Inorganic anions dependent orientation of ammonium cations in crown ether-ammonium cation-inorganic anion system

Five supramolecular assembly complexes: 2-hydroxypropane-1,3-diammonium-perchlorate-18-crown-6 ([C3H12N2O-(18-crown-6)(2)](2+)center dot 2[ClO4](-), 1); 2-hydroxypropane-1,3-diammonium-tetrafluoroborate-18-crown-6 ([(C3H12N2O)(2)-(18-crown-6)(3)](2+)center dot 2[BF4](-), 2); 4-methylanilinium perchlorate-18-crown-6 ([C7H10N-(18-crown-6)](+)center dot[ClO4](-), 3); 4-iodineanilinium-tetrafluoroborate-18-crown-6 ([C6H7NI-(18-crown-6)](+)center dot[BF4](-), 4); 4-methylanilinium tetrafluoroborate-18-crown-6 ([C7H10N-(18-crown-6)](+)center dot.[BF4](-), 5), for the investigation of the influence of different inorganic anions on the orientation of ammonium cation and host-guest interaction of crown ethers, have been synthesized and characterized. The results revealed that ClO4- anion lead to the 2:1 composition of crown and ammonium cation in monoclinic space group and 3:2 composition of crown and ammonium cation in the presence of BF4- anion for double-anilinium system (complexes 1 and 2). While for the single-anilinium system (complexes 3, 4, and 5), the different inorganic anions lead to quite different orientation of the ammoniums in orthorhombic space group. We also studied the TGA/DSC properties, Raman spectrascopy and hot stage microscopy for the five complexes. (C) 2013 Elsevier Ltd. All rights reserved.