Chiral discrimination during photoinduced electron transfer from L/D-tryptophan to electron-excited uranyl ion as a part of UO22+ ⊂ α–CD inclusion complex

Abstract

Spectral-luminescent research indicates the formation of inclusion complexes during the interaction of uranyl nitrate and α–cyclodextrin (α–CD) in aqueous solutions. The chiral α–CD matrix imparts optical activity to the electronically excited uranyl ion *UO₂²⁺_aq in the clathrate, which manifests itself in the chiral discrimination of the quenching of *UO₂²⁺_aq by tryptophan enantiomers. It was found that the Stern-Volmer constant for D–Trp is 1.8 ± 0.2 times higher than that for L–Trp. A mechanistic explanation for the observed effect is proposed by DFT calculations.