A new ferrimagnetically ordered charge-transfer complex based on high-spin iron(III) chelate tetracyanoethenide with a Tc of 10 K

• Published in: Journal of magnetism and magnetic materials Vol. 246; no. 1; pp. 283 - 289
• Main Authors: Müller, Bernd R., Leibeling, Guido, Jäger, Ernst-G.
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 01.04.2002; Elsevier Science
• Subjects: Canted ferrimagnet; Charge-transfer complex; Chelate; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Exact sciences and technology; Iron; Magnetic properties and materials; Molecular magnet; Molecular magnets; Physics; Studies of specific magnetic materials; TCNE; Canted ferrimagnet; TCNE; Charge-transfer complex; Iron; Chelate; Molecular magnet; Organic ligand; Alternated chain model; Experimental study; Magnetic susceptibility; Molecular magnetism; High spin states; Iron complexes; Ferrimagnetism; Canted spin arrangements; Coercive force; Spin Hamiltonians; Charge transfer complexes; Chelates; Exchange interactions; Saturation magnetization
• ISSN: 0304-8853
• DOI: 10.1016/S0304-8853(02)00075-6

The reaction of the high-spin iron(II) quadridentate chelate complex [Fe(L)], (L=diethyl( E, E)-2,2′-[1,2-phenylenebis-(iminomethylidyne)]-bis-[3-oxobutanoate]), with the electron acceptor tetracyanoethylene (TCNE) leads to the formation of the 1:1 charge-transfer (CT) complex [Fe(L)] +[TCNE] −. The magnetic characterisation of the CT salt indicates a chain structure with alternating S= 5 2 high-spin iron(III) and S= 1 2 TCNE − radicals in which the spin centres are antiferromagnetic correlated. The antiferromagnetic intrachain interaction parameter is very weak ( J intra≈−8 cm −1) based on the spin Hamiltonian H=−J intra S i S j . At T=2 K and H=5.5 kG the magnetisation for the CT complex is about 83% of the saturation magnetisation value expected for a S total =( 5 2 − 1 2 )=2 system. A magnetic hysteresis loop was observed at T=2 K with a coercive field of 200 G. Below 10 K, the complex shows a weak spontaneous magnetisation characteristic for a canted ferrimagnet.