Frontier Molecular Orbital Energies Research Articles

DFT study, and natural bond orbital (NBO) population analysis of 2-(2-Hydroxyphenyl)-1-azaazulene tautomers and their mercapto analouges

Theoretical research on the keto-enol tautomerization of 2-(2-Hydroxyphenyl)-1-aza azulene (2HPhAZ) and its thiol-thione (2MPhAZ) analouge has been performed using the density functional B3LYP method with the 6–311 + + G(2d,2p) basis set in gas and ethanol phases. The findings of the MO computation on the energy scale and the prediction of the frontier molecular orbital (FMO) energies demonstrate that the tautomeric structures exist in a static mixture in the ground state, with the enol and thiol structure being more stable than the keto and thione structures in gas phase. The ethanol solvent causes some reordering of the relative stability of 2HPhAZ and 2MPhAZ conformers. The geometries created at the B3LYP/6–311 + + G(2d,2p) level of theory were used for NBO analysis. In the tautomerization of 2HPhAZ and its mercapto analogue 2-(2-Mercaptophenyl)-1-azaazulene (2MPhAZ), it has been found that the O(S)-C sigma bond is weak due to nO(S)—> σ*C25-O26(S26) and nO(S)—> σ*C15-N16 delocalization. It is also noted that the resulting p character of the corresponding oxygen (sulfur) natural hybrid orbital (NHO) of σO(S)-C bond orbital is related to the decreased occupancy of the localized σO(S)-C orbital in the idealized Lewis structure or the increased occupancy of σ*O(S)-C of the non-Lewis orbital and their subsequent impact on molecular stability and geometry (bond lengths) in gas phase and ethanol. Additionally, the energy of charge transfer decreases as the potential rotamers' Hammett constants (R1–R3 for O(S) atoms) increase. The partial charge distribution on the skeleton atoms demonstrates that the intra- and intermolecular interactions can be significantly influenced by the electrostatic attraction or repulsion between atoms. Lastly, the currently applied NBO-based HB strength indicator enables a fair prediction of the frequency of the proton donor NH stretching mode, but this simple picture is hidden by abundant hype conjugative effects.

Resolving molecular frontier orbitals in molecular junctions with kHz resolution

The current–voltage characteristics of molecular junctions can be measured with a time resolution two orders of magnitude higher than previous methods, allowing detailed characterization of electronic states during mechanical modulation.

Cyano modified triphenylmethyl radical skeletons: higher stability and efficiency.

We introduced cyano groups to replace chlorine atoms in the tris(2,4,6-trichlorophenyl)methyl (TTM) radical skeleton, resulting in two cyano-modified TTM skeletons. The incorporation of cyano groups effectively suppresses nonradiative transition processes and lowers the frontier molecular orbital energy levels compared to those of the TTM radical. Consequently, enhanced photoluminescence quantum efficiency (PLQE) and a shift towards longer-wavelength emission in solution were achieved. Furthermore, the cyano-modified TTM skeletons exhibited improved stabilities. The development of these two skeletons adds diversity to stable organic luminescent radical skeletons.

Machine learning study of D:A1:A2 ternary organic solar cells

Introducing third component into donor:acceptor heterojunction provide new dimension to improve power conversion efficiency of organic solar cells (OSCs). However, the combining different donors and acceptors, as well as optimizing fabricating procedures are exhaust and tedious by experiment for ternary OSCs. Herein, we constructed the database, including 280 groups of D:A1:A2 type ternary OSCs with non-fullerene acceptors. The descriptors include the mass ratios, the root-mean-square roughness of morphology, the frontier molecular orbital energies and molecular fingerprints. Four kinds of machine learning (ML) models, including random forest (RF), extra tree regression, gradient boosted regression tree and adaptive boosting, were trained and tested. The coefficient of determination R2, Pearson's correlation coefficient r, root mean square error and mean absolute error were used to score the prediction results of ML models. The score and the slope of regression lines indicate RF model is prevail to other ML models in power conversion efficiency (PCE) prediction. Combining donors and acceptors in the constructed dataset generates 429,688 groups of D:A1:A2 type new ternary OSCs. Their photovoltaic performances were predicted with the trained RF model and screened. There are 138 groups of new ternary OSCs with the predicted PCE greater than 18.50%, and the champion predicted PCE (18.83%) corresponds to D18:AQx-18:ZH2 ternary OSC. The results of this work provide the guidance for optimizing ternary OSCs and can accelerate the development of high performance ternary OSCs.

