A New Alternating Ferro- and Antiferromagnetic, One-Dimensional Manganese(II) Azide Complex, [Mn(dpa)(N3)2] − Crystal Structure and Spectroscopic and Magnetic Properties

Abstract

The synthesis, crystal structure, and spectroscopic and magnetic properties of a new alternating ferro- and antiferromagnetic, one-dimensional manganese(II) azide complex, [Mn(dpa)(N3)2] (where dpa is the 2,2′-dipyridylamine ligand), are reported. The compound’s crystal structure has been resolved at room temperature. The complex crystallizes in the monoclinic P21/c space group, with a = 7.089(2), b = 19.090(4), and c = 9.682(4) Å, β = 104.61(2) °, and Z = 4. The structure consists of neutral chains in which each MnII cation is alternatively bridged by two end-on and two end-to-end azido bridges. The octahedral coordination of the metallic cation is completed by two dpa ligand nitrogen atoms. Reflectance measurements confirm the hexacoordination of the MnII ions in the complex. The ESR spectra at room temperature and at 4.2 K are isotropic, with a mean g-value of 2.010(1). Magnetic data were analyzed on the basis of an alternating ferro- and antiferromagnetic Heisenberg chain of MnII ions. The J-exchange parameters found are 64.3 and −75.7 K. A spin canting phenomenon has been observed in this compound, with a remnant magnetization which vanishes above 15 K. Magnetostructural correlations in manganese(II) systems of alternating magnetic sign are discussed.