Structural, Spectroscopic, and Thermal Behaviour of Bis-(thiosaccharinate)-aqua-cadmium(II)

Abstract

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.

Structural and Spectroscopic Characterization of Bis(thiosaccharinato)-trispyridine-cadmium(II)

“…Besides, deformational modes involving this group are found at practically the same position in both complexes. Most interesting is the observation that the strong band located at 1005 cm Ϫ1 in the case of [Cd(tsac) 2 (H 2 O)], and essentially assigned to the CϭS stretching, somewhat coupled with other motions of the sulfothioamide skeleton [1,11], is now clearly split, in agreement with the presence of two structurally different thiosaccharinate moieties. On the basis of the differences in C-S distances found for both units (cf.…”

“…The six-fold coordination is completed with other two pyridine molecules at the bipyra- Here, the Cd 2ϩ cation is five-fold coordinated to the S-atoms of two symmetry related thiosaccharinate anions, to two sulfonyl oxygen atoms of another two, symmetry related, thiosaccharinates and to a water molecule [1]. Probably, steric hindrance in the more ligandcrowded [Cd(tsac) 2 (py) 3 ] prevents the formation of stronger Cd-S bonds.…”

“…The proposed assignments are based on the general information analyzed and discussed in our previous paper [1].…”

“…A comparison with the thermal behaviour of the previously investigated [Cd(tsac) 2 (H 2 O)] complex [1] shows that this has a lower thermal stability. The degradation of the thiosaccharinate moieties starts immediately after the loss of water, which occurs between 75 and 128°C.…”

“…Recently, we have begun some systematic studies in relation to the coordination properties of thiosaccharin (1,2-benzothiazol-3(2H)-thione-1,1-dioxide; for brevity tsac) and could determine the crystal and molecular structure of one simple complex of this ligand with cadmium(II), namely [Cd(tsac) 2 (H 2 O)] [1].…”