X-ray photoelectron Moessbauer, magnetic, and electrical conductivity study of SnS2(CoCp2)0.31

Intercalation of SnS2 with CoCp2 (Cp = η-C5H5) under mild conditions leads to the formation of SnS2(CoCp2)0.31. Its physical properties have been investigated with a variety of techniques. X-ray photoelectron spectroscopy reveals the presence of Co3+, Co2+, Sn4+, and probably Sn2+. Electron paramagnetic resonance spectra showed the presence of radicals with g values close to those observed for cobaltocene intercalated into CdPS3. Magnetic measurements showed that the sample obeyed the Curie-Weiss expression between 4 and 300 K with Θ = -9.17 K, and μeff = 0.12 μB. 119Sn Moessbauer spectroscopy revealed the presence of a resonance assignable to a reduced tin site that could be formulated as Sn2+ and an integrated Sn2+:Sn4+ ratio of 0.11. Diffuse reflectance spectroscopy showed the onset of a broad absorption in the near-IR region at 0.6 eV, in addition to the band gap of SnS2 at 2.1 eV. Electrical conductivity showed that the intercalated material is 200 times more conductive than the unreacted host but still showed semiconducting behavior with an activation energy Ea = 0.11 eV, similar to that of unintercalated SnS2. The stoichiometry of the intercalated material can best be described as (Sn4+0.9Sn2+0.1)S2((Co3+Cp2)+0.2(Co2+Cp2)0.1) which is remarkable due to the multiple mixed valency of the material. 35 refs., 10 figs., 4 tabs