Reactions of iron halides with thiols containing nitrogen donor atoms; the structure of an iron(III) complex of 2,2′-dimercaptodipyridine

By reaction of iron(II) and iron(III) with 2-mercaptopyridine (HMP) and 2,5-dimercapto-1,3,4-thiadiazol (H2DMTD), the complexes FeCl2(HMP)2 FeCl4(HDMP) (DMP=2,2′-dimercaptodipyridine) and Fe (HDMTD)2 have been prepared and characterized by IR and Mossbauer spectroscopies. The crystal structure of FeCl4(HDMP) has been determined by an X-ray diffraction study. The compound is triclinic, space group P1, with a = 7.946(1), b = 14.067(2), c = 7.623(1) A, α = 97.0(1), β = 92.7(1), γ = 78.4(1)°, Z = 2. The structure consists of discrete [HDMP+] cations and [FeCl4−] anions; the cation is formed by two pyridine rings connected by an SS bridge formed by oxidation of HMP without any short contact with the anion which forms a nearly perfect tetrahedron.