Polyhedr on Vol. 2, No. 8, pp. 145-748, 1983 Pr int ed in Great Britain. 0277-5387/ 83 $3.00 + .Ot l Pergamon Press Ltd. zyxwvutsr HALOMETALLATES OF l-METHYL-4,4-DIMERCAPTO- PIPERIDINIUM. EVIDENCE OF STRONG HYDROGEN BONDS WITH PARTICIPATING THIOL GROUPS H. BARRERA and F. TEIXIDOR” Departament de Quimica Inorganica, Universitat Autonoma de Barcelona, Bellaterra, Barcelona, Spain (Received 21 September 1982; accepted 20 January 1983) Abstract-Chlorometallates of transition and B subgroup elements are readily prepared and precipitated by reaction of the corresponding metallic salts with l-methyl-4,4- dimercaptopiperidinium chloride. These chlorometallates investigated were [ZnC1,12-, [CdCl,]- , zyxwvutsrqponmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBA [CoCl,]‘- , [CuCl=J3- and [FeC1.J2-. Strong S-H . . . Cl interactions, but not N-H . . . Cl, have been evidenced by IR spectroscopy in the zinc, cadmium and cobalt complexes. The S-H and N-H absorptions are observed at = 2480 cm - ’ and 3060 cm-‘, respectively. Partial deuteration of the [ZnC1,12- complex with d,-methanol, shifted these IR signals to 1800 and 2260 cm -I, clearly evidencing a X-hydrogen type of bond. The S-H . . . Cl interaction is smaller in the [FeCld12- complex, and practically nonexistent in the [CuC1,13- complex. Ambidentate ligands which may, in principle, co- was prepared according to a reported method.4 ordinate through nitrogen or sulfur have received Hydriodic acid (Merck) was purified by the hypo- considerable interest. A great deal of work has phosphorous acid method.s Unless specifically been done with /I-mercaptoamines2 and recently mentioned all other reagents and solvents were with 1-methyl-4-mercaptopiperidine.2*3 How commercial grade and were used without further ever, amino-gem-dithiols, i.e. ligands with two purification. Elemental analyses were performed in thiol groups on the same carbon and an amine our laboratories. All melting points are un- group in the molecule, have not been studied. corrected. We report in this communication the syntheses of halocomplexes of the first transition series and I-B and II-B subgroups, which are crystallized as salts of I-methyl-4,4-dimercaptopiperidinium, an amino-gem-dithiol cation. These compounds (the copper compound excepted), display strong S-H . . . Cl interactions. In addition, the N-H bond is very little externally perturbed if at all. The complexing ability of the I-methyl-4,4-dimer- captopiperidine ligand will be the object of a following communication. [C,H,,NS,]X (X = Cl, Br, I) Bromide (II) and iodide(II1) salts of [C,H,,NS,] have been prepared following the procedure used for chloride(I).4 Hydriodic acid (57%) and hydro- bromic acid (48%) have been utilized instead of hydrogen halides. General EXPERIMENTAL IR spectra were determined on a Beckman IR- 20A as KBr pellets. The IR spectral data are listed in Table 1. The UV-visible spectra were recorded on a Beckman, Acta III. The 1-methyl4- piperidone (Fluka) was distilled before use. The gem-dithiol 1 -methyl-4,4-dimercaptopiperidine A solution containing 2 g (14.6 mmol) of ZnCl, finely divided in ethanol and 1.5 cm3 of hydro- chloric acid (36%) was slowly poured into a stirred solution of 2 g of [C,H,4NS2]Cl (10 mmol) in eth- anol previously filtered. A white, crystalline solid separated, m.p. 116S”C (dec). Found: Zn, 12.2; Cl, 26.4; S, 23.3. Calc: Zn, 12.2; Cl, 26.5; S, 23.9%. [C,H,4NSJCdC13.1.5H20 (V) *Author to whom correspondence should be ad- dressed. A stream of hydrogen chloride was passed through a methanolic solution of 1 g (4.4 mmol) of CdC1,.2.5H20, for 5-10min. A methanolic solu- tion of 1.3 g (6.5 mmol) of [CsH,,NS2]Cl was