Synthesis, crystal structure, and magnetic properties of binuclear Mn III-azido and 1D polymeric Mn II-μ 1,3-thiocyanato novel species based on a neutral hexadentate Schiff base

Abstract

A binuclear manganese(III) complex [Mn 2(L 1)(N 3) 6] ( 2) and an unprecedented 1D chain of manganese(II) binuclear units bridged by two end-to-end thiocyanato anions { [ Mn 2 II ( L 1 ) ( NCS ) 4 ] · 2 CH 3 CN } n ( 3 · 2CH 3CN) have been prepared from N-(1-pyridin-2-ylbenzylidene)- N′-[2-({2-[(1-pyridin-2-ylbenzylidene)amino]ethyl}amino)ethyl]ethane-1,2-diamine (L), manganese(II) salts and azide/thiocyanate anions in air. L 1, N-(1-pyridin-2-ylbenzylidene)- N-[2-(4-{2-[(1-pyridin-2-ylbenzylidene)amino]ethyl}piperazin-1-yl)ethyl]amine, results from an alkylating cyclization of the flexible hexadentate Schiff base L occurring along the course of the complexation reactions. Both complexes have been characterized by single crystal X-ray diffraction studies. The Mn centres of complexes 2 and 3 are in distorted octahedral ( 2: Mn IIIN 6, 3: Mn IIN 5S) coordination environments with intramolecular Mn⋯Mn distance ( 2: 6.473(2) Å, 3: 6.437(1) Å) consistent with the absence of intramolecular magnetic interactions. Compound 3, exhibits weak intermolecular antiferromagnetic interactions ( J = −1.5 cm −1) between pairs of Mn II ions bridged via two μ 1,3-NCS.