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Radical-cation salts of formula β?-(BEDT-TTF)4[(H3O)Fe(C2O4)3]·guest have produced a large number of superconductors and provided a route to introduce magnetism and chirality into the same multifunctional material. A relationship has been found in these salts between the length of the b axis and the superconducting Tc. Increasing the b axis length by introducing larger guest molecules, such as benzonitrile and nitrobenzene, gives the highest superconducting Tcs in this family of salts. Smaller guests such as pyridine show no superconducting transition, whilst asymmetrical guests which are larger than nitrobenzene have given a different bilayered structure. Other potential guest molecules have been limited by their ability to be used as the solvent in which the crystals are grown via electrocrystallisation. This paper reports a method which introduces guest molecules into the crystal which are a solid or liquid additive within the crystal-growing solvent 1,2,4-trichlorobenzene:ethanol. We present the crystal structures of five new BEDT-TTF radical-cation salts with tris(oxalato)ferrate anions using guest molecules toluene, phenol, benzaldehyde, 4-bromobenzaldehyde, and kojic acid. [ABSTRACT FROM AUTHOR]

The purely organic paramagnetic charge-transfer salt (TTF)3(PO-CON(CH3)C2H4SO3)2was prepared. The anisotropic anion forms a head-to-head arrangement in the anionic layer, giving dual donor layers with different oxidation states. SQUID magnetometry indicates that spins are localized not only on the free radical (PO) but also on both TTF layers. [ABSTRACT FROM AUTHOR]

We have prepared a novel organic molecule, 2-sulfo-3,5,6-trichloro-1,4-benzoquinone (1), that has both an electron acceptor part (chloranil) and an anionic part (sulfonate). The reduction potential of the PPh4salt is −0.34 V (vs.SCE in PhCN) which indicates it is a weaker acceptor than chloranil (−0.18 V). The anionic acceptor provided one TTF (tetrathiafulvalene) and two BEDT-TTF (bis(ethylenedithio)tetrathiafulvalene) salts, the structures and physical properties of which are reported. [ABSTRACT FROM AUTHOR]

The synthesis, columnar behaviour and magnetic properties of the first examples of radical discotics are reported. These organic molecular systems with spin sources have been accomplished by covalently linking triphenylene with molecular radicals. The columnar mesomorphism of these new radicals has been established unambiguously using several complementary techniques. Magnetic susceptibility measurements in the fluid columnar, frozen columnar and solid states reveal the antiferromagnetic intermolecular interactions of Curie–Weiss behaviour. [ABSTRACT FROM AUTHOR]

SQUID magnetometry and transport measurements combined with crystal structure refinement have been used to examine the variation in superconducting properties (Tc and Meissner fraction) in the molecular superconductor β″-(BEDT-TTF)4[(H3O)Fe(C2O4)3]·C6H5CN on replacing the C6H5CN guest molecule with pyridine (C5H5N). Up to approximately 65% pyridine substitution there is only a small decrease in Tc and Meissner fraction but above that the superconductivity is suppressed. [ABSTRACT FROM AUTHOR]