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Anticancer-drug delivery is now becoming a challenging approach for researchers as it allows controlled drug delivery near cancerous cells with minimized generic collection and the avoidance of secondary side effects. Hence in this work, the applications of nanostructures as anticancer drug-delivery carriers were widely investigated to target cancerous tissues. Based on DFT calculations, we investigated the transition metal-doped boron nitride nanostructure as a drug-delivery agent for the gemcitabine drug utilizing the B3LYP/6-31G (d, p) level of theory. In this research, the adsorption energy and electronic parameters of gemcitabine on the interaction with the metal-doped BN nanostructures were studied. It has been observed that metal doping significantly enhances the drug-delivery properties of BN nanostructures. Among the investigated nanostructures, Ni-BN has been found to be the most prominent nanostructure to transport gemcitabine with an elevated value of adsorption energy in both the gas phase (-45.79) and water media (-32.46). The interaction between gemcitabine and BN nanostructures was confirmed through frontier molecular orbitals and stabilization energy analysis. The fractional charge transfer, MEP, NCI, and NBO analyses exposed the charge transfer from drug molecule to the BN nanostructures. Transition density maps and UV-VIS spectra were also plotted to investigate the excited-state properties of the designed complexes. Thus, the present study provides an in-depth interaction mechanism of the gemcitabine drug with BN, which reveals that metal-doped BN nanostructures can be a favorable drug-delivery vehicle for the gemcitabine anticancer drug.

Furocoumarins are the useful derivatives of coumarin, and they act as skin photosensitizing material due to their exciting exciplex states. Dendrimers also form exciplexes when they contain coumarin as core and used for light harvesting. A number of ingredients in human nutrition contain coumarins. The apiaceae family is the most common example of this class that contains carrots, celery and parsley etc. Rutaceae family is also an important food source that contains coumarins and provides citrus food. Besides fruits and vegetables, beverages like coffee, wine, black and green tea also incorporates coumarin derivatives. Few coumarin dyes show absorption and one emission peak but it can show a double amplified spontaneous emission band due to the generation of super exciplexes in coumarins. Exciplex formation of different coumarin derivatives including 7-methoxy coumarin, 7-hydroxy coumarin show wide application in synthesis of various other derivatives and they can be used as dye due to their prominent fluorescence properties. Exciplexes and excimers of coumarin are widely used in lasers. Both singlet and triplet state exciplexes are considered. Thus a comprehensive review of excited state complexes of coumarin derivatives is discussed here with emphases on the interaction and overlap of the energy levels.

In the present investigation, quantum chemical calculations have been performed in a systematic way to explore the optoelectronic, charge transfer, and nonlinear optical (NLO) properties of different bis(dicyanomethylene) end-functionalized quinoidal oligothiophenes. The effect of different conformations (linking modes of thiophene rings) on conformational, optoelectronic, and NLO properties are studied from the best-performed dimer to octamer. The optical and NLO properties of all the selected systems (1–7) are calculated by means of density functional theory (DFT) methods. Among all the designed compounds, the largest linear isotropic (αiso) polarizability value of 603.1 × 10–24 esu is shown by compound 7 which is ∼12, ∼16, ∼9, ∼11, ∼10, and ∼4 times larger as compared to compounds 1–6, respectively. A relative investigation is performed considering the expansion in third-order NLO polarizability as a function of size and conformational modes. Among all the investigated systems, system 7 shows the highest value of static second hyperpolarizability ⟨γ⟩ with an amplitude of 7607 × 10–36 esu at the M06/6-311G** level of theory, which is ∼521, ∼505, ∼38, ∼884, ∼185, and ∼15 times more than that of compounds 1–6, respectively. The extensively larger ⟨γ⟩ amplitude of compound 7 with higher oscillator strength and lower transition energy indicates that NLO properties are remarkably dependent upon linking modes of thiophene rings and its chain length. Furthermore, to trace the origin of higher nonlinearities, TD-DFT calculations are also performed at the same TD-M06/6-311G** level of theory. Additionally, a comprehensive understanding of the effect of structure/property relationship on the NLO polarizabilities of these investigated quinoidal oligothiophenes is obtained through the inspection of Frontier molecular orbitals, the density of states (TDOS and PDOS), and molecular electrostatic potential diagrams including the transition density matrix. Hence, the current examination will not just feature the NLO capability of entitled compounds yet additionally incite the interest of experimentalists to adequately modify the structure of these oligothiophenes for efficient optical and NLO applications.

