| A macrocyclic compound,benzo[6]uril 1?-COOH?,was synthesized,and the host-guest interaction of the macrocyclic host with succinylcholine and acetylcholine were investigated by fluorescence titration and 1H NMR titration.Fluorescence spectroscopies showed that the addition of succinylcholine and acetylcholine,had some degree of quenching effect on the fluorescence emission of benzo[6]uril 1,and a 1:1interaction ratio was obtained by the Job's plot analysis.The association constants of obtained host–guest complexes were 1.4×104 L·mol-1 and 6.3×103 L·mol-1,respectively,via non-linear curve fitting.1H NMR titration illustrated the host-guest interations of benzo[6]uril 1 with succinylcholine and acetylcholine were driven by hydrogen bindings.The electroluminescence property of benzo[6]uril 1 was discovered in the aqueous solution,and the mechanism was proposed to be the promoted excited state of benzo[6]uril 1 by superoxide radicals.With introduction of co-reactant hydrogen peroxide?H2O2?to generate more superoxide radicals,the electrochemical luminescence signal of benzo[6]uril 1 was enhanced,and specific and sensitive recognition to succinylcholine was achieved through optimized conditions.The limits of detection of the electrochemical luminescence sensor was obtained to be low to 1.0×10-15 L·mol-1;the supramolecular interaction between the host and succinylcholine guest was investigated by means of electrochemical luminescence to provide the corresponding association constant of?1.1±0.4?×104 L·mol-1;the molecular simulation was employed to study the quenching mechanism of electrochemical luminescence of benzo[3]uril 1 in the presence of succinylcholine,that is,the superoxide radicals generated in the reaction could be quenched by the positive charge on the N of the guest staying outside the cavity,which caused the quenching of electrochemical luminescence signal of benzo[3]uril 1,thereby establishing a highly sensitive recognitive chemiluminescence sensor of succinylcholine.With successful synthesis of macrocyclic compound benzo[3]uril 2?-CH3?,the electrochemical property was explored.The electrochemical luminescence signal of benzo[3]uril 2 was enhanced by introduction of the co-reactant HEPES,and the possible mechanism could be the electron transfer was accelerated by positive ion radical generated in the presence of ammonium.with optimization of the control conditions,a highly sensitive electrochemical luminescence sensor for detecting iron ions was constructed to provide a detection limit low to 0.14 n M.The related experiments showed that the sensor has good stability and reproducibility,and good performance for iron ion.The results of recovery experiments conformed that the HEPES-enhanced electrochemical luminescence of benzo[3]uril 2 offered good accuracies for quantitative determination of iron ions in human serum. |
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