Synthesis and biological evaluation of novel benzenesulfonamide incorporated thiazole-triazole hybrids as antimicrobial and antioxidant agents.

A library of 20 novel benzenesulfonamide incorporating thiazole tethered 1,2,3-triazoles 1-4a-e was synthesized and screened for their antimicrobial, antioxidant,and cytotoxicity studies. Amoxicillin and fluconazole were used as reference antibacterial and antifungal drugs, respectively. Further, energies of frontier molecular orbitals were calculated for all the synthesized target compounds 1-4a-e to correlate electronic parameters with the observed biological results. Global reactivity descriptors, includinghighest occupied molecular orbitals-lowest unoccupied molecular orbitals energy gap, electronegativity, chemical hardness, chemical softness, and electrophilicity index, were also calculated for the synthesized molecules. All the tested compounds possessed moderate to excellent antibacterial potency; however, 3d and 4d exhibited the overall highest antibacterial effect (minimum inhibitory concentration [MIC] values 5-11 µM) while 2c showed the highest antifungal effect (MIC value 6 µM). Compound 3c exhibited the highest antioxidantactivity with a % radical scavenging activity value of 95.12. The cytotoxicity of the compounds 1-4a-e was also checked against an animal cell line and a plant seed germination cell line, and the compounds were found to be safe against both the tested cell lines.

Synthesis, characterization, molecular docking, and cytotoxicity study of ruthenium (II/III) polypyridyl complexes

A new polypyridyl ligand 4‐(4‐nitrophenoxy)‐N,N‐bis (pyridin‐2‐ylmethyl)aniline (L1) and its three ruthenium (II/III) complexes, [Ru (Cl)3L1] (C1), [Ru(L1)2]Cl (C2), and [RuCl (dpa)L1] (C3) where dpa = 2,2‐dipyridylamine, have been successfully synthesized and characterized using Fourier‐transform infrared spectroscopy (FTIR), elemental analysis, proton nuclear magnetic resonance (1H NMR), high‐resolution electrospray ionization mass spectrometry (HR‐ESI‐MS), thermal analysis (thermogravimetric analysis [TGA] and differential scanning calorimetry [DSC]), UV/Vis absorption, and magnetic susceptibility. The structures of the ligand and the complexes were optimized, and the structural characteristics were determined by density functional theory (DFT) using the B3LYP‐GD3/6‐311G++(d,p) method. Optimized FTIR vibrational frequencies and 1H NMR chemical shifts agreed well with the corresponding experimental FTIR and 1H NMR data. In vitro cytotoxicity of the ligand and the complexes were evaluated against the MCF‐7 breast cancer cell line. Ligand L1 was the most potent with an IC50 of 38.45 μM, followed by C2 with an IC50 of 45.23 μM. However, the ligand and the complexes showed low antiproliferative activity compared to cisplatin, which had an IC50 of 9.67 μM. To predict the reactivity trend of L1 and the complexes, frontier molecular orbital (FMO) analysis was performed. The FMO energy gap (Eg = ELUMO − EHOMO) for C2 was found to be 1.675 eV, which was the lowest among all the complexes or L1. In addition, molecular docking studies were carried out so as to predict the binding capacity of L1 and the complexes to estrogen receptor alpha (ER‐α). The results showed that C2 has the most negative binding energy score (−9.63 kcal/mol), which indicates more stable adducts with the key amino acid residues at the active sites of ER‐α. Furthermore, C2 displayed the lowest inhibition constant (Ki) of 0.09 μM compared to all the complexes or L1. These results are very promising and show that the novel complex C2 may help in the development of anticancer drugs.

