Lowest Unoccupied Molecular Orbital Energy Research Articles

Quantum chemical and experimental studies on the extraction of acid blue 80 and acid red 1 from their aquatic environment using tetrabutylammonium bromide based deep eutectic solvents

In this study, the highest occupied molecular orbital (HOMO) energy, the lowest unoccupied molecular orbital (LUMO) energy, HOMO–LUMO energy gap, chemical potential (µ), electronegativity (χ), electrophilicity index (ω), global hardness (η), and global softness (s) of dyes; acid blue 80 (AB80), acid red 1 (AR1) and deep eutectic solvents: tetrabutylammonium bromide with glycerol {[TBAB][Gly]}, tetrabutylammonium bromide with decanoic acid {[TBAB][DA]} and tetrabutylammonium bromide with oleic acid {[TBAB][OA]} were predicted and calculated using quantum chemical calculation. The polarity of all the studied molecules also predicted in terms of screening charge density and plotted sigma profile and sigma potential. Further, the extraction experiment was conducted for the extraction of acid blue 80 (AB80) and acid red 1 (AR1) using tetrabutylammonium bromide with decanoic acid {[TBAB][DA]} and tetrabutylammonium bromide with oleic acid {[TBAB][OA]} as the potential solvent. The process was characterized by means of distribution coefficient and efficiency. Finally, the extraction process feasibility was studied and discussed in terms of and

Electron density, charge transfer, solvent effect and molecular spectroscopic studies on 2,2-Dimethyl-N-pyridin-4-yl-propionamide – A potential antioxidant

Quantum-level theoretical studies employing density functional theory and spectral methods such as Fourier Transform-Raman, Fourier Transform-Infrared, and Ultraviolet–Visible have been conducted on the chemical 2,2-Dimethyl-N-pyridine-4-yl-propionamide (2DNP4YP). Density functional theory computes the equilibrium geometry, numerous molecular components, atom bonding, and vibrational frequencies. The 2DNP4YP has undergone topological analyses using the Quantum Theory of Atoms in Molecules (QTAIM) to determine the inter and intramolecular charge transfer as well as calculated the Natural Bond Orbital study. By the Time Dependent-Density Functional Theory (TD-DFT) technique with several solvents and a simulated UV–Vis spectrum, the absorption of maximum wavelengths is found. The biological activity of the 2DNP4YP is explained by all other significant electronic factors utilizing the Highest Occupied Molecular Orbital and Lowest Unoccupied Molecular Orbitals energy values from the Density Functional Theory style. The Non-Linear Optical (NLO) properties of 2DNP4YP were investigated by changing the keyword in the same basis set. Molecular Electrostatic Potential (MEP) and Fukui function studies are used to identify the reactive regions around the molecule.

Novel low-bandgap donor–acceptor thiophene-phenylene co-oligomers for light-emitting semiconductor devices

Thiophene-phenylene co-oligomers (TPCOs) have shown their high potential for organic light-emitting devices because of their high luminescence and efficient charge transport. However, unsubstituted TPCOs have relatively wide optical bandgaps and the high-lying lowest unoccupied molecular orbital (LUMO) energies so that efficient electron transport is a challenge. Electron-withdrawing groups (EWGs) and fluorinated fragments embedded into the TPCO molecule structure could result in the lower LUMO energy and narrower optical bandgap. Here, we report the synthesis of two novel TPCOs series with either phenylene or perfluorinated phenylene central core and end-capped with various EWGs (aldehyde, 2-ethylhexyl cyanoacetate, hexyl rhodanine and dicyanorhodanine) and with long alkyl terminal and side chains increasing the solubility. All the oligomers synthesized were found to be thermally stable and crystalline materials with relatively low LUMO energies (down to −3.50 eV), narrow bandgaps (down to 1.9 eV), and efficient photoluminescence in the green – deep red spectral regions both in solution and solid-state. The TPCOs with 2-ethylhexyl cyanoacetate EWG were crystallized in large-area single-crystal monolayers, which showed strongly polarized photoluminescence and demonstrated their high potential as active layers in solution-processed single-layer organic light-emitting transistors.

