The coordination chemistry of (2-thiazolin-2- yl)hydrazine hydrochloride (TzHyHCI) III. Study of its interaction with cobalt and crystal structure of [Co(TzHy)3]Cl3" 2H20

-The complexation equilibria of (2-thiazolin-2-yl)hydrazine hydrochloride (TzHyHCI) with cobalt(II) have been studied in aqueous solution at 298 K and 0.1 M ionic strength in NaCIO4. The formation constants were determined and discussed in terms of the characteristics of the ligand. The compound [Co(TzHy),] C13"2H20 has been isolated and characterized by IR, UV-vis-NIR diffuse reflectance and thermal measurements, and its crystal and molecular structure determined by X-ray analysis. In this compound the complex cation shows a distorted octahedral geometry with the cobalt atom coordinated to three terminal hydrazine nitrogen atoms [average Co--N = 1.973 A] and three thiazoline nitrogen atoms [average Co--N = 1.900 A]. Angles N C o N for adjacent nitrogen donors are comprised between 94.9 and 82.8. According to the position of the ligands, the complex can be described as a facial isomer. A hydrogen bond scheme is present in the structure interlinking TzHy ligands, water molecules and chloride ions. Copyright ~ 1997 Elsevier Science