Insights into structural, vibrational, and chemical shift characteristics, solvents impact (polar and nonpolar) on electronic properties and reactive sites, ADMET predictions, and ligand-protein interactions for antiviral drugs safrole and isosafrole: An in-silico approach

The safrole and isosafrole are constitutional isomers that have been theoretically characterized utilizing Density Functional Theory (DFT) employed with the B3LYP/6-311++G(d,p) basis set to simulate geometrical parameters, vibrational aspects, electronic properties, and chemical shifts and explored the solvent effect on electronic spectra of safrole and isosafrole in different solvents, including polar solvents such as acetone, Dimethyl sulfoxide (DMSO), and methanol, nonpolar solvents such as chloroform, cyclohexane, and toluene, and the gas phase using Time Dependent-Density Functional Theory (TD-DFT) methods. In addition, Natural Orbital (NBO), Mulliken population analysis, and Molecular Electrostatic Potential (MEP) surface have been simulated to understand better the reactive sites in the molecular structures of safrole and isosafrole. The frontier molecular orbitals (FMO) energy gaps of safrole and isosafrole were simulated in polar and nonpolar solvents, confirming the safrole and isosafrole kinetic stability and chemical reactivity. The in-silico ADMET indices were utilized to ascertain the probable pharmacokinetic and biological features of safrole and isosafrole. A molecular docking investigation was also conducted to investigate the potential biological activity of safrole and isosafrole against the SARS-CoV-2 spike protein, providing more support for its antiviral efficacy.

Theoretical Study on Functionalizing A–D–A Type Non‐Fullerene Acceptor by Fused Rings and Side Chains for Organic Solar Cells

AbstractThe modification of fused rings in the central backbone, side chains, and end groups of the non‐fullerene acceptor (NFA) for organic solar cells (OSCs) can modulate properties and photovoltaic performance. In order to investigate the effect of fused rings and side chains on photovoltaic performance, PBDB‐T is selected as electron donor and IDTIC, IDIC, IDIC‐PhC6, IDIC‐C4Ph, 4TIC, ITIC‐OE, IDTTIC, ITC6‐IC, ITIC, and C8‐ITIC are selected as NFAs. Based on quantum chemistry calculations, the geometries, electronic structures, excitation properties, excited‐state lifetimes, and electrostatic potentials (ESPs) of the monomer and the PBDB‐T:NFA complexes are studied, and the rate constants of charge transfer (CT), exciton dissociation (ED) and charge recombination (CR) processes are analyzed. The results show that the increase of fused‐ring in NFA's backbone by substituting phenyl or thienyl with bithiophene can elevate the highest occupied molecular orbital energies, reduce the gap of frontier molecular orbital energies, induce red‐shift of absorption spectrum, increase CT energy, improve CT and ED rates. This work provides a detailed understanding of tuning optoelectronic properties and photovoltaic performance by modifying NFA's side chains and extending backbones.

Evaluation of Antioxidant Properties and Molecular Design of Lubricant Antioxidants Based on QSPR Model

Two quantitative structure–property relationship (QSPR) models of hindered phenolic antioxidants in lubricating oils were established to help guide the molecular structure design of antioxidants. Firstly, stepwise regression (SWR) was used to filter out essential molecular descriptors without autocorrelation, including electronic, topological, spatial, and structural descriptors, and multiple linear regression (MLR) was used to construct QSPR models based on the screened variables. The two models are statistically sound, with R2 values of 0.942 and 0.941, respectively. The models’ reliability was verified by the frontier molecular orbital energy gaps of the antioxidants. A hindered phenolic additive was designed based on the models. Its antioxidant property is calculated to be 20.9% and 11.0% higher than that of typical commercial antioxidants methyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate and 2,2′-methylenebis(6-tert-butyl-4-methylphenol), respectively. The structure–property relationship of hindered phenolic antioxidants in lubricating oil obtained by computer-assisted analysis can not only predict the antioxidant properties of existing hindered phenolic additives but also provide theoretical basis and data support for the design or modification of lubricating oil additives with higher antioxidant properties.

Preparation of chlorophyll compounds and simulation of DFT optical properties assisted screening of photosensitizers from Ginkgo biloba leaves

