CONFORMATIONAL CHANGE OF A MACROBICYCLIC COMPLEX - STRUCTURE OF FREE LIGAND AND INTERACTIONS WITH DMSO

An X-ray crystal structure determination has been carried out on a fre e macrobicyclic ligand pytren 26,31,39,42,43,44,-undeca-azapentacyclo- [13.13.13. 4,6(42),7,9,11,48,20(43),21,23,25,31,33(44),34,36, 38-penta decane). It shows a different conformation from its Ba complex for dir ection of lone pairs of the six imine nitrogen atoms. Addition of dime thylsulfoxide (DMSO) to the acetonitrile solution of the Ba complex ca uses the conformational change of pytren ligand and driving out of the Ba ion from the cavity due to interactions of the complex with DMSO.