Anion inclusion without auxiliary hydrogen bonds: X-ray structure of the iodide cryptate of a macrotricyclic tetra-quaternary ammonium receptor

Abstract

The X-ray Crystal and molecular structure of [I–L4+]3+ 3I–˙3MeCN·H2O, L = N4Me4(C6H12)6, shows on iodide anion to be encapsulated symmetrically into the spherical intramolecular cavity of the macrotricycle L4+ and held in place by the ectrostatic potential of the four quaternary ammonium sites arranged at the corners of an almost perfect tetrahedron; the N+⋯ I– distances average to 4.54(2)A whereas the distances between iodide and the carbon atoms of the [CH2]6 chains are of van der Waals type or longer.