Electric and magnetic properties of organometallic TCNQ salts

Three salts [( ν 5 -C 5 H 5 )FeAr] + [(TCNQ) 2 ] − (Ar = 2,4,6-C in 6H 3 rmMe 3 , C 6 Me 6 , C 6 Et 6 ) have been characterized by d.c. conductivity, thermoelectric power and e.s.r. measurements. Quasi-semiconducting properties of electric transport have been found, with a temperature-dependent energy gap in the case of the first two salts and a constant gap for the third salt. The magnetic properties have been shown to be determined by the non-paired electrons of TCNQ. The angular dependences of the g factor and the e.s.r. linewidth have been analysed with regard to the crystal structure. The spin interactions and localization of electrons have been found to be dependent on the ligand size in the aromatic ring of the cation.