SYNTHESIS, CRYSTAL-STRUCTURE AND MAGNETIC-PROPERTIES OF THE ONE-DIMENSIONAL CHAIN COMPOUND CATENA-POLY[AQUABIS (4,4'-BIS-1,2,4-TRIAZOLE-N1)( SE-MU-[4,4'-BIS-1,2,4-TRIAZOLE-N1,N1']THIOCYANATE]

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 mang anese(II) ion is six-coordinated and has both bridging and monodentate btr ligands. Two monodentate btr ligands are cis-oriented and two oth er 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 th iocyanate 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 N-N bond of the btr ligand varies from approximately 90 degre es to as low as 51.6 degrees, 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)] (N CS): orthorhombic, space group P2(1)2(1)2(1) with a = 6.6946(15), b = 13.559(3), c= 26.607(7) Angstrom, Z=4, V= 2415.2(10) Angstrom(3), R-W = 0.046 on 1915 unique reflections. (C) 1998 Elsevier Science S.A. All rights reserved.