Investigations of p-tolyloxy-1,3,4-oxadiazole propionamides as soybean 15-lipoxygenase inhibitors in comforting with in vitro and in silico studies

Inflammatory disorders are the prime contributor to public health issue and the development of more effective and safer anti-inflammatory drugs in addition to other therapeutic alternatives to treat inflammatory illnesses, particularly chronic inflammatory diseases, is one of the foremost current issues. In this regard, our present work is concerned with the synthesis of a new series of N-alkyl/aralkyl/aryl derivatives (7a–o) of 5-((p-tolyloxymethyl)-4H-1,3,4-oxadiazole-2-ylthio)propionamide which was instigated by the successive conversions of p-tolyloxyacetic acid into ester, hydrazide and 5-(p-tolyloxymethyl)-4H-1,3,4-oxadiazole-2-thiol. The planned compounds (7a–o) were attained by the reaction of 5-(p-tolyloxymethyl)-4H-1,3,4-oxadiazole-2-thiol with variety of N-alkyl/aralkyl/aryl electrophiles in potassium hydroxide and were characterized by FTIR, 1H-, 13C-NMR spectroscopy, EI-MS and HR-EI-MS spectrometry and probed for their inhibiting potential against soybean 15-lipoxygenase (15-LOX) enzyme. The compounds 7a, 7n, 7 g, 7e, 7h, 7i, 7j and 7b promulgated the potent inhibiting potential with IC50 values 9.43 ± 0.45, 16.75 ± 0.49, 19.45 ± 0.37, 21.32 ± 0.46, 22.64 ± 0.56, 23.53 ± 0.62, 24.32 ± 0.45 and 29.15 ± 0.57 µM, respectively, while excellent to good inhibitory activities were shown by 7o, 7 m, 7k, 7f, 7c, 7 l and 7d with IC50 values in the range 30.29 ± 0.56 to 52.54 ± 0.64 µM. Compounds 7i–o maintained 91.12 ± 1.5 to 98.23 ± 1.2% blood mononuclear cells (MNCs) viability at 0.25 mM by MTT assay whilst compounds 7d–h observed 46.51 ± 1.3 to 57.12 ± 1.4% viability where as the most toxic compounds were 7b (12.51 ± 1.4%), 7a (28.12 ± 1.5%) and 7c (38.23 ± 1.5%) as compared with controls. Pharmacokinetic profiles predicted good oral bioavailability and drug-likeness properties of molecules as per rule of five. Molecular docking studies displayed hydrogen bonding between the compounds and the enzyme with Arg378 which was common in 7n, 7 g, 7h and baicalein. In 7a and quercetin, hydrogen bonding was established through Asn375; Tyr512 and Val589 were also involved in bonding with other analogues. RMSD (root mean square deviation) values exhibited good inhibitory profiles in the order quercetin (0.73 Å)<7 g (0.98 Å)<baicalein (1.23 Å)<7a (1.27 Å)<7n (1.75 Å)<7h (1.81 Å) whereas the binding free energies (kJ/mol) increasing order: (−37.56 kJ/mol)< quercetin (−35.43 kJ/mol)<7n (−34.55 kJ/mol)<7 g (−33.38 kJ/mol)<7h (31.75 kJ/mol)<7a (−31.63 kJ/mol). Density functional theory (DFT) data established good correlation between the IC50 values of compounds and HOMO–LUMO (highest occupied and lowest unoccupied molecular orbitals) energy calculations. It was found that compounds with more stabilized LUMO orbitals had significant biological activity. The work collectively supports steps taken forward in search for potential ‘leads’ as anti-inflammatory agents wherein compounds 7a, 7n, 7i, 7j possessed ‘lead’ like properties for further investigations. Communicated by Ramaswamy H. Sarma

Achieving High‐Efficiency in Binary Organic Solar Cells by the Structural Fine‐Tuning of Coumarin‐Based Donor