Chlorophyll compounds (Chls) from Ginkgo biloba leaves (GBL) are non-toxic natural pigments characterized by highly conjugated molecules and special spectra, making them ideally potential photosensitizers (PSs) in photodynamics therapy (PDT). In this study, 4 Chls were isolated from Ginkgo biloba polyprenols (GBPPs) wastes by using silica gel column separation and high performance liquid chromatography (HPLC). In addition, two new chlorophyll derivatives were successfully synthesized with chlorin e6 as the primary raw material. To evaluate and identify superior chlorophyll PSs, Density Functional Theory (DFT) and Density Functional Theory (TD-DFT)were employed to decode the microscopic and spectral properties of Ginkgo biloba Chls (GBChls). The spectral absorption, optical stability and reactive oxygen species (ROS) production of GBChls were further analyzed through comparisons of their frontier molecular orbital layout, charge distribution and excitation energy properties. Our results show that about 63 % absorption in the Q band for 14 GBChls comes from the π⇢π* transition from the highest occupied orbital (HOMO) to the lowest unoccupied orbital (LUMO), indicating the favorable delocalization effect of these GBChls. In particular, those GBChls with the long chain of the phytyl group exhibited higher total electron energy and thus could significantly increase the light stability. However, the large spatial volume and hydrophobicity of these compounds with the phytyl group chain was unfavorable for cellular uptake, leading to low ROS in cells. The electronegativity of porphin macrocycles in GBChls positively correlates with the intracellular ROS production rate, meaning that the former likely promotes the energy transfer between PSs and molecular oxygen during type II photoreaction. Among the GBChls, chlorin e6 demonstrated the highest ROS yields in DMF, while purpurin 18 compounds displayed long-wavelength absorption (698 nm), strong Q-band absorption, good optical stability, and high intracellular ROS production. Our findings highlight that chlorin e6 and purpurin 18 are most potential PSs anticancer drugs and offer new research perspectives for the processing and utilization of GBL resources.

Endowing the Operability of Supercapacitors at High Temperatures by Regulating the Solvation Structure in Dilute Hybrid Electrolyte with Trimethyl Phosphate Cosolvent.

The redox stabilities of different oxygen donor solvents (C═O, P═O and S═O) and lithium salt anions for supercapacitors (SCs) electrolytes have been compared by calculating the frontier molecular orbital energy. Among six lithium difluoro(oxalate)borate (LiDFOB)-based mono-solvent electrolytes, the dilute LiDFOB-1,4-butyrolactone (GBL) electrolyte exhibits the highest operating voltage but suffers from electrolyte breakdown at elevated temperatures. Trimethyl phosphate (TMP) exhibits the highest redox stability and a strongly negative electrostatic potential (ESP), making it suitable for promoting the dissolution of LiDFOB as expected. Therefore, TMP is selected as a co-solvent into LiDFOB-GBL electrolyte to regulate Li+ solvation structure and improve the operability of electrolytes at high temperatures. The electrochemical stable potential window (ESPW) of 0.5m LiDFOB-G/T(5/5) hybrid electrolyte can reach 5.230 V. The activated carbon (AC)-based symmetric SC using 0.5m LiDFOB-G/T(5/5) hybrid electrolyte achieves a high energy density of 54.2Whkg-1 at 1.35kWkg-1 and the capacitance retention reaches 89.2% after 10000 cycles. The operating voltage of SC can be maintained above 2V when the temperature rises to 60°C.

Crystallographic, spectroscopic, and antimicrobial activities of nickel(II) and cadmium(II) complexes with N-heterocycle: TD/DFT calculations and Hirshfeld surface analysis

Two 1-D, 2-D, 3-D supramolecular complexes, namely [Ni(L1)2(CH3OH)2](NO3)2 (1) and [Cd(L2)2(NO3)2] (2) with N-heterocycle ligands (L1 = 2-(4-imidazolyl)-4-methyl-1,2-dihydroquinazoline-N3-oxide, L2 = 2-(2-thiazolyl)-4-methyl-1,2-dihydroquinazoline-N3-oxide), were synthesized by corresponding nitrate and characterized by elemental analysis and spectroscopic methods. X-ray diffraction displayed that both complexes were hexa-coordination geometries and had 2:1 ligand-to-metal ratios. Ni(II) in 1 was coordinated with two L1 and two lattice methanol molecules, counterbalanced by nitrate ions, whereas Cd(II) in 2 by two L2 and nitrate ions. In the crystal structures, 1 based on an infinite 1-D chains to form 2-D wavy-like and 3-D supramolecular self-assembly. Similarly, 2 further developed 2-D and 3-D network structure by several interactions. The electrochemical behavior of 1 in DMF revealed the electronic effects on redox potential of the groups. Most conspicuously, the investigation of antibacterial activities demonstrated that both complexes had good activity against two selected bacteria strains. Density functional theory (DFT) by B3LYP method was used to obtain optimizations, frontier molecular orbital energies and electrostatic potential (ESP) of both complexes. On the basis of optimized geometries, time-dependent DFT (TD-DFT) recorded the specific electronic transitions in the UV-Vis spectra. In addition, the non-covalent interactions in 1 and 2 were analyzed by Hirshfeld surface analysis (HSA).

