SYNTHESIS, VIBRATIONAL-SPECTRA AND CRYSTAL-STRUCTURE OF [NN(NCS)(2)(4,4'-BIS-1,2,4-TRIAZOLE)(H2O)(2)], A POLYMERIC MANGANESE(II) CHAIN

The manganese(II) ion in [Mn(NCS)(2)(4,4'-bis-1,2,4-triazole)(H2O)(2)] has an all-trans pseudo-octahedral configuration with two N-coordinat ed NCS- ions, two water molecules and two ligand N atoms. The 4,4'-bis -1,2,4-triazole (btr) ligand bridges, via its N1 and N1' atoms, two ma nganese ions generating polymeric chains running along [(1) over bar 0 1]. The molecular geometry of the btr ligand, usually hardly affected by coordination in earlier described coordination compounds, now shows a conformational variation, the torsional angle of the central N-N-bo nd being changed from about 90 to 74 degrees. Crystal data for [Mn(NCS )(2)(C4H4N6)(H2O)(2)]: monoclinic, space group C2/c with a = 19.431(6) , b = 5.928(4), c = 12.181(5) Angstrom and beta = 111.71(2)degrees, Z = 4, V = 1304(1) Angstrom(3), R = 0.030 on 1444 reflections. The dista nces Mn-NCS are 2.152(2) Angstrom, Mn-OH2 2.201(2) Angstrom and Mn-N(b tr) 2.320(2) Angstrom. The infrared and Raman spectra of the free and metal-coordinated ligand are correlated to the torsion angle about the central N-N bond.