Noble Metal Organometallic Complexes Display Antiviral Activity against SARS-CoV-2.

SARS-CoV-2 emerged in 2019 as a devastating viral pathogen with no available preventative or treatment to control what led to the current global pandemic. The continued spread of the virus and increasing death toll necessitate the development of effective antiviral treatments to combat this virus. To this end, we evaluated a new class of organometallic complexes as potential antivirals. Our findings demonstrate that two pentamethylcyclopentadienyl (Cp*) rhodium piano stool complexes, Cp*Rh(1,3-dicyclohexylimidazol-2-ylidene)Cl2 (complex 2) and Cp*Rh(dipivaloylmethanato)Cl (complex 4), have direct virucidal activity against SARS-CoV-2. Subsequent in vitro testing suggests that complex 4 is the more stable and effective complex and demonstrates that both 2 and 4 have low toxicity in Vero E6 and Calu-3 cells. The results presented here highlight the potential application of organometallic complexes as antivirals and support further investigation into their activity.

Crystal structures of (η4-cyclo-octa-1,5-diene)bis(1,3-di-methyl-imidazol-2-yl-idene)iridium(I) iodide and (η4-cyclo-octa-1,5-diene)bis-(1,3-di-ethyl-imidazol-2-yl-idene)iridium(I) iodide.

The title complexes, (η4-cyclo-octa-1,5-diene)bis-(1,3-di-methyl-imidazol-2-yl-idene)iridium(I) iodide, [Ir(C5H8N2)2(C8H12)]I, (1) and (η4-cyclo-octa-1,5-di-ene)bis-(1,3-di-ethyl-imidazol-2-yl-idene)iridium(I) iodide, [Ir(C7H12N2)2(C8H12)]I, (2), were prepared using a modified literature method. After carrying out the oxidative addition of the amino acid l-proline to [Ir(COD)(IMe)2]I in water and slowly cooling the reaction to room temperature, a suitable crystal of 1 was obtained and analyzed by single-crystal X-ray diffraction at 100 K. Although this crystal structure has previously been reported in the Pbam space group, it was highly disordered and precise atomic coordinates were not calculated. A single crystal of 2 was also obtained by heating the complex in water and letting it slowly cool to room temperature. Complex 1 was found to crystallize in the monoclinic space group C2/m, while 2 crystallizes in the ortho-rhom-bic space group Pccn, both with Z = 4.