Solvent-manipulated Guest Binding and Signaling of a Fluorescent Resorcin[4]arene Cavitand with 1,3,2-Benzodiazaboryl D‑π‑A Conjugation Flaps

The conformation of resorcin[4]­arene cavitand system 1 was controlled by DMSO through a hydrogen bonding network between benzodiazaborole NHs of the cavitand flaps and DMSO molecules to stabilize the vase form. Subsequently, a guest-binding cavity of 1 was formed to accommodate tetraalkylammonium guest 3, permitting the monitoring of the guest by the unaided eye as a result of a CH−π interaction between the benzodiazaborole π-donor group and the guest.