Characterization by Potentiometric Procedures of the Stability Constants of the Binary and Ternary Complexes of Cu(II) and Duloxetine Drug with Amino Acids
Table 2
Stability coefficients of Cu(II) complexes of the binary system at 25°C and 0.10 mol·L−1 ionic strength.
Systems
l
p
q
r
log βa
Cu(II)-D
1
1
0
0
8.07 (0.003)
1
2
0
0
12.65 (0.01)
Cu(II)-Gly
1
0
1
0
8.15 (0.02)
1
0
2
0
14.89 (0.04)
Cu(II)-Ala
1
0
1
0
8.13 (0.03)
1
0
2
0
14.77 (0.05)
Cu(II)-Val
1
0
1
0
8.11 (0.02)
1
0
2
0
14.73 (0.03)
CuII-Prol
1
0
1
0
8.60 (0.03)
1
0
2
0
15.97 (0.05)
Cu(II)-Phe
1
0
1
0
8.35 (0.02)
1
0
2
0
14.25 (0.03)
Cu(II)-Met
1
0
1
0
8.10 (0.01)
1
0
2
0
14.81 (0.02)
Cu(II)-Thr
1
0
1
0
8.34 (0.02)
1
0
2
0
14.80 (0.04)
1
0
1
−1
1.06 (0.01)
Cu(II)-Orn
1
0
1
0
11.85 (0.04)
1
0
2
0
15.95 (0.07)
1
0
1
1
19.69 (0.03)
Cu(II)-Lys
1
0
1
0
11.83 (0.02)
1
0
2
0
15.12 (0.03)
1
0
1
1
19.44 (0.02)
Cu(II)-Hisd
1
0
1
0
10.65 (0.01)
1
0
2
0
18.68 (0.03)
1
0
1
1
18.39 (0.02)
Cu(II)-Hist
1
0
1
0
9.39 (0.02)
1
0
2
0
15.12 (0.05)
1
0
1
1
17.34 (0.02)
Cu(II)-Imz
1
0
1
0
4.23 (0.01)
1
0
2
0
7.57 (0.02)
Note: l, p, q, and r represent stoichiometric constants corresponding to Cu(II), D, L, and H+, respectively. Coefficient −1 reflects proton loss. aStandard deviation is presented in parentheses.