Corrosion inhibition of polyelectrolytes to the Al anode in Al-air battery: A comparative study of functional group effect

Al-air battery is a promising alternative to electrochemical storage systems because of their high energy density and low cost. However, the hydrogen evolution corrosion in alkaline electrolytes is a major obstacle before this technology can be commercially viable. In this paper, three polyelectrolytes as corrosion inhibitors for pure Al anodes in KOH electrolytes are investigated by electrochemical methods, hydrogen evolution rate (HER) tests, weight loss measurements, and surface characterization. The Attenuated Total internal Reflectance Fourier Transform Infrared spectroscopy (ATR-FTIR) and theoretical simulation results show that all the polyelectrolytes can be adsorbed on Al to form a protective barrier against the corrosive species. In particular, poly(allylamine) (PAH) exhibits the highest corrosion inhibition efficiency. Furthermore, galvanostatic discharge measurement reveals that the Al-air battery in PAH electrolyte exhibits the highest specific discharge capacity (1495.2 mA h g−1). Computational analysis shows that the inhibition performance depends on the frontier molecular orbital energy and adsorption energy.

Theoretical investigation of the vibrational and electronic properties of tetraphenylammonium and its boron, aluminum, gallium, carbon, silicon, germane, phosphorus and arsenic analogues

Tetraphenyl ammonium (Ph4N+ ) has long been considered a phantom ion due to the difficulty in synthesizing aryl ammonium compounds. Following the successful synthesis of Ph4N+ last year (2022), the equilibrium geometries of Ph4X (X = B-, Al-, and Ga- of group 13; C, Si, and Ge of group 14; and P+ and As+ of group 15) have been optimized using the B3LYP/6-31G(d,p) method with no symmetry constraints. According to the optimized structural data, Ph4N+ is considered the most sterically hindered molecule in this series of compounds, which reflects the difficulty of its synthesis. The calculated total energies of the Ph4X compounds reveal that their energies decrease down the group, and the cationic forms (group 15) are less energetic than their neutral (group 14) and anionic (group 13) counterparts. The optimized geometrical parameters were used to compute the UV–vis, IR, 1H NMR, and 13C NMR spectra of the nine terephenyl compounds. The frontier molecular orbital energies were used to determine ionization potentials, electron affinity, and other global reactivity descriptors of the nine Ph4X compounds. An accurate assignment of vibrational bands was made using the potential energy distribution (PED) method. The B3LYP/6-31G(d,p) method yielded good agreement with available experimental data for the molecules. The low HOMO-LUMO gaps suggest potential nonlinear optical properties of these compounds.

Development of New 5‐(Oxazol‐2‐yl)Pyrimidine Derivatives with Promising Anticancer Activities

AbstractA novel series of oxazolyl‐pyrimidine derivatives (11 a–j) have been synthesized and structures were confirmed by spectral data. The synthesized compounds were assessed for cytotoxic profile towards human cervix cancer (SiHa), lung cancer (A549), breast cancer (MCF‐7), and colon cancer (Colo‐205) cell lines by employing MTT assay and using etoposide as the positive control. The heteroaryl compounds having the terminal pyridyl (11 a) and thiazolyl (11 b) groups showed superior cytotoxic potency against cervix and lung cancer cell lines and varying methoxy substituted derivatives 11 c–11 e have excellent to good cytotoxic properties. Compound 11 a and 11 b have IC50 values in the range of 0.01±0.0034 to 0.17±0.059 μM and 0.10±0.038 to 0.66±0.077 μM respectively in the tested cell lines. The selected compounds 11 a and 11 b were studied by molecular docking to assess the binding interactions, binding energies, and possible mechanisms. The in‐silico ADME properties were calculated and all the compounds have the desired properties of drug‐like molecules. The toxicity results indicate that all the compounds are free from toxicity except 11 j, which has high tumorigenic properties. The optimized structure, energies of frontier molecular orbitals, molecular electrostatic potential, and NLO parameters for compound 11 a were determined using DFT/B3LYP level with a 6‐311++G(d,p) basis set.

