Selective Self-Assembly of Supramolecular Helices and Macrocycles Directed by Halogen Bonding.

In this study, several hydrogen-bonded arylamide foldamers (compounds 1-5) with the same degree of polymerization were designed and synthesized. The polyfluoroiodobenzene or iodoethynyl polyfluoroiodobenzene segment was modified as a halogen donor at the end of the monomer, and pyridine or pyridine oxynitride served as the corresponding halogen acceptor segment. The crystal structure of compound 1 indicates that the supramolecular double helices were constructed by stacking a P helix and an M helix in an antiparallel manner in the direction of intermolecular I⋅⋅⋅O-N halogen bonding.

Enantiospecific Analysis of Carboxylic Acids Using Alkaloid Dimers as Chiral Solvating Agents.

alkaloid derivatives as Brønsted base catalysts have attracted considerable attention in the field of asymmetric catalysis. However, their potential application as chiral solvating agents has not been described. In this research, we investigated the use of the alkaloid dimer, namely, (DHQ)PHAL, as a chiral solvating agent for discerning various mandelic acid derivatives through H NMR spectroscopy.