Synthesis and molecular structure of catena((μ2-4,4,10,10-tetramethyl-1,3,7,9-tetraazaspiro[5.5]undecane-2,8-dione-O,O')- aquadinitratocadmium(II))

Abstract

A coordination polymer, catena((μ₂-4,4,10,10-tetramethyl-1,3,7,9-tetraazaspiro[5.5]undecane- 2,8-dione-O,O')-aquadinitratocadmium(II) {[Cd(C₁₁H₂₀N₄O₂)(H₂O)(NO₃)₂]}_n} (I), has been prepared for the first time from cadmium(II) nitrate and the bicyclic bisurea 4,4,10,10-tetramethyl-1,3,7,9-tetraazaspiro[5.5]undecane-2,8-dione (TTSU). Its molecular structure has been determined (CIF file CCDC no. 903387). Triclinic crystals: space group P1̅, a = 8.9967(4) Å, b = 9.6011(4) Å, c = 12.5131(7) Å, α = 76.307(4)°, β = 73.465(5)°, γ = 63.310(5)°, V = 918.26(8) ų, ρ_calc = 1.789 g/cm³, Z = 2. The Rietveld refinement was carried out at 293 K to confirm the single-phase constitution of the obtained powder sample of I: a = 8.9972(4) Å, b = 9.6104(4) Å, c = 12.5203(4) Å, α = 76.373(3)°, β = 73.485(3)°, γ = 73.485(3)°, V = 919.80(6) ų. A number of lines not corresponding to the main phase and not identified from PDF-2 database are observed on the powder X-ray diffraction pattern. The Rietveld refinement showed that the sample contains 91.4 wt % of the main compound I and 8.6 wt % of the TTSU nitrate admixture. The cadmium atom is coordinated by the O(1) and O(1)ⁱ atoms of two molecules of the organic ligand (L) generated by the symmetry operation (ⁱ1–x,–y,–z), the O(2)ⁱⁱ atom of the third ligand L molecule bound with the supporting one with the symmetry operation (ⁱⁱ–x,–y,–z), a water molecule, and a bidentate and a monodentate nitrate anions. The coordination number of the cadmium atom is 7, the coordination polyhedron is a distorted pentagonal bipyramid. The Cd···Cd distance is 4.0208 (3) Å.