Comparison of mono- and di-substituted triphenylamine and carbazole based sensitizers @(TiO2)38 cluster for dye-sensitized solar cells applications

Transition metal-catalyzed regioselective functionalization of carbazoles and indolines with maleimides

The directing group-assisted regioselective C-H activation of carbazoles and indolines is achieved via transition metal-catalyzed reactions. This C-H functionalization protocol provides a rapid approach to install diversely functionalized succinimide groups at the C-1 position of the carbazole moiety. In addition, this protocol demonstrates the intrinsic reactivity of indolines in providing C-2 succinimide-substituted indoles via cascade direct oxidation and C-H functionalization. This protocol also provides C-7 succinimide-substituted indolines under mild reaction conditions. The features of this reaction include a wide substrate scope and excellent regioselectivity for the installation of the succinimide moiety on biologically interesting molecules.

Synthesis and investigation of anti-COVID19 ability of ferrocene Schiff base derivatives by quantum chemical and molecular docking

The recent outbreak of coronavirus disease (COVID-19) has rampaged the world with more than 236 million confirmed cases and over 4.8 million deaths across the world reported by the world health organization (WHO) till Oct 5, 2021. Due to the advent of different variants of coronavirus, there is an urgent need to identify effective drugs and vaccines to combat rapidly spreading virus varieties across the globe. Ferrocene derivatives have attained immense interest as anticancer, antifungal, antibacterial, and antiparasitic drug candidates. However, the ability of ferrocene as anti-COVID-19 is not yet explored. Therefore, in the present work, we have synthesized four new ferrocene Schiff bases (L1-L4) to understand the active sites and biological activity of ferrocene derivatives by employing various molecular descriptors, frontier molecular orbitals (FMO), electron affinity, ionization potential, and molecular electrostatic potential (MEP). A theoretical insight on synthesized ferrocene Schiff bases was accomplished by molecular docking, frontier molecular orbitals energies, active sites, and molecular descriptors which were further compared with drugs being currently used against COVID-19, i.e., dexamethasone, hydroxychloroquine, favipiravir (FPV), and remdesivir (RDV). Moreover, through the molecular docking approach, we recorded the inhibitions of ferrocene derivatives on core protease (6LU7) protein of SARS-CoV-2 and the effect of substituents on the anti-COVID activity of these synthesized compounds. The computational outcome indicated that L1 has a powerful 6LU7 inhibition of SARS-CoV-2 compared to the currently used drugs. These results could be helpful to design new ferrocene compounds and explore their potential application in the prevention and treatment of SARS-CoV-2.

Isolation of phytochemicals from Malva neglecta Wallr and their quantum chemical, molecular docking exploration as active drugs against COVID-19

The Covid-19 pandemics caused by SARS-CoV-19, and the inadequacy of targeted medications, compelled scientists to seek new antiviral drugs. We present our current understanding of plant extracts containing polyphenols that inhibit Covid-19. Natural phytochemicals (polyphenols) derived from plants have the potential to establish research using extracts and/or individual compounds in the treatment and prevention of coronavirus. The polyphenolic drugs (antivirus) capable of inhibiting the coronavirus protein, that are vital for infection and virus replication. The benefit of phytochemicals is that they promote patient well-being while causing minimal side effects. To understand the antiviral behavior of isolated phytochemicals 1–6, various molecular descriptors, molecular electrostatic potential (MEP), and frontier molecular orbitals (FMO) were investigated. A systematic analysis of isolated phytochemicals was accomplished then molecular descriptors, docking score, active sites, and FMOs energies were compared to the commonly used drugs recently to treat COVID19, namely favipiravir, remdesivir dexamethasone and hydroxychloroquine. Using a molecular docking technique, we demonstrate for the first time that these plant phytochemicals can be inhibited by the core protease (6LU7) protein of COVID19.

