A study of polyamine complex formation with H+, Cu(II), Zn(II), Pb(II), and Mg(II) in aqueous solution

Interaction centres of pyrimidine nucleotides: Cytidine-5′-diphosphate (CDP) and cytidine-5′-triphosphate (CTP) in their reactions with tetramines and Cu(II) ions

“…The chromophore {N2,O} involves the oxygen atoms of the phosphate group of the nucleotide and two deprotonated nitrogen atoms of the polyamine. The equilibrium constant of formation of the complex Cu(CDP)H 2 (Spm) is log K e = 7.79 (Table 3) and it is higher than the analogous value for the complex CuH 2 Spm in which also two nitrogen atoms of the polyamine take part in the coordination (log K eðCuH 2 SpmÞ ¼ 6.35 [47]), which means that the ligand-ligand interactions in Cu(CDP)H 2 (Spm) additionally stabilise the complex. In the NMR spectra of the system Cu(II)/CDP/Spm at pH 7 (the range of Cu(CDP)H 2 (Spm) domination) shifts of the signals assigned to C(2) and C(4) atoms from CDP and those assigned to the carbon atoms of the polyamine (C(1), C(2), C(3), C(4) and C(5)) are 0.063, 0.052, 0.039, 0.071, 0.082, 0.071 and 0.059 ppm, respectively.…”

“…At low pH values only the phosphate group from the nucleotide is partly deprotonated and capable of interactions with still totally protonated polyamine [46,47]. Thus, in the systems with 3,3,3-tet, in contrast to the system with spermine, the phosphate group of the nucleotide is the main interaction centre with the polyamine.…”

“…In the pH range of occurrence of Cu(CDP)H 4 (Spm) and Cu(CTP)H 4 (Spm) (pH from 3 to 6) spermine is totally protonated, while the nucleotide is partly deprotonated (as indicated by the protonation constants of this ligand [42][43][44][45]47]), therefore spermine is ineffective in copper ions coordination, which suggests that Cu(CDP)H 4 (Spm) and Cu(CTP)H 4 (Spm) are the molecular complexes in which totally protonated polyamine is engaged in noncovalent interactions with the anchoring binary complex Cu(CDP) and Cu(CTP) [30,[48][49][50]. The low equilibrium constants of reaction of formation, equal 4.04 and 3.20 for Cu(CDP)H 4 (Spm) and Cu(CTP)H 4 (Spm), respectively, exclude the mode of interactions described for the analogous systems with AMP and ATP, in which the copper atom is coordinated by the oxygen atoms of the phosphate group from the nucleotide and the nitrogen atoms from the polyamine [49].…”

The Coordination Chemistry of the Pentadentate 2,2,6,6‐Tetrakis(aminomethyl)‐4‐azaheptane (ditame)

“…This assignment is supported by the characteristics of the d-d band with λ max ϭ 619 nm in comparison to λ max ϭ 616 nm reported for [Cu (3,3-tri)] 2ϩ . [55] E. Prenesti et al reported an empirically derived equation for the estimation of λ max in equatorially coordinated Cu II (amine) complexes, [56] yielding a value of 608Ϯ10 nm for such a meridional triamine configuration.…”

Structure‐Activity Relationships for Some Diamine, Triamine andSchiff Base Derivatives and Their Copper(II) Complexes

“…An attempt has been made also to trace [14][15][16]. For the pu complex several species were found, CuHL, CuLz(OH)+, and at pH 9 precipitation is known to occur [16].…”