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A novel strategy was developed to fabricate FeNx-doped carbon quantum dots (Fe-N-CQDs) to detect Cu2+ ions selectively as a fluorescence probe. The Fe-N-CQDs were synthesized by an efficient electrolysis of a carbon cloth electrode, which was coated with monoatomic iron-anchored nitrogen-doped carbon (Fe-N-C). The obtained Fe-N-CQDs emitted blue fluorescence and possessed a quantum yield (QY) of 7.5%. An extremely wide linear relationship between the Cu2+ concentration and the fluorescence intensity was obtained in the range from 100 nM to 1000 nM (R2 = 0.997), and the detection limit was calculated as 59 nM. Moreover, the Fe-N-CQDs demonstrated wide range pH compatibility between 2 and 13 due to the coordination between pyridine nitrogen and Fe3+, which dramatically reduced the affection of the protonation and deprotonation process between H+ and Fe-N-CQDs. It is notable that the Fe-N-CQDs exhibited a rapid response in Cu2+ detection, where stable quenching can be completed in 7 s. The mechanism of excellent selective detection of Cu2+ was revealed by energy level simulation that the LUMO level of Fe-N-CQDs (−4.37 eV) was close to the redox potential of Cu2+, thus facilitating the electron transport from Fe-N-CQDs to Cu2+.

Four oxovanadium (IV) complexes with different ligands have been prepared and characterized by different spectral techniques such as (FTIR, UV–Vis., Mass) spectra, magnetic susceptibility, and DFT theoretical studies. Ligands used in this study were 8-hydroxyquinoline (HQ), oxalate (ox), dithiooximid (DTO), and 3-aminopyridine (APY). All the spectroscopic data and the theoretical calculations confirmed that the oxovanadium (IV) complexes are paramagnetic and have distorted square pyramidal structures. The FTIR spectra explain that the ligands were bidentate by (N, O), (O, O), (N, N) ligands, and monodentate (N-donor) 3-aminopyridine ligand. The mass spectral data confirmed that the complexes are mononuclear. Theoretical calculations of the free ligands and the prepared complexes have been done by using DFT calculations with proper basis sets for each other. The complexes were very stable and their energies ranged from (−775.86 to −1164.09 a.u.) and were very different from that of the free (HQ, ox, DTO and APY) ligands. The prepared complexes are more polar (5.69 to 15.54 Debye) than the free ligands. The HOMO orbitals energies of the complexes are ranged from (−0.098 to −0.392 a.u.), whereas the ligands are ranged from (−0.216 to −0.262 a.u.), and the LUMO orbitals energies of the oxocomplexes are ranged from (−0.007 to −0.296 a.u.)

Dye-sensitized system holds great potential for the development of visible-light-responsive photocatalysts not only because it can enhance the light absorption and charge separation efficiency of the systems but also because it can tune the band structure of catalysts. Herein, two-dimensional (2D) Fe-MOF nanosheets (Fe-MNS) with a LUMO potential of 0.11 V (vs. RHE) was prepared. Interestingly, it has been found that when the 2D Fe-MNS catalyst was functionalized with visible-light-responsive [Ru(bpy)]32+ as a dye-sensitizer, the electrons from the [Ru(bpy)]32+ can effectively inject into the 2D Fe-MNS, which resulted in a negative shift of the LUMO potential of the 2D Fe-MNS to −0.15 V (vs. RHE). Consequently, the [Ru(bpy)]32+/Fe-MNS catalytic system exhibits a sound photocatalytic CO2-to-CO activity of 1120 μmol g-1h−1 under visible-light-irradiation. The photocatalytic CO production was further ameliorated by regulating the electronic structure of the 2D Fe-MNS by doping Co ions, achieving a remarkable photocatalytic activity of 1637 μmol g-1h−1. This work further supports that the dye-sensitized system is an auspicious strategy worth exploring with different catalysts for the development of visible-light-responsive photocatalytic systems.

Thermally activated delayed fluorescent (TADF) materials capable of efficient solution-processed non-doped organic light-emitting diodes (OLEDs) are of important and practical significance for further development of OLEDs. In this work, a new electron-donating segment, 2,7-di(9H-carbazol-9-yl)-9,9-dimethyl-9,10-dihydroacridine (2Cz-DMAC), was designed to develop solution-processable non-doped TADF emitters. 2Cz-DMAC can not only simultaneously increase the solubility of compounds and suppress harmful aggregation-caused quenching, but also efficiently broaden the delocalization of the highest occupied molecular orbital and promote the reverse intersystem crossing process. Three new TADF emitters, 2-(2,7-di(9H-carbazol-9-yl)-9,9-dimethylacridin-10(9H)-yl)dibenzo[b,d]thiophene 5,5-dioxide (2Cz-DMAC-BTB), 2-(2,7-di(9H-carbazol-9-yl)-9,9-dimethylacridin-10(9H)-yl)-9H-thioxanthen-9-one (2Cz-DMAC-TXO), 2-(2,7-di(9H-carbazol-9-yl)-9,9-dimethylacridin-10(9H)-yl)thianthrene 5,5,10,10-tetraoxide (2Cz-DMAC-TTR), were developed by using 2Cz-DMAC segment as the electron-donor. As anticipated, the solution-processed non-doped OLEDs employing 2Cz-DMAC-BTB, 2Cz-DMAC-TXO and 2Cz-DMAC-TTR as the emitters respectively exhibited green, orange and red emissions with maximum external quantum efficiencies of 14.0%, 6.6% and 2.9%. These results successfully demonstrate the feasibility and convenience of developing efficient solution-processable non-doped TADF emitters based on 2Cz-DMAC segment.

