Weak Metamagnetic-like 1D Manganese(II) Complex with a Double μ_1,1-Azido Bridge:  A Structure and Magnetic Study

The azido-bridged manganese complex of formula [Mn(tptz)(μ_1,1-N₃)₂]_n [1; tptz = 2,4,6-tris(2-pyridyl)-1,3,5-triazine] has been synthesized and characterized by single-crystal X-ray diffraction analysis and a low-temperature magnetic study. The complex 1 crystallizes in the orthorhombic space group Pbcn, with a = 17.911(5) Å, b = 15.804(5) Å, c = 6.6538(18) Å, and Z = 4. The Mn atoms are coordinated by three N atoms of the tptz ligands and connected to each other by double end-on (EO) azide ligands, forming a neutral 1D chain. The adjacent 1D chains are connected by face-to-face π−π-stacking interactions and C−H···π interactions of pyridine rings of the tptz ligands, which leads to the formation of a supramolecular 2D sheet structure. Temperature- and field-dependent magnetic analyses reveal dominant intrachain ferromagnetic interactions with EO azide-bridge and weak interchain antiferromagnetic interactions with overall metamagnetic behavior having 3D magnetic ordering at 2.7 K. The critical field is approximately 80 G, at which the interlayer antiferromagnetic ground-state switches to a ferromagnetic state.