Organometallic complexes of neodymium have unique coordinating ability to form both micro and macromolecules as well as metal-based polymers. These complexes have been reported in different fields and play a tremendous role in luminescence, catalytic, biological and magnetic applications. So, the current study will comprise all possible routes for the synthesis of organometallic complexes of neodymium. Neodymium complexes have been synthesized of single, double, triple and tetra linkages with H, C, N, O as well as S, B, and X. The detailed synthetic routes have been classified into four categories but in brief, neodymium forms complexes by reacting metal chloride, nitrate or oxide (hydrated or dehydrated) as precursor along with appropriate ligand. Most applied solvents for neodymium complexes were Toluene and THF. These complexes required a range of temperature based on the nature of complexes as well as linkages. The authors have surveyed the research work published through 2011–2020 and provide a comprehensive overview to understand the synthetic routes of organometallic complexes of neodymium.

Recently, non-fullerenes acceptor based solar cells have replaced the fullerenes based ones due to their higher enhanced photochemical and thermal stability. Hence, in this work, six molecules based on D–A and D–A–D topologies have been designed, where dipyridophenazine as acceptor (which is attached with a metal atom) is attached with triphenylamine as the donor fragment. In case of D–A topology based A1–A3 molecules, donor: acceptor ratio is 1:1 while in D–A–D type B1–B3 molecules it is 1:2. Computational analyses based on density functional and time-dependent density functional are carried out to investigate the effect of Ca, Mg, and Be metals in both topologies. Reduced orbital energy levels in all designed molecules refer to them as good acceptors in both topologies. Ca-complexed (A1 and B1) acceptors in both topologies after the optimal function have shown a smaller energy gap of 0.6 eV than those of reference R and all other designed molecules. In case of D–A–D topology, B1 showed a significant red-shift of 72 nm than that of R. While D–A topology-based A1 showed a more or less similar absorption wavelength like R. Besides, absorption peaks of Mg and Be-complexed molecules are stronger in the case of D–A–D topology. In a nutshell, this computational investigation approved these molecules as efficient and effective for non-fullerene organometallic based acceptors for organic solar cell devices.

The investigation of photocatalytic and fuel additive properties of bismuth ferrite (BiFeO3) microparticles is main objective of this work. Individual properties of bismuth and iron are synergistically reinforce in BiFeO3. X-ray diffraction spectroscopy is used to analyze the phase, phase purity and lattice structure of BiFeO3. Fuel additive and photocatalytic nature are linked to morphology and size of particles. Morphological analysis showed that rod like particles are arranged in the form of star like structures. Fuel additive role of BiFeO3 is analyzed by testing calorific value, flash point, fire point, surface tension, kinematic viscosity, cloud point and pour point of fuel loaded with 20, 40, 60 and 80 ppm additive. Amount of additive has affected all the properties of fuel. So additive role of BiFeO3 is analyzed which helps to decide whether BiFeO3 can be used as additive on large scale or not. Photocatalytic degradation of dyes is studied in aqueous medium using BiFeO3 as photocatalyst. Photocatalytic role of BiFeO3 is analyzed by measuring apparent rate constant (kapp), percentage degradation and degradation time of all dyes. kapp of dyes is as follows: CV (0.0371 min−1), RB5 (0.0186 min−1), MR (0.0159 min−1), MB (0.0147 min−1), EBT (0.0142 min−1), MX (0.0135 min−1), CR (0.0133 min−1), FG (0.0098 min−1) and SN (0.0088 min−1). Comparison of all these parameters helps to analyze that degradation of dyes is linked to their structure and nature.

Tungsten is an elegant substance, and its compounds have great significance because of their extensive range of applications in diverse fields such as in gas sensors, photocatalysis, lithium ion batteries, H2production, electrochromic devices, dyed sensitized solar cells, microchip technology, and liquid crystal displays. Tungsten compounds exhibit a more efficient catalytic behavior, and tungsten-dependent enzymes generally catalyze the transfer of an oxygen atom to or from a physiological donor/acceptor with the metal center. Furthermore, tungsten has an n-type semiconductor band gap. Tungsten forms complexes by reacting with several elements such as H, C, N, O, and P as well as other numerous inorganic elements. Interestingly, all tungsten reactions occur at ambient temperature, usually with tetrahydrofuran and dichloromethane under vacuum. Tungsten has extraordinarily high-temperature properties, making it very useful for X-ray production and heating elements in furnaces. Tungsten coordinates with diverse nonmetallic elements and ligands and produces interesting compounds. This article describes an overview of the synthesis of various organometallic compounds of tungsten.