A rational design of efficient low-band-gap non-fullerene acceptors (NFAs) for high-performance organic solar cells (OSCs) remains challenging; the main constraint being the decrease in the energy level of the lowest unoccupied molecular orbitals (LUMOs) as the bandgap of A-D-A-type NFAs decrease. Therefore, the short current density (Jsc) and open-circuit voltage (Voc) result in a trade-off relationship, making it difficult to obtain efficient OSCs. Herein, three NFAs (IFL-ED-4F, IDT-ED-4F, and IDTT-ED-2F) were synthesized to address the above-mentioned issue by introducing 3,4-ethylenedioxythiophene (EDOT) as a π-bridge. These NFAs exhibit relatively low bandgaps (1.67, 1.42, and 1.49 eV, respectively) and upshifted LUMO levels (-3.88, −3.84, and −3.81 eV, respectively) compared with most reported low-band-gap NFAs. Consequently, the photovoltaic devices based on IDT-ED-4F blended with a PBDB-T donor polymer showed the best power conversion efficiency (PCE) of 10.4% with a high Jsc of 22.1 mA cm−2 and Voc of 0.884 V among the examined NFAs. In contrast, IDTT-ED-4F, which was designed with an asymmetric structure of the D-π-A type, showed the lowest efficiency of 1.5% owing to the poor morphology and charge transport properties of the binary blend. However, when this was introduced as the third component of the PM6:BTP-BO-4Cl, complementary absorption and cascade energy-level alignment between the two substances could be achieved. Surprisingly, the IDTT-ED-4F-based ternary blend device not only improved the Jsc and Voc, but also achieved a PCE of 15.2%, which is approximately 5.3% higher than that of the reference device with a minimized energy loss of 0.488 eV. In addition, the universality of IDTT-ED-2F as a third component was effectively demonstrated in other photoactive systems, specifically, PM6:BTP-eC9 and PTB7-Th:IEICO-4F. This work facilitates a better understanding of the structure–property relationship for utilizing efficient EDOT-bridged NFAs in high-performance OSC applications.

The structure of 3-Bromo Phenyl Acetic acid (3BPAA) is optimized and its special features are probed by the FTIR, FT-Raman, UV-Visible and NMR with density functional theory calculations by B3LYP level with 6-311++G(d,p) basis set. The electronic properties were discussed with help of UV-Vis spectrum, MEP (Molecular electrostatic potential) and HOMO-LUMO (Highest occupied molecular orbital and Lowest unoccupied molecular orbital) plots. The energy band gap is found as 4.4437eV. The chemical shift is determined from proton and carbon NMR (Nuclear magnetic resonance) plot by Gauge Independent Atomic Orbital (GIAO) method. The surface analysis such as ELF (Electron localization function), LOL (Localized orbital locator) and ESP (Electrostatic potential) maps are plotted by wave function analyzer. Thermodynamic functions are studied and correlated with the graph. FMO and Fukui functions were calculated and found that the title compound is a chemically soft material. The NLO behavior of the compound is also examined and reported to have higher hyperpolarizability value greater than urea, the reference material ensuring good non-linear optical (NLO) activity. The molecular docking is performed by AUTODOCK tool, its study reveals that the title compound binds well with the protein L- glucorante reductose inhibition. Thus the present work study reports the structural, chemical, electronic, thermodynamic and biological activities of 3BPAA.

Electronic structure calculation explores the molecular structure and geometric conformations of the molecules from only the knowledge of its constituent atoms. In the present work, quantum mechanical calculations of a 3-phenyl-1-(methyl-sulfonyl)-1H-pyrazolo[3,4-d]pyrimidine-4-amine molecule have been performed by Density Functional Theory using the standard 6-31G** basis set with the GAUSSIAN09. The electronic structure, dipole moment, frontier orbitals energy, thermal parameters (entropy, enthalpy, internal energy, and Gibb’s potential), Infrared (IR) spectral lines of the title molecule are elaborated. To study the chemical reactivity; molecular electrostatic potential (MEP) surface, HOMO-LUMO surface, and some other properties of the molecule were also investigated.

At present, polymer PM6 is most widely used donor, many researches focus on the improvement of PM6 performance. Most commonly used strategy of modifying polymer PM6 is to achieve ternary random copolymer by incorporating a third component. However, mostly reported modified PM6 terpolymers are with strictly equal D unit and A unit, while the third component has the disadvantage of high cost and complex synthesis. Herein, we develop four novel D-A-D-D1-type copolymer donors (PM6-T5, PM6-T10, PM6-T15 and PM6-T20 with D1 unit molar ratios of 5%, 10%, 15% and 20%, respectively) by introducing a component (BDT-T) with low synthetic complexity into the backbone of PM6 with unequal D and A unit (D/A unit ratio>1). Compared with alternate D-A copolymer PM6, four D-A-D-D1-type copolymers show the up-shifted lowest unoccupied molecular orbital (LUMO), down-shifted highest occupied molecular orbital (HOMO), higher degree of self-assembly. As a result, owing to the suitable level energy, crystallinity, better absorption, higher hole mobility and prolonger the exciton life, the PM6-T15:Y6-based OSCs achieved high power conversion efficiency (PCE) of 16.61% with a remarkably enhanced short-circuit current density (JSC) of 27.02 mA/cm2 and higher fill factor (FF) simultaneously, which performed better than the reference PM6:Y6-based OSCs (PCE:14.51%).

In the current investigation, a triazole, namely 1-Amino-2-mercapto-5-(4-(pyrrol-1-yl)phenyl)-1,3,4-triazole (AMPPT), was synthesized and characterized using ¹H and ¹³C nuclear magnetic resonance (NMR) and Fourier transform infrared (FTIR) spectroscopies in addition to CHN micro elemental analysis. A preliminary study of the title compound as corrosion inhibitor for mild steel in 1 M hydrochloric acid solution was evaluated by performing gravimetrical, electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization measurements in addition to scanning electronic microscope (SEM). The obtained experimental results indicated that AMPPT works perfectly as a corrosion inhibitor for mild steel in 1 M HCl solution and its effectiveness is up to 96.3% at 500 ppm and corrosion inhibition efficiency increase with increasing the concentration of tested inhibitor, suggests that the adsorption of AMPPT molecules on the mild steel surface obeyed the Langmuir adsorption model. Polarization measurements show that the studied inhibitor is a mixed type. EIS measurements revealed that the charge transfer resistance increases with increasing concentration of AMPPT. The free energy (ΔGoads) value showed that the adsorption of AMPPT molecules suggesting a mixed-mode of physisorption and chemisorption. Density functional theory (DFT) calculations were performed on AMPPT molecules to determine the quantum parameters and the relationship between the inhibitor structure and inhibiting efficiency. The molecular parameters, such as energy gap and frontier molecular orbitals (HOMO and LUMO), the absolute electronegativity (χ) value, and the fraction transfer of electrons (∆N) were also calculated and correlated with inhibition activity. The theoretical outcomes showed that the inhibition efficiency of AMPPT increased with the increase the energy of HOMO, and the nitrogen and sulphur atoms are the most likely sites for bonding by giving electrons to the unoccupied 3d-orbitals of Fe atoms on the mild steel surface.

