This paper presents an investigation of oxidation state and charge transport in the low-dimensional materials Ni(dpg)2Br10 and Pd(dpg)2Bru, dpg = diphenylglyoximato. Resonance Raman structure-spectra correlations are discussed for polybromides, and Br5” is assigned as the predominant halogen species in both of these materials. Thus, the M(dpg)2 units are formally in fractional oxidation states of ca. +0.20 (2) (M = Ni) and +0.22 (2) (M = Pd). In the optical spectra of both materials, a broad transition at 500 nm is related to the polybromide chains. Four-probe single crystal electrical conductivities (dc) in the stacking direction at 300 K are as high as 9.1 X 10~1 234 5(cm)-1 (Ni(dpg)2BrL0) and 1.5 X -4 (cm)-1 (Pd(dpg)2Bru) The conductivity is demonstrated to be thermally activated with activation energies of 0.33 and 0.21 eV, respectively. The transport properties of the brominated materials are found to be very similar to those of the related M(dpg)2I materials (M = Ni, Pd), a result contrary to expectations if the halogen chains were the major charge carrier.
ASJC Scopus subject areas
- Colloid and Surface Chemistry