The current research work presents a low cost, efficient and innovative active aerostatic thrust bearing which is controlled through a combination of the Arduino board, feedback transducers and high-speed valves. The purpose is to make low cost, compact active aerostatic thrust bearing with overall small dimensions and compact size. A prototype design is done in solid works with small dimensions and components are produced with the help of the high precision machining process. There are two high-speed electropneumatic valves which are controlled through pulse width modulation techniques. These high-speed electro-pneumatic valves modify the supply pressure of aerostatic bearing to achieve desired air height gap. There are two novel pressure sensors which provide a feedback signal for control. The test bench to perform experiments has been explained. The performance of the proposed aerostatic bearing is checked both in open loop and closed loop configuration with respect to static and dynamic conditions.

Optoelectronic properties of PDI derivatives (PDI-1–PDI-28) have been studied by inserting functional groups (–CN, –NO2 and –SO2) at different positions, by using DFT and TD-DFT functional at CAM-B3LYP/6-31 (d) level of theory. Absorption spectra of investigated PDI derivatives cover whole UV-Visible region which indicate that studied molecules could be used efficiently for photovoltaics. The R*(λmax – λmin) value of PDI derivatives is red shifted due to CN substitution while it resulted in slightly blue shift due to NO2 substitution. In addition, reorganization energy (λ) values found to be lowered by all substituents but more efficiently by SO2 and CN substituents. Molecular electrostatic potential surfaces and chemical reactivity indices have also been calculated to verify results. Furthermore, investigated acceptor molecules have been matched with suitable donors (based on benzo [2.1-b:3.4-b′] dithiophene derivatives D1–D5) to verify their practical efficiency. The calculated open circuit voltage (Voc) of investigated PDI derivatives is fairly high with donors D1 (0.95–1.34) and D2 (0.54–0.92). This study can be beneficial in future investigations of donor-acceptor materials for organic photovoltaic devices.

Graphic abstract An outbreak of respiratory disorder caused by coronavirus has been named as coronavirus infection 2019 (COVID-19). To find a specific treatment against this disease researchers are at the frontline. To cure COVID-19, favipiravir (FPV) has been reported as an effective drug based on its high recovery rate. Among nanomaterials, fullerene C60 has achieved enormous attention as a drug delivery vehicle due to its good bioavailability and low toxicity. Hence, in this work, we have investigated the potential of metal-doped fullerene as a drug carrier, based on DFT calculations by using M06-2X functional and 6-31G(d) basis set in water media. In this research electronic parameters and adsorption energy of FPV on interaction with metal-doped (Cr, Fe, and Ni) fullerene is studied. The charge transfer between drug and doped fullerene has been studied through electrophilicity indexes. The structural and electronic properties are explored in terms of adsorption energy through frontier molecular orbital (FMO) and density of state (DOS). It is observed that doping of fullerene C60 with Cr, Fe, and Ni metals significantly enhances the drug delivery rate and provides numerous advantages including controlled drug release at specific target sites which minimize the generic collection in vivo and reduce the side effects. Thusly, it is suggested that our designed metal-doped complexes might be efficient candidates as drug delivery materials for COVID-19 infection. Supplementary Information The online version contains supplementary material available at 10.1007/s11696-021-01815-4.

