Carbon-13 nuclear magnetic resonance study of binding of copper(II) to purine nucleotides

Noncovalent interactions and coordination reactions in the systems consisting of copper(II) ions, aspartic acid and diamines

“…The results were also carefully verified with the equilibrium data and electronic spectra observations. A similar problem has been earlier discussed for other systems with Cu(II) ions [22,42,43].…”

Phosphoserine and specific types of its coordination in copper(II) and adenosine nucleotides systems – Potentiometric and spectroscopic studies

“…When oxygen atoms (not originating from water molecules) are replaced by nitrogen ones in the tetragonal geometry in cupric ion, the maximum absorption wavelength shifts to smaller values, indicating an appearance of a stronger ligand field, and the molar absorptivity usually increases (k max for {3N} coordination it is 600 nm, for {4N} 550 nm and for {3N1O} k max is 584 nm) [35,36]. The information was supported by the analysis of the chemical shifts in the 13 C and 31 P NMR spectra of the ligand in the complex with respect to those of the free ligand, interpreted according to our experience and taking into account the limitations of this method following from the presence of paramagnetic ions in the systems studied [37][38][39][40]. In order to minimize the NMR signal broadening, the spectra were recorded for very low concentrations of the metal.…”

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

“…Significant changes in the chemical shifts were only observed in the pH ranges in which the occurrence of the complexes was deduced on the basis of the potentiometric measurements. The NMR method has been earlier applied in order to study similar systems [31,40,50,55,56].…”