The compound 2-Chloroquinoline-3-carboxamide (2CQ3CA) was characterised by vibrational spectra such as FT-IR, FT-Raman. The optimized molecular geometry, the complete vibrational frequency assignments, the Infrared intensities and the Raman scattering were measured by using density functional theory B3LYP/6–311++G (d,p) basisset. The Highest Occupied Molecular Orbital and Lowest Occupied Molecular Orbital band gap energies calculated and is confirm that charge transfer take place within the molecule. The hyper conjugative interaction energy E(2) and donor (i) and acceptor (j) bonds electron densities were found using NBO analysis. Molecular Electrostatic Potential (MEP), Non-Linear Optical (NLO) behaviourand thermodynamic properties were studied. Besides the Mulliken charge dispersal and Fukui function were analysed. Molecular docking was done for the title molecule to study the biological action of the examination molecule, into the active spot of the protein 1JQE and 4MF3 which belongs to the class of proteins revealing the property of anti-malarial, antagonist activity respectively.

In this paper, the optimization of the structure of di(hydroxybenzyl) diselenide and its studies on HOMO and LUMO energy levels, hardness and Mulliken population using density functional theory (DFT)are reported. Molecular optimization is carried out at all the eight GGA functionals. The total minimum energy is calculated for the titled molecule at various functionals are in the order of BLYP > RPBE > BOP > PBE > PW91 > VWN-BP > BP > HCTH. Therefore, the results obtained at BLYP functional are considered for the remaining study of this work. From the contribution of the bands, the calculated HOMO-LUMO electronic transition is 2.101 eV. The study of HOMO and LUMO is extended to the calculation of the electron affinity, the ionization potential, and the chemical hardness. Chemical shifts for 1H and 13C NMR are also predicted. In 1H and 13C NMR, H25/ H32 and C5/C16 resonance signals are expected to be highly deshielded based on the Mulliken population analysis.

Benzobisthiazole polymer with resonance-assisted hydrogen bonds (RAHBs) has been synthesized for both organic field-effect transistor and polymer solar cell applications. The properties of the hydrogen bonded polymer are compared with the reference polymer without RAHBs. Single-crystal X-ray diffraction analyses of the building block reveal that the RAHB interactions are formed between the carbamate hydrogen and imine nitrogen of the thiazoles. The hydrogen donor and acceptor are connected by π-conjugated molecular framework and the hydrogen-bridged quasi aromatic rings lock the conformation of the building block. The building block adopted a layered sandwich packing in crystal instead of slipped herringbone stacking which was often found in the crystal of benzobisthiazole derivatives. The polymer PCBTZ-TT with RAHBs showed deeper HOMO/LUMO energy level (about 0.2 eV) than reference polymer. The PCBTZ-TT demonstrated the hole mobility of 0.96 cm2 V-1 s-1 in field-effect transistor devices and achieved power conversion efficiency of 13.6% in solar cell devices with Y6 as acceptor without any additive.

In this work, we demonstrated that the co-crystallization strategy has offered an efficient and promising alternative route to achieve high-performance n-type semiconductors through charge-transport switching from pristine p-type systems. By using a simple “green synthesis” process through molecular “doping” with F4TCNQ into a p-type planar azaacene derivative TMIQ (0.27 cm2 V−1 s−1) host, charge transport characteristic switching occurs with a high electron mobility of 0.12 cm2 V−1 s−1 under atmospheric conditions obtained for the D–A complex TMF4TQ (cocrystal). The reasons for such switching lie in the ingenious energy level and molecular packing arrangement tailoring. Specifically, the insertion of F4TCNQ molecules has led to packing transformation from herringbone stacking (TMIQ) to a dense 2D brick arrangement and the low-lying LUMO levels (−4.55 eV) aligned to gold electrodes, thereby facilitating efficient electron injection and transport, and ensuring the air-stable nature, which is further confirmed using theoretical calculations. We believe that our work would provide new insights into high-performance air-stable n-type organic semiconductors exploration.

The present manuscript deals with the study of optoelectronic properties and structure analysis of low molecular weight conjugated moieties, acetaminophen, and quinone oxime as its oxidation product. The proposed study is executed with DFT method adopting 6-31G (d, p) set at B3LYP (Becke’s three parameters and Lee– Yang–Parr functional) level. The present contemplation includes a variety of parameters related to structure, thermodynamics, electrophilicity (ω), potential (µ), hardness (η), max amount of electronic charge transfer (△Nmax), the electrostatic potential for proposed compounds. The stability of the molecule is ascertained through NBO (Natural bond orbital) investigation. The non-linear optical attributes had also been deduced for proposed compounds. The structure-activity liaison has been taken by the process of molecular electrostatic potential surfaces. The relocation of charges within the molecule has been evinced by the highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) energy. These reckon also assist in an explication of complex throughout proposed experimental conditions and facilitate to define appropriateness of substance for a particular purpose.

The nature of the group 15 analogs of the five-membered NHCs (G15-Rea (G15 = N, P, As, Sb, and Bi)) was studied employing five methodologies: calculations of the NICS (the nucleus-independent chemical shifts), the ACID (anisotropy of the current-induced density), the PA (proton affinity), the electrophilicity, and the Fukui functions using density functional theory (DFT). The deep analysis of the results indicates the reactivity of heavy G15′-Rea (G15′ = P, As, Sb, and Bi) is governed by its lowest unoccupied molecular orbital, a vacant p-π orbital. Conversely, the highest occupied molecular orbital, a nonbonding sp2 lone pair orbital, determines the reactivity of N-Rea. To probe the origin of activation barriers of chemical reactions for group 15 analogs of G15-Rea, two types of model reactions (C–H bond insertion of methane and alkene cycloaddition) were theoretically examined with the help of the activation strain model (ASM). Our theoretical evidences reveal that the origin of the activation energies of the model reactions can be explained in terms of the atomic radii of the pivotal group 15 elements and electronic factors of the five-membered G15-Rea species. Interestingly, our theoretical findings strongly suggest that both aromaticity and singlet-triplet energy splitting ΔEst of the G15-Rea molecules can be used as a diagnostic tool for the prediction of the reactivity of diverse five-membered monocationic group 15 NHCs with saturated and saturated hydrocarbons.