Purpose This paper’s aim is modeling and simulation of an advanced controller design for a novel mechatronics system that consists of a hydrostatic journal bearing with servo control. The proposed mechatronic system has more worth in tribology applications as compared to the traditional hydrostatic bearing which has limited efficiency and poor performance because of lower stiffness and load-carrying capacity. The proposed mechatronic system takes advantage of active lubrication to improve stiffness, rotor’s stability and load-carrying capacity. Design/methodology/approach The current work proposes extended state observer-based controller to control the active lubrication for hydrostatic journal bearing. The advantage of using observer is to estimate unknown state variables and lumped effects because of unmodeled dynamics, model uncertainties, and unknown external disturbances. The effectiveness of the proposed mechatronic system is checked against the traditional hydrostatic bearing. Findings Proposed mechatronics active hydrostatic journal bearing system is checked against traditional hydrostatic journal bearing. It is found that novel active hydrostatic journal bearing with servo control has good tribology performance factors such as stiffness, less rotor vibration, no wear and friction under starting conditions and high load-carrying capacity under different conditions of spindle speed, temperature, initial oil pressure and external disturbance. The result shows that proposed mechatronics system has more worth in rotary tribology applications. Originality/value The current manuscript designs a novel active hydrostatic journal bearing system with servo control. The mathematical model has advantages in term of estimating unknown state variables and lumped effects because of unmodeled dynamics, model uncertainties and unknown external disturbances. The result shows improvement in dynamic characteristics of a hydrostatic journal bearing under different dynamic conditions.

As substantial building units, different shapes and topologies enhance optical and electronic properties. Hence, in this paper, twelve anisotropic molecules of different shapes (star or S, π and H) based on D-π-D and D-π-A-π-D topologies have been designed and investigated theoretically applying a double overlapping wave band strategy for organic photovoltaic applications. This analysis indicates that stronger electron withdrawing A1 fragment, D-π-A-π-D topology, star and π shaped molecules impart toward lower LUMO and smaller Eg values than those of D-π-D type and X or H- shaped molecules. According to TD-DFT calculations, start-shaped molecules show broader spectra with intense peaks in both topologies covering not only visible region but also IR region of spectrum. Furthermore, the optical analysis also demonstrates that π-π* absorptions in short and middle wavelength region are because of central anisotropic multibranched donor (Bi)n-2DF-(Bi)n moiety, where A components exhibit absorptions in the ML wavelength region of spectrum. In General, smaller λe and λh values are exhibited for star and π-shaped molecules because of better dimensionality, whereas H and X-shaped (D1b) display more or less similar values. The predicted electron and hole mobility values for DAD1-S are as; µe = 2.46 (cm2/Vs) and µh = 0.0540 (cm2/Vs), respectively. Thus, results of these calculation prove that our theoretical studies provide a deep insights to confirm that investigated donor compounds would be appropriate vs PDIs acceptors for OSCs.

Magnesium–zinc (Mg–Zn) bimetallic nanoparticles are prepared by reflux assisted co-precipitation method using ethanol–water as a solvent. X-ray diffraction technique is used for structural modeling of Mg–Zn. It is found that positions of all magnesium atoms are same, but zinc atoms are located at five different co-ordinates in unit cell. Elemental composition of synthesized product is investigated by energy dispersive X-ray diffraction technique and morphological characterization is carried out by scanning electron microscopy. The Mg–Zn nanoparticles are used as catalyst for reduction of p-nitrophenol and degradation of reactive black 5 dyes respectively. Fuel additive property of Mg–Zn nanoparticles is also evaluated at 10, 20, 30 and 40 ppm dosage level. It is observed that Mg–Zn nanoparticles have significantly influenced the calorific value, kinematic viscosity and surface tension of fuel.

Castor is an important oil crop for bioenergy production and other valuable applications. NIAB Gold is first mutant variety of Pakistan developed by using gamma radiation. In this study, the oil was extracted from this new castor variety and was used for biodiesel production and as bio-pesticide. Due to high viscosity of castor oil, it was first refined with hot water degumming process. The degummed oil was used for biodiesel production in which important process parameters have been optimized. Maximum biodiesel yield (85%) was obtained by using 5:1 methanol to oil ratio, 3% catalyst dose, 70 ᵒC reaction temperature and 400 rpm stirring speed. The synthesized biodiesel was characterized by determining its important physico-chemical properties including specific gravity, viscosity, calorific value, acid value, iodine value, cetane number etc. Extracted castor oil was also tested as bio-pesticide against two insect species; Tribolium castaneum and Trogoderma granarium. By using 15% castor oil concentration and 72 h of exposure time, maximum larvicidal effect recorded against Tribolium castaneum was 32.17% and for Trogoderma granarium, it was found to be and 23.85%. LC50 values for Tribolium castaneum were also determined at different exposure times. The study results indicated that the NIAB Gold castor oil biodiesel meets the ASTM standards and NIAB Gold castor oil has good potential as bio-pesticide to control harmful insect pests.

