Stereoselective chiral supramolecular structures

We present here a few examples of enantiomeric supramolecular absolute structures. In fact, many supramolecular diastereomers with chiral ligands have been isolated stereoselectively. For example, enantiomers of the chiral self-assembled triple helicates trinuclear [Ni3(L)3](C104)6 (L = tris(bpy)) and dinuclear [Co2(L)3]4 + (L = 5-bismpmb) were partially resolved by SP Sephadex chromatography.63,64 The ligands and structures are given in Figure 5.17a and b. 

Introduction of the tricarbonylchromium group into cyclophane chemistry has great potential for the preparation of planar- (or helical-)chiral compounds. Besides structure/chiroptics relationships, carrying out stereoselective reactions is of major importance. Recently, inclusion of ferrocenes and benzene-Cr(CO)3 into the cavity of a cyclodextrine was achieved and this makes the connection to supramolecular chemistry [183]. 

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