CRYSTAL-STRUCTURES OF 30-CROWN-10 AND ITS TETRAHYDRATE

Detailed characterization of 30-crown-10 (30C10) with NMR spectroscopy, TGA, DSC, and X-ray crystallography is reported. The anhydrous 30C10 crystal is orthorhombic, belonging to space group Pbca: a = 8.606(1) Angstrom, b = 8.260(1) Angstrom, and c = 33.310(4) Angstrom. The 30C10.4H(2)O crystal is monoclinic, belonging to the space group P2(1)/c and having unit-cell parameters of a = 8.332(4) Angstrom, b = 9.083(2) Angstrom, c = 18.665(5) Angstrom, and b = 90.24(3)degrees. The four water molecules located in the cavity are bound to each other and to the crown ether but not to water or crown ether molecules of neighboring units. The stacking of the 30C10 molecules forms channels through the crystal lattice. In 30C10.4H(2)O the water molecules occupy the channels formed by the stacking of the crown ether molecules. This study is the first X-ray diffraction study of a simple aliphatic crown ether larger than 18-crown-6 and also the first such study of a tetrahydrate complex of any crown ether in the absence of other guest species.