The electronic, magnetic and optical properties of Ni-doped CdSe diluted magnetic semiconductors have been explored by density functional theory-based FPLAPW method as incorporated in the Wien2k code. The band structure and density of states analysis for up spin channel and down spin channel illustrate half-metallic ferromagnetic behaviour. The calculated values of the band gap in an insulating channel (down spin channel) increases from 0.4 to 0.8 eV with increasing the doping concentration of Ni from 6.25 to 25%. The magnetic moment of Ni decreases and magnetic moment on nonmagnetic side increases, which shows the strong pd-hybridization. Furthermore, the optical properties are characterized in terms of dielectric constants, refractive index, extinction coefficient, absorption coefficient and optical loss factor. The static values of the dielectric constant and refractive index are consistent with each other.

The aquatic environment is continuously being polluted by heavy metals released from industrial, domestic, agricultural, and medical applications. It is difficult to remove heavy metals, as they are nonbiodegradable. Heavy metals cause genotoxicity and serious carcinogenic disorders. Various conventional methods have been used for the removal of heavy metals, but these are time-consuming and not economical, so green methods, being economical, are preferred over conventional methods. Adsorption, being effective, environmentally friendly, and cheap, is often preferred. The present investigation investigated the adsorption efficiency of agrowaste-based biosorbents for removal of Pb(II) ion from the synthetic wastewater. Mixed biomass of banana peel and potato peels was used to create biosorbents. The biosorbents were characterized in terms of structural and surface morphology by SEM, while functional groups were analyzed by FT-IR and XRD analysis. The adsorption of Pb(II) was studied by a batch method, and various experimental parameters were studied. Optimum conditions for the removal of lead were pH = 5, concentration = 10 ppm, adsorbent dosage = 1.0 g, and contact time = 2 h. Kinetic modelling studies showed that the adsorption of Pb(II) ions followed a pseudo-second-order mechanism, and the Langmuir isotherm model was found to fit well for this study. Highlights: Synthesis of biosorbents (mixed biomass of potato peel and banana peel, biochar, TiO2 nanocomposites). Characterization of prepared biosorbents (SEM, XRD, FT-IR). Optimized parameters (pH, initial concentration, adsorbent dosage, and contact time) for removal of pollutant.

A series of nine phenothiazine-based derivatives (PTZ1-PTZ9) have been computationally designed and investigated as organic fluorophores by employing two different topologies i.e., D-π-D-π-D and D-π-D-π-A in our scheme of study. All these designed derivatives consist of a phenothiazine core as central donor fragment (DF), thiophene/furan/pyrrole as π-spacers (P1/P2/P3), triphenylamine as terminal electron donor unit (DF1), and terminal acceptor unit (A1/A2). The effect of these substituents was studied on their optoelectronic and stability characteristics. TD-DFT calculations explores that bathochromically-shifted absorption (423–994 nm) and emission (524–1103 nm) bands of the designed derivatives cover the visible region and are also extended to the infrared regions of the spectrum. Among all designed fluorescent emitters, PTZ7-PTZ9 derivatives exhibit the lowest energy levels, energy gaps (1.44–1.57 eV), exclusive broad absorption, and emission peaks owing to their strong electron-withdrawing fragments. The computational analysis of frontier molecular orbitals, population analysis, and natural transition orbital analysis has revealed that PTZ1-PTZ3 derivatives exhibited π-π* excitations while the remaining six molecules (PTZ4-PTZ9) displayed ICT in addition to π-π* electronic transitions. The dipole moments of all investigated molecules (3.30–18.78 D) are higher than the reference molecule (2.20 D), indicating their greater solubility in dichloromethane solvent. The nine newly designed fluorescent materials are also studied for their charge transport/injection properties like radiative lifetime and light harvesting efficiency. This theoretical study has disclosed PTZ-derivatives as potential fluorescent emitters with intense and pure color emission for semiconductor devices.

