DOI: 10.1002/zaac.200800201 Synthesis, Spectrothermal and Structural Characterization of Saccharinatobis(tris-hydroxymethylaminomethane)zinc(II)saccharinate Complex, [Zn(sac)(tham) 2 ](sac) Zerrin Heren a , Hümeyra Pas¸aogˇlu b , Gökhan Kas¸tas¸ b, *, and Kamber Akdagˇ b Kurupelit, Samsun / Turkey, Ondokuz Mayıs University, Faculty of Arts and Sciences, a Department of Chemistry and b Department of Physics Received March 18 th , 2008; accepted May 15 th , 2008. Abstract. A novel Zn II complex of the saccharinate ligand (sac) with tris-hydroxymethylaminomethane (tham) was synthesized and characterized by elemental analysis, FT-IR spectroscopy, simul- taneous TG and DTA techniques, and X-ray diffraction. The com- plex, [Zn(sac)(tham) 2 ](sac), crystallizes in monoclinic system with space group P2 1 /c [a  7.55954(3) A ˚ , b  13.0532(6) A ˚ , c  27.7777(10) A ˚ , β  100.539(3)°, Z  4]. The Zn II ion has a dis- torted octahedral coordination. The tham ligand has chemically different functions in the structure, acting as both bidentate and 1 Introduction Saccharin (3H-benzisothiazol-3-one 1,1-dioxide) is a well- known artificial sweetener. The molecule is readily depro- tonated to form the corresponding saccharinato anion (sac), which is a versatile polyfunctional ligand [1]. Because of the biological importance of saccharin, there has been increased interest in metal complexes, especially with first- row transition metals. Saccharin, or its anion, may bond to metals by means of their imino nitrogen, carbonyl oxygen, or sulfonyl oxygen atoms. Thefirst systematic syntheses and structural studies of aqua complexes of metal saccharinates were reported by the groups of Haider [2, 3] and Cotton [4, 5]. In the last two decades, the synthesis and spectro- scopic properties [69], particularly vibrational properties [1012], of the metal saccharinates and metal complexes including saccharin and various N-donor ligands (mono- or bidentate) have been intensivelystudied by many investi- gators. A number of crystal structures and the thermal properties of metal saccharinato and mixed-ligand com- plexes have been studied [1320]. In the present study, the mixed-ligand Zn II complex of saccharinate with hydroxyalkyl groups is described. To our knowledge, this is the first metal complex of tham ligand * Gökhan Kas¸tas¸, Ondokuz Mayıs University Faculty of Arts and Sciences Department of Physics TR55139, Kurupelit, Samsun / Turkey Telephone: 90 362 312 19 19 (ext: 5253) Fax: 90 362 457 60 81 Email: gkastas@omu.edu.tr Z. Anorg. Allg. Chem. 2008, 634, 19331936 © 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim 1933 tridentate ligands. There are also sac moieties to act as N-bonded ligand and as a counter anion. The molecular packing of the com- plex is provided by moderate hydrogen bonds as well as π···π inter- actions between the sac moieties. The IR spectra and the thermal decomposition of the complex are also discussed. Keywords: Zinc; Saccharinato complex; Tris-hydroxymethylamino- methane; Crystal structure; Thermal decomposition as both bidentate and tridentate ligands although a number of examples containing both coordinated and non-coordi- nated sac ions have been reported previously [2124]. In this context, we report the synthesis, IR spectra, thermal analysis and crystal structure of the Zn II complex of sac with tris-hydroxymethylaminomethane (tham), [Zn(sac)- (tham) 2 ](sac). The structure of the complex is as shown in Scheme 1. Scheme 1 The structure of the complex [Zn(sac)(tham) 2 ](sac). 2 Results and Discussion 2.1 Crystal structure of the complex The crystallographic analysis reveals that the title com- pound consists of [Zn(sac)(tham) 2 ]  complex cation and a sac molecule outside the coordination sphere (Fig. 1). Inter-