ABSTRACT
In our own work, we have recognized the benefits of Scheme 15 for the detection of mono-and bicyclic aromatic hydrocarbons. We have modified the rim of P-CD with an azamacrocycle, which ligates Eu3+ ion as the reporter site [405]. Tethered at only one nitrogen, the azacrown of 82 is able to swing away from the bottom of the hydrophobic interior of the CD bucket. Whereas the Eu3+ ion remains dark under direct irradiation of 82 with blue light, the arrival of aromatics such as benzene in the CD bucket triggers a weak red luminescence (intensity enhancement of 2 for —440 ppm benzene). We showed the presence of an AETE process by examining the emission characteristics of the assembly as the excitation wavelength of light is scanned. The intensity of the red luminescence from an Eu3+ ion tracked the absorption profile of benzene
and not the Eu3+ ion itself, unequivocally establishing that the Eu3+ emission is excited by light passing through benzene.