The research exploration will comprise of investigating the hyperpolarizability, frontier molecular orbital analysis and NBO, the data analyzed through theoretical methods using Density Functional Theories (DFT) involves the basic principle of solving the Schrodinger equation for many body systems. The results of the organic amine 2–4-difluoroaniline is analyzed and discussed using higher basis set 6-311++G(d, 2p). The energy gap between the HOMO and the LUMO of 2, 4-difluoroaniline is found to be 5.2186 eV. The chemical hardness of the 2, 4-difluoroaniline molecule is found to be 2.6093, indicating that the chemical hardness is very high and hence, the compound is chemically stable. The electrophilicity index of the title molecule using the B3LYP method is 2.3371 for 2, 4-difluoroaniline molecule. Thus the chosen molecule is a potential candidate for NLO applications.

Narrow bandgap conjugated polymers have received great attention due to their wide applications in optoelectronic devices. Because of the synthetic difficulty, it is greatly challenging to develop n-type conjugated polymers with a narrow bandgap with quinoidal character. Herein, we report an n-type narrow-bandgap organoboron polymer with quinoidal character, PBN-TP. PBN-TP is designed with alternating units of BNBP (double B ← N bridged bipyridine) and quinoidal TP (thieno[3,4-b]pyrazine). Direct arylation polymerization of the di-bromo BNBP unit and the di-hydro TP unit affords the organoboron polymer with a high number-average molecular weight of 28.3 kDa. Compared with the control polymer with alternating units of BNBP and thiophene, PBN-T, the replacement of the thiophene unit with a quinoidal TP unit reduces the bond length alternation (BLA) of carbon–carbon bonds and planarized the polymer backbone of PBN-TP, leading to an enhanced contribution of the polymer quinoidal resonance structure. As a result, compared with PBN-T, PBN-TP shows a much reduced bandgap of 1.50 eV, which is among the lowest reported for n-type organoboron polymers based on BNBP. Moreover, due to the low LUMO energy level, PBN-TP could be readily n-doped and used as an n-type polymer thermoelectric material. This work provides a new n-type narrow bandgap conjugated polymer with quinoidal character.

The compound of L-Glycinium 5-Nitrouracilate were grown by slow solvent evaporation technique at room temperature method. Structural investigation by single crystal XRD reveals that LGY5N crystallizes in monoclinic system with space group P21/c. Vibrational spectroscopic studies were performed by utilizing FT–IR spectral analysis along with DFT/B3LYP/6-311++G(d,p) method using GAUSSIAN 06 software. The molecular structure of LGY5N crystal has also been optimised by using Density Functional Theory (DFT) using method with B3LYP/6-311++G (d, p) basis methods in order to find the whole characteristics of the molecular complex. The HOMO and LUMO energy results show that good exchange of charge happened inside the molecule. The electronic absorption spectrum of organic molecules that shows alteration due to the solvation processes was evaluated by TD-DFT in the gas and solvent phase in addition to the recorded UV–visible spectrum. Second harmonic generation (SHG) efficiency measurement was done to examine the enhancement in the nonlinear optical characteristics of the grown crystal.

Acenapththylene-imide (AnI), similar to naphthalene diimide (NDI), is an outstanding building block for organic functional materials and has gained a lot of research attention. Herein, Sulphur and Selenium-embedded AnI-containing polycyclic aromatic hydrocarbon molecules, AnI-SQ and AnI-SeQ, with [1,2,5]thiadiazolo[3,4-g]quinoxaline (SQ) and [1,2,5]selenadiazolo[3,4-g]quinoxaline (SeQ) are designed and synthesized with low-lying LUMO energy levels. The absorption and emission of AnI-SQ and AnI-SeQ displayed a bathochromic shift upon protonation of the C = N bond. Besides, theoretical calculation indicates remarkable rigid planar backbones for both AnI-SQ and AnI-SeQ. Through self-assembly with polymeric Pluronic® F-127, corresponding hydrophilic nanoparticles (NPs) were prepared with low cytotoxicity. And AnI-SQ NPs could be applied for in vitro two-photon fluorescence imaging.

In this work, a series of acenaphthene derivatives (AC-derivatives) were designed and synthesized by incorporating imidazole as an electron deficient moiety and triphenylamine (TPA) as an electron rich moiety with different functional groups at the N1 position of imidazole. All the dyes were structurally characterized by spectroscopic methods (1H NMR, 13C NMR, IR, and Mass) and some of the dyes were characterized by single crystal X-ray diffraction. The detailed thermal, photophysical and electrochemical properties were systematically investigated. All the dyes showed good thermal stability with high thermal decomposition (Td) temperatures ranging from 400 to 430 °C. All the dyes had similar absorption behaviour, with peak wavelengths at 240 nm and 350 nm assigned to the π → π* transitions of the aromatic segments. All the dyes exhibited a broad bluish-white to yellowish-orange emission with the emission maximum in the range of 520–600 nm. Electrochemical analysis was performed to discover the HOMO and LUMO energy levels of the dyes, which were verified using DFT calculations. Theoretical investigations, such as optimization, singlet–triplet and HOMO and LUMO energy levels calculations, were calculated using DFT and TD-DFT analysis. The excited singlet–triplet energy gaps of the dyes were estimated and correlated to the structural and energetic characteristics of the known host materials. In addition, examinations were carried out to find the optical, electronic, charge transport and stability properties of dyes for use as emissive and charge transport materials in organic light emitting devices (OLEDs). All the dyes are good emissive materials with their hole transporting nature more favourable than the electron transporting nature. The theoretical investigations clearly indicate that AC-mCF3 has more potential as an emitter for OLED applications.

