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; H ₂L2 = 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.