Received March 16, 1984 The title ligand (MAMI) was prepared by reaction of 2-ethyl-4-methylimidazole and diethanolamine under basic (pH 11) Mannich conditions and treatment of the resultant alcohol with thionyl chloride. The nitrogen mustard formed was derivatized with thiourea to afford a bis(isothiuronium) salt. Hydrolysis of this material to a dimercaptide could only be accomplished efficiently in the presence of transition-metal salts. Treatment of the isothiuronium salt with NiCl2under basic conditions afforded an incompletely characterized derivative in which, by IR spectroscopy and C:N ratio, the ligand had been completely hydrolyzed to a dimercaptide. Oxidation of this material by I2and extraction into HCC13afforded the title ligand. Changes in the13C NMR spectrum of MAMI in Me2SO-d6as a function of added Cd(NO3)2revealed the formation of a 1:1 complex with K(˜ 60 M-1.The coordinated and free ligand are in fast exchange on the13C NMR scale, and the assessement of the groups involved in complex formation was unclear. However,113Cd NMR is consistent with coordination by the two N donors in MAMI. The 1:1 complex is in slow exchange on the113Cd NMR time scale. Crystalline complexes of MAMI with CdCl2and CdBr2were isolated. The CdBr2complexwas investigated by X-ray methods. Crystal data: P21/n, a = 12.988 (4) Å, b = 10.899 (3)Å,c = 13.148 (3)Å, γ = 108.74 (2)°, Z = 4, R = 0.0235 for 1474 independent reflections.
ASJC Scopus subject areas
- Physical and Theoretical Chemistry
- Inorganic Chemistry