New quasi-one-dimensional tetracyanidoplatinate, Cs4[Pt(CN)4](CF3SO3)2: Synthesis, structure, and physical characterization

A. A. Gapud
A. P. Weber
J. A. Alexander
L. Pham
A. Khan
R. I. Leatherbury
A. P. Reyes
L. L. Lumata
P. L. Kuhns
Edward J. Valente, University of Portland
R. E. Sykora

Journal of Physics and Chemistry of Solids, 2014, Volume 75, Issue 3, 447-452.

© 2014 Elsevier

Linked version is the final published version.

Abstract

The synthesis and some physical properties of a new quasi-one-dimensional tetracyanidoplatinate, Cs4[Pt(CN)4](CF3SO3)2 (CsCP(OTf)) are reported and described in comparison to the well-known K2[Pt(CN)4]Br0.30·3.2H2O (KCP). Single-crystal X-ray diffraction reveals Pt–Pt spacings to be greater than those of KCP by 5% longitudinal and 38% transverse, but much shorter than comparable spacings in other non-partially oxidized platinates. Anomalies are observed between temperatures 100 K and 200 K: (1) Longitudinal DC conductivity is two orders of magnitude higher and is non-monotonic with temperature, showing a minimum at around 170 K. (2) Nuclear magnetic resonance (NMR) longitudinal relaxation time T1 is at least three orders of magnitude higher than that of KCP, and is also non-monotonic with temperature, showing a sharp peak at around 120 K. Since X-ray diffraction reveals no structural transition at 120 K, these suggest a possible lattice freezing or stiffening at around 120 K.