Vibrational study and Natural Bond Orbital analysis of serotonin in monomer and dimer states by density functional theory

Ab-initio and density functional theory (DFT) computational study of the effect of fluorine on the electronic, optical, thermodynamic, hole and electron transport properties of the circumanthracene molecule

In this paper, a systematic study of the electronic, optical, thermodynamic, optoelectronic, and nonlinear optical properties with RHF, B3LYP, wB97XD and BPBE methods using the cc-pVDZ basis set have been described to investigate the influence of fluorine (F) atom, which is an electron donor, on the circumanthracene (C40H16). Global reactivity descriptors, hole and electron transport properties were also calculated and compared with other studies on the same molecule. DFT/B3LYP results show that the undoped C40H16 molecule (Egap = 2.135 eV) and its fluorine-doped derivatives (C40F16 and C40H10F6) are semiconducting materials. However, doping the C40H16 molecule with the fluorine atom, partially or totally, favors the creation of a strong donor-acceptor system by considerably reducing its energy gap (Egap). The energy gap values of molecules doped using DFT/B3LYP method are 2.020 eV and 2.081 eV for the C40F16 and C40H10F6 molecules, respectively. These gap energies are below 3 eV, which favours the electronic properties of these molecules. They can be used to design organic solar cells. The nonlinear optical parameters were calculated and compared with those of urea. The values of βmol and μ calculated for C40F16 and C40H10F6 are higher than those of urea; this shows that these two materials have good nonlinear optical properties and therefore, are very good candidates for the design of optoelectronics and photonics devices. Futhermore, our results show that the perfluorination effect on the circumanthracene molecule increases the hole and electron reorganization energies, the vertical and adiabatic electron affinities and ionization energies, the optoelectronic and nonlinear optical properties, the transition excitation energy and the reactivity indices. The reorganization energies values suggest that these materials have promising transport properties. The natural bond orbital (NBO) analysis was also performed to determine the stability energy and charge delocalization in molecules. The theoretical results of the compounds studied in our work are in agreement with the experimental results. This confirms their molecular structures.

DFT study on the structural and chemical properties of Janus kinase inhibitor drug Baricitinib

Baricitinib is a small molecule used to treat moderate to severe rheumatoid arthritis (RA) in adults. It is an inhibitor of Janus kinase 1 and 2 (JAK1 and JAK2). It has also been repurposed as a potential treatment for Covid 19. The current study has been carried out to understand the structural and chemical properties of this molecule. The molecule is optimized by using density functional theory (DFT) method. The DFT calculations are performed using Gaussian 09 W software package. The bond lengths and bond angles between atoms in the molecules are investigated. The intramolecular interaction within the molecule is identified using the natural bond orbital (NBO) study. The atom in molecule (AIM) study is performed using Multiwfn software. All the calculations are performed at B3LYP /6311G++ (d, p) level of theory. The molecular parameters, such as first-order hyperpolarizability, HOMO-LUMO energy gap, global electrophilicity index, dipole moment, chemical potential, hardness, ionization energy and electron affinity are determined from the calculation. The molecular docking analysis of Baricitinib is also carried out against different target proteins such as 6VSB, 6W9C and 6LU7.