Structural Diversity and Physical Properties of Paramagnetic Molecular Conductors Based on Bis(ethylenedithio)tetrathiafulvalene (BEDT-TTF) and the Tris(chloranilato)ferrate(III) Complex

Electrocrystallization of bis­(ethylenedithio)­tetrathiafulvalene
(BEDT-TTF) in the presence of the tris­(chloranilato)­ferrate­(III) [Fe­(Cl2An)3]3– paramagnetic chiral anion
in different stoichiometric ratios and solvent mixtures afforded three
different hybrid systems formulated as [BEDT-TTF]3[Fe­(Cl2An)3]·3CH2Cl2·H2O (1), δ-[BEDT-TTF]5[Fe­(Cl2An)3]·4H2O (2), and
α‴-[BEDT-TTF]18[Fe­(Cl2An)3]3·3CH2Cl2·6H2O (3). Compound 1 presents an unusual structure
without the typical alternating organic and inorganic layers, whereas
compounds 2 and 3 show a segregated organic–inorganic
crystal structure where layers formed by Λ and Δ enantiomers
of the paramagnetic complex, together with dicationic BEDT-TTF dimers,
alternate with layers where the donor molecules are arranged in the
δ (2) and α‴ (3) packing
motifs. Compound 1 behaves as a semiconductor with a
much lower conductivity due to the not-layered structure and strong
dimerization between the fully oxidized donors, whereas 2 and 3 show semiconducting behaviors with high room-temperature
conductivities of ca. 2 S cm–1 and 8 S cm–1, respectively. The magnetic properties are dominated by the paramagnetic S = 5/2 [Fe­(Cl2An)3]3– anions whose high-spin character is confirmed by electron paramagnetic
resonance and magnetic susceptibility measurements. The correlation
between crystal structure and conductivity behavior was studied by
means of tight-binding band structure calculations, which support
the observed conducting properties.