Crystal structure and magnetic properties of [Fe{N(CN)2}2(MeOH)2] a 2-D layered network consisting of hydrogen-bonded 1-D chains

Abstract

A novel 2-D layered network structure [Fe{N(CN) ₂ } ₂ (MeOH) ₂ ] was synthesized and characterized by X-ray crystallography, vibrational, and magnetic susceptibility. The neutral 2-D stair-like framework consists of hydrogen-bonded infinite 1-D {Fe[N(CN) ₂ ] ₂ } ribbons that pack in a staggered arrangement where nearest-neighboring chains are slipped a/2 relative to one another. Two methanol molecules are coordinated to the Fe ^II center via the oxygen atoms in a trans configuration resulting in a compressed FeN ₄ O ₂ octahedron. Hydrogen-bond interactions occur via N(2)‥H(1)-O(1) where N(2) is the amide nitrogen atom of a nearby ribbon. The magnetic susceptibility was interpreted according to an S=2 expression which includes the Weiss constant and zero-field splitting giving g=2.04, θ=–2.0 K, and D=–1.7 K. Intrachain exchange interactions were determined from a fit to an S=2 antiferromagnetic chain model leading to g=2.04 and J/k _B =–0.23 K. Further interchain interaction via the hydrogen bond was determined by incorporation of a molecular-field correction term yielding J′/k _B =–0.02 K indicating very weak antiferromagnetic coupling between chains.