CONFORMATIONAL STUDY OF THE MACROCYCLE 1,4,7-TRITHIACYCLONONANE IN METAL-COMPLEXES

Computational studies have been carried out on the macrocycle 1,4,7-trithiacyclononane [9]aneS3 in the free state and in metal complexes. A range of metal complexes of [9]aneS3 has been studied by molecular mechanics and good agreement has been obtained with experimental structural data. The macrocycle forms a series of octahedral complexes M([9]aneS3)2, with M-S bond lengths ranging between 2.241 angstrom for Fe(II) to 2.725 angstrom for Ag(I). Changes in the geometry of the macrocycle upon binding to different metals in these complexes have been successfully modelled. Also studied were a range of less-symmetric structures containing this macrocycle and the reasons for the wide variations in conformation have been established.