Electron-deficient Research Articles

A deep-red fluorophore based on naphthothiadiazole as emitter with hybridized local and charge transfer and ambipolar transporting properties for electroluminescent devices.

Herein, we report the synthesis and characterization of an efficient ambipolar charge-carrier-transporting deep-red fluorophore (TPECNz) based on a donor-acceptor-donor (D-A-D)-type molecule and its application as a non-doped emitter in an organic light-emitting diode (OLED). The fluorophore TPECNz contains naphtho[2,3-c][1,2,5]thiadiazole (Nz) as a strong acceptor unit symmetrically functionalized with N-(4-(1,2,2-triphenylvinyl)phenyl)carbazole as a donor and aggregation-induced emission (AIE) luminogen. The experimental (solvatochromic and emission in THF/water mixtures studies) and theoretical investigations prove that TPECNz retains cooperative hybridized local and charge transfer (HLCT) and weak AIE features. Thanks to its D-A-D-type structure with a proper twist angle between the D and A units, a strong electron deficiency of the Nz unit, and electron-donating and hole-transporting natures of carbazole, TPECNz exhibits a strong deep red emission (λem = 648 nm) with a high fluorescence quantum yield of 96%, outstanding thermal property (Tg = 236 °C), and ambipolar charge-carrier-transporting property with a decent balance of mobility of electrons (1.50 × 10-5 cm2 V-1 s-1) and holes (4.42 × 10-6 cm2 V-1 s-1). TPECNz is successfully employed as a non-doped emitter in an OLED which displays deep red electroluminescent emission peaked at 659 nm with CIE coordinates of (0.664, 0.335)), an EQEmax of 3.32% and exciton utilization efficiency (EUE) of 47%.

Directional surface hydroxylation on 6H-SiC induces surface electron polarization and proton activation promoting photocatalytic water splitting for hydrogen

Photocatalytic water splitting for hydrogen production is a promising solution to converse solar energy to green fuel. A high-performance photocatalyst system always requires fast surface reaction rate and efficient charge separation. Herein, a novel strategy that photo-assisted silanizing-hydrolyzing method is used to trigger in situ surface hydroxylation selectively on Si atoms of micro-sized 6H-SiC particles. Due to this functionalization, the results show that the silanizing-hydrolyzing process occurs at the Si sites while the C is passivated, leading the Si atoms with electron deficiency property by XPS characterization. It also drives the SiC surface from native hydrophobicity to hydrophilicity, which is benefit to proton absorption and desorption of generated H2 by FT-IR and contact angle (CA) result. Furthermore, the photo-electron-chemical characterization demonstrate the charge migration and separation of SiC are promoted. The DFT calculation further indicates these surface properties changes are mainly attribute to the surface electron polarization through the hydroxylation, inducing the Si-O spatial charge separation. More importantly, the positive Si atoms exhibit an appropriate proton absorption energy, resulting in easily H2 desorption from SiC surface. The hydrogen evolution is significantly enhanced by 33 times compared to pristine SiC without any cocatalysts introduced. Our method provides an efficient route to design an environmental-friendly photocatalytic material SiC and construct highly efficient solar energy conversion systems, which can simultaneously facilitate carrier generation, transportation and surface reduction reaction rate.

Corner-Sharing Tetrahedrally Coordinated W-V Dual Active Sites on Cu2 V2 O7 for Photoelectrochemical Water Oxidation.

The sluggish four-electron oxygen evolving reaction is one of the key limitations of photoelectrochemical water decomposition. Optimizing the binding of active sites to oxygen in water and promoting the conversion of *O to *OOH are the key to enhancing oxygen evolution reaction. In this work, W-doped Cu2 V2 O7 (CVO) constructs corner-sharing tetrahedrally coordinated W-V dual active sites to induce the generation of electron deficiency active centers, promote the adsorption of ─OH, and accelerate the transformation of *O to *OOH for water splitting. The photocurrent obtained by the W-modified CVO photoanode is 0.97mA cm-2 at 1.23V versus RHE, which is much superior to that of the reported CVO. Experimental and theoretical results show that the excellent catalytic performance may be attributed to the formation of synergistic dual active sites between W and V atoms, and the introduction of W ions reduces the charge migration distance and prolongs the lifetime of photogenerated carriers. Meanwhile, the electronic structure in the center of the d-band is modulated, which leads to the redistribution of the electron density in CVO and lowers the energy barrier for the conversion of the rate-limiting step *O to *OOH.

