Crystal structure of diaquatetrakis[μ-2,2′-(methylene-bis(sulfanediyl))bis(pyridine 1-oxide)dicopper(II) dibromide diperchlorate, [Cu2(H2O)2(C11H11N2O2S2)4]Br2(ClO4)2

Abstract

Source of material 2,2'-(Methylene-bis(sulfanediyl))bis(pyridine 1-oxide) (mspo) and copper salts thereof were prepared, comprising the following steps: oxidizing a2-acetylaminopyridine with hydrogen peroxide in an inert solvent to give a2-acetamido-pyridine 1-oxide, cleaving the acetyl group with mineral acid to give a2-aminopyridine 1-oxide, diazotizing the 2-aminopyridine 1-oxide and treating the diazonium salt with hydrochloric acid to give a2-chloropridine 1-oxide, treating the 2-chloropridine 1-oxide with asulfhydryl-donor to give a2-mercaptopyridine 1-oxide, treating the latter with a CH 2 Br 2 to give a2,2'-(methylenebis(sulfanediyl))bis(pyridine 1-oxide). Asolution of CuBr 2 (223 mg, 1m mol) in water (5 mL) was dropped slowly into asolution of mspo (532 mg, 2mmol) in EtOH (20 mL) and the pH was adjusted to 7-8 with HClO 4 .The mixed solution was stirred for 2hat80°Cand was then cooled to room temperature to give brown-yellow microcrystals, which were collectedbyfiltration, washed successivelywithH 2 Oand EtOH,and driedinvacuo.Brown-yellowsquare crystals suitable for X-ray analysis were obtained by recrystallization of the precipitate from N,N-dimethylformamide and alcohol (1:1). Experimental detailsThe non-hydrogen atomsw ere refined anisotropically, and hydrogen atomswere added according to theoretical models. In the crystal structure, O5 and O5',O6and O6',Br1 and Br1' are disordered with occupancies of 0.86:0.14, 0.86:0.14, and 0.36:0.14, respectively. It is very difficult to locate the hydrogen atomsofcoordinated water molecules, so their information is not provided. DiscussionThe practical interest in heteroaromatic N-oxides is caused first of all by the fact that many of them show biological activity and extraction properties [1,2].Among N-oxides, there are substances possessing carcinogenic, cancerostatic, mutagenic, insecticidal, herbicidal,fungicidal, anticonvulsant,analgesic andplantgrowingp roperties. Both biological activity ande xtractional properties areconnected with complexation of N-oxide. We have been interested in the study of metal complexes of 2-mercaptopyridine 1-oxide (Hmpo) due to the fact that these complexes have been successfully used as bactericidaland antifungal agents [3][4][5]. The Cu(II) complex is adinuclear cage compound. Each Cu(II) coordination sphere is formed by four mspo ligands and one 96 Z. Kristallogr.