ChemInform Abstract: Ferromagnetic Behavior of (Fe(C5Me5)2)·+(TCNE).times± Structural and Magnetic Characterization of Decamethylferrocenium Tetracyanoethenide, (Fe(C5Me5)2)·+(TCNE).times±times.MeCN, and Decamethylferrocenium Pentacyanopropenide, (Fe(C5Me5)2)·+(C3(CN)5)-.
Abstract
The reaction of Fe(C5Me5)2 and tetracyanoethylene, TCNE, leads to the isolation of the two title compounds.
ChemInform Abstract
The reaction of Fe(C5Me5)2 and tetracyanoethylene, TCNE, leads to the isolation of the two title compounds. Crystals of the (TCNE)·- salt as the MeCN solvate (yield 82%) belong to the space group C2/c with Z = 8. The salt's linear chain motif is comprised of alternating S = 1/2 cations and S = 1/2 anions. MeCN is lost on isolation of the crystals, and the lattice transforms into an orthorhombic Cmc21 lattice. This desolvated complex can be prepared from THF (yield 33%) and possesses chains of alternating cations and disordered anions. The (C3(CN)5)- salt belongs to the same space group (C2/c, Z=4), and the motif is comprised of alternating S = 1/2 cations and S = 0 anions. The magnetic properties of these salts are measured via the Faraday technique and discussed. The 57Fe Mößbauerspectra of the (TCNE)·- salt are analyzed. A qualitative model based on the mixing of an excited state with the ground state for stabilizing ferromagnetic coupling and leading to bulk ferromagnetism is discussed.
