Intermolecular axial solvation of bound cations by sidearm donor groups in lariat ethers: formation of a supramolecular network

Previously studied disubstituted 4,13-diaza-18-crown-6 derivatives, RR, in which the substituents were cyanomethyl or propargyl did not show intramolecular, lariat-type cation solvation. The ring-bound cation in the propargyl derivative is solvated by the six macroring heteroatoms and apically by a bifurcated interaction of the type F⋯K+⋯F. In contrast, when the sidearm is cyanoethyl, an extended intermolecular network forms when the bound cation is either Na+ or K+.