J. Dillen, T. H. Lenstra, J. Haasnoot
1983
Citations
0
Influential Citations
41
Citations
Journal
Polyhedron
Abstract
Abstract 5,7-Dimethyl[1,2,4]triazolo[1,5-a]pyrimidine (dmtp) is used as a ligand for divalent metal thiocyanates. Compounds of formula M(NCS)2(dmtp)2(H2O)x are formed, with x = 2 for M = Mn, Fe, Co, Ni and Cd and x = 0 for M = Zn and Hg. Infrared and ligand field spectra are discussed. The crystal structures of compounds Cd(NCS)2(dmtp)2(H2O)2 and Hg(SCN)2(dmtp)2 are described. Cd(NCS)2(dmtp)2(H2O)2 is monoclinic, C2/c, a = 15.823(8)A, b = 8.358(7)A, c = 17.650A, β = 102.82(5)°, Z = 4, dc = l.634Mg·m−3, R = 4.8% based on 2437 reflections. Cd2+ is (distorted) octahedrally coordinated by two N(3)-bonded ligands (trans-oriented) with Cd-N = 2.366(2)A, two water molecules (cis) with Cd-O = 2.344(4)A and two N-bonded NCS ions with Cd-N = 2.259(4)A. The molecules are held together by Van der Waals forces and OH … S hydrogen bonds (O … S = 3.263(2)A). Hg(SCN)2(dmtp)2 is triclinic, P1, a = 10.343(7)A, b = 13.225(8)A, c = 8.060(6)A, α = 97.15(4)A, β = 103.43(3)0, γ = 79.01(4), Z = 2, dc = 1.941 Mg·m−3, R = 7.8% based on 3218 reflections. The (distorted) tetrahedral coordination around Hg2+ consists of two N(3)-bonded ligands with Hg-N = 2.386(8) and 2.427(8)A and two S-bonded tiocyanate ions with Hg-S = 2.414(4) and 2.441(4)A; the valence angles S-Hg-S and N-Hg-N are 134.9(1)0 and 98.0(3)0 respectively. The crystal packing is determined solely by Van der Waals forces. The ligand geometry appears to be the same for both compounds, within experimental error.