Understanding the structure–property relationships in antiaromatic molecules is crucial for controlling their electronic properties and designing new organic optoelectronic materials. Here we report the design, synthesis, and characterization of three new antiaromatic molecules (Pn, n = 1–4) based on the pentalene (P) antiaromatic core, to investigate how electron-donating and electron-accepting substituents affect P1–P4 properties. As expected, the optical, HOMO and LUMO energy levels and electronic structure are greatly modulated by core substitution. Compared to the unsubstituted compound (P1), P3 and P4 containing strong electron-withdrawing units reduced antiaromaticity as assessed by nucleus-independent chemical shift (NICS) calculations compared with P2, which is functionalized with strong electron-donating units, showing that substitution strongly tunes local antiaromaticity. Organic field-effect transistors (OFETs) fabricated using these materials indicate that P2 has an average hole mobility of ∼10−4 cm2 V−1 s−1 while P3 has an average electron mobility of up to 0.03 cm2 V−1 s−1, versus FET-inactive P1. Therefore, introduction of strong π-extended electron-withdrawing or electron-donating substituents onto an antiaromatic core is an effective strategy to switch-on charge transport capacity.

Pyridine and its derivatives are the most important nitrogen based heterocyclic compounds which play a vital role in catalysing biological systems. In the present study, FT -IR, FT- Raman spectra of the title compound 2-Amino-5-chloro-3-nitropyridine have been recorded. Quantum mechanical analysis of the title compound have been carried out by DFT/B3LYP using 6–311++G (d, p) basis set. The vibrational frequencies obtained from the above said DFT method has been compared with the experimental spectral data recorded. The vibrational assignments of wave numbers have been calculated using the Potential Energy Distribution. The electronic properties such as HOMO -LUMO energies, energy gap, local softness, Fukui functions were determined. NBO analysis have been performed to analyse the stability of the molecule. The Molecular Electrostatic Potential and the NLO properties in terms of first order hyperpolarizability and dipole moment have also been accounted in the study. The thermodynamic parameters for different temperatures have been calculated. Molecular docking studies have been performed to investigate the biological activity of the title compound in preparation of new compounds to act as an antagonist and also to determine its binding energy.

The present work investigates on structural and chemical studies on 1-Phenyl Sulfonyl Pyrrole(1PSP) using quantum computational methods. The revamped geometric structure and its parameters were obtained through density functional theory (DFT). The electronic absorption transitions were discussed with different solvents were carried out by TD-DFT (Time Dependent Density Functional Theory) method. The IR intensities and Raman activites are tabulated for vibrational wavenunbers and its corresponding PED (Potential Energy Distribution) assignments in percentage were obtained from VEDA4 software. The inter and intra molecular interactions, electrophilic, nucleophilic and chemical reactivity sites are identified by Molecular electrostatic Potential (MEP), HOMO-LUMO (Highest Occupied Molecular Orbital and Lowest Unoccupied Molecular Orbital) and GCRD (Global chemical reactivity descriptors). Mulliken atomic charges were discussed with Natural Bond Orbital (NBO) analysis. Thermodynamic property and Non-linear optical deportment of the title compound is also talked about. Besides the electron localization function map, the density of states are also mapped with Multiwfn software, a wavefunction analyzer.

It was recently shown by Jeon et al. [Angew. Chem., 2018, 57, 4607] that air stability for more than 1000 hours under light illumination can be achieved in methyl-ammonium (MA) lead iodide perovskite solar cells when Li+ is replaced by Li+@C60 in a dopant material used in the p-type donor layer. In order to demonstrate the role of Li+@C60 in the hole transporting material, we carried out first-principles electronic structure calculations of Li+@C60 adsorbed on MAPbI3 using the van der Waals corrected density functional theory. We used finite slab models of tetragonal MAPbI3 (001) surfaces with MAI terminations. Using the most stable MAPbI3 surfaces, we introduced one Li+@C60 molecule on various positions of the MAI surface and performed geometrical optimizations. Then, we found that the Li+@C60 was adsorbed at the aboveC position with almost 100% ionization. There is not much difference between the top and bottom positions of Li+ inside C60, but the bottom position is slightly more stable than the top position. In the MAPbI3/Li+@C60 system, the Kohn–Sham (KS) wave functions of the HOMO and HOMO-1 levels are spread out in MAPbI3 and those of the LUMO, LUMO+1, LUMO+2 levels are localized in Li+@C60; the energy gap between these levels is 0.6 eV. Thus, in the neutral, spin-polarized MAPbI3/Li@C60 system, the KS wave functions of the HOMO (SOMO, – spin) and LUMO (+spin) levels are both localized in Li@C60 and their energy gap of 0.125 eV is very small. This HOMO (SOMO) level behaves as a hole level when it loses an electron to become Li+@C60. Since there are three almost degenerate LUMO+1 and LUMO+2 levels, it is expected to behave as a good hole conductor. As such, we conclude that the use of Li+@C60 molecules in place of the bare Li-ions as dopant materials in the MAPbI3 solar cells can prevent degradation. In any case, regardless of the adsorption geometry, our results clearly show the existence of the energetically isolated hole level localized in the Li@C60, which may successfully contribute to the suppression of the oxidation of the MAPbI3 surface.

Simply adding ITIC derivatives, which can form a cascade energy alignment between the host donor and acceptor LUMO levels, as a small amount (5 wt%) of A2 acceptor molecules in TOSCs improved the PCE by up to 10% more than that of the BOSC system.