Synergistic insights into pyrazinophenazine based hybrid materials for advancing optoelectronics

The crucial point of present organic light emitting diode (OLED) research is the improvement of device stability and electroluminescent efficiency. Recently, cheaply available organic compound based thermally activated delayed fluorescent (TADF) emitters are promising to resolve current issues of OLEDs. In this context, we have designed and successfully synthesized a two novel hybrid molecules 3-(4-(9,9-dimethylacridin-10(9H)-yl)phenyl)-12,13- diphenyldibenzo[a,c]pyrazino[2,3-i]phenazine (Ac-DibzPyrQx) and 3-(4-(3,6-di‑tert‑butyl‑9H-carbazol-9-yl)phenyl)-12,13 diphenyldibenzo[a,c]pyrazino [2,3-i]phenazine (tCz-DibzPyrQx), comprising electron-donating (9,9-dimethyl-9,10-dihydroacridine, 3,6-di‑tert‑butyl‑9H-carbazole) and electron accepting Pyrazinophenazine groups. The incorporation of highly planar and rigid pyrazinophenazine electron-accepting moieties holds significant importance due to their unique properties. Their planar structure facilitates strong π-π stacking interactions and efficient charge transfer within the molecular framework, leading to improved exciton formation and enhanced intersystem crossing (ISC) rates, which are critical for TADF processes. The two different electron-donating groups with pyrazinophenazine were synthesized with the view to tune the photophysical and electrochemical properties of the hybrids. These compounds showed high thermal and morphological stability, as well as appropriate frontier molecular orbital (FMO) energy levels. These synthesized molecules show decomposition temperatures (262 °C and 282 °C) and exhibited good glass transition temperatures (328 °C and 300 °C), indicating their significant stability and potential utility as TADF emitters.

Synthesis, crystal structures, spectroscopy, and quantum chemical studies on the 4-dimethylaminopyridinium-2,4-dinitrophenolate: an organic NLO material for optoelectronics.

In this work, the 4-dimethylaminopyridinium-2,4-dinitrophenolate (4DMAP + 2,4DNP) by slow evaporation solution growth method has been presented. The Fourier transform infrared (FT-IR) (4000-400cm-1) and FT-Raman (4000-50cm-1) spectra were recorded for the grown crystal. The computational calculation has been carried out with density functional theory (DFT) in ground state with Gaussian program package. Optimized geometrical parameters (bond distances, bond angles, and dihedral angles) have been obtained and compared with X-ray crystallography data. The calculated fundamental vibrational frequencies from DFT/B3LYP with 6-311 + + G(d,p) level of theory were scaled so as to agree with the observed results, and the scaling factors were reported. Experimental and computed ultraviolet-visible (UV-Vis) spectra in acetone and methanol solvents were found comparable to each other. Furthermore, the frontier molecular orbitals (FMOs) energies, molecular electrostatic potential (MEP), nonlinear optical (NLO), hirshfeld surface (HS), and global chemical descriptors of the molecule were also calculated. The thermal stability and the melting point of the title compound were analyzed by the thermogravimetric analysis/differential thermal analysis (TGA/DTA) techniques. The mechanical behavior of the organic single crystal was measured by Vickers micro-hardness method. The third-order nonlinear optical properties such as nonlinear refractive index (n2), nonlinear absorption coefficient (β), optical nonlinear susceptibility Reχ(3), and optical nonlinear susceptibility Imχ(3) were calculated by using the open and closed aperture Z-scan technique. The theoretical and experimental NLO values clearly proposed that the nonlinearity of 4DMAP + 2,4DNP molecule could be helped as a potential candidate for optical limiting, frequency doubling, and optical switching applications.

Theoretical study of the effect of D-A type polymer donors on the performance of Y6-based organic solar cells

