Transition and Group IIB Metal Complexes With “Active Aldehyde” Derivatives of Thiamine

Abstract

The Zn²⁺, Cd²⁺, Hg²⁺, Co²⁺ and Ni²⁺ ions produce zwitterionic type complexes with the ligands (L), 2-(α-hydroxy-benzyl)thiamine=HBT and 2-(α-hydroxy-cyclohexyl-methyl)thiamine = HCMT, of the type MLCl₃. The ligands are in the S conformation, the metals are bound to N₁, of the pyrimidine moiety of thiamine and the complexes have a trigonally distorted tetrahedral structure, as the crystal structure of the complex Zn(HCMT)Cl₃ (orthorombic, a=14.4 b=14.1 c=17.4 β=105.6^O V=3392A³ R=13.8%), the one and two dimensional ¹H nmr spectra of the Zn²⁺, Cd²⁺ and Hg²⁺ complexes and the electronic spectra of the Co²⁺ and Ni²⁺ complexes show. A brief review of the previous techniques (structure of the Hg(HBT)Cl₃ complex, IR-Raman spectra, ¹³C nmr in solution and solid state etc) used to characterize these complexes, is also given here and the proper conclusions drawn.

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