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

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 (Ki) 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 (Ki) of 4.639 and 5.742 µM, respectively. The study predicts that 1 and 2 may be used as anti-SARS CoV-2 agents.