Synthesis, Crystal Structure, and Characterization of the Charge‐Transfer Salt (BEDT‐TTF)[Fe(C2O4)Cl2](CH2Cl2), {BEDT‐TTF = Bis(ethylenedithio)tetrathiafulvalene}

Abstract

AbstractThe synthesis, crystal structure, Raman spectra, conductivity, and magnetism of the title charge‐transfer salt (1) composed of BEDT‐TTF [bis(ethylenedithio)tetrathiafulvalene], one‐dimensional [Fe(C2O4)Cl2–]n, and the solvent CH2Cl2, are described and interpreted. Electrochemical oxidation of neutral BEDT‐TTF in the presence of [(C2H5)3NH][Fe(C2O4)Cl2] in a CH2Cl2/CH3OH solution yields crystals of 1, which crystallizes in triclinic form. In 1, two donor molecules stack in a face‐to‐face manner as a BEDT‐TTF dimer. The BEDT‐TTF dimers form a (4,4) grid in the ab plane. The cavity of the (4,4) grid is occupied by two CH2Cl2 molecules. The donor layers are separated by sheets of [Fe(C2O4)Cl2–]n anions with a zigzag chain along the a axis. There are S···S interactions between the donors, and S···Cl interactions between the donor and the anion. On the χ vs. T plot, a broad maximum is observed around 45 K, showing the existence of antiferromagnetic interactions between the metal atoms in the low‐dimensional system. The formal charge of the donor molecules is assigned 1.0+ based on the bond lengths of the TTF core and on the Raman spectra. The material is a semiconductor with σrt = 1.8 × 10–5 S/cm.