253590-55-5Relevant academic research and scientific papers
Interactions of metal ions with the intermediate of thiamine catalysis: Crystal structures of Cd(II), Hg(II) and Pt(II) complexes of 2-(α-hydroxybenzyl)thiamine
Hu, Ning-Hai,Norifusa, Toshio,Aoki, Katsuyuki
, p. 2987 - 2994 (2008/10/09)
Five complexes of formulae Cd(HBT)X3·H2O, Hg2X5(HBT) (X=Cl, Br), and Pt(HBT)(NO2)3 were prepared by reacting CdX2, HgX2 and K2Pt(NO2)4 with 2-(α-hydroxybenzyl)thiamine (HBT), an active intermediate of thiamine catalysis, and their crystal structures were determined by X-ray diffraction. The metal ion binds to the N(1′) site of the pyrimidine ring in each case, despite the different shapes and sizes of metal coordination units; a tetrahedral unit in the cadmium complexes, a double-metal unit consisting of two tetrahedral Hg(II) ions in the mercury complexes and a square-planar unit in the platinum complex. The HBT ligands in these complexes adopt the S conformation, as usually observed in C(2)-substituted derivatives of thiamine, with average torsion angles φT being ±99° and φP being ±175°. A 'two-point' anion-bridge between the amino group of the pyrimidine ring and the cationic thiazolium ring of the same molecule is found in all the structures, being of the form N(4′α)-H...X1-M-X2...thiazolium-ring (M=metal ion), which is one of the factors that affect the S conformation. Stacking interactions between the pyrimidine and phenyl rings play an important role in the molecular conformation and crystal packing. The intramolecular close contact between the oxygen of the C(2)-substituent and the sulfur of the thiazolium ring is also a common feature to these complexes, which gives the mechanistic implications. Elsevier Science Ltd.