The choice of molecular material plays a crucial role in improving the performance of organic solar cells. Herein, two coumarin‐based small molecules are designed and synthesized in which the π‐system is extended by the introduction of double bonds. The molecules are differed by the attachment of central acceptor units. The replacement of the carbonyl group in C3 by the dicyanomethylene unit in C3–CN red‐shift the absorption, reduced the energy gap, and stabilized the highest occupied molecular orbital and lowest unoccupied molecular orbital energy levels. When blended with a complementary absorbing all‐fused acceptor F13, the binary devices using C3 donor delivered a power conversion efficiency (PCE) of 11.09%. In contrast, C3–CN:F13‐based binary device displayed an impressive PCE of 14.84% due to the obvious increase in all open circuit voltage, short circuit current density, and fill factor values. The inclusion of CN group to the molecular backbone induces a tighter intermolecular packing, which is beneficial for the charge transport properties. The study demonstrates that the subtle modification in conjugation length and tuning of the energy level by the proper choice of acceptor could be a promising way to improve the device's performance.

An Azo‐Based Electrode for All‐Around High‐Performance Flexible Supercapacitors

The photo‐rechargeable supercapacitor enables the self‐powering of flexible wearable electronics. However, flexible wearable electronics require supercapacitors not only with excellent flexibility but also with high energy density. P‐diaminoazobenzene (P‐Azo) as a new type of organic electrode material with NN is directly connected to the benzene ring and forms a large π‐conjugated system, which makes it have a lower lowest unoccupied molecular orbital (LUMO) energy level, is beneficial to transfer of electrons, and increases the conductivity of organic molecules. In addition, NN can realize the transfer of two electrons, which makes P‐Azo have a higher energy density. Asymmetric flexible supercapacitors are fabricated by assembling P‐Azo, activated carbon, and an adhesive electrolyte, with 425.2 mW h cm−2 (55.19 Wh kg−1) energy density at a power density of 80 mW cm−2 (10.38 W kg−1), and 90.7% capacitance retention after 80 000 cycles of bending. In this work, supercapacitors and perovskite submodules are coupled to prepare a photo‐rechargeable supercapacitor to achieve a 7% overall energy‐conversion efficiency. Therefore, this supercapacitor paves a practical route for powering future wearable electronics.

Efficient recovery of phosphate by Fe3O4/La-MOF: An insight of adsorption performance and mechanism from electrochemical properties

Phosphorus (P) is known as a valuable resource, and recycling it from wastewater can avoid environmental pollution and resource waste. Herein, a regenerable magnetic Fe3O4 and La-based metal–organic framework functional material (Fe3O4/La-MOF) was synthesized by solvent thermal method and its adsorption performances of phosphate were evaluated. The as-prepared magnetic Fe3O4/La-MOF exhibited magnetic separation efficiency of 97.9% and it could maintain the high adsorption capacity over a wide pH range from 3 to 10, as well as showed an excellent P adsorption selectivity in presence of Cl-, NO3–, HCO3–, CO32– and SO42-. The isotherm data were consistent with the Langmuir model, and the adsorption kinetic data conformed to the pseudo-second-order model, revealing that there was chemical adsorption between Fe3O4/La-MOF and phosphate. The electrochemical behavior of Fe3O4/La-MOF before and after phosphate adsorption showed that the band gap energy of LUMO (Lowest Unoccupied Molecular Orbital) and HOMO (Highest Occupied Molecular Orbital) of P adsorbed Fe3O4/La-MOF was lower than that of the material itself, which indicated the successful adsorption of phosphate on Fe3O4/La-MOF and the forming of a perfect hybrid structure. The characterization analysis of FT-IR and XPS illustrated that intra-sphere complex (LaOP) formed between Fe3O4/La-MOF and phosphate by ligand exchange, which might be the dominant mechanism, followed by electrostatic attraction and precipitation. This study highlighted the great promise of magnetic reusable Fe3O4/La-MOF composite for application in phosphate removal and recovery.

