Chiral discrimination of quinine and quinidine based on notable room temperature phosphorescence lifetime differences with gamma-cyclodextrin as chiral selector.
Upon addition of small amount of bromocyclohexane (BrCH), quinine (QN) and quinidine (QD) display strong room temperature phosphorescence (RTP) in gamma-cyclodextrin (gamma-CD) solution without deoxygenation. The associated phosphorescence decay curves can be best fitted to biexponential patterns and quite different RTP lifetimes are obtained for QN (86.9 and 12.5ms) and QD (12.1 and 4.17ms), indicating a distinct chiral discrimination of gamma-CD toward this pair of pseudo-enantiomers. The corresponding association constants evaluated for QN/gamma-CD/BrCH and QD/gamma-CD/BrCH are 3.47x10(5) and 4.67x10(4)Lmol(-1), respectively. It can be inferred that their different ability to form complexes with the chiral gamma-CD is accounted for the notable difference in RTP lifetimes between QN and QD.
Zhang
Xiao Hua
XH
School of Chemistry and Chemical Engineering, Shanxi University, Taiyuan 030006, PR China.
Wang
Yu
Y
Jin
Wei Jun
WJ