The structure shows the complex formation of a marine
natural product (westiellamide or also named cycloxazoline,
isolated from an ascidian from the great barrier reef in
Australia) with four silver cations. A very unusual feature
of this sandwich complex is that the four cations are held
as a triangle with a central silver ion in a plane inbetween
the two macrocyclic natural products. The charge repulsion
is compensated by strong binding interaction with the
Wipf, P.; Venkatraman, S.; Miller, C. P.; Geib, S. J., "Metal-complexes of marine peptide metabolites - a novel Ag4 cluster." Angew. Chem. Int. Ed. Engl. 1994, 33, 1516.
This art illustrates some of the research of Prof. Peter Wipf's group at the University of Pittsburgh.
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