Enhanced n‐Type Thermoelectric Performance of Conjugated Polymers Based on an Indandione‐Terminated Quinoidal Unit through Comonomer Optimization

Comprehensive SummaryConjugated polymers (CPs) containing quinoidal units are promising in n‐type organic thermoelectric materials because of their deep‐positioned lowest unoccupied molecular orbital (LUMO) energy levels and planar conjugated backbones. Herein, three CPs have been synthesized by copolymerizing an indandione‐terminated quinoidal unit with bithiophene derivatives. Owning to the high electron affinity of the indandione‐terminated quinoidal unit, all polymers showed deep LUMO energy levels below –4.10 eV. Incorporating electron‐withdrawing substituents (F or CN) on the bithiophene comonomer can further downshift the LUMO energy levels. As a result, a more efficient n‐doping process can be realized when employing 4‐(2,3‐dihydro‐1,3‐dimethyl‐1H‐benzimidazol‐2‐ yl)‐N,N‐dimethylbenzenamine (N‐DMBI) as the dopant. Ultimately, the polymer with CN substituents delivered the best thermoelectric performance with a power factor of up to 2.14 μW·m−1·K−2, because it possessed the lowest LUMO energy level among the three CPs. This work highlights that the modulation of LUMO energy level is an effective strategy to optimize the thermoelectric performance of CPs.

Electronic Structure and Photoactivity of Organoarsenic Hybrid Polyoxometalates

Organofunctionalization of polyoxometalates (POMs) allows the preparation of hybrid molecular systems with tunable electronic properties. Currently, there are only a handful of approaches that allow for the fine-tuning of POM frontier molecular orbitals in a predictable manner. Herein, we demonstrate a new functionalization method for the Wells-Dawson polyoxotungstate [P2W18O62]6- using arylarsonic acids which enables modulation of the redox and photochemical properties. Arylarsonic groups facilitate orbital mixing between the organic and inorganic moieties, and the nature of the organic substituents significantly impacts the redox potentials of the POM core. The photochemical response of the hybrid POMs correlates with their computed and experimentally estimated lowest unoccupied molecular orbital energies, and the arylarsonic hybrids are found to exhibit increased visible light photosensitivity comparable with that of arylphosphonic analogues. Arylarsonic hybridization offers a route to stable and tunable organic-inorganic hybrid systems for a range of redox and photochemical applications.

Structural Fusion Yields Guest Acceptors that Enable Ternary Organic Solar Cells with 18.77 % Efficiency.

The design and selection of a suitable guest acceptor are particularly important for improving the photovoltaic performance of ternary organic solar cells (OSCs). Herein, we designed and successfully synthesized two asymmetric silicon-oxygen bridged guest acceptors, which featured distinct blue-shifted absorption, upshifted lowest unoccupied molecular orbital energy levels, and larger dipole moments than symmetric silicon-oxygen-bridged acceptor. Ternary devices with the incorporation of 14.2 wt % these two asymmetric guest acceptors exhibited excellent performance with power conversion efficiencies (PCEs) of 18.22 % and 18.77 %, respectively. Our success in precise control of material properties via structural fusion of five-membered carbon linkages and six-membered silicon-oxygen connection at the central electron-donating core unit of fused-ring electron acceptors can attract considerable attention and bring new vigor and vitality for developing new materials toward more efficient OSCs.

Structural Fusion Yields Guest Acceptors that Enable Ternary Organic Solar Cells with 18.77 % Efficiency

AbstractThe design and selection of a suitable guest acceptor are particularly important for improving the photovoltaic performance of ternary organic solar cells (OSCs). Herein, we designed and successfully synthesized two asymmetric silicon–oxygen bridged guest acceptors, which featured distinct blue‐shifted absorption, upshifted lowest unoccupied molecular orbital energy levels, and larger dipole moments than symmetric silicon–oxygen‐bridged acceptor. Ternary devices with the incorporation of 14.2 wt % these two asymmetric guest acceptors exhibited excellent performance with power conversion efficiencies (PCEs) of 18.22 % and 18.77 %, respectively. Our success in precise control of material properties via structural fusion of five‐membered carbon linkages and six‐membered silicon–oxygen connection at the central electron‐donating core unit of fused‐ring electron acceptors can attract considerable attention and bring new vigor and vitality for developing new materials toward more efficient OSCs.

