Journal of the American Chemical Society 2011-05-11

Connection of metallamacrocycles via dynamic covalent chemistry: a versatile method for the synthesis of molecular cages.

Anton Granzhan, Clément Schouwey, Thomas Riis-Johannessen, Rosario Scopelliti, Kay Severin

Index: J. Am. Chem. Soc. 133(18) , 7106-15, (2011)

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Abstract

A modular approach for the synthesis of cage structures is described. Reactions of [(arene)RuCl(2)](2) [arene = p-cymene, 1,3,5-C(6)H(3)Me(3), 1,3,5-C(6)H(3)(i-Pr)(3)] with formyl-substituted 3-hydroxy-2-pyridone ligands provide trinuclear metallamacrocycles with pendant aldehyde groups. Subsequent condensation reactions with di- and triamines give molecular cages with 3, 6, or 12 Ru centers in a diastereoselective and chemoselective (self-sorting) fashion. Some of the cages can also be prepared in one-pot reactions by mixing [(arene)RuCl(2)](2) with the pyridone ligand and the amine in the presence of base. The cages were comprehensively analyzed by X-ray crystallography. The diameter of the largest dodecanuclear complex is ∼3 nm; the cavity sizes range from 290 to 740 Å(3). An amine exchange process with ethylenediamine allows the clean conversion of a dodecanuclear cage into a hexanuclear cage without disruption of the metallamacrocyclic structures.© 2011 American Chemical Society