Quinoline Schiff bases are notified for their extensive pharmacological applications which paved way for the continuous exploration of their properties by the chemists of various fields. The theoretical exploration of organic compounds finds new dimensions in the recent advances of science intend us to study the nonlinear optical behaviour of Schiff Bases. In this context, four series of substituted hydrazinoquinoline Schiff bases 1–4 [ 4-methyl-2-salicylidenehydrazinoquinoline (1), 4,6-dimethyl-2-salicylidene hydrazine quinoline (2), 6-chloro-4-methyl-2salicylidenehydrazinoquinoline (3), 4-methyl-6-methoxy-2-salicylidene hydrazine quinoline (4)] were synthesised and characterised by IR and 1H NMR spectral studies. The DFT studies of the synthesised compounds viz., Frontier Molecular Orbital analysis and first hyperpolarisabilty were carried out by using B3LYP functional 6-31G (d,p) basis level. From the DFT results, the first hyperpolarisability suggest that the studied compounds have good non-linear properties. The global reactivity descriptors value indicates that the synthesised compounds are hard with greater kinetic stability. Having lower band gap energy of 4.1 eV–3.73 eV and a low lying LUMO, the synthesised compounds might be a excellent NLO candidate and also act as superconductors, and may have prospective used in both technological as well as pharmaceutical related applications.

Photosensitization analyses of models of (–HC = CH–)n assisted coronene-cytosine complexes assigned by Cor-n-Cyt; n varying by 0, 1, 2, and 3, were investigated in this work by performing density functional theory (DFT) calculations. The investigated models were optimized and chemical descriptors were evaluated. To achieve the goal of this work, energy levels of the highest occupied and the lowest unoccupied molecular orbitals (HOMO and LUMO) were evaluated to reach the absorption energy requirement for innovating photosensitizer (PS) compounds. The models indicated that the complex formations could help the structures to participate in interactions easier than the singular models, in which HOMO-LUMO descriptors indicated lower required absorption energy for them to increase their safety for human health level. The required absorption energies of complexes with n = 0, 1, and 2, were in ultraviolet (UV) region whereas that of complex with n = 3 was moved to visible region. In this regard, the idea of new PS compounds innovation was examined here to introduce Cor-n-Cyt complexes for possible applications in photodynamic therapy (PDT).

The amino-functionalized cage-opened [60]fullerene derivatives were synthesized by reactions with phenylenediamine. In this reaction, the diamine undergoes direct addition to the α,β-unsaturated carbonyl moiety. Further C-C bond scission is promoted by the intramolecular SN2 reaction. These amino-functionalized derivatives possess high-lying highest occupied molecular orbital levels as suggested by electrochemical analyses. These compounds showed intense near-infrared absorption bands that tail to 900 nm, reflecting the optical transition with π-π* and charge transfer character.

The deposition of metal oxides is essential to the fabrication of numerous multicomponent solid-state devices and catalysts. However, the reproducible formation of homogeneous metal oxide films or of nanoparticle dispersions at solid interfaces remains an ongoing challenge. Here we report that molecular hexaniobate cluster anion complexes of structurally and electronically distinct fragments of cubic-spinel and monoclinic Co3O4 can serve as tractable yet well-defined functional analogues of bulk cobalt oxide. Notably, the energies of the highest-occupied and lowest-unoccupied molecular orbitals (HOMO and LUMO) of the molecular complexes, 1, closely match the valence- and conduction-band (VB and CB) energies of the parent bulk oxides. Use of 1 as a molecular analogue of the parent oxides is demonstrated by its remarkably simple deployment as a cocatalyst for direct Z-scheme reduction of CO2 by solar light and water. Namely, evaporation of an aqueous solution of 1 on TiO2-coated fluorinated tin oxide windows (TiO2/FTO), immersion in wet acetonitrile, and irradiation by simulated solar light under an atmosphere of CO2 give H2, CO, and CH4 in ratios nearly identical to those obtained using 20 nm spinel-Co3O4 nanocrystals, but 15 times more rapidly on a Co basis and more rapidly overall than other reported systems. Detailed investigation of the photocatalytic properties of 1 on TiO2/FTO includes confirmation of a direct Z-scheme charge-carrier migration pathway by in situ irradiated X-ray photoelectron spectroscopy. More generally, the findings point to a potentially important new role for coordination chemistry that bridges the conceptual divide between molecular and solid-state science.

Series tunneling across peptides composed of various amino acids is one of the main charge transport mechanisms for realizing the function of protein. Histidine, more frequently found in redox active proteins, has been proved to be efficient tunneling mediator. While how it exactly modulates charge transport in a long peptide sequence remains poorly explored. In this work, we studied charge transport of a model peptide junction, where oligo-alanine peptide was doped by histidine at different position, and the series of peptides were self-assembled into a monolayer on gold electrode with soft EGaIn as top electrode to form molecular junction. It was found that histidine increased the overall conductance of the peptide, meanwhile, its position modulated the conductance as well. Quantitative analysis by transport model and ultraviolet photoelectron spectroscopy (UPS) indicated a sequence dependent energy landscape of the tunneling barrier of the junction. Density-functional theory (DFT) calculation on the electronic structure of histidine doped oligo-alanine peptides revealed localized highest occupied molecular orbital (HOMO) on imidazole group of the histidine, which decreased charge transport barrier.

The role of hole transport material (HTM) layer is critical to obtain high performances for perovskite solar cells (PSCs). The development of novel HTMs with good stability, low cost, and high hole mobility for PSCs is an essential research direction. Herein, new isoindigo-based HTMs were designed and investigated using density functional theory (DFT) computations combined with Einstein relation and Marcus theory. It was found that the energies of HOMO and LUMO levels were increased with an enhancement in the electron-donating character of substituents located on the diphenylamine moieties. The molecules with X = N(Me)2, NHMe, NH2, OMe, OH, and Me substituents exhibited appropriate energy level alignments with respect to MAPbI3, which indicated the hole could be injected from the MAPbI3 to the designed HTMs. Based on the solvation energies, the designed HTMs would be expected to be soluble in the dichloromethane solvent. The results of the absolute hardness and electrostatic surface potential calculations revealed that the stability of such HTMs was decreased with an increase in the electron-donating character of the substituents positioned onto the diphenylamine groups. All of the designed HTMs, except for the X = OH molecule, illustrated considerably greater hole mobility than that of the Spiro-OMeTAD. In view of the matched HOMO level, good hole mobility, plus acceptable solubility and stability, the designed isoindigo based HTMs would have the potential for replacing the Spiro-OMeTAD in PSCs.

