Pressure-Induced Structural and Charge-Transfer Phase Transitions for a Two-Dimensional Mixed-Valence Iron(II,III) Coordination Polymer

Abstract

A two-dimensional (2D) mixed-valence iron(II,III) coordination polymer, (Ph4P)[FeIIFeIII(dto)3] (1; Ph4P = tetraphenylphosphonium, dto = 1,2-dithiooxalato), was prepared, and its crystal structure was revealed. Compound 1 exhibited a 2D honeycomb structure and a rigid layered framework, due to a hydrogen bond between the cation and anion layers. The temperature dependence of the magnetic susceptibilities for 1 under high pressure showed a thermal hysteresis loop corresponding to a charge-transfer phase transition, although there was no charge-transfer phase transition under ambient pressure.