1) Å, b = 8.528 (4) Å, c = 17.779 (8) Å, β = 107.20 (2)°, V = 3745 Å3, Pcalcd = 1.756 g/cm3, and Pobsd (25 °C) = 1.72 (1) g/cm3. The structure has been refined by least-squares methods to a final R index on F of 0.025 for the 219 variables and the 4931 data. Three chloro ligands and atom N(1') of the pyrimidine ring of the thiamine molecule complete an uncommon tetrahedral coordination about the Cd(II) ion. This is the first structural report of a thiamine ion bonded to a metal ion. In general the structural effect on thiamine of Cd(II) coordination is similar to that of protonation but smaller. The thiamine ligand is in the uncommon S conformation with torsional angles øT= +112.6° and øp = +129.8°.
ASJC Scopus subject areas
- Colloid and Surface Chemistry