Nano-crystallites of a ruthenium(iii) violurate complex: synthesis, characterization, PXRD and DFT structural analysis. DNA/HSA-binding, antiviral activity against COVID-19 and molecular docking study

Abstract

A bis-(violurate)-based ruthenium(III) complex was synthesized in a pure form as nano-crystallites. Mass spectrum, elemental and thermal analysis, as well as molar conductance measurements, assigned the molecular formula [Ru(VA)₂ClH₂O]. FTIR, UV-vis, magnetic moment and ESR investigations suggested the structural formula as a distorted octahedron. Structural analysis by DFT calculations and processing of the PXRD data by the computer program Expo 2014 confirmed the proposed structure. Electronic and emission spectroscopy in addition to viscosity measurements displayed the greater binding capability of the [Ru(VA)₂ClH₂O] complex towards the studied biomolecules DNA and HSA as compared to uncomplexed violuric acid (VA). In vitro antiviral investigations against SARS-CoV-2 of violuric acid and the Ru(III) complex revealed greater activity in the case of the latter. Molecular docking studies reported that [Ru(VA)₂ClH₂O] binds more strongly to the spike protein of the tested virus cells (Vero-E6 cells), DNA, and HSA than the uncomplexed bis-(violurate) ligand system, consistent with the experimental results.