UNUSUAL HOST-GUEST PI-ARENE ... H-BONDING IN A HOODED CAVITAND - THE FIRST SOLID-STATE STRUCTURE OF A CALIX[4]RESORCINARENE WITH UNDERIVATISED HYDROXY-GROUPS

Treatment of phenylcalix[4]resorcinarene 1 with dipropylamine and para formaldehyde leads to the formation of a deep cleft cavitand 2, in whi ch the cavity is extended by a collar of exquisite intramolecular dono r-acceptor hydrogen bonding networks which all proceed in the same dir ection around the upper rim imparting chirality on the individual cavi tands; the amine groups involvement in intramolecular hydrogen bonding draws the N-alkyl substituents inward to form an encapsulating 'hood' over an included CH2Cl2 guest molecule.