Metal-Azide-Pyrimidine Complexes M(N3)2(pm) with a Three-Dimensional Network Showing Weak Ferromagnetism for M = Mn and Fe and Antiferromagnetism for M = Co and Ni

Abstract

Abstract Antiferromagnetic phase transitions of M(N3)2(pm) were observed at 51, 39, 41, and 46 K for M = Mn, Fe, Co, and Ni, respectively; here pm denotes pyrimidine. Single-crystal X-ray crystallographic analysis for M = Mn, Fe, and Co and powder X-ray diffraction measurements for M = Ni revealed that they were isomorphous. The N3 and pm moieties contribute μ-1,3-bridged two-dimensional and μ-1,3-bridged one-dimensional structures, respectively, thus forming a three-dimensional framework. Antiferromagnetic couplings through the bridging ligands are consistent with superexchange mechanisms based on the coordination geometry determined. Small spin canting was observed below the transition temperature for M = Mn and Fe. The cant angles are estimated to be 0.06 and 0.13°, respectively, from the spontaneous magnetization at 10 K.