Isomeric constellations

Scheme 10.10 (a) social isomerism in capsule (10.54)2, (b) isomeric constellations in (10.54)2. If the capsule holds a mixture of two chloroform and one C1CH(CH3)2 guest then two different isomeric arrangements are possible in which the C1CH(CH3)2 is in the middle or at one end (reproduced with permission from Reference 46). 

Fig. 32.8 (a) Social isomers (A and B) generated from the self-assembly of dimeric capsule 12 12 in CHCI3 (blue) in the presence of p-ethyltoluene. Both extremes of p-ethyltoluene (ethyl and methyl groups) are highlighted in different colors (pink and green, respectively), (b) Possible arrangements for co-encapsulated CHCI3 (blue) and isopropyl chloride 18 (pink) within capsule 12 12. Complexes II and III (and IV and V) are isomeric constellations... 

So-called isomeric constellations (arrangements of several molecules) within this cyUndri-cal host that encapsulates two different solvent guests (chloroform and isopropyl chloride) have been studied in [93], and almost all their... 

Shivanyuk A, Rebek J Jr (2003) Isomeric constellations of encapsulation complexes store infoimation on the nanometer scale. Angew Chem Int Ed 42(6) 684-686... 

Fig. 7.13 Top the capsule accommodates either three molecules of chloroform or three molecules of isopropyl chloride. Bottom New diastereomeric arrangements (isomeric constellations) can be observed in the space when both solvents are present...

An intriguing class of hydrogen-bonded self-assembled molecular capsule is that of the Rebek dimeric capsules based on deep cavitands prepared from resorcin[4] arene derivatives [3,12,22], The importance of this class of dimeric capsules arises from their elongated shape which resulted in anisotropic imsymmetrical cavities which gave birth to several phenomena such as social and constellational isomerism, [23a-b] which could not be observed in the bulk or in other capsules... 

We have also observed that three small chiral molecules, e.g., three propylene sulfides, can be accommodated inside the cylindrical capsule. The odd number of molecules inside has the ineluctable consequence that each capsule is chiral the constellational isomerism shown here involves diastereomers (Fig. 7.15) [38]. The assignments could be made using an optically pure propylene sulfide and the gradual addition of racemic material and at 60 % ee each isomer could be assigned. Put another way, it is possible to use encapsulation to determine enantiomeric excesses of small molecules inside, but there are many other ways to do this. 

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