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 σ300K=10−1 S cm. 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.
Code of conduct: An organic–inorganic hybrid (BEDT-TTF)2Cu2 (HCOO)5 composed of a θ-BEDT-TTF+0⋅5 layer and square lattice anionic sheet [Cu2(HCOO)5-]n is synthesized. The crystal shows long-range magnetic ordering at 8.0 K and is semiconducting with σrt=0.1 S cm. Thus, an antiferromagnetic square lattice is introduced into a molecular crystal.