Single-component conductors: A sturdy electronic structure generated by bulky substituents

Authors

A. Filatre-Furcate, N. Bellec, O. Jeannin, P. Auban-Senzier, M. Fourmigué, J. Íñiguez, E. Canadell, B. Brière, V. Ta Phuoc, and D. Lorcy

Reference

Inorganic Chemistry, vol. 55, no. 12, pp. 6036-6046, 2016

Description

While the introduction of large, bulky substituents such as tert-butyl, −SiMe₃, or −Si(isopropyl)₃ has been used recently to control the solid state structures and charge mobility of organic semiconductors, this crystal engineering strategy is usually avoided in molecular metals where a maximized overlap is sought. In order to investigate such steric effects in single component conductors, the ethyl group of the known [Au(Et-thiazdt)₂] radical complex has been replaced by an isopropyl one to give a novel single component molecular conductor denoted [Au(iPr-thiazdt)₂] (iPr-thiazdt: N-isopropyl-1,3-thiazoline-2-thione-4,5-dithiolate). It exhibits a very original stacked structure of crisscross molecules interacting laterally to give a truly three-dimensional network. This system is weakly conducting at ambient pressure (5 S·cm^–1), and both transport and optical measurements evidence a slowly decreasing energy gap under applied pressure with a regime change around 1.5 GPa. In contrast with other conducting systems amenable to a metallic state under physical or chemical pressure, the Mott insulating state is stable here up to 4 GPa, a consequence of its peculiar electronic structure.

Link

doi: 10.1021/acs.inorgchem.6b00556