哌啶氮氧自由基与环糊精作用的电化学研究

Electrochemical Studies on the Interaction between Piperidine Nitroxyl Radical and Cyclodextrin

采用循环伏安法测量水溶液中β-环糊精(β-CD)/哌啶氮氧自由基(以2,2,6,6-四甲基哌啶-1-氧化物(TEMPO)为例)体系氧化还原电位及峰值电流,并基于此探讨TEMPO与β-CD之间的包结反应。电化学测量表明,在pH=7.4的磷酸盐缓冲溶液中,以玻碳电极为工作电极,随β-CD浓度增大,β-CD/TEMPO体系的峰电位不断增大,峰电流不断减小。通过电位法测得TEMPO与β-CD的包络比为1∶1,包络常数KS为154L/mol,与电流法测得的包络常数基本吻合。

Oxidation/reduction potentials and peak currents were measured by cyclic voltammetry for theβ-cyclodextrin（β-CD）/piperidine nitroxyl radicals system（2,2,6,6-tetramethylpiperidinyl-1-oxide,TEMPO）in aqueous solution.Based on these results,inclusion reaction between TEMPO and β-CD was investigated.Electrochemical measurements demonstrated that the peak potential increased and the peak current decreased with increasing concentration of β-CD.The inclusion ratio between β-CD and TEMPO was 1∶1.And the inclusion constant measured by the potential method was 154L/mol,which was close to the value measured by the current method.