- Interaction of Zn2+, Cd2+, and Hg2+ with 2-(α-hydroxybenzyl)thiamin and 2-(α-hydroxy-α-cyclohexylmethyl)thiamin. Crystal structure of the complex Hg(2-(α-hydroxybenzyl)thiamin)Cl3·H2O
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The reactions of ZnCl2, CdCl2, and HgCl2 with the active aldehyde derivatives of thiamin, 2-(α-hydroxybenzyl)thiamin (HBT) and 2-(α-hydroxycyclohexylmethyl)thiamin (HCMT) were studied in methanolic and aqueous solutions. Complexes of the formulas M(HBT)Cl3 and M(HCMT)Cl3, (M = Zn2+, Cd2+, Hg2+) were isolated and characterized as solid adducts with elemental analyses, conductivity measurements, and IR spectra. The crystal structure of the complex Hg(HBT)Cl3 was also solved. The compound is monoclinic (P21/n) with a = 9.588 (6) A?, b = 7.644 (3) A?, c = 31.412 (20) A?, β = 90.41 (5)°, V = 2302 (2) A?3, and Z = 4. The HBT ligand is found in the S conformation, as expected for C(2)-substituted derivatives of thiamin, with φP = 172.7° and φT = -100.0°. It is concluded from the IR spectra that all the isolated complexes are isostructural and in the same S conformation, as in the compound Hg(HBT)Cl3, in the solid state. The facile formation of complexes of bivalent metals with the active aldehyde derivatives of thiamin, which contain direct metal-ligand (M-N(1′)) bonding, may indicate that the intervention of metal ions could follow the formation of these intermediates in the enzymatic action of thiamine.
- Louloudi, Maria,Hadjiliadis, Nick,Feng, Jin-An,Sukumar, Sunanda,Bau, Robert
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p. 7233 - 7238
(2007/10/02)
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