The crystal structures of complexes of 2,5,8,11,14,18,21,24,27,30-decaoxatricyclo[13.17.0.0]dotriacontane with potassium thiocyanate (1 : 1), barium thiocyanate (1 : 1) dihydrate, and ammonium thiocyanate (1 : 2)

Abstract

Crystal structures for three complexes of the macrotricyclic polyether (I), containing a cyclohexane ring which shares opposite pairs of carbon atoms with two 15-crown-5 rings have been determined. All three compounds form 2 : 2 complexes. The cations are sandwiched between 15-crown-5 rings from two molecules, rather than between the two rings of one molecule of (I) in the hoped-for ‘clam’ conformation. The K⁺ and Ba²⁺ ions are 10-co-ordinated in their complexes; the NH₄⁺ ion forms three simple and one bifurcated N–H ⋯ O bonds to oxygens in (I). The anions in the K⁺ complex are disordered and isolated from the complex cations. For the Ba²⁺ complex crystals, however, the two anions form infinite hydrogen-bonded chains along the crystal c axis with the two molecules of water. In the ammonium complex crystals, the second NH₄⁺ cation and two thiocyanate anions form infnite hydrogen-bonded chains, also along the crystal c axis.