Large calixarenes: Structure and conformation of a calix[16]arene complexed with neutral molecules

A crystal of an inclusion compound between a calix[16]arene and molecules o f acetonitrile and dichloromethane, used as solvents, has been obtained and its X-ray structure studied. The cell is monoclinic, space group C2/c with a = 38.508(8) Angstrom, b = 21.593(4) Angstrom, c = 26.625(5) Angstrom and 121.34(3)degrees. The macrocycle is in the form of two superimposed celtic torcs connected by their extremities.(1) Two acetonitrile molecules are si tuated in the middle of this double torc, two dichloromethane molecules are encapsulated in the pseudo calix[4]arenes obtained on both extremities of the torcs by the folding of the last four phenolic rings. A disorder is obs erved for the other acetonitrile and dichloromethane molecules situated out side the macrocycle.