Determination of the structural, electronic, optoelectronic and thermodynamic properties of the methylxanthine molecules theophylline and theobromine

RHF and DFT (wB97XD and B3LYP) methods with the 6-31++G** basis set have been used to study structural, optoelectronic and thermodynamic properties of Theophylline and Theobromine. Dipole moment, average polarizability, anisotropy, first-order molecular hyperpolarizability, second-order molecular polarizability, HOMO and LOMO energy gap, molar refractivity, chemical hardness, chemical softness, electronic chemical potential, electronegativity, electrophilicity index, dielectric constant, electric susceptibility, refractive index and their thermodynamic properties have equally been calculated. To understand the vibrational analysis of our system, IR and RAMAN frequencies were calculated and described. Results reveal that molecules can have applications in linear and nonlinear optical devices, photonic devices and in molecular electronics. Equally, from dipole moment, average polarizability, anisotropy, first-order molecular hyperpolarizability, second-order molecular polarizability, HOMO and LOMO energy gap, molar refractivity, chemical hardness, chemical softness, electronic chemical potential, electronegativity, electrophilicity index and literature we suggest that Theophylline and Theobromine be consider as candidates for the treatment of COVID-19 and other respiratory diseases.

Computational study of physicochemical, optical, and thermodynamic properties of 2,2-dimethylchromene derivatives

CONTEXT

A large number of heterocyclic compounds are used as drugs, mainly due to the duality of lipophilicity playing in hydrophobic interactions and solubility with at least one hydrogen bond acceptor. The study of electronic properties is then important to better understand not only these charge distribution effects but also some other physicochemical properties involved in bioactivity to directly assess the bioavailability of these compounds and a possible classification in related applications. Phytomolecules such as chromenes are very accessible molecules exhibiting a bioactivity. Our study is focused on the impact of a number of functional groups acting on some 2,2-dimethylchromene derivatives, namely their global reactivity from the frontier molecular orbitals and local reactivity from the Fukui functions, where the carbonyl group acting as an electron withdrawal group has the most relevant effect, the solubility from the partition coefficient Log P strongly depending on the charge distribution and electronegative sites, the optical effects from the delocalization in the vinyl group, as well as the evaluation of the entropy associated with the molecular flexibility also acting on the bioactivity. Despite the effects of the wave function or density methods on the order of magnitude of these properties, these compounds are consistent with the rules for a potential oral drug candidate.

METHODS

The calculations of the electronic properties were performed through two levels of theory: Hartree-Fock level as a wave function-based method as an ab initio reference including some physically consistent eigenvalues and density functional theory DFT as a correlation consistent method using different functionals: hybrid or with a long-range correction. The basis set used is a 6-311++G(d,p) Pople basis set including diffuse and polarization basis functions. The basis set is adapted to the size of the molecules and consequently to the degree of electronic localization. Gaussian 09 software was used for the computation.

Comparative study of physico-chemical properties of some molecules from Khaya Grandifoliola plant

The three molecular compounds: A (17-epi-methyl-6-hydroxylangolensate), B (7-deacetoxy-7-oxogedunin) and C (7-deacetoxy-7R-hydroxygedunin) isolated from Khaya Grandifoliola, a plant of the Meliaceae family, able to protect the normal human hepatocyte cell line against paracetamol-induced hepatotoxicity were studied using HF and DFT methods. It appears from this study that compound A has the greatest capacity of donating charges while compound B, which is the most reactive compound according to the HOMO-LUMO energy gap, has a greater capacity to accept charges. From the calculation of certain donor-acceptor parameters, it comes out that compound C is the most easily oxidizable substance and therefore the most effective free radical scavenger. Of the three molecular compounds, A is the best antioxidant while B is the best antireductant. From the values ​​obtained for compounds A, B and C, we concluded that these compounds are better antioxidants than β-carotene and better antireductants than vitamins A, C and E. Compounds A, B, and C are less efficient electron acceptors than fluorine and more efficient electron donors than Na. The calculation of certain thermodynamic parameters shows that, the molecular compounds studied can easily bind to a biomolecular complex. UV-vis spectrum analysis shows that the maximum peaks are located in the UV region between 230 and 356 nm. The nonlinear optical parameters along with vibrational frequencies of these compounds were calculated and compared.