No abstract

The crystal structure of [Zn(sac)2(py)2] has been de termined by single-crystal X-ray diffractometry. It crystallizes in the monoclinic space group C2/c with Z = 4. We propose and discuss an assignment of its IR and Raman spectra, compatible with the structural characteristics. Its thermal behavior was investigated by means of TG and DTA methods. Some comparisons with related compounds are made.

The crystal structure of the title complex, [Cd(tsac) 2 (H 2 O)], has been determined by single crystal X-ray diffraction methods. It crystallizes in the monoclinic space group C2/c (a 12.236(3), b 8.919(3), c 16.655(3) A Ê , 96.18(2) , Z 4). The molecular structure was solved from 1705 independent re¯ections with I b 2'I and re®ned to R 1 0X0489. Infrared and Raman spectra of the complex were recorded and are brie¯y discussed. Its thermal behaviour was investigated by thermogravimetry and differential thermal analysis.

A rationalization of the conspicuous different abilities of saccharin and thiosaccharin to form coordination compounds with the first series of transition metal elements and to interact with heavy metal cations is sought. Their electronic molecular structures as well as those of their respective ions are compared performing natural bond orbitals (NBO) analyses of the four species. Upon deprotonation, the negative charge at the N atom in saccharin is almost constant while it decreases in thiosaccharin and the negative charge at the monocoordinated chalcogen atom is notably more increased in the latter than in the former. Apparently, the negative charge reorganization makes difficult the coordination of thiosaccharin with the first series of transition metal elements and favors its experimentally observed interaction with heavy metal cations such as cadmium, lead, mercury, silver, and thallium.

The crystal structure of [Ni(sac)2py4] · 2 py (sac = saccharinate anion; py = pyridine) has been solved by single crystal X‐ray diffractometry. lt crystallises in the orthorhombic space group Pcan with Z = 4. Coordination of the saccharinate anion to the metal centre occurs, in a rather unusual way, through the carbonylic oxygen atom. The IR and Raman spectra of the complex have been analyzed in detail and assigned on the basis of the structural data. The thermal behaviour was investigated by means of TG and DTA methods.