Abstract:

The binding ability and chiral discrimination of β-cyclodextrin(β-CD), 2,2′-diseleno-bridged β-cyclodextrins(2-SeCD)and 2,2′-ditelluro-bridged β-cyclodextrins(2-TeCD)with PPs were investigated in aqueous solution by using UV-Vis and fluorescence spectroscopy as well as MM2 calculation. The stability constants of complexes were obtained by using least-square curve fitting. From the results of UV-Vis and fluorescence spectroscopy, it was shown that β-CD could not form inclusion complexation with PPs while 2-SeCD and 2-TeCD could. The binding ability between 2-TeCD and PDP was higher(Ks=2.33×10⁴ L/mol) than that of 2-SeCD/PDP(Ks=3.03×10³ L/mol). Meanwhile, the high chiral discrimination of PPs was also performed in binding with 2-TeCD(KD/KL=3.84)and 2-SeCD(KD/KL=2.61). Furthermore, the MM2 calculation illustrates that PPs were located between the two cavities of 2-SeCD or 2-TeCD, however, the dihedral angle between phenyl ring and pyrene ring was different from each other when they were included in two bis-cyclodextrins. Meanwhile, MM2 also demonstrates that the intermolecular hydrogen bonding interaction in 2-TeCD/PPs complex was relative stronger than that in 2-SeCD/PPs.

Key words: N-[4(1-pyrene)butyroyl]-D/L-phenylalanine; 2,2′-Diseleno bridged bis-β-cyclodextrin; 2,2′-Ditelluro bridged bis-β-cyclodextrin; Least-square curve fitting; MM2 simulation