Different hydroxyl radical scavenging activity of water-soluble β-alanine C60 adducts

Three C60 derivatives [C60 (NHCH2CH2COONa)n(H)n], n=1, 5, 9] (A, B, C) with different additional number of β-alanine were synthesized by the control of relative amount of C60 and β-alanine added. Hydroxyl radical scavenging activity of the adducts was evaluated in a copper-catalyzed Haber–Weiss reaction by chemiluminescence technology. The 50% inhibition concentrations (IC50ʹs) of A, B, and C were 147.2 μmol/L, 76.3 μmol/L, and 96.2 μmol/L, respectively. The difference should be closely related to the numbers of residual C=C bonds in C60, steric effect and electron-withstanding effect of amino group especially.