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

Abstract

The two one-dimensional chain compounds [Mn(L1)(N-3)]center dot H2O (1 center dot H2O; H(2)L1 = 2,2'-((1E,1'E)-ethane-1,2-diyIbis(azan-1-yl-1-ylidene))bis(phenylmethan-1-yl-1-ylidene)diphenol) and [Mn(L2) (N-3)] (2; H(2)L2 = 2,2'((1E,1'E)-2,2-dimethylpropane-1,3-diyObis(azan-l-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 30 on the torsion angle is established in terms of the torsion angle Mn-N-ax center dot center dot center dot N-ax-Mn (ax = axial) for the first time.