Charge-Transfer Salts of Octamethylferrocenyl Thioethers with Organic Acceptors (TCNQ and TCNQF₄) and Trihalides (Br₃⁻ and I₃⁻). Synthesis, Structure, and Physical Properties

Six charge-transfer (CT) complexes containing three different octamethylferrocene derivatives (Fe(η 5 -C 5 Me 4 SMe) 2, 1; Fe(η 5 -C 5 Me 4 S t Bu) 2, 2; Fe(η 5 -C 5 Me 4 S) 2 S, 3 ) and TCNQ or TCNQF 4, respectively ( 4 − 9 ), have been prepared and fully characterized. X-ray crystal structural studies of 4, 5, 7, and 9 have been carried out. The CT complexes 4 and 5, containing TCNQ, display stacks of acceptor molecules with noncommon donor/acceptor stoichiometries of 3:7 for 4 and 1:3 for 5, whereas the charge-transfer complexes 7 and 9, containing TCNQF 4, display strongly interacting dimers of acceptor anions. The compounds 4 − 6 behave as semiconductors with room-temperature conductivities up to 3.5 S cm - 1 for 6 . Magnetic susceptibility measurements indicate strong antiferromagnetic interaction for the (TCNQF 4 ) 2 2 - dimers in 7 − 9, the dimers being diamagnetic ( S = 0) at room temperature. Antiferromagnetic interactions are also observed for the three compounds 4 − 6 . To obtain more accurate Land é-g factors for the three possible cations from 1 − 3, the corresponding trihalogenide salts with Br 3 - ( 10 − 12 ) and I 3 - ( 13 − 15 ) were prepared and fully characterized. Their magnetic properties, only deriving from the cations, were measured, and X-ray crystal structural studies have been carried out for the compounds 11, 12, 14, and 15 . For the two compounds containing the tert -butyl substituent ( 11 and 14 ), a DADA structural motif was observed, and with the trithiaferrocenophanium, chains ( 12 ) and networks ( 15 ) of alternating sulfur bridges and trihalogenide anions were observed.