The N-truncated beta-amyloid (A beta) isoform A beta(4-x), is known to bind Cu2+ via a redox-silent ATCUN motif with a conditional K-d = 30 fM at pH 7.4. This study characterizes the Cu2+ interactions and redox activity of A beta(x-16) (x = 1, 4), and 2-[(dimethylamino)-methyl-8-hydroxyquinoline, a terdentate 8-hydroxyquinoline (8HQ) with a conditional K-d(CuL) = 35 pM at pH 7.4. Metal transfer between Cu(A beta(1-16)), CuL, CuL2, and ternary CuL(N-Im(A beta)) was rapid, while the corresponding equilibrium between L, and A beta(4-16) occurred slowly via a metastable CuL(N-Im(A beta)) intermediate. Both. CuL and, CuL2 were redox-silent in the presence of ascorbate, but a CuL(N-Im) complex can generate reactive oxygen species. Because the N-Im(A beta), ligand will be readily exchangeable with N-Im ligands of ubiquitous protein His side, chains in vivo, this class of 8HQ ligand could transfer Cu2+ from inert Cu(A beta(4-x) to redox-active CuL(N-Im). These findings have implications for the use of terdentate 8HQs as therapeutic chelators to treat neurodegenerative disease.