Molecular Docking of the Inhibitory Activities of Selected Phytochemicals in Artemisia Afra Against NADH-Ubiquinone Oxidoreductase of Plasmodium Falciparum (PfNDH2)

Nicotinamide Adenine Dinucleotide Hydrogen (NADH)-ubiquinone oxidoreductase in Plasmodium falciparum (PfNDH2) constitute a feasible target for anti-malarial drug discovery. This work aims at investigating the inhibitory activities of selected phytochemicals in Artemisia Afra against NADH-Ubiquinone Oxidoreductase of Plasmodium Falciparum. 50 phytochemicals were selected based on structural stability. Quantum mechanical Density Functional Theory (DFT) studies with B3LYP at 6-311G* level was done on pfNDH2 as the apoprotein control. Pharmacokinetic ADMET profiling, bioactivity assessment, physicochemical studies, molecular docking was used to study the PfNDH2 inhibiting activities of the 50 compounds from Artemisia afra. Out of these 50 phytochemicals, 2,4,6-Triphenyl-1,3 dioxane (2,4,6 TPD), chamazulene, aromadendrene, 1-epi-bBicyclosesquiphellandrene (1-EBSP) and cis-muurola-3,5-diene (CM3,5D) passed the physicochemical properties of the Lipinski rule of 5, binding mode, molecular interaction and ADMET calculations. These five compounds also showed high binding affinity of -8.9 kJ/mol, -7.7kJ/mol, -7.3kJ/mol, -7.1kJ/mol and -7.1kJ/mol at the binding pores of PfNDH2 respectively. The reactivity of these compounds was also investigated by the electron donating and accepting activities of the compounds using Density Functional Theory calculated Higher Occupied Molecular Orbital, Lower Unoccupied Molecular Orbital energy and HOMO/LUMO energy gap revealed the stability of the compounds due to the low energy gap values obtained. The values obtained showed that aromadendrene and chamazulene were potential inhibitors of PfNDH2 and were the most potent and therefore, recommended for therapeutic efficacy investigation.

Poly(ethylene glycol)–Fullerene Composite Films and Free-Standing Nanosheets for Flexible Electronic Devices and Sensors

A series of ultrathin (80–100 nm) poly(ethylene glycol)–fullerene (PEG-C60) composite films were fabricated by three different methods, denoted immersion, one-pot, and reflux. These films are composed of cross-linked amine-/epoxy-decorated STAR-PEGs and disk-shaped C60 clusters with an average diameter of 314–329 nm and narrow size distribution. The clusters are located either on the surface of the films (immersion) or embedded in their bulk, coupling either physically (one-pot) or chemically (reflux) to the PEG network. The content of C60 in the composite films varies depending on the preparation method and is highest (∼30%) in the case of reflux, featuring also a shift of the lowest unoccupied molecular orbital energy of C60 by ∼70 meV compared to the immersion case. These films exhibit distinct optical and electrochemical properties of C60, merged with some favorable characteristics of the PEG matrix and resulting, in particular, in good electrochemical conductivity and high elasticity. The films can be separated from the substrate, forming composite nanosheets, which can be either used as free-standing ones or transferred to a secondary substrate with the preservation of the original properties. Potential applications of PEG-C60 films and nanosheets include flexible electronic devices, photodetectors, and electrochemical sensors, including biosensors in particular.

Controlling Morphology and Voltage Loss with Ternary Strategy Triggers Efficient All-Small-Molecule Organic Solar Cells

Herein, an emerging acceptor L8-BO as the third component was combined with the B1:BO-4Cl system for constructing efficient ternary all-small-molecule organic solar cells (ASM-OSCs). Theoretical, morphological, and crystallographic studies reveal that L8-BO and BO-4Cl possess good compatibility, resulting in alloy-like state formation of two acceptors in ternary blends. The synergistic effect of two acceptors is conducive to forming favorable phase separation and molecular stacking for promoting charge splitting and extraction, which contributes to simultaneously boosting short-circuit current density and fill factor. Furthermore, the alloy-like state of two acceptors and the higher lowest unoccupied molecular orbital energy level of L8-BO assist ternary ASM-OSCs in achieving lower voltage loss with respect to the binary devices. The optimal ternary ASM-OSCs with 20 wt % L8-BO deliver a top-level efficiency of 17.10%. This work demonstrates that not only the morphology but also the voltage loss of the small molecular matrix can be well-manipulated by employing the ternary strategy.