In this study, ternary organic solar cells (OSCs) are fabricated with the PBDB-T-2F as a polymer donor and NCBDT-4Cl as a fullerene-free acceptor, double side chain fullerene derivative NC70BA as a third component material and single side chain fullerene PC71BM as reference third component materials. The NC70BA-based ternary OSCs exhibit the highest PCE of 13.82%, which is 10% higher than that of PBDB-T-2F:NCBDT-4Cl binary OSCs and slightly higher than PC71BM-based ternary OSCs (13.24%). Detailed studies suggest that the shallow LUMO levels and double side chain for NC70BA is beneficial to broaden energy bandgap and improve compatibility, which is enhancing JSC and FF value. This work suggests that double side chain fullerene derivative NC70BA as third component materials is a promising way to finely tune the detailed photovoltaic parameters and further improve the photovoltaic performance of OSCs.

Rechargeable aluminum batteries are believed as a promising next-generation energy-storage system due to abundant low-cost Al sources and high volumetric specific capacity. The Al-storage cathodes, however, are plagued by strong electrostatic interaction between host materials and carrier ions, leading to large overpotential and undesired cycling stability as well as sluggish ion diffusion kinetics. Herein, sulfur-linked carbonyl polymer based on perylene-3,4,9,10-tetracarboxylic dianhydride (PTCDA) as the cathode materials for ABs is proposed, which demonstrates a small voltage polarization (135 mV), a reversible capacity of 110 mAh g−1 at 100 mA g−1 even after 1200 cycles, and rapid Al-storage kinetics. Compared with PTCDA, the sulfide polymer possesses higher working voltage because of its lower LUMO energy level according to theoretical calculation. The ordered carbonyl active sites in sulfide polymer contribute to the maximized material utilization and rapid ion coordination and dissociation, resulting in superior rate capability. Besides, the bridged thioether bonds endow the polysulfide with robust and flexible structure, which inhibits the dissolution of active materials and improves cycling stability. This work implies the importance of ordered arrangement of redox active moieties for organic electrode, which provides the theoretical direction for the structural design of organic materials applied in multivalent-ion batteries.

By synergizing the advantages of homogeneous and heterogeneous catalysis, single-site heterogeneous catalysis represents a highly promising opportunity for many catalytic processes. Particularly, the unprecedented designability and versatility of metal-organic frameworks (MOFs) promote them as salient platforms for designing single-site catalytic materials by introducing isolated, well-defined active sites into the frameworks. Herein, we design new MOF-supported single-site catalysts for CO2 hydrogenation to methanol (CH3OH), a reaction of great significance in CO2 valorization. Specifically, N-heterocyclic carbene (NHC), a class of excellent modifiers and anchors, is used to anchor coinage metal hydrides M(I)-H (M = Cu, Ag, and Au) onto the organic linker of UiO-68. The strong metal-ligand interactions between NHC and M(I)-H verify the robustness and feasibility of our design strategy. On the tailor-made catalysts, a three-stage sequential transformation is proposed for CH3OH synthesis with HCOOH and HCHO as the transit intermediates. A density functional theory-based comparative study suggests that UiO-68 decorated with NHC-Cu(I)-H performs best for CO2 hydrogenation to HCOOH. This is further rationalized by three linear relationships for the Gibbs energy barrier of CO2 hydrogenation to HCOO intermediate, the first with the NBO charge of the hydride in NHC-M(I)-H, the second with the electronegativity of M, and the third with the gap between the lowest unoccupied molecular orbital of CO2 and the highest occupied molecular orbital of the catalyst. It is confirmed that the high efficiency of MOF-supported NHC-Cu(I)-H for CO2 transformation to CH3OH is via the proposed three-stage mechanism, and in each stage, the step involving heterolytic dissociation of H2 together with product generation is the most energy-intensive. The rate-limiting step in the entire mechanism is identified to be H2 dissociation accompanying with simultaneous HCHO and H2O formation. Altogether, the tailor-made UiO-68 decorated with NHC-Cu(I)-H features well-defined active sites, enables precise manipulation of reaction paths, and demonstrates excellent reactivity for CO2 hydrogenation to CH3OH. It is also predicted to surpass a recently reported MOF-808 catalyst consisting of neighboring Zn2+-O-Zr4+ sites. The designed MOFs as well as the proposed strategy here establish a new paradigm and can be extended to other hydrogenation reactions.

Charge-transfer (CT) complexes of 4,4′-bis(9H-carbazol-9-yl)-1,1′-biphenyl (CBP) and three acceptors emitted cyan, green, and orange fluorescence, and lower LUMO energy levels of the acceptors prom...

We have investigated the structures, electronic properties, hole and electron mobilities of perfluorinated, perchlorinated and percyanated coronene molecules, using the density functional theory (DFT) and Time Dependent DFT (TDDFT) at the B3LYP-D3/6-311++G(d,p) and $$\omega$$ B97XD/6-311++G(d,p) levels and Markus-Hush charge transfer theory. The calculated geometric parameters for coronene and perchlorocoronene are in good agreement with the experimental data. Our theoretical investigations have shown that B3LYP-D3 functional is suitable to well define vibrational assignments for studied molecules. The quantified effect of the complete substitution of peripheral hydrogen atoms with cyanide groups for the key properties relevant for optoelectronic and photonics such as electron affinities, ionization energies, HOMO-LUMO energies, reorganisation energies, optical absorption spectra, and electron mobilities were discussed. Compared to perfluorination and perchlorination, the percyanation of coronene considerably increases the adiabatic/vertical electron affinities (AEAs/VEAs), the electron mobilities, the HOMO-LUMO gap and reduces the LUMO energy level thus indicating an ambipolar behavior and air-stable material. We have discussed the possible implications of cyanide groups as important substitutes for the design of the new organic compounds useful in electronics.

