| Research Abstract |
Doubly interlocking catenanes are chiral and complex topologies which have only been described recently. Our approach is to combine the two methods, based on coordination chemistry, which are termed as "template" and "self-assembly" strategies. In the template strategy, copper(I) complexes have been used as precursors, affording simple to topologically very complex catenanes.
On the other hand, the self-assembly process furnishes in one chemical step sophisticated structures, including interlocking rings, from very simple molecular fragments and under mild conditions. A new method based on these two strategies has been used to construct a 4-crossing [2]catenane. The ligand used contains a central 1, 10-phenanthroline site attached to two pendent/4-pyridyl groups. The central site is used to complex a copper(I) center whereas the lateral pyridine groups are coordinated to palladium(II). The stepwise complexation procedure is virtually quantitative. It can be carried out both ways (copper(I) followed by palladium(II) or reverse) : The final complex is a chiral species incorporating 4 ligands, 2 copper(I) and 4 palladium(II) centers. It has been characterized in solution and its structure has been evidenced by ESI-MS.
|
