X-ray structural study of lanthanide complexes with a p-tert-butylthiacalix[4]arene bearing phosphoryl pendant arms

A new lower-rim substituted thiacalix[4]arene, 5,11,17,23-tetra-tert-butyl-25,26,27,28-tetrakis(diphenylphosphinoylmethoxy) thiacalix[ 4]arene (L) has been synthesized and structurally characterized as an adduct L$0.5MeOH$1.5H2O, monoclinic, space group P21/n. The ligand adopts a cone conformation. Trivalent lanthanide ion complexes of this ligand have been synthesized and characterized by elemental analysis and IR spectra. The crystal structures of La3C and Nd3C complexes were determined by X-ray diffraction method. They are isostructural and belong to tetragonal system, I41/acd space group. In each complex, the calixarene retains the cone conformation, the metal ion is nine-coordinated to four oxygen atoms from phosphine oxide substituents, four oxygen atoms from two bidentate nitrate anions and one oxygen atom from a hydroxyl ion. The coordination polyhedron is a single-capped square antiprism. The complex assembles to a novel infinitely 1D helical structure through p–p stacking, and further crosses each other forming a nanometer scale chessboard-like pore structure along c direction. q 2005 Elsevier B.V. All rights reserved.