Copper(II) complexes with sulfonamides derived from 2-picolylamine and their use as chemical nucleases

Reaction between 2-picolylamine (2-aminomethylpyridine) with 2-mesitylenesulfonyl and 4-tert-butylbenzene sulfonyl chlorides leads to the formation of 2,4,6-trimethyl-N-[pyridin-2-ilmethyl]benzenesulfonamide (Hpmesa) and 4-ter-butyl-N-[pyridin-2-ilmethyl]benzenesulfonamide (Hptbsa). These compounds react with Cu(II) salts to yield coordination compounds with CuL2 stoichiometry. The immediate environment of the metal ion is a highly distorted tetrahedron, the sulfonamide ligands acting in a bidentate fashion. Compound Hpmesa crystallizes in monoclinic space group P21/c (number 14), with Z = 4; complex [Cu(pmesa)2] crystallizes in monoclinic space group P1¯ (number 2), with Z = 4 and complex [Cu(ptbsa)2] crystallizes in monoclinic space group Pca21 (number 29), with Z = 4. Both complexes have been characterized by spectroscopic methods. EPR measurements show rhombic spectra with parameters indicating that the unpaired electron is in dx2-y2dx2-y2 orbital. The two complexes act as chemical nucleases in the presence of ascorbate/H2O2, the reactive oxygen species being the hydroxyl and the singlet oxygen-like species.

Graphical abstractCopper(II) complexes with sulfonamides act as chemical nucleases in the presence of ascorbate/H2O2. In these complexes the copper cations are coordinated by four nitrogen atoms, adopting a highly distorted tetrahedral geometry, and the sulfonamides act as bidentate ligands. The electronic paramagnetic resonance spectra show that both complexes are rhombic.Figure optionsDownload full-size imageDownload as PowerPoint slide