Chiral Metallo-macrocycles with Organometallic Half-sandwich Complexes

6 Chiral Metallo-macrocycles with Organometallic Half-sandwich Complexes 

Organometallic half-sandwich piano stool compounds Cp M and/or (arene)M as building blocks for supramolecular chemistry (reprinted with permission from reference ). 

This implies that solvent molecules in [Cp M(solvent)3] (M = Rh, Ir) 

Several groups have investigated the synthesis of such compounds, for instance the cationic metallo-macrocycles [(t -ring)M(Aa)]3[BF4]3 (Aa = amino acidate) act as catalysts for hydrogen transfer to ketones while the neutral metallo-macrocycles [( -ring)ML]3 are efficient hosts for alkali metals (Li and Na). However, the chiral aspect of these species in solution was not investigated and only Yamanari and coworkers have reported diastereomeric separations, but no NMR studies have been made to differentiate these chiral macrocycles by the use of a chiral auxiliary. Recently the chemistry of these macrocycles was reviewed by Severin, who contributed largely to the development of this field. 

I and other chiral L-a-PhCH2 C— aminocarboxylate mono-NH2 O anionic ligands 

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