Crystal Structure of Diaqua(2.2.2-cryptand)strontium Bis(thiocyanate)

Abstract

The crystal structure of the title compound, [Sr(C₁₈H₃₆N₂O₈)(H₂O)₂]²⁺·2SCN^– (I), was investigated by X-ray diffractometry: space group $P2_1 /n$, a = 10.724(3), b = 15.512(3), c = 16.826(4) Å, β = 97.96(3)°, Z = 4. The structure was solved by direct methods. The full-matrix least-squares anisotropic refinement converged to R = 0.038 for all 3837 independent measured reflections (CAD-4 automatic diffractometer, $\lambda MoK_\alpha$). In the structure of I, the Sr²⁺ cation (c.n. 10) lies in the cavity of the cryptand ligand and is coordinated by all of its eight heteroatoms (6O+2N) and two O atoms of the two water molecules; its coordination polyhedron is a distorted two-base-centered bicapped trigonal prism. The cryptand ligand in I has an asymmetric conformation. The crystal structure of I has interionic hydrogen bonds (formed by the H atoms of the ligand water molecules) linking the complex cations and the SCN^– anions into complex infinite chains.