Non-fullerene organic solar cells (OSCs) based on Y6 molecule have developed rapidly in recent years, and the power conversion efficiency (PCE) varies greatly when the OSC device constructed by Y6 and donor molecules with small structural difference. In this work, the influence of six donor-acceptor (D-A) polymer donors on Y6-based OSCs were focused. The ground-state properties (planarity, frontier molecular orbital energy levels, driving force), excited-state properties of donors (primary indicators, Coulomb attraction) and donor/acceptor interfaces (Frenkel excitation (FE) and charge transfer (CT) states, electron coupling and charge separation rates) were discussed. The results show that symmetrical alkyl chains in the acceptor unit is favorable for maintaining planarity of molecule, while fluorination induces twisting in the thiophene bridge and acceptor unit. And the investigated high-performance molecules have desirable driving force, smaller Coulomb attraction and significant degree of holes and electrons delocalization. Also, the highest-performance system has multiple charge transfer pathways, which can improve charge separation efficiency. At the same time, high-performance systems often have better planarity and more favorable substituent positions. The high-performance donor/Y6 systems have more advantage in charge separation than the low-performance systems. This work provides a fundamental understanding of the impact of D-A type donor materials on the cell performance and theoretical guidance for further optimization of polymer donor materials in Y6-based OSCs.

Structural, spectroscopic, theoretical calculation and Hirshfeld surface analyses of 3-D supramolecular dinuclear zinc(II) and copper(II) complexes

Two three-dimensional dinuclear zinc(II) and copper(II) complexes, [Zn2(L2)2(CH3COO)2] (1) and [Cu2(L2)2(NO3)2] (2) (HL2 = 1-(2-{[(E)-2-hydroxy-benzyli-dene]amino}phenyl)ethanone oxime), were synthesized by Zn(II) acetate tetrahydrate or Cu(II) nitrate trihydrate with based ligand HL1 (2-(2-phenoxy)-4-methyl-1,2-quinazoline-N3-oxide, H is the deprotonate hydrogen) originally. HL1 and both complexes were characterized by elemental analyses and spectroscopic methods, as well as were confirmed by single-crystal X-ray crystallography. It was revealed that two complexes had 2:2 ligand-to-metal ratios and 1 was hexa-coordinated whereas 2 was penta-coordinated. In the crystal structures, HL1 showed a chain-like, while complexes showed 2-D network stacking constructions, and both complexes further formed a 3-D supramolecular structure. The frontier molecular orbital energy of all compounds was calculated, and TD-DFT calculations were performed to analyze the electronic transitions of HL1 and both complexes. Additionally, the structural optimization and electronic transitions of the molecules were obtained via DFT calculations, molecular electrostatic potential (ESP), Hirshfeld surface analysis (HSA), and two-dimensional fingerprint (2D-FP), supporting X-ray diffraction results with the existence of the H···H and C/O···H bonds as the main interactions in the crystal lattice. Especially, cyclic voltammetry (CV) and electron paramagnetic resonance (EPR) spectroscopy properties of 2 were further analyzed. In terms of biological applications, all compounds were investigated for antibacterial activity, and the results displayed two complexes had the best antibacterial performance than others.

Cu (II)-catalyzed: synthesis of imidazole derivatives and evaluating their larvicidal, antimicrobial activities with DFT and molecular docking studies

This paper deals with the evaluation of novel imidazole molecules for their antimicrobial and larvicidal activities. A series of imidazole derivatives 1(a–f) and 2(a–e) were prepared by the Mannich base technique using a Cu(II) catalyst. The Cu(phen)Cl2 catalyst was found to be more effective than other methods. FTIR, elemental analyses, mass spectrometry, 1H NMR, and 13C NMR spectroscopy were performed to elucidate the structures of the synthesised compounds. Antimicrobial and larvicidal activities were investigated for all compounds. The antibacterial activity of compounds (2d) and (2a) were highly active in S.aureus (MIC: 0.25 μg/mL) and K.pneumoniae (MIC: 0.25 μg/mL) compared to ciprofloxacin. Compound (1c) was significantly more effective than clotrimazole in C.albicans (MIC: 0.25 μg/mL). Molecular docking studies of compound 2d showed a higher binding affinity for the 1BDD protein (− 3.4 kcal/mol) than ciprofloxacin (− 4.4 kcal/mol). Compound 1c had a higher binding affinity (− 6.0 kcal/mol) than clotrimazole (− 3.1 kcal/mol) with greater frontier molecular orbital energy and reactivity properties of compound 1c (∆E gap = 0.13 eV). The activity of compound 1a (LD50: 34.9 μg/mL) was more effective in the Culex quinquefasciatus than permethrin (LD50: 35.4 μg/mL) and its molecular docking binding affinity for 3OGN protein (− 6.1 kcal/mol). These newly synthesised compounds can act as lead molecules for the development of larvicides and antibiotic agents.