Charge-transfer chemistry of azithromycin, the antibiotic used worldwide to treat the coronavirus disease (COVID-19). Part II: Complexation with several π-acceptors (PA, CLA, CHL)

Abdel Majid A Adam; Hosam A Saad; Amnah M Alsuhaibani; Moamen S Refat; Mohamed S Hegab

doi:10.1016/j.molliq.2020.115121

Charge-transfer chemistry of azithromycin, the antibiotic used worldwide to treat the coronavirus disease (COVID-19). Part II: Complexation with several π-acceptors (PA, CLA, CHL)

J Mol Liq. 2021 Mar 1:325:115121. doi: 10.1016/j.molliq.2020.115121. Epub 2020 Dec 23.

Authors

Abdel Majid A Adam¹, Hosam A Saad¹, Amnah M Alsuhaibani², Moamen S Refat¹, Mohamed S Hegab³

Affiliations

¹ Department of Chemistry, College of Science, Taif University, P.O. Box 11099, Taif 21944, Saudi Arabia.
² Department of Physical Sport Science, Princess Nourah bint Abdulrahman University, 4545 - King Khalid Airport Unit No. 1, Riyadh 13415-7132, Saudi Arabia.
³ Deanship of Supportive Studies (D.S.S.), Taif University, P.O. Box 11099, Taif 21944, Saudi Arabia.

Abstract

Finding a vaccine or cure for the coronavirus disease (COVID-19) responsible for the worldwide pandemic and its economic, medical, and psychological burdens is one of the most pressing issues presently facing the global community. One of the current treatment protocols involves the antibiotic azithromycin (AZM) alone or in combination with other compounds. Obtaining additional insight into the charge-transfer (CT) chemistry of this antibiotic could help researchers and clinicians to improve such treatment protocols. Toward this aim, we investigated the CT interactions between AZM and three π-acceptors: picric acid (PA), chloranilic acid (CLA), and chloranil (CHL) in MeOH solvent. AZM formed colored products at a 1:1 stoichiometry with the acceptors through intermolecular hydrogen bonding. An n → π* interaction was also proposed for the AZM-CHL CT product. The synthesized CT products had markedly different morphologies from the free reactants, exhibiting a semi-crystalline structure composed of spherical particles with diameters ranging from 50 to 90 nm.

Keywords: Azithromycin; Charge–transfer; Chloranil; Chloranilic acid; Picric acid.