Axially Chiral Shape-Persistent Encapsulating Agents

Abstract

In this review is presented the results of investigations during the last two decades on molecular recognition processes, mainly chiral host–guest systems insofar as they deal with intermolecular recognition events. Attention is devoted to those systems involving chiral hosts whose chirality does not arise from the presence of a chiral center and that possess a defined cavity to accommodate guests. Thus, the scope of this short review is restricted to chiral containers in which size, shape, and functionality are critical aspects, while those examples involving chirality transfer processes are excluded. The systems covered are those with axial chirality, including helical chirality, in which the chirality, that can be inherent or induced by steric interactions, originates from the 3D helical array of substituents. More specifically, the focus is on both macrocycles that bear open cavities and molecular cages with more enclosed voids.1 Introduction2 Encapsulating Agents: Macrocycles3 Encapsulating Agents: Molecular Cages4 Conclusions

Deciphering the degree of proton-transfer in pyrido-cyclophanes by chiroptical outcomes in non-aqueous solvents

“…[15][16][17][18] Our research group has exploited pyridines and allenes as construction motifs in the synthesis of chiral shape-persistent cyclophanes with applicability in the field of molecular recognition in non-aqueous solvents. 19 We reported the preparation and full characterization of pyrido-cyclophane 1 (hereafter, pyrido-allenophane to evidence the presence of allenyl motifs, Fig. 1), which showed one of the strongest chiroptical responses described for small organic molecules with a g-factor ‡ of 0.011.…”