fig19

Figure 19. (A) Schematic representation of the chiral adaptive recognition of C19 for D/L-dipeptides; CD spectra of C19 titrated with (B) D-TrpTrp, (C) L-TrpTrp, (D) D-PhePhe, and (E) L-PhePhe in phosphate buffer. (Inset) Plots of gabs vs. equiv. of guests; (F) CD spectra of C19 in the presence of D/L-TyrTyr mixtures with ee ranging from -100% to +100%. (G) The calibration curve obtained for the CD signals (390 nm) upon varying ee values for D/L-dipeptides; Fluorescence spectra of C19 titrated with (H) L-TrpTrp and (I) L-PhePhe in phosphate buffer. (Inset) Plots of fluorescence intensity vs. equiv. of guests; (J) CPL spectra of C19 with D/L-PhePhe (chartreuse) and D/L-TyrTyr (light purple) in phosphate buffer. CD: Crcular dichroism; ee: enantiomeric excess; CPL: circularly polarized luminescence.