Achieving high electrical conductivity and thermoelectric power factor simultaneously for n-type organic thermoelectrics is still challenging. By constructing two new acceptor-acceptor n-type conjugated polymers with different backbones and introducing the 3,4,5-trimethoxyphenyl group to form the new n-type dopant 1,3-dimethyl-2-(3,4,5-trimethoxyphenyl)-2,3-dihydro-1H-benzo[d]imidazole (TP-DMBI) , high electrical conductivity of 11 S cm -1 and power factor of 32 μW m -1 K -2 are achieved. Calculations using Density Functional Theory show that TP-DMBI presents a higher singly occupied molecular orbital (SOMO) energy level of -1.94 eV than that of the common dopant 4-(1, 3-dimethyl-2, 3-dihydro-1H-benzoimidazol-2-yl) phenyl) dimethylamine (N-DMBI) (-2.36 eV), which can result in a larger offset between the SOMO of dopant and lowest unoccupied molecular orbital (LUMO) of n-type polymers, though that effect may not be dominant in the present work. The doped polymer films exhibit higher Seebeck coefficient and power factor than films using N-DMBI at the same doping levels or similar electrical conductivity levels. Moreover, TP-DMBI doped polymer films offer much higher electron mobility of up to 0.53 cm 2 V -1 s -1 than films with N-DMBI doping, demonstrating the potential of TP-DMBI, and 3,4,5-trialkoxy DMBIs more broadly, for high performance n-type organic thermoelectrics.

International audience; A number of factors contribute to orbital energy alignment with respect to the Fermi level in molecular tunnel junctions. Here, we report a combined experimental and theoretical effort to quantify the effect of metal image potentials on the highest occupied molecular orbital to Fermi level offset, ε(h), for molecular junctions based on self-assembled monolayers (SAMs) of oligophenylene ethynylene dithiols (OPX) on Au. Our experimental approach involves the use of both transport and photoelectron spectroscopy to extract the offsets, ε(h)(trans) and ε(h)(UPS), respectively. We take the difference in these quantities to be the image potential energy eV(image). In the theoretical approach, we use density functional theory (DFT) to calculate directly eV(image) between positive charge on an OPX molecule and the negative image charge in the Au. Both approaches yield eV(image) ∼ -0.1 eV per metal contact, meaning that the total image potential energy is ∼-0.2 eV for an assembled junction with two Au contacts. Thus, we find that the total image potential energy is 25-30% of the total offset ε(h), which means that image charge effects are significant in OPX junctions. Our methods should be generally applicable to understanding image charge effects as a function of molecular size, for example, in a variety of SAM-based junctions.

Epoxidation reactions catalyzed by high-valent metal-oxo species are key reactions in various biological and chemical processes. Because the redox potentials of alkenes are higher than those of most high-valent metal-oxo species, the electron transfer (ET) from the alkene to the high-valent metal-oxo species in the epoxidation reaction is endergonic and must be coupled with another exergonic process. To reveal the mechanism of the ET, we performed a Marcus plot analysis for the epoxidation reaction of the oxoiron(IV) porphyrin π-cation radical complex (compound I) with alkene. The Marcus plots can be simulated with a linear line with the gradient of 0.50 when the redox potential of compound I varies and 0.07 when the redox potential of alkene varies. These results indicate that the ET process is involved in the rate-limiting step and coupled with the following O-C bond formation process: ET coupled bond formation mechanism. The DFT calculations support this conclusion and disclose the details of the mechanism. As the alkene comes close to the oxo ligand, the energy of the highest occupied molecular orbital (HOMO) of the alkene increases and the energy for the ET becomes small enough to allow the ET. Finally, the ET occurs from the HOMO of the alkene to the porphyrin π-radical orbital. The shift of one electron from the HOMO of the alkene by the ET simultaneously results in the O-C half bond formation between the oxo ligand and the alkene. The ET process itself is still endergonic and reversible, but the bond formation coupled with the ET changes the overall process to exergonic and irreversible. We also discuss the similarity with the aromatic hydroxylation reaction and the relevance to the epoxidation reactions of other metal-oxo complexes and peracid.

Metal 2,2':6',2″-terpyridine (tpy) complexes are readily used as building blocks in metallo-supramolecular polymers that stand out for their photophysical properties in solar energy assemblies. Furthermore, Resonance Raman (RR) excitation profiles are sensitive indicators of the electronic properties of chromophores. Previously, using RR spectroscopy, we studied the [Fe(tpy)2]2+ complex and metallo-supramolecular polymers formed by tpy derivatives and Fe(II) ions. Here, we compare RR spectra of iron (Fe(II)) complexes with 4'-substituted tpy ligands─[Fe(4'-R-tpy)2]2+, with R = H (1a), Cl (2a), 4-chlorophenyl (3a), and 2-thienyl (4a) to describe changes in their electronic structure after functionalization. By combining theoretical calculations, RR, and UV/vis spectra, we elucidated differences in the RR excitation profiles of 1a, 2a, and 4a complexes. In all Raman modes, complexes 1a and 2a showed maximal enhancement only at 532 nm excitation, whereas complex 4a exhibited maximal enhancement selectively at either 532 or 633 nm excitations. Based on our calculations, the mixed metal/ligand character of the highest occupied molecular orbital (HOMO) of 4a complex manifests itself through selective enhancement of vibration modes, mainly localized on the 2-thienyl unit at 633 nm excitation, which may explain the unique behavior of this complex. Therefore, complex 4a is a prospective candidate for further detailed photophysical explorations toward developing sensitizers for solar cells.

Singly occupied molecular orbital−highest occupied molecular orbital (SOMO−HOMO) conversion (inversion), SHC, is a phenomenon in which the SOMO is lower in energy than the doubly occupied molecular orbitals (DOMO, HOMO). A non-Aufbau electronic structure leads to unique properties such as a switch in bond dissociation energy and the generation of high-spin species on one-electron oxidation. In addition, the pronounced photostability of these species has been reported recently for application in organic light-emitting devices. In this review article, we summarise the chemistry of SOMO−HOMO converted (inverted) species reported to date.

Herein, we describe the enantioselective C(sp3)-H bond functionalizations of 2-alkyl azaarenes using a cooperative dual Lewis acid catalysis. An achiral Lewis acid activates the unactivated azaarene partner without the need for a strong base. Orthogonally, a chiral-at-metal Lewis acid catalyst enables LUMO lowering and induces chirality. This method tolerates a range of complex molecular scaffolds and exhibits good to excellent yields and selectivity while accepting a wide variety of functional groups.