Synthesis and characterization of Ag(I) and Cu(I) complexes of triphenylphosphine: crystal structures, Hirshfeld surface analyses, and molecular docking with SARS-CoV-2 and its Omicron variant

Abstract

Two new coordination complexes, a Ag(I) complex [Ag(PPh₃)₃(Sal)] (1) and a Cu(I) complex [Cu(PPh₃)₃Cl] (2), have been synthesized (PPh₃ = triphenylphosphine, Sal = 3,5-dichlorosalicylaldehyde). Both complexes were characterized via single crystal X-ray crystallography. Complexes 1 and 2 were crystallized in monoclinic and trigonal crystal systems, respectively, in the P21/_c and P3 space groups. Both possess tetrahedral coordination geometries. DFT calculations provided structure-property information. The Hirshfeld surface analyses and 2D fingerprint plots were performed to investigate the intermolecular interactions in the crystal structures. To explore potential SARS-CoV-2 drug candidates, we have examined the molecular docking of 1 and 2 with the SARS-CoV-2 spike protein (PDB ID: 8GOP) and with the SARS-CoV-2 Omicron spike protein (PDB ID: 7WRV). Complexes 1 and 2 showed good docking results with the SARS-CoV-2 spike protein (PDB ID: 8GOP) where the binding energies (ΔG) and respective inhibition constants (K_i) correlation values are −7.4 kcal/mol (4.321 µM) and −7.9 kcal/mol (5.012 µM), respectively. The molecular docking results revealed that 1 and 2 with the SARS-CoV-2 Omicron spike protein (PDB ID: 7WRV) resulted in the binding energy (ΔG) of −7.6 kcal/mol and −8.2 kcal/mol with an inhibition constant (K_i) of 4.639 and 5.742 µM, respectively. The study predicts that 1 and 2 may be used as anti-SARS CoV-2 agents.

Graphical Abstract

Keywords:

• Ag(I) and Cu(I) complexes
• SARS-CoV-2
• Hirshfeld surface
• structure-property evaluation
• DFT calculation

Acknowledgments

The author is thankful to the Sophisticated Analytical Instrument Facility (SAIF), IIT Madras, India for single crystal data collection of 1 and 2. For computer time, this research used the resources of the computational facility at the Department of Chemistry, NIT Patna, India.

Disclosure statement

No potential conflict of interest was reported by the authors.