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=105.6O V=3392A3 R=13.8%), the one and two dimensional H1 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, C13 nmr in solution
and solid state etc) used to characterize these complexes, is also given here and
the proper conclusions drawn.