In recent epochs, the researchers are exploring for boost in the opto-electronic properties of active materials fabricated in Organic solar cell (OSCs). Herein, the eminent molecule Subphthalocyanines (SubPcs) is picked up as a reference molecule (R) and designed four 3D novel molecules by attaching electron withdrawing (EW) groups at six peripheral positions of R, giving them identity; M1, M2, M3, and M4. These 3D non-fullerene acceptors are theoretically analysed for UV-Vis absorption, frontier molecular orbitals (FMOs), density of states (DOS), transition density matrix (TDM), internal molecular reorganization energy, the binding energy, and interaction with renowned donor PTB7-Th. Comparative to molar absorption and HOMO/LUMO band gap of R (λ max = 650.2 nm and Eg = 1.633 eV), novel acceptors has better results i.e., λ max ranges from 733–801.5 nm and Eg ranges from 1.088–1.438 eV. While, the hole reorganization energy (i.e., in range of 0.111773–0.33002) and binding energies (i.e., 0.170–0.252) of all novel molecules is noticed lower comparative to R (λh = 0.178402 and Eb = 0.277, respectively). Exceptionally, M3 is prompted as promising light harvesting material with better molar absorption (λ max = 975.0 nm), lower band gap (Eg = 1.088 eV), less hole reorganization energy (λh = 0.033002 eV) and lower binding energy (0.182). Due to exceptional properties of M3 comparative to other designed acceptor molecules, it is analysed with donor PTB7-Th as donor/acceptor interface. Ultimately, it is proved to be efficient interface due to better charge transition. Meanwhile, all designing 3D acceptors are more efficient than R with exceptionally better opto-electronic properties of M3.

In view of auspicious adsorption efficiency of nanocomposites (NCs), nanocomposites of graphene oxide (GO) were prepared with Fe3O4 by ultrasonic-assisted co-precipitation procedure and characterized by Fourier Transform Infra-red (FTIR), Scanning Electron Microscopy (SEM), X-Ray Diffraction (XRD) and Energy Dispersive X-Ray (EDX). The GO-Fe3O4 NCs were employed for adsorptive elimination of nitrate (NO3¯) and phosphate (PO43¯) ions from aqueous medium as a function of pH (1-10), GO-Fe3O4 NCs dose (0.05-0.1 g), contact time (0-1444 min) and ions concentration (10-100 mg L-1). Among kinetic and isotherms models, NO3¯ and PO43¯ ions removal followed the pseudo second order and Freundlich isotherm models. The maximum elimination capacity was achived up to 89 and 93 (%) for NO3¯ and PO43¯ ions, respectively at optimum operating conditions viz. pH 2, ions inital concentration 100 mg L-1, NCs dose 0.5 g and contact time 120 min. For the optimization of process variables response surface methodology (RSM) was emplyed. The results revealed that GO-Fe3O4 NCs have promising adsorption capacity for NO3¯ and PO43¯ ions and can be employed for the removal of NO3¯ and PO43¯ ions from effluents.

First approach towards fabrication of zirconium-microgels@graphene is developed in this work. Hybrid microgels are loaded onto graphene sheets to boost the electron relay among pollutants and borohydride ions. For this purpose, poly(N-isopropylacrylamide-co-methacrylic acid) p(NIPAM-MAA) microgel is synthesized through precipitation polymerization method. Zirconium nanoparticle is fabricated inside microgels through in-situ reduction of zirconium ions then hybrid microgels are decorated onto graphene. Zr-p(NIPAM-MAA)@graphene composite is used as catalyst for reduction of following organic pollutants: Congo red, 4-nitrophenol, Safranine, methylene orange, methylene blue, 4-nitroanisole, 2,4 dinitrophenol and 4-nitrobenzoic acid. Values of apparent rate constant, percentage reduction and reduction time are calculated and compared.

Graphical abstract, In the current study, the interaction of SARS-CoV-2 protein (A and B chains of nsp13) with different recently synthesized phenolic compounds (Sreenivasulu et al., Synthetic Communications, 2020, 112–122) has been studied. The interactions have been investigated by using molecular docking, quantum chemical and molecular dynamics simulations methods. The molecular structures of all the ligands are studied quantum chemically in terms of their optimized structures, 3-D orbital distributions, global chemical descriptors, molecular electrostatic potential plots and HOMO-LUMO orbital energies. All the ligands show reasonably good binding affinities with nsp-13 protein. The ligand L2 shows to have better binding affinities to Chain A and Chain B of nsp13 protein, which are −6.7 and −6.4 kcal/mol. The study of intermolecular interactions indicates that L2 shows different hydrophobic and hydrogen bond interactions with both chains. Furthermore, molecular dynamic simulations of the nsp13-L2 complex are obtained over a time scale of 60 ns, which indicates its stability and flexibility behavior as assessed in terms of its RMSD and RMSF graphs. The ADMET analysis also shows no violation of Lipinski rule (RO5) by studied phenolic compounds. We believe that the current findings will be further confirmed by in vitro and in vivo studies of these recent phenolic compounds for their potential as inhibitors for SARS-Co-V-2 virus.

