Sulphur-nitrogen chelating agents. III. Metal complexes of 2-methylthiomethylpyridine

Abstract

Complexes of 2-methylthiomethylpyridine (mmp) have been obtained with cobalt(II), nickel(II), copper(II), copper(I), palladium(II), platinum(II), silver(I), and mercury(II). The compounds MX2 mmp2 (M = Co, Ni; X = Cl, Br, SCN) and NiI2 mmp2 are high-spin and their reflectance spectra indicate that the complexes are octahedral in the solid state. The visible absorption spectrum of CoCl2 mmp2 in nitrobenzene indicates that the complex is tetrahedral in solution with the ligand probably coordinated through the pyridine nitrogen only. The tris-chelated complexes [M mmp3](ClO4)2 were also characterized. Spectral data indicate that the complexes CuX2 mmp (X = Cl, Br) possess a tetragonal polymeric structure in the solid state. Conductimetric titration of the perchlorate [Cu mmp2](ClO4)2 with chloride ion in nitromethane demonstrated the formation of [CuCl mmp2]+ in solution. This was confirmed by the isolation of [CuCl mmp2]ClO4 and [CuBr mmp2]ClO4. The bis-chelated complex CuCl2 mmp2 gives a solution in nitrobenzene which is virtually non-conducting. The complexes PdX2 mmp (X = Cl, Br, I, SCN), Pt(SCN)2 mmp, [M mmp2]- (ClO4)2 (M = Pd, Pt, Hg), [Pt mmp2][PtCl4], and [Cu mmp2]ClO4 were also isolated. The silver(I) complex Ag mmp ClO4 probably contains the dimeric cation [Ag2 mmp2]2+.