Charge-transfer complexation of TCNE with azithromycin, the antibiotic used worldwide to treat the coronavirus disease (COVID-19). Part IV: A comparison between solid and liquid interactions

Abdel Majid A Adam; Moamen S Refat; Tariq A Altalhi; Khaled Saleh Alsuhaibani

doi:10.1016/j.molliq.2021.117224

Charge-transfer complexation of TCNE with azithromycin, the antibiotic used worldwide to treat the coronavirus disease (COVID-19). Part IV: A comparison between solid and liquid interactions

J Mol Liq. 2021 Oct 15:340:117224. doi: 10.1016/j.molliq.2021.117224. Epub 2021 Aug 11.

Authors

Abdel Majid A Adam¹, Moamen S Refat¹, Tariq A Altalhi¹, Khaled Saleh Alsuhaibani²

Affiliations

¹ Department of Chemistry, College of Science, Taif University, P.O. Box 11099, Taif 21944, Saudi Arabia.
² College of Pharmacy, King Saud University, Riyadh, Saudi Arabia.

Abstract

Finding a cure or vaccine for the coronavirus disease (COVID-19) is the most pressing issue facing the world in 2020 and 2021. One of the more promising current treatment protocols is based on the antibiotic azithromycin (AZM) alone or in combination with other drugs (e.g., chloroquine, hydroxychloroquine). We believe gaining new insight into the charge-transfer (CT) chemistry of this antibiotic will help researchers and physicians alike to improve these treatment protocols. Therefore, in this work, we examine the CT interaction between AZM (donor) and tetracyanoethylene (TCNE, acceptor) in either solid or liquid forms. We found that, for both phases of starting materials, AZM reacted strongly with TCNE to produce a colored, stable complex with 1:2 AZM to TCNE stoichiometry via a n → π* transition (AZM → TCNE). Even though both methodologies yielded the same product, we recommend the solid-solid interaction since it is more straightforward, environmentally friendly, and cost- and time-effective.

Keywords: Azithromycin; Charge-transfer; Eco-friendly method; Liquid–liquid interaction; Solid–solid interaction; TCNE.