One-electron oxidation of [Fe2(η-C5H5)2(µ-CO)2{µ-Ph2PN(Et)PPh2}] by 7,7,8,8-tetracyano-p-quinodimethane: formation of a charge-transfer salt with a novel solid-state stoichiometry and structure

Abstract

Treatment of [Fe₂(η-C₅H₅)₂(µ-CO)₂{µ-Ph₂PN(Et)PPh₂}] with 7,7,8,8-tetracyano-p-quinodimethane, TCNQ, affords, on crystallization from acetonitrile, a charge-transfer salt, [Fe₂(η-C₅H₅)₂(µ-CO)₂{µ-Ph₂PN(Et)PPh₂}]₂(TCNQ)₃·2MeCN, with a novel 2 : 3 Stoichiometry; the cations and anions in this species are distributed in segregated stacks, the TCNQ anions packing as trimers along the stack with an intratrimer separation of 3.24(1)Å and an intertrimer separation of 3.39(1)Å.