The influence of copper(ii) ions on noncovalent interactions in the systems including phosphoserine and biogenic amines

Abstract

Ternary systems of copper(II) complexes with phosphoserine and biogenic amines (putrescine or spermidine or spermine) have been investigated. The studies were performed in aqueous solution using the potentiometric method with computer analysis of the data, ¹³C and ³¹P nuclear magnetic resonance, visible and electron paramagnetic resonance spectroscopies. The composition and overall stability constants of the complexes were determined by the pH-metric study and the coordination sites were identified by spectroscopic methods. The reaction centres are phosphate, carboxyl and amine groups from phosphorylated serine as well as amine groups from polyamine. These centres are also the potential sites of the noncovalent interactions (in the systems without metal). In the systems studied only protonated complexes formed. Besides the heteroligand complexes and heteroligand complexes with intermolecular interactions, molecular complexes with the protonated bioamine in the outer coordination sphere appeared. In these molecular species polyamine was involved in noncovalent interactions with the anchoring phosphoserine complex.