Parametrization of the Magnetic Behavior of the Triangular Spin Ladder Chains Organically Templated:  (C2N2H10)[M(HPO3)F3] (MIII = Fe, Cr, and V). Crystal Structure and Thermal and Spectroscopic Properties of the Iron(III) Phase

• Published in: Inorganic chemistry 2006-04, Vol.45 (8), p.3240-3248
• Main Authors: Fernández-Armas, Sergio, Mesa, José L, Pizarro, José L, Clemente-Juan, Juan Modesto, Coronado, Eugenio, Arriortua, María I, Rojo, Teófilo
• Format: Article
• Language: English
• ISSN: 0020-1669; 1520-510X
• DOI: 10.1021/ic051804o

A new iron(III) phosphite templated by ethylenediamine has been synthesized using solvothermal conditions under autogenous pressure. The (C2N2H10)[Fe(HPO3)F3] compound has been characterized by single-crystal X-ray diffraction data and spectroscopic and magnetic techniques. The crystal structure is formed by chains extended along the c axis and surrounded by ethylenediammonium cations. A study by diffuse-reflectance spectroscopy has been performed, and the calculated Dq, B, and C parameters for the FeIII cations are 1030, 720, and 3080 cm-1, respectively. The Mössbauer spectrum at room temperature is characteristic of FeIII ions. The electron spin resonance (ESR) spectra carried out at different temperatures show isotropic signals with a g value of 2.00(1). The thermal evolution of the intensity of the ESR signals indicates the existence of antiferromagnetic interactions for the FeIII phase. The magnetic susceptibility data of the CrIII and VIII compounds show antiferromagnetic couplings. The J-exchange parameters of the FeIII and CrIII compounds have been calculated by using a model for a triangular spin ladder chain. The values are J 1 = −1.63(1) K and J 2 = −0.87(2) K with g = 2.02 for the FeIII phase and J 1 = −0.56(2) K and J 2 = −0.40(2) K with g = 1.99 for the CrIII compound. In the case of the VIII phase, the fit has been performed considering a linear chain with the magnetic parameters D = 2.5 cm-1 and J = −1.15(1) K.