Heterocyclic hexagonal B5O7− and B5O8− clusters: Inorganic benzenes and phenolate anions, dual 3c-4e hypervalent π bonds, and superhalogen anions

Boron oxide clusters show structural diversity, unique electronic properties, and exotic chemical bonding, owing to boron's intrinsic electron deficiency. We report on the structural, electronic, and bonding properties of two boron oxide clusters, B5O7− and B5O8−, using computer global-minimum (GM) searches and quantum chemical calculations. These clusters have a heteroatomic B3O3 hexagonal ring as their structural core, which is terminated and chemically saturated by the boronyl, OBO, and O− ligands. Chemical bonding analyses reveal a π sextet in the clusters, thus rendering them new members of the “inorganic benzene” family, or more precisely, inorganic analogs of phenolate anion. The latter chemical identity gives rise to their extremely high electron binding energies beyond 5.3 eV, which are electronically robust and can be classified as superhalogen anions. The terminal OBO ligands also have dual three-center four-electron (3c-4e) hypervalent π bonds, which are a crucial mechanism that helps stabilize these boron oxide species.

Relative Local Electron Density Tuning in Metal-Covalent Organic Frameworks for Boosting CO2 Photoreduction.

The high electron density and efficient charge carrier separation are two important factors to affect photocatalytic activity, especially for the CO2 photoreduction reaction. However, the systematic studies on the structure-functional relationship regarding the above two factors based on precisely structure model are rarely reported. Herein, as a proof-of-concept, we developed a new strategy on the evaluation of local electron density by controlling the relative electron-deficient (ED) and electron-rich (ER) intensity of monomer at a molecular level based on three rational-designed vinylene-linked sp2 carbon-covalent organic frameworks (COFs). As expected, the as-prepared vinylene-linked sp2 carbon-conjugated metal-covalent organic framework (MCOFs) (VL-MCOF-1) with molecular junction exhibited excellent activities for CO2-to-HCOOH conversion (283.41 μmol g-1 h-1) and high selectivity of 97.1%, much higher than the VL-MCOF-2 and g-C34N6-COF, which is due to the synergistic effect of the multi-electronic metal clusters (Cu3(PyCA)3) (PyCA = pyrazolate-4-carboxaldehyde) as strong ER roles and cyanopyridine units as ED roles and active sites, as well as the boosted photo-induced charge separation efficiency of vinyl connection and increased light utilization ability. These results not only provide a strategy for regulating the electron-density distribution of photocatalysts at the molecular level but also offers profound insights for metal clusters-based COFs to effective CO2 conversion.

Relative Local Electron Density Tuning in Metal‐Covalent Organic Frameworks for Boosting CO2Photoreduction

AbstractThe high local electron density and efficient charge carrier separation are two important factors to affect photocatalytic activity, especially for the CO2photoreduction reaction. However, the systematic studies on the structure‐functional relationship regarding the above two factors based on precisely structure model are rarely reported. Herein, as a proof‐of‐concept, we developed a new strategy on the evaluation of local electron density by controlling the relative electron‐deficient (ED) and electron‐rich (ER) intensity of monomer at a molecular level based on three rational‐designed vinylene‐linked sp2carbon‐covalent organic frameworks (COFs). As expected, the as‐prepared vinylene‐linked sp2carbon‐conjugated metal‐covalent organic framework (MCOFs) (VL‐MCOF‐1) with molecular junction exhibited excellent activities for CO2‐to‐HCOOH conversion (283.41 μmol g−1 h−1) and high selectivity of 97.1 %, much higher than the VL‐MCOF‐2 and g‐C34N6‐COF, which is due to the synergistic effect of the multi‐electronic metal clusters (Cu3(PyCA)3) (PyCA=pyrazolate‐4‐carboxaldehyde) as strong ER roles and cyanopyridine units as ED roles and active sites, as well as the boosted photo‐induced charge separation efficiency of vinyl connection and increased light utilization ability. These results not only provide a strategy for regulating the electron‐density distribution of photocatalysts at the molecular level but also offers profound insights for metal clusters‐based COFs to effective CO2conversion.

New electron-deficient 2,1,3-benzothiadiazole-cored donor–acceptor compounds: Synthesis, photophysical and electroluminescent properties

Three new 2,1,3-benzothiadiazole-containing luminophores with different electron deficiency of acceptor block have been prepared via the Pd-catalyzed Suzuki cross-coupling and nucleophilic fluorine substitution with cyano group. Photophysical and electroluminescent properties of the compounds obtained were investigated to estimate their potential for optoelectronic applications. The introduction of two fluorine atoms in the benzothiadiazole moiety leads to the hypsochromic shift of the electroluminescent emission, whereas the incorporation of two cyano groups shifts it into the long-wave region. All synthesized compounds were used as emissive layers in OLED devises.

