The Preparation of a Double Metallahelicate Containing 28 Copper Atoms

摘要

Molecules of great complexity that are prepared by the self-organization of simple components have garnered consider-able recent attention. Among these compounds are metal-lamacrocycles such as the helicates,~[a-b] molecular squares,~[2a,b] and the metallacrowns,~[3a-e] The latter molecular class is reminiscent of organic crown ethers; however, the {O-C-C}_n Metallacrowns have been prepared with ring sizes ranging from 9-metallacrown-3 (9-MC-3) to 30-MC-10.~[4a-c] The 15-MC-5 complexes, in particular, have been of interest as these can be prepared using alpha-amino acid-derived ligands. As such they are inherently chiral and can form cavities capable of selective anion recognition~[5a] or resolved, fourfold symmetric, amphiphilic metallahelices.~[5b] Herein, we demonstrate that a new class of self-assembled complex, a metallahelicate, can alsobe isolated by our synthetic strategy.