Journal of Physical Chemistry B, Vol.103, No.48, 10566-10571, 1999
Preparation and spectroscopic characterization of [Pt(en)(2)I-2][Pt(CN)(4)]: A new quasi-one-dimensional mixed valence chain material in a completely ordered lattice
The unique linear chain compound [Pt(en)(2)I-2][Pt(CN)(4)] {where en = ethylenediamine} has been synthesized through a standard method. The results of a structural analysis by X-ray crystallography reveal this new MX compound to be quasi-one-dimensional with complete chain-to-chain registry to give a completely ordered structure. The results of resonance Raman, IR, diffuse reflectance, and X-ray crystallography reveal that the Pt centers are highly charge disproportionated with a large commensurate distortion of the iodide sublattice about the Pt center of higher charge. These results reveal that this material is the strongest CDW MX compound, containing iodide bridges, reported to date. Resonance Raman experiments have shown that five A(g) (C-2h Site symmetry) Raman bands are strongly enhanced. These correspond to three in-chain Pt-I modes and two (chain perpendicular) CN stretches and are interpreted in terms of strong phonon coupling to the IVCT band.