REACTION OF CU(II) WITH LIX 65N IN HOMOGENEOUS SOLUTION

The nature of the complexes formed between Cu(II) and LIX 65N (H2L) in ethanol has been studied by UV-visible spectrophotometry and the kinetics of the reaction between Cu(II) and H2L by stopped-flow spectrophotometry at 25°C. The major complex, Cu(HL)2, has a formation constant β2 = [Cu(HL)2]/[Cu][HL-]2 of log β2 = 26.5 l2 mol-2 in 0.04 M NaClO4. An additional complex, probably Cu(HL)+, can be detected in the absence of added NaClO4. A third complex, identified as Cu2(HL)22+, was observed at higher copper concentrations with formation constant Kd = [Cu2(HL)2]/[Cu(HL)2][Cu] 1.7 × 104 l mol-1 in 0.04 M NaCIO4. The rate of reaction of Cu(II) with H2L to form Cu(HL)2 obeys the rate equation, d[Cu(HL)2]/d t = Krate[Cu]1[H2L]1[H+]0 where Krate has the value of 2.9 × 104 l mol-1 s-1 in the absence of added electrolytes. © 1979.