An exchange interaction of the antiferromagnetic nature in benzoate bridged Mn(ii) chains

Two novel 1D chains based on heptacoordinated Mn(ii) ions bridged by variously derived benzoate ligands were prepared. The unusual structures of [Mn-II(L-1)(L-2)(4)](n)1 and [Mn-II(L-1)(L-3)(4)](n)2 (where L-1 = 2,6-dimethanolpyridine, L-2 = 3,5-dinitrobenzoic acid, L-3 = 4-chloro-3,5-dinitrobenzoic acid) were confirmed by single-crystal X-ray diffraction. Within the structures a zig zag pattern appears from perpendicularly located 2,6-dimethanolpyridines to sheets of benzoic acids. Both compounds possess the {MnNO6} chromophore and show paramagnetic behaviour with an exchange interaction of antiferromagnetic nature. Weak interaction constants J/hc = -0.54 cm(-1) (1) and J/hc = -0.58 cm(-1) (2) between high spin (S = 5/2) magnetic centres have been revealed using a finite-ring Hamiltonian model.