Side‐Chain Methylthio‐Based Position Isomerism of Hole‐Transport Materials for Perovskite Solar Cells: From Theoretical Simulation to Experimental Characterization

AbstractHole transporting materials (HTMs) are imperative for promoting the development of perovskite solar cells (PSCs). Herein, three isomers of RQ4, RQ5, and RQ6 are constructed by methylthio (‐SMe) group in the para, meta, and adjacent sites of terminal benzene on the side‐chain of carbazole‐arylamine derivatives based HTMs, and investigated by means of the theoretical simulation and experimental characterization. As a result of the theoretical simulation, the isomeric HTMs of RQ4‐RQ6 exhibit appropriate highest occupied molecular orbital /lowest unoccupied molecular orbital energy levels and good optical properties. However, by comparison with RQ4 and RQ5, a better planar configuration and closer molecular stacking for RQ6 may be beneficial to promote the hole coupling, interface interaction, and charge transfer at perovskite/HTMs interface. In order to verify the accuracy of the theoretical model, the designed RQ4‐RQ6 are synthesized to be used to assemble PSCs devices. In comparison to isomers RQ4 (20.07%) and RQ5 (18.18%) based devices, the RQ6 based devices has higher power conversion efficiency of 21.03% because of its high hole mobility, the film formation ability, and large charge transfer at perovskite/HTMs interface. The experimental results confirm the reliability of the theoretical simulation and provide an effective strategy to obtain potential HTMs through isomerization of side‐chain functional groups.

Y-Type Non-Fullerene Acceptors with Outer Branched Side Chains and Inner Cyclohexane Side Chains for 19.36% Efficiency Polymer Solar Cells.

Raising the lowest unoccupied molecular orbital (LUMO) energy level of Y-type non-fullerene acceptors can increase the open-circuit voltage (Voc ) and thus the photovoltaic performance of the current top performing polymer solar cells (PSCs). One of the viable routes is demonstrated by the successful Y6 derivative of L8-BO with the branched alkyl chains at the outer side. This will introduce steric hindrance and reduce intermolecular aggregation, thus open up the bandgap and raise the LUMO energy level. To take further advantages of the steric hindrance influence on optoelectronic properties of Y6 derivatives, two Y-type non-fullerene acceptors of BTP-Cy-4F and BTP-Cy-4Cl are designed and synthesized by adopting outer branched side chains and inner cyclohexane side chains. An outstanding Voc of 0.937V is achieved in the D18:BTP-Cy-4F binary blend devices along with a power conversion efficiency (PCE) of 18.52%. With the addition of BTP-eC9 to extend the absorption spectral coverage, a remarkable PCE of 19.36% is realized finally in the related ternary blend devices, which is one of the highest values for single-junction PSCs at present. The results illustrate the great potential of cyclohexane side chains in constructing high-performance non-fullerene acceptors and their PSCs.

Corrosion Inhibition Potential of Thiosemicarbazide Derivatives on ALuminium: Insight from Molecular Modelling and QSARs Approaches

The potentials of six thiosemicarbazide derivatives towards corrosion inhibition were investigated theoretically using density functional theory (DFT) and quantitative structural-activity relationships (QSARs) methods. Their performance as corrosion inhibitors were evaluated using their calculated quantum chemical parameters such as molecular weight, softness, electronegativity, dipole moments, hardness, bandgap energy (\Delta E), highest occupied molecular orbital energy (EHOMO), and the lowest unoccupied molecular orbital energy (ELUMO). Regression analysis was carried out using the ordinary least square method to develop a model that establishes the relationship between chemical parameters and inhibition efficiencies that have been measured experimentally. According to the results, quantum chemical parameters confirm the inhibition potential of TSC5 to be greater than TSC2, while the predicted inhibition efficiencies of the studied thiosemicarbazide derivatives correspond to experimentally reported values with a root mean square error (%) of 1.116 and correlation coefficient of 0.998. The high correlation demonstrates and validates the quantum chemical approach’s reliability in studying corrosion inhibition on a metal surface. The validation of the developed model internally and externally demonstrates that it is robust and stable, with high predictability

