BETS3[Cu2(C2O4)3](CH3OH)2: an organic–inorganic hybrid antiferromagnetic metal (BETS = bisethylene(tetraselenfulvalene))

Abstract

The organic–inorganic hybrid charge-transfer salt of BETS and a two-dimensional oxalate–metalate: BETS₃[Cu₂(C₂O₄)₃](CH₃OH)₂ (1) was obtained by the electrochemical oxidation of neutral BETS in the presence of [(C₂H₅)₃NH]₂Cu(C₂O₄)₂ in a C₆H₅Cl–CH₃OH solution. 1 crystallizes in a triclinic crystal system with cell parameters: a = 8.7716(3) Å, b = 16.9903(6) Å, c = 20.5716(7) Å, α = 104.794(2)°, β = 102.209(2)°, γ = 92.243(2)°, V = 2883.1(2) ų and P1 in 293 K. Donor layers and Jahn–Teller distorted honeycomb anions stack alternatively along the c axis in 1. The crystal structure of 1 is similar to the reported compound [BEDT–TTF]₃[Cu₂(C₂O₄)₃](CH₃OH)₂ (BEDT–TTF = bis(ethylene-dithio)tetrathiafulvalene, ET). Compared with the BEDT–TTF salt, the c axis expands by 2.3% at room temperature, the shorter interaction between the donor molecules increases, the room temperature conductivity increases from 4 S cm⁻¹ to 140 S cm⁻¹ and the antiferromagnetic interaction between the metal atoms with Jahn–Teller distortion through the oxalato-bridge enhances.