UV-Vis, FTIR, 1H, 13C NMR spectra and thermal studies of charge transfer complexes formed in the reaction of Gliclazide with π- and σ-electron acceptors

Preparation, spectroscopic, characterizations and biological studies of new charge transfer complexes formed between fluconazole drug with various acceptors

Charge transfer complexes developed during the interaction of Fluconazole drug (FLU) as an electron donor with different types of electron acceptors, including σ-type as iodine (I₂), and π-types as 2,3-dinitrosalsylic acid (HDNS), Tetracyanoethylene (TCNE) and 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ). The formed complexes were characterized using various techniques as UV-Vis spectra, Thermal analyses, spectrophotometric measurements, ¹H NMR and FTIR Spectroscopy. It was found that the stoichiometry of all developed complexes was a 1:1 M ratio between fluconazole and acceptors (I₂, HDNS, TCNE and DDQ). The characteristic physical parameters data such as ionization potential (I_D), The oscillator strength (ƒ), formation constant (K_CT), transition dipole moment (μ), free energy (ΔG), and energy of interaction (E_CT) of the formed CT-complexes have also been reported. Eventually, the synthesized complexes were screened for their microbial and antioxidant activities.

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)

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.

Charge-transfer chemistry of azithromycin, the antibiotic used worldwide to treat the coronavirus disease (COVID-19). Part I: Complexation with iodine in different solvents

Around the world, the antibiotic azithromycin (AZM) is currently being used to treat the coronavirus disease (COVID-19) in conjunction with hydroxychloroquine or chloroquine. Investigating the chemical and physical properties of compounds used alone or in combination to combat the COVID-19 pandemic is of vital and pressing importance. The purpose of this study was to characterize the charge transfer (CT) complexation of AZM with iodine in four different solvents: CH2Cl2, CHCl3, CCl4, and C6H5Cl. AZM reacted with iodine at a 1:1 M ratio (AZM to I2) in the CHCl3 solvent and a 1:2 M ratio in the other three solvents, as evidenced by data obtained from an elemental analysis of the solid CT products and spectrophotometric titration and Job's continuous variation method for the soluble CT products. Data obtained from UV-visible and Raman spectroscopies indicated that AZM strongly interacted with iodine in the CH2Cl2, CCl4, and C6H5Cl solvents by a physically potent n→σ* interaction to produce a tri-iodide complex formulated as [AZM·I+]I3 -. XRD and TEM analyses revealed that, in all solvents, the AZM-I2 complex possessed an amorphous structure composed of spherical particles ranging from 80 to 110 nm that tended to aggregate into clusters. The findings described in the present study will hopefully contribute to optimizing the treatment protocols for COVID-19.

Spectrophotometric determination of ozone in solutions: Molar absorption coefficient in the visible region

A new approach for the determination of ozone concentration in solutions in organic liquids based on spectrophotometric absorbance measurements in the visible region was proposed and substantiated. The molar absorption coefficient of ozone in the absorption maximum at ~600nm is 8.0mol^-1 L cm^-1 for hydrocarbons (hexane, heptane, isooctane), CHCl₃ and CCl₄, and 5.3mol^-1 L cm^-1 for methanol and 4.5mol^-1 L cm^-1 for water (±10%). The coefficient monotonically decreases with increasing dielectric constant of the liquid. The low molar absorption coefficient allows the use of spectrophotometric measurements for determination of high ozone concentrations ranging from approximately 1·10^-2mol L^-1 up to 1.0mol L^-1.