Prediction of nodal-line fermion and phonon-mediated superconductivity in bilayer α-borophene

The electron deficiency of boron allows the formation of a variety of monolayer or few-layer two-dimensional structures (borophenes) with interesting physical properties. Recent experiments have also confirmed that interlayer covalent bonding makes the bilayer structure more stable than the monolayer. In this work based on α-borophene, we propose three free-stranding bilayer structures with dynamic stability. In these three metallic structures, the electronic band crossings around Fermi level form nodal lines. All these structures also exhibit strong electron-phonon couplings. The Bardeen–Cooper–Schrieffer superconducting critical temperature T c of the type-II structure went as high as 28.2 K, which was further improved to 32.0 K by the enhancement effect of Li adatom at the Debye frequency. However, no increase in critical temperature was observed in other Li-doping cases. Specifically, Li intercalation inside the bilayer causes a significant abrupt decrease in the critical temperature of type-I structure. Our results indicated that the bilayer borophene would be an ideal platform for the coexistence of topological electronic states and superconducting states.

Phosphorus-doped nanoflower-like porous carbon with well-dispersed RuP sites embedded for enhancing hydrogenation of 4-nitrophenol

Heteroatom doping has emerged as a pivotal application in the synthesis of catalytic materials within the realm of catalysis. Herein, we present an innovative synthetic strategy for fabricating phosphorus-doped nanoflower-like porous carbon embedded with uniformly dispersed RuP sites (Ru/P-NFPC) originating from ruthenium-organic frameworks. This unique material was employed for the selective hydrogenation of 4-nitrophenol (4-NP) to 4-aminophenol (4-AP). The observed result reveals that Ru/P-NFPC exhibits outstanding catalytic activity, achieving a remarkable yield of 99.9 % for 4-AP within 180 s at ambient temperature. Comprehensive characterization techniques and experimental outcomes demonstrated that the incorporation of phosphorus atoms altered the electronic structure of the carbon nano-scaffold, facilitating the anchoring of RuP alloys and mitigating aggregation. Density Functional Theory (DFT) calculations validated the partial charge reorganization and electronic coupling effect in the unique Ru/P-NFPC catalysts. These analyses disclosed that phosphorus doping instigated electron transfer at the active catalyst interface, with P species acquiring additional electrons due to Ru's electron deficiency, thereby optimizing the catalytic reaction.

Effect of Honey Administration on The Histopathology of The Duodenum of Wistar Rats as a Inhibition of The Toxic Effects of Borax (Sodium tetraborate)

Background: Borax can result in oxidative stress and cause the onset of gastrointestinal ulcerations that will dampen the duodenal villi to become shorter and can even disappear. Cell damage due to oxidative stress can be prevented by administering antioxidants. Antioxidants will inhibit the onset of chain reactions in the formation of free radicals by complementing the existing electron deficiency. Honey is one of the natural ingredients that is rich in antioxidants and part of thibbun Nabawi as one of the inhibitors of the toxic effects of borax. Objective : The purpose of this study is to to analyze the effect of honey administration on the histopathological description of submucosa and epithelial mucosa of duodenal wistar rats as an inhibitor of the toxic effects of borax (Sodium tetraborate). Methods: This study used the true experimental method with Post Test Only Control Group Design using 25 mice which will be divided into five groups, namely K (negative control), P (positive control), M1 (borax and honey dose 1), M2 (borax and honey dose 2), M3 (borax and honey dose 3). This study was conducted for 22 days then. Took the duodenal organ on all samples and then made histological preparations with HE staining. Observations were made with an Olympus microscope to see submucosal edema and damage to the epithelium of the duodenal mucosa. Results: The results of the study found that borax 26 mg / head / day had an influence on the histopathological picture of duodenal borax. In addition, the administration of honey dose 75 mg / Kg BB provides a toxic inhibitory effect of borax in the duodenum best among other treatment groups. However, statistically there was no effect of honey administration on the histopathological picture of the duodenum of wistar rats as an inhibitor of the toxic effect of borax (Sodium Tetraborate) with p˃0.05. Conclusion: Statistically it can be concluded that there is no effect of the administration of honey on the histopathology picture of the duodenum of wistar rats as an inhibitor of the toxic effects of borax (Sodium tetraborate).

Low-Voltage Hydrogen Production via Hydrogen Peroxide Oxidation Facilitated by Oxo Ligand Axially Coordinated to Cobalt in Phthalocyanine Moiety.