Exploring the charge injection aptitude in pyrazol and oxazole derivatives by the first-principles approach

Azole derived products acquired significant consideration in everyday life based on their improved biological potential to the semiconducting substances. The research focused in-depth within pyrazol, and oxazole compounds 1–4 concerning charge transport, structural, optical as well as electronic properties. The density functional theory (DFT) along with time-dependent DFT were used for the optimization of their ground state geometries and excitation energies. We also investigated the molecule’s electron coupling constants (|V RP|) as well as electron injection (ΔG inject) values. For better understanding, charge transport and electronic characteristics were performed through quantum chemical computations. The |V RP| and ΔG inject values of pyrazole, as well as oxazole molecules, exhibited that these compounds could be competent for dye-sensitized solar cell applications. The pyrazole higher diagonal band gap enlightening these might have enhanced fill factor (FF) along with short-circuit current density (J sc ). We have also explored the electron injection, energy level offset, dissociation of excitons, and band alignment of studied compounds to shed light on the functionality of these compounds for photovoltaic and semiconductor device applications.

Comparison in optoelectronic properties of triphenylamine-imidazole or imidazole as donor for dye-sensitized solar cell: theoretical approach

In the present work, the structural and electronic properties of the D-D'-π-A organic dye with two donors have been calculated theoretically by DFT/time-dependent DFT method. In order to prove their efficiency as sensitizers, a comparative study was performed with a series of D-π-A architecture with one donor. The results of light-harvesting efficiency (LHE), open circuit voltage (Voc), free energy injection (∆G_inj), free energy dye regeneration∆G_reg,excited-state lifetimes for the two series reveal that the D-D'-π-A dyes are promising for the design of new sensitive dyes in solar cells.

Effects of heteroatoms in π-conjugated linkers on the optical and electronic properties of modified triphenylamine based dyes: towards DSSCs' applications

Optoelectronic properties of triphenylamine dyes arising from the embedded five-membered π-linkers C₄H₄X (X = O, NH, S, Se, Te) and varying anchoring groups, cyanoacrylic acid and hydantoin, in D-π-π-A model are examined. The reported properties for both, isolated dyes and dye@TiO₂ complexes, are realized through density functional theory (DFT) and time-dependent DFT. The study reveals that chalcogen doping (X = S, Se, Te) enhances absorption and fluorescent emission spectra in the visible and NIR regions. The adsorption of the dyes on the TiO₂ cluster has been simulated. Alteration of the UV-Vis spectra and electron density redistribution for the complexes from individual dyes are examined and analyzed. The binding energies relate to the nature of the heteroatoms X; the complexes dye@TiO₂ with heavier heteroatoms Se and Te demonstrate stronger binding. Graphical abstract.

Theoretical Study of the Effect of π-Bridge on Optical and Electronic Properties of Carbazole-Based Sensitizers for DSSCs

Eight novel metal-free organic sensitizers were proposed for dye-sensitized solar cells (DSSCs), theoretically calculated and studied via density functional theory with D-π-A structure. These proposals were formed to study the effect of novel π-bridges, using carbazole as the donor group and cyanoacrylic acid as the anchorage group. Through the M06/6-31G(d) level of theory, ground state geometry optimization, vibrational frequencies, the highest occupied molecular orbital, the lowest unoccupied molecular orbital, and their energy levels were calculated. Further, chemical reactivity parameters were obtained and analyzed, such as chemical hardness (η), electrophilicity index (ω), electroaccepting power (ω+) and electrodonating power (ω-). Free energy of electron injection (ΔGinj) and light-harvesting efficiency (LHE) also were calculated and discussed. On the other hand, absorption wavelengths, oscillator strengths, and electron transitions were calculated through time-dependent density functional theory with the M06-2X/6-31G(d) level of theory. In conclusion, the inclusion of thiophene groups and the Si heteroatom in the π-bridge improved charge transfer, chemical stability, and other optoelectronic properties of carbazole-based dyes.