Reaction of aqueous solutions containing CO2+ or Ni2+ and PF6−, or AsF6− with excess 3-methylpyridine yields crystals of compounds of composition M(H2O)2(3mpy)6(EF6)2. Blue crystals of diaquohexakis(3-methylpyridine)nickel(II) hexafluorophosphate, C36H46F12NiN6O2P2, are monoclinic, a = 10.497(1), b = 20.074(3), c = 21.836(5) Å, β = 103.93(2)°, Z = 4, space group Cc. The structure was determined with MoKα CAD4 diffractometer data by direct methods, and refined by full-matrix least-squares procedures to R = 0.048 for 2723 reflections with I ≥ 3σ(I). The structure consists of {Ni(3mpy)4[(OH2)(3mpy)]2}2+ cations and PF6− anions. The cation contains a NiN4O2 chromophore with water molecules occupying trans positions of a distorted octahedron about nickel. One additional 3-methylpyridine molecule is H-bonded to each of the water molecules with [Formula: see text] distances of 2.717(11) and 2.719(11) Å. Weak interaction of each water molecule via its second hydrogen atom with a PF6− ion is indicated by the positioning of the anions. The [Formula: see text] distances are 2.958(11) and 2.959(11) Å. Two other complexes of this type, where M is Ni and E is As and where M is Co and E is P, are reported here and on the basis of spectroscopic and magnetic studies are assigned structures similar to the Ni/P complex.Decomposition of the aquo complexes under mild conditions yields compounds of composition M(3mpy)4(EF6)2. Ni(3mpy)4(PF6)2 is assigned a square planar structure with weakly interacting PF6−, anions in axial positions. Both Co(3mpy)4(EF6)2 complexes, where E is P or As, have tetrahedral [Co(3mpy)4]2+ cations and non-coordinated anions.
The Crystal and Molecular Structure of a trans Square-Planar Complex of Tellurium Dimethanethiosulphonate with Thiourea.