A cobalt phthalocyanine having an electron-poor CoN4 (+δ) in its phthalocyanine moietywas presented as an electrocatalyst for hydrogen peroxide oxidation reaction (HPOR). Wesuggested that hydrogen peroxide as an electrolysis medium for hydrogen production and therefore as a hydrogen carrier, demonstrating that the electrocatalyst guaranteed high hydrogen production rate by hydrogen peroxide splitting. The electron deficiency of cobalt allows CoN4 to have the highly HPOR-active monovalent oxidation state and facilitates HPOR at small overpotentials range around the onset potential. The strong interaction between the electron-deficient cobalt and oxygen of peroxide adsorbates in Co─OOH- encourages an axially coordinated cobalt oxo complex (O═CoN4 ) to form, the O═CoN4 facilitating the HPOR efficiently at high overpotentials. Low-voltage oxygen evolution reaction guaranteeing low-voltage hydrogen production is successfully demonstrated in the presence of the metal-oxo complex having electron-deficient CoN4 . Hydrogen production by 391mA cm-2 at 1V and 870mA cm-2 at 1.5V is obtained. Also, the techno-economic benefit of hydrogen peroxide as a hydrogen carrier is evaluated by comparing hydrogen peroxide with other hydrogen carriers such as ammonia and liquid organic hydrogen carriers.

Cyano-Functionalized Fused Bithiophene Imide Dimer-Based n-Type polymers for High-Performance Organic Thermoelectrics.

Doped n-type polymers usually exhibit low electrical conductivities and thermoelectric power factors (PFs), restricting the development of high-performance p-n junction-based organic thermoelectrics (OTEs). Herein we report the design and synthesis of a new cyano-functionalized fused bithiophene imide dimer (f-BTI2), CNI2, which synergistically combines the advantages of both cyano and imide functionalities, thus leading to substantially higher electron deficiency than the parent f-BTI2. On the basis of this novel building block, a series of n-type donor-acceptor and acceptor-acceptor polymers were successfully synthesized, all of which show good solubility, deep-lying frontier molecular orbital levels, and favorable polymer chain orientation. Among them, the acceptor-acceptor polymer PCNI2-BTI delivers an excellent electrcial conductivity up to 150.2 S cm-1 and a highest PF of 110.3 μW m-1 K-2 in n-type OTEs, attributed to the optimized polymer electronic properties and film morphology with improved molecular packing and higher crystallinity assisted by solution-shearing technology. The PF value is the record of n-type polymers for OTEs to date. This work demonstrates a facile approach to designing high-performance n-type polymers and fabricating high-quality films for OTE applications. This article is protected by copyright. All rights reserved.

Molecular Electrostatic Potential Topology Analysis of Noncovalent Interactions.

ConspectusThe topology of molecular electrostatic potential (MESP), V(r), derived from a reliable quantum chemical method has been used as a powerful tool for the study of intermolecular noncovalent interactions. The MESP topology mapping is achieved by computing both ∇V(r) data and the elements of the Hessian matrix at ∇V(r) = 0, the critical point. MESP minimum (Vmin) as well as MESP at a reaction center, specific to an atom (Vn), have been employed as electronic parameters to interpret the variations in the reactivity (activation/deactivation) of chemical systems with respect to the influence of substituents, ligands, π-conjugation, aromaticity, trans influence, hybridization effects, steric effects, cooperativity, noncovalent interactions, etc. In this Account, several studies involving MESP topology analysis, which yielded interpretations of various noncovalent interactions and also provided new insights in the area of chemical bonding, are highlighted. The existence of lone pairs in molecules is distinctly reflected by the topology features of the MESP minima (Vmin). The Vmin is able to probe lone pairs in molecules, and it has been used as a reliable electronic parameter to assess their σ-donating power. Furthermore, MESP topology analysis can be used to forecast the structure and energetics of lone pair π-complexes. The MESP approach to rationalize lone pair interactions in molecular systems has led to the design of cyclic imines for CO2 capture. The MESP topology analysis of intermolecular complexes revealed a hitherto unknown phenomenon in chemical bonding theory─formation of a covalent bond due to the influence of a noncovalent bond. The MESP-guided approach to intermolecular interactions provided a successful design strategy for the development of CO2 capture systems. The MESP parameters Vmin and MESP at the nucleus, Vn, derived for the molecular systems have been used as powerful measures for the extent of electron donor-acceptor (eDA) interactions in noncovalent complexes. Noncovalent bond formation leads to more negative MESP at the acceptor nucleus (VnA) and less negative MESP at the donor nucleus (VnD). The strong linear relationship observed between ΔΔVn = ΔVnD - ΔVnA and bond energy suggested that MESP data provide a clear evidence of bond formation. Furthermore, MESP topology studies established a cooperativity rule for understanding the donor-acceptor interactive behavior of a dimer D...A with a third molecule. According to this, the electron reorganization in the dimer due to the eDA interaction enhances electron richness at "A", the acceptor, and enhances electron deficiency at "D", the donor. Resultantly, D in D...A is more accepting toward trimer formation, while A in D...A is more donating. MESP topology offers promising design strategies to tune the electron-donating strength in various noncovalent interactions in hydrogen-, dihydrogen-, halogen-, tetrel-, pnicogen-, chalcogen-, and aerogen-bonded complexes and thereby to predict the interactive behavior of molecules. To sum up, MESP topology analysis has become one of the most effective modern techniques for understanding, interpreting, and predicting the intermolecular interactive behavior of molecules.

