Crystal and molecular structures of complex between ammonium iodide monohydrate and the cis-syn-cis isomer of dicyclohexano-18-crown-6

The structure of the [(DCH-6A . NH4)(H2O)I](2) complex obtained by the reac tion between the cis-syn-cis isomer of dicyclohexano-18-crown-6 (DCH-6A) an d NH4I has been determined by X-ray diffraction analysis. The crystals are triclinic, a = 9.314(3) Angstrom, b = 11.951(2) Angstrom, c = 12.040(1) Ang strom, alpha = 77.36(1)degrees, beta = 81.59(1)degrees, gamma = 80.41(2)deg rees, space group P (1) over bar, Z = 2, and the final R factor is 0.044. T he structure is built up of the (DCH-6A . NH4)(+) cationic complexes, iodid e anions, and water molecules. The ammonium ion forms three hydrogen bonds of the NH ... O type [N ... O, 2.881(5)-2.890(5) Angstrom] with the oxygen atoms of the crown ether molecule. The organic cations are joined together into centrosymmetric dimers through the system of hydrogen bonds of the NH ... OH ... I type. The I-... O distances (where the O atom belongs to the b ridging water molecule) fall in the range 3.558(4)-3.610(4) Angstrom. (C) 2 000 MAIK "Nauka/Interperiodica".