Guest-Induced Conformational Switching in "One Wall" Calix[4]pyrrole Cavitands Functionalized with an Inwardly Directed Carboxylic Acid.

ABSTRACT: We report the design, synthesis, and conformational analysis of two aryl-extended calix[4]-pyrrole (AE-C[4]-P) cavitands that feature a single methylene bridge and an opposed aromatic bridging wall with an inward-facing carboxylic acid. Inspired by Rebek's introverted acid motif, these cavitands were developed to explore guest-induced conformational switching between "equatorial" and "axial" orientations of the bridging aromatic wall. Binding studies with N-oxide guests, capable of monotopic or ditopic hydrogen bonding, revealed that the nature of the bridging aromatic spacer critically governs the host behavior. The benzimidazole-based cavitand showed strong affinity for DABCO mono-N-oxide but resisted conformational change. In contrast, the quinoxaline-imidazole analogue un

SUBMITTER: Zhao M 

PROVIDER: S-EPMC12679308 | biostudies-literature | 2025 Dec

REPOSITORIES: biostudies-literature