Dimethyl sulfoxide as a strongly coordinating solvent: 3′,4′-dihydroxyflavone-Cu(II)-DMSO system case study

Abstract

Dimethyl sulfoxide (DMSO) is an aprotic organic solvent widely used in laboratory practice due to its ability to dissolve both polar and nonpolar compounds. However, DMSO is also commonly known as a strongly coordinating solvent, especially towards transition metal containing complexes. In this study, estimation of the coordination ability of DMSO towards the Cu(II) ion was attempted, employing a model system composed of 3′,4′-dihydroxyflavone-Cu(II) complex in the presence of explicit DMSO molecules, using the density functional theory (DFT). Nature of the Cu-DMSO chemical interaction (i.e. Cu-O bonding) was studied within the framework of quantum theory of atoms in molecules (QTAIM). Impact of DMSO coordination on the charge and spin distribution at Cu(II) ion was inspected using Mulliken population and QTAIM analysis.

The effect of Cu(II) ion on antioxidant and DNA‐binding mechanism of baicalein and scutellarein: Spectroscopic, theoretical, and molecular docking study

“…The same coordination environments as in the case of baicalein must be considered, as the shifts of the peak I, associated with benzoyl moiety absorption, were monitored. It must be noted that DMSO is a strongly coordinated solvent with a high donor number (30), 63 providing a strong interaction with the Cu(II) ion, as the electron density within the DMSO molecule is shifted because of the mesomeric effect leading to the formation of a partial negative charge on the oxygen atom. Hence, a formation of complex between the DMSO and Cu(II) ion may occur as well 63 …”