Figure 2: Distribution curves of 1:1:1:1 Cu(II)-Co(II)-valine-uracil system; (1) H2L1, (2) HL1, (3) HL2, (4) Cu(OH)+, (5) Cu(OH)2, (6) Co(OH)+, (7) Co(OH)2, (8) CuL1, (9) CuL2, (10) CoL1, (11) CoL2, (12) CuL1L2, (13) CoL1L2 and (14) CuCoL1L2.