Substitutional effects on the Na-involved electrochemical properties of isomeric benzoquinones

The possibility of the isomeric benzoquinones, 1,2-benzoquinone (1,2-BQ) and 1,4-benzoquinone (1,4-BQ) with electron withdrawing functional groups (-PO3H2, –COOH, –NO2 and –CN), as prospective cathodes in sodium ion batteries is explored applying Density Functional Theory (DFT) approach. In order to investigate the redox behavior of the first and second discharged states, the sodiation of the considered derivatives with one and two number of sodium ions are made. The obtained redox potentials (ΔEred) of bare quinones are in good agreement with the experimental ΔEred. A linear correlation fit with R2>∼0.95 is found to exist between the obtained LUMO (lowest unoccupied molecular orbital) energies and ΔEred. In general, higher ΔEred of ∼ 4.2 V with charge capacities of 186mAh/g and 258mAh/g is observed for NO2 and CN containing BQ derivatives. Unexpected deviation in ΔEred of phosphonate derivatives emphasizes the role of intramolecular hydrogen bonds, conformational changes and steric hindrance on the redox properties.

Theoretical Insight on the High Reactivity of Reductive Elimination of NiIII Based on Energy- and Electron-Transfer Mechanisms.

Iridium/nickel (Ir/Ni) metallaphotoredox dual catalysis overcomes the challenging reductive elimination (RE) of Ni(II) species and has made a breakthrough progress to construct a wide range of C-X (X = C, N, S, and P) bonds. However, the corresponding reaction mechanisms are still ambiguous and controversial because the systematic research on the nature of this synergistic catalysis is not sufficient. Herein, IrIII/NiII and IrIII/Ni0 metallaphotoredox catalysis have been theoretically explored taking the aryl esterification reaction of benzoic acid and aryl bromide as an example by a combination of density functional theory (DFT), molecular dynamics, and time-dependent DFT computations. It is found that an electron-transfer mechanism is applicable to IrIII/NiII metallaphotoredox catalysis, but an energy-transfer mechanism is applicable to IrIII/Ni0 combination. The IrIII/NiII metallaphotoredox catalysis succeeds to construct a NiI-NiIII catalytic cycle to avoid the challenging RE of Ni(II) species, while the RE occurs from triplet excited-state Ni(II) species in the IrIII/Ni0 metallaphotoredox catalysis. In addition, the lower lowest unoccupied molecular orbital energy level of Ni(III) species than that of Ni(II) species accelerates RE from Ni(III) one. The triplet excited-state Ni(II) species can resemble a Ni(III) center, considering the metal-to-ligand charge transfer character to promote the RE.

Fused phthalimide-based A–DA′D–A small molecule: New protocol for n-type organic semiconductors

Development of well-conjugated building blocks by a concise and efficient synthetic procedure is crucial for organic electronics. In particular, for A–DA′D–A-type (A = donor and D = acceptor) organic semiconductors, which are the most popular and successful small molecular acceptors, the limited number DA′D fused cores limits the variety of these molecules. Herein, we report a new A–DA′D–A-type small molecule, TIIC, containing an entirely new DA′D fused core. The complete synthetic procedure, including a well-designed photocyclization step, resulted in above 50% total yield over five steps. TIIC shows strong light absorption in the complete visible region because of the extended π-conjugation and strong intramolecular charge transfer. The deep lowest unoccupied molecular orbital energy level (−4.0 eV) of TIIC, which indicates the n-type semiconductor property, was further confirmed by the organic field-effect transistor performance with unipolar electron mobility of 3.51 × 10−4 cm2 V−1 s−1.