The 1,4,7,10,13-Pentaoxacyclohexadecane-14,16-Dione Complex with Potassium Thiocyanate: Crystal Structure

Abstract

The complex of 1,4,7,10,13-pentaoxacyclohexadecane-14,16-dione (L) with potassium thiocyanate, C11H18O7· KNCS (I), is prepared and characterized by X-ray diffraction analysis: space group C2/c, a = 26.810 A, b = 7.834 A, c = 20.504 A, β = 129.19°, Z = 8. The crystal structure is solved by the direct method and refined anisotropically by the full-matrix least-squares method to R = 0.038 for all 2929 unique measured reflections (CAD4 automated diffractometer, λMoKα). Structure I is built of [KL(NCS)] monomers of the host–guest type, which are united into [K2L2(NCS)2] dimers containing four-membered KNKN cycles. In the crystal, the dimers are united into infinite polymeric double chains (along the b axis) by K···O=C outer bonds. The K+ cation (CN 8) does not lie in the plane of the L crown ligand but is located above it. The coordination polyhedron of the K+ cation is irregular; its vertices are occupied by five ether O atoms of one L ligand, two N atoms of two SCN ligands, and one carbonyl O atom of the adjacent L ligand.