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 an d having unit-cell parameters of a = 8.332(4) Angstrom, b = 9.083(2) A ngstrom, c = 18.665(5) Angstrom, and b = 90.24(3)degrees. The four wat er 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 u nits. The stacking of the 30C10 molecules forms channels through the c rystal lattice. In 30C10.4H(2)O the water molecules occupy the channel s formed by the stacking of the crown ether molecules. This study is t he first X-ray diffraction study of a simple aliphatic crown ether lar ger than 18-crown-6 and also the first such study of a tetrahydrate co mplex of any crown ether in the absence of other guest species.