Structural studies of Cu(II) binding to the novel peptidyl derivative of quinoxaline: N-(3-(2,3-di(pyridin-2-yl)quinoxalin-6-yl)alanyl)glycine

The coordination properties of the novel conjugate towards copper ions were investigated. The performed studies exhibited the unusual binding properties of the ligand molecule having two potential strong coordination sites, namely dipeptidic chain and pyridyl nitrogens. On the basis of potentiometric and spectroscopic studies the binding at the low pH values to the aromatic entity is suggested, while the rise of pH (including physiological one) yielded the dimeric head-to-tail complex formation. This stable species possesses three nitrogen donors involved in Cu(II) chelation: N(pirydyl), NH2 and N−(amide).

Graphical abstractThe coordination studies of the novel class of conjugates N-(3-(2,3-di(pyridin-2-yl)-quinoxalin-6-yl)alanyl)glycine towards copper(II) ions revealed the unexpected formation of head-to-tail dimeric structure.Figure optionsDownload full-size imageDownload as PowerPoint slide