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

Abstract

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 Fe(III) cations are 1030, 720, and 3080 cm(-1), respectively. The Mössbauer spectrum at room temperature is characteristic of Fe(III) 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 Fe(III) phase. The magnetic susceptibility data of the Cr(III) and V(III) compounds show antiferromagnetic couplings. The J-exchange parameters of the Fe(III) and Cr(III) compounds have been calculated by using a model for a triangular spin ladder chain. The values are J1 = -1.63(1) K and J2 = -0.87(2) K with g = 2.02 for the Fe(III) phase and J(1) = -0.56(2) K and J2 = -0.40(2) K with g = 1.99 for the Cr(III) compound. In the case of the V(III) 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.

Organically templated open-framework phosphites

“…5) between Heisenberg spins. 27 Calculations, performed using the MAGPACK package, 28,29 produced the best fit of the data for J 1 ¼ À1.63 K, J 2 ¼ À0.87 K and g ¼ 2.02, J 1 and J 2 being the nearest-and next-nearest neighbour coupling constants and g the Land e gyromagnetic ratio.…”

Analysis of Spin Exchange Interactions in (C2N2H10)[Fe(HPO3)F3] on the Basis of Electronic Structure Calculations

“…In magnitude, the θcal values are greater than the experimental value (i.e., -28.0 K) by a factor of approximately 2. The θ value estimated with J 1 and J 2 by Fernández-Armas et al 2 is -14.6 K which is inconsistent with the experimental value. The overestimation of the θ cal is not surprising because DFT electronic structure calculations generally overestimate the magnitude of spin exchange interactions by a factor approximately up to four.…”

“…To make the O 2p orbital more diffuse, the ζ 2 value should be reduced. To assess how the diffuseness of the O 2p orbital affects the relative strengths of the SSE interactions between adjacent FeO 3 F 3 octahedra, we replace ζ 2 with (1 ± x)ζ 2 and calculate the < (∆e) 2 > values for three values of x, i.e., 0.00 and ±0.05.…”

“…[1][2] The crystal structure of (C2N2H10) . In addition, the magnetic susceptibility data have been fitted by using a linear chain model with second nearest neighbor interaction and the best fitting result obtained with J1 = -1.63 K and J 2 = -0.87 K, 2 respectively.…”

Offene Gerüststrukturen von Übergangsmetallen

“…90 In ihr sind CrF 3 O 3 ‐Oktaeder und HPO 3 ‐Einheiten zu einer einfachen Leiterstruktur mit endständigen Cr‐F‐Bindungen verknüpft. Ähnliche Strukturen wurden auch mit Vanadium, [C 2 N 2 H 10 ][V(HPO 3 )F 3 ],89 und Eisen, [C 2 N 2 H 12 ][Fe(HPO 3 )F 3 ],91b gebildet. Alle diese Verbindungen weisen antiferromagnetische Wechselwirkungen auf.…”