Dielectric Jump and Negative Electrostriction in Metallosupramolecular Ionic Crystals.

ABSTRACT: In natural ionic solids, cationic and anionic species are alternately arranged to minimize electrostatic energy. Aggregation of identical ionic species is commonly prohibited due to the repulsive, long-range nature of Coulombic interactions. Recently, we synthesized unique ionic solids, [AuI4CoIII2(dppe)2(D-pen)4]X2·nH2O (dppe?=?1,2-bis(diphenylphosphino)ethane, D-pen?=?D-penicillaminate), in which complex cations are self-assembled into a cationic supramolecular octahedron, while monovalent or divalent inorganic anions are aggregated into an anomalous anionic cluster accommodating several water molecules. This quite unusual aggregation manner originates from various molecular-level non-Coulombic interactions such as hydrogen bonds and CH-? interactions; thus, this class of ionic solids is referred to as non-Coulombic ionic solids, abbreviated as NCISs. Herein, we report that the NCISs with a peculiar charge-separated (CS) structure in a cubic lattice show a negative, isotropic electrostriction phenomenon that has never been found in any ionic solids, as well as an anomalously large relaxer-like dielectric jump phenomenon reaching to an application level of ?'/?0 ~ 105. The appearance of these phenomena was explained by the cooperative dynamics of inorganic anions and dipolar water molecules in the pliable anionic clusters that are surrounded by a rather robust cationic metallosupramolecular framework with a meso-scopic scale.

SUBMITTER: Yamashita S 

PROVIDER: S-EPMC5805720 | biostudies-literature | 2018 Feb

REPOSITORIES: biostudies-literature