Synthesis, crystal structure and magnetic properties of the one-dimensional chain compound catena-poly[aquabis(4,4′-bis-1,2,4-triazole-N1) (thiocyanato-N)-manganese-μ-[4,4′-bis-1,2,4-triazole-N1,N1′]thiocyanate

Abstract

The structure of [Mn(btr)3(NCS)(H2O)](NCS) (btr=4,4′-bis-1,2,4-triazole) was solved by the use of X-ray diffraction methods. The manganese(II) ion is six-coordinated and has both bridging and monodentate btr ligands. Two monodentate btr ligands are cis-oriented and two other btr ligands, also cis-oriented, are bridging between manganese ions, leading to a one-dimensional puckered chain structure running along the [100] direction. One thiocyanate ion and a water molecule complete the hexacoordination and are present in the trans mode. The second thiocyanate ion is not coordinated but is constrained to the complex by a strong hydrogen bond to the water molecule. The torsion angle of the central NN bond of the btr ligand varies from approximately 90° to as low as 51.6°, caused by steric effects of the lattice NCS− anion. Magnetic susceptibility and electron paramagnetic resonance measurements indicate a very weak antiferromagnetic coupling between the manganese(II) ions. Crystal data for [Mn(C4H4N6)3(NCS)(H2O)](NCS): orthorhombic, space group P212121 with a = 6.6946(15), b = 13.559(3), c = 26.607(7)Å, Z = 4, V = 2415.2(10)Å3, Rw = 0.046 on 1915 unique reflections.