THE COORDINATION CHEMISTRY OF (2-THIAZOLIN-2-YL)HYDRAZINE HYDROCHLORIDE (TZHYHCL) .3. STUDY OF ITS INTERACTION WITH COBALT AND CRYSTAL-STRUCTURE OF [CO(TZHY)(3)]CL-3-CENTER-DOT.2H(2)O

The complexation equilibria of (2-thiazolin-2-yl)hydrazine hydrochlori de (TzHyHCl) with cobalt(II) have been studied in aqueous solution at 298 K and 0.1 M ionic strength in NaClO4. The formation constants were determined and discussed in terms of the characteristics of the ligan d. The compound [Co(TzHy)(3)] Cl-3 . 2H(2)O has been isolated and char acterized by IR, UV-vis-NIR diffuse reflectance and thermal measuremen ts, and its crystal and molecular structure determined by X-ray analys is. In this compound the complex cation shows a distorted octahedral g eometry with the cobalt atom coordinated to three terminal hydrazine n itrogen atoms [average Co-N = 1.973 Angstrom] and three thiazoline nit rogen atoms [average Co-N = 1.900 Angstrom]. Angles N-Co-N for adjacen t nitrogen donors are comprised between 94.9 and 82.8 degrees. Accordi ng to the position of the ligands, the complex can be described as a f acial isomer. A hydrogen bond scheme is present in the structure inter linking TzHy ligands, water molecules and chloride ions. Copyright (C) 1997 Elsevier Science Ltd.