Computational study on four Acceptor-Donor-Acceptor (A-D-A) type of donor molecules namely, dimethyl cyanoacetate terthiophene di(methylthiophene) benzo[1,2-b: 4,5-b'] dithiophene (DMCATDMTBDT) (M1 ...

A theoretical comparison of the photophysical and photochemical properties has been made among a series of diarylethene-containing Pt(II) complexes that have two kinds of isomers exhibiting different optical behaviors. It is found that the extension of conjugated systems and electron-withdrawing substituents on a host-ligand promotes the rigidity of structures, which is beneficial to electron transfer during excitation. Moreover, the phosphorescence emission and quenching of complexes can be controlled by utilizing the contrasting optical performance of their two isomers. In closed-ring forms, the complexes suffer phosphorescence quenching due to the inefficient involvement of Pt in the excitation and the low energy gap between the first triplet excited state and the ground state. In open-ring forms, the shift of conjugated systems makes the excitation switch from diarylethene to Pt so that the spin–orbit coupling effect can be achieved, which leads to an effective phosphorescence emission. In addition, the calculation of the radiative decay rate constant kr is proposed to give an evaluation of the radiative decay process of open-ring forms. And the analysis of the potential energy surface of the triplet-excited state presents an in-depth description of the role of isomerization in its non-radiative decay process. All the above results show the tunability and applicability of diarylethene in organometallic materials. Based on these results, new complexes have been designed as promising candidates with better photoresponsive and phosphorescence performance.

Geometrical parameters, electronic structures and photophysical properties of three new triphenylamine (TPA) and diphenylamine (DPA) based electron donor materials M1 M3 (for organic solar cells) have been investigated through density functional theory (DFT) methods at the B3LYP/6-31G(d) level of the theory. TPA and DPA are used as donor moieties due to their electron donating ability while benzothiazole, cyanide and cyanomethylacetate (CMA) moieties have been taken as acceptor moieties. The time dependent-DFT (TD-DFT) method has been employed [TD-B3LYP/6-31G (d)] for the computation of excited state properties in the gas phase and in solvent (chloroform). The polarization continuum model is applied for calculations in the solvent phase. The designed molecules exhibited broad absorption in the visible and near infra-red region of spectrum with respect to a reference molecule “R” of a similar class of compounds. Based on reorganization energies calculations, these materials could act as excellent hole transport materials.

A series of twelve Acceptor-π-Donor-π-Acceptor (A-π-D-π-A) topology-based donor molecules, where diketopyrrolopyrrole (DPP) as donor core unit is connected through furan which acts as conjugated π-bridge (CB) to aromatic derivatives (Ar) as acceptor units, have been investigated by making substitutions in acceptor units by using density functional theory(DFT) and time-dependent density functional theory (TD-DFT) for organic solar cell applications. The comparative study of optoelectronic properties indicates that thiadiazole with pyridine units containing molecules (M6b) exhibit lower energy of highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) energy levels than those of oxadiazole and pyridine containing units (M6b). Among our investigated donors, the smallest Eg of 1.60 eV was observed for both M6a and M6b with distinctive broad absorption at 843 and 857 nm, respectively. Overall, smaller electron transfer (λe) values in contrast to hole transfer (λh) demonstrate that these donor compounds would be best for λe. The calculated open circuit voltage (Voc) is 2.45 and 2.17 eV, regarding bisPCBM and PC60BM (phenyl-C61-butyric acid methyl ester) acceptors. Thus, these theoretical calculations not only endorse the deep consideration between the chemical structures and optoelectronic characteristics of the donor-acceptor systems but also suggest appropriate materials for high-performance Organic Photovoltaics (OPV).