(BEDT-TTF)2Cu2(HCOO)5: An Organic-Inorganic Hybrid Conducting Magnet

(BEDT-TTF)2Cu2(HCOO)5: An Organic-Inorganic Hybrid Conducting Magnet

A dual‐functional organic–inorganic hybrid (BEDT‐TTF)₂Cu₂(HCOO)₅ (1) (BEDT‐TTF=bis(ethylenedithio)tetrathiafulvalene) was obtained through the electrochemical oxidation of neutral BEDT‐TTF in the presence of an ammonium salt of the one‐dimensional copper‐formate framework [(C₂H₅)₃NH]₂Cu₂(HCOO)₅ in a C₆H₅Cl–C₂H₅OH solution. Compound 1 was composed of organic donor BEDT‐TTF⁺⁰⋅⁵ in a θ‐phase arrangement and Jahn–Teller distorted (4,4) grid anion sheets [Cu₂(HCOO)₅^‐]_n with S=1/2. We identified the material as a semiconductor with values of σ_300K=10⁻¹ S cm⁻¹. The anion sheet is a coordination isomer of [Cu₂(HCOO)₅^‐]_n and, compared with the starting material, shows antiferromagnetic behavior as the well‐known inorganic Cu−O, Co−O square layers for creating inorganic conducting magnets. Long‐range antiferromagnetic ordering was observed at 8.0 K.