Synthesis, Structures, and Magnetic Properties of End-to-End Azide-Bridged Manganese(III) Chains: Elucidation of Direct Magnetostructural Correlation

The two one-dimensional chain compounds [Mn­(L1)­(N₃)]·H₂O (1·H₂O; H₂L1 = 2,2′-((1E,1′E)-ethane-1,2-diylbis­(azan-1-yl-1-ylidene))­bis­(phenylmethan-1-yl-1-ylidene)­diphenol) and [Mn­(L2)­(N₃)] (2; H₂L2 = 2,2′-((1E,1′E)-2,2-dimethylpropane-1,3-diyl)­bis­(azan-1-yl-1-ylidene)-bis­(phenylmethan-1-yl-1-ylidene)­diphenol) bridged by single end-to-end azides were prepared via a self-assembly process. Each Mn­(III) ion exhibits a characteristic Jahn–Teller elongation along the chain direction. For both compounds, antiferromagnetic interactions between Mn­(III) spins within a chain are transmitted through the azide ligands, together with the apparent occurrence of spin canting at low temperatures. Remarkably, the coupling constants (J) for 1 and 2 exceed those reported for end-to-end azide-linked Mn­(III) systems. A systematic magnetostructural relationship based on the torsion angle is established in terms of the torsion angle Mn–N_ax···N_ax–Mn (ax = axial) for the first time.