Supramolecular chemistry. Supramolecular rectangles and their guests

Two molecular spacers which cofacially dispose terpyridyl-palladium(II)-ace tonitrile units separated by similar to7 Angstrom are described. The spacer s are polyaromatic molecules, one spacer is fully aromatic whereas the othe r has two symmetrically disposed reduced aromatic rings. Addition of the li nker, 4,4'-dipyridyl, to solutions of these spacer-chelator complexes leads to the rapid and quantitative formation of supramolecular rectangles. It i s found that the reduced rectangle forms a 4:1 adduct with 9-methylanthrace ne whereas the oxidized rectangle forms a 5:1 adduct with 9-methylanthracen e. The possible reasons for this high level of agglomeration and the differ ence in adduct formation for the two systems are discussed.