A computational study of substituent effects on the stability and geometry of carbazole‐pyridine complexes

Abstract

Hydrogen bonding between carbazole and pyridine is known to quench fluorescence emission of carbazole. Three carbazolopyridinophanes—compounds composed of carbazole and pyridine subunits such that an intramolecular hydrogen bond may exist between them—have been pursued as reversible fluorescent sensors that detect given analytes through fluorescence restoration. However, these sensors exhibit background fluorescence believed to be related to the proportion of non‐hydrogen‐bonded conformers present. In this computational investigation, the potential energy surfaces of various hydrogen‐bonded carbazole:pyridine complexes are investigated using density functional theory with the intent of explaining the observed background fluorescence for the carbazolopyridinophanes. The results indicate carbazolopyridinophane conformers most resembling the geometry of their corresponding free carbazole:pyridine complexes exhibit the least background fluorescence.

in/out Isomerism of cyclophanes: a theoretical account of 2,6,15-trithia-[34,10][7]metacyclophane and [34,10][7]metacyclophane as well as their halogen substituted analogues

“…1,2 Cyclophanes are molecules which have more than two atoms of an aromatic ring incorporated into a larger ring system, that is, at least two non-adjacent atoms on the ring are connected with an aliphatic chain. [3][4][5] There has been great interest in cyclophane chemistry 6 due to their unique properties [7][8][9][10] arising from proximity of either aromatic rings, or atoms and groups to an aromatic ring. They have found applications in polymers and material science, 11 metal-ion receptor structures 12,13 and are promising catalysts.…”