Chiroptical sensing of perrhenate in aqueous media by a chiral organic cage.

A chiral cage is proposed as an effective chiroptical sensor for perrhenate (surrogate for TcO) in water, fruit juice and artificial urine media. The key mechanism for the chiroptical sensing resides in the change of dihedral angle of the binaphthyl unit and H-bonds with the guest, resulting in ample changes of the CD signal as a consequence of the binding event.