Introduction Thiolate complexes still attract much attention, since they can be widely used in medicine, agriculture, in- dustry or analytical and organic chemistry [1]. Model compounds of several biologically relevant species [2] should be also mentioned. The knowledge of thermal behavior is a very important feature espe- cially in industry since a given substance must be suf- ficiently stable for an effective action. Therefore, the interest in the stability of thiolates has been recently greatly enhanced because of their utilization as cata- lysts [3] or precursors of sulfides thin films [4]. TG is the simplest method that can be utilized to determine the compound stability within the given temperature range or the mode of its thermal decomposition. Not only the well-established thermogravimetry but also DSC techniques have been reliably used over last decades in characterization of many organic compounds (particularly solids) as well as studying the thermal behavior and properties of various types of complexes and evaluating the thermal parameters for their degradation processes [5]. Numerous coordination compounds of transition metals with S-donor ligands have been investigated nevertheless the thermal analysis in the case of earlier transition elements comparing to the later 1 st row ones seems to be undeveloped. It is associated with a small number of known S-donor ligated complexes formed by the ‘a’ class metals which show greater affinity to ligands with hard oxygen than soft sulfur atom. The thermal behavior of complexes (mainly with O-donors) based on Mn(II) is widely discussed in the literature [6–8] what is in sharp contrast to Mn(II) thiolate complexes. Till now, the conditions of thermal decomposition of various complexes of manganese(II) with such rests as thiolate have not been studied. A survey of the available literature also shows that relatively little work on thermal decomposition of other complexes with Mn–S bond [9–14], as well as silanethiolates [15] has been done so far. Recently, we have reported on syntheses of a series of heteroleptic manganese(II) tri-tert-butoxy- silanethiolates incorporating solvent molecules (MeCN, MeOH) [16], chelating N-donors (phen, bipy, neo) [17] and monodental N-donor ligands (Py, MePy, ImH, etc.) [18, 19] as coligands. What more, we have found that the complex with 2-methylimidazole is in fact a N–H···S hydrogen bonded assembly of two complexes [Mn{SSi(OBu t ) 3 } 2 (2-MeIm)] and [Mn{SSi(OBu t ) 3 } 2 (2-MeIm)(MeOH)] [18]. The last one has MnNOS 2 core closely related to the ZnNOS 2 kernel of horse liver alcohol dehydrogenase catalytic site. Now, we have focused our attention on thermal properties of these species, since this is one of the most important factors, which have to be considered if we want to think about application of these 1388–6150/$20.00 Akadémiai Kiadó, Budapest, Hungary © 2007 Akadémiai Kiadó, Budapest Springer, Dordrecht, The Netherlands Journal of Thermal Analysis and Calorimetry, Vol. 88 (2007) 2, 463–470 HETEROLEPTIC TRI-TERT-BUTOXYSILANETHIOLATE COMPLEXES OF MANGANESE(II) Thermal studies Anna KropidÓowska 1* , M. Strankowski 2 , Maria Gazda 3 and Barbara Becker 1 1 Inorganic Chemistry Department, GdaÕsk University of Technology, Narutowicza Str. 11/12, 80-952 Gdañsk, Poland 2 Polymer Technology Department, Chemical Faculty, GdaÕsk University of Technology, Narutowicza Str. 11/12 80-952 Gdañsk, Poland 3 Faculty of Applied Physics and Mathematics, GdaÕsk University of Technology, Narutowicza Str. 11/12, 80-952 Gdañsk, Poland The thermal behavior of Mn(II) silanethiolate series [Mn(SR) 2 L(MeOH) n ], where R=SSi(OBu t ) 3 , L=heterocyclic nitrogen base and n=0, 1 or 2 has been comparatively investigated using differential scanning calorimetry (DSC), thermogravimetry (TG) and TG-infrared spectoscopy (IR) techniques. The TG curves indicate the differences in the thermal decomposition due to presence of distinct N-donor ligands and labile MeOH molecules coordinated to the central atom. The first step on the TG curves (60–110°C) corresponds to the elimination of alcohol from respective complexes. The main step (150–350°C) can be assigned to the decomposi- tion of the complexes yielding Mn 3 O 4 and silica as the main final products, identified by X-ray diffraction patterns. Keywords: manganese(II) complexes, metal thiolates, pyridine, silanethiolate, thermal analysis * Author for correspondence: anna@urethan.chem.pg.gda.pl