Alkaline lignin-derived N-doped biochars as peroxymonosulfate activators for acetaminophen degradation: Performance and catalytic bridging mediated Electron-Transfer mechanism

Carbon-catalyzed persulfate activation processes are promising techniques for oxidizing aqueous organic pollutants, while high-performance and low-cost carbocatalysts are urgently needed. To address this issue, nitrogen-doped biochar catalyst from alkaline lignin was developed to activate peroxymonosulfate (PMS) for acetaminophen (APAP) degradation. The optimized N-doped biochar achieved a complete removal of 50 ppm APAP within 15 min under the conditions of 0.1 g/L catalyst and 0.5 mM oxidant across a wide pH range of 4–10. Notably, the optimized N-doped biochar exhibits remarkable stability, retaining 75% APAP removal after four cycles. Moreover, a comprehensive investigation, including quenching tests, electron paramagnetic resonance measurements, and electrochemical analyses, elucidated the electron-transfer mechanism involved in the nonradical N-doped biochar/PMS system. Surprisingly, the results indicated that the primary species responsible for APAP oxidation was an activated state of N-doped biochar with electron deficiency generated from the interactions between the catalyst and PMS. This work not only provides cost-effective and high-performance biochar catalyst for selectively removing APAP from actual water body, but also sheds new light on the electron-transfer mechanism involved in nonradical carbon/PMS systems.

Realizing high-temperature superconductivity in borophene with Dirac states assembled by kagome and honeycomb boron layers

Boron's unique electron deficiency allows for the formation of various borophene polymorphs that have the potential for superconductivity. Herein, we have introduced a new route to realize high superconductivity in borophene through kagome and honeycomb boron layers assembly. We have designed a tri-layer borophene, named hP8-B, consisting of two AA-stacked kagome layers with a honeycomb layer serving as the interlayer. hP8-B possesses high superconductivity with an estimated Tc of 35.6 K, holding the highest value in any elemental 2D materials. The high Tc is mainly contributed by the strong coupling of σ-bonding electrons of the kagome layers and in-plane vibrational modes, which differs from that in other superconductive borophene polymorphs. Electronic band structure calculations showcase the existence of a Dirac cone near the Fermi level, indicating that hP8-B may be a potential topological superconductor. The superconductivity of hP8-B can be enhanced to 46.4 K under a biaxial tensile strain of 3% and doping density of 0.0375 holes per atom, due to the softening of the in-plane vibrational modes.

Size-dependent electronic interface effect of Pd nanocube-based heterojunctions on universally boosting phenol hydrogenation reactions

As mainstream catalysts for phenol hydrogenation with good reusability and high selectivity under mild conditions, Pt- and Pd-based heterogeneous catalysts suffer from unsatisfied catalyst costs. The structures of metals (i.e., particle sizes, alloy structures, and porosity) and the acidity of the support were optimized to boost the intrinsic activity of noble metal nanocatalysts with a maximum promoting factor of 3.3. There is considerable scope for exploring more powerful methods for boosting the mass activity of metal catalysts. Herein, we demonstrate a novel size-dependent electronic interface effect in the heterojunctions of Pd nanocubes and sulfur-doped carbon (SC) supports to enhance phenol hydrogenation activity. Theoretical calculations and experimental results indicate that the size-dependent electron deficiency of Pd nanocubes on the designed SCs as electron acceptors results in an unexpected and universal promotion of phenol hydrogenation activity, outperforming free-standing Pd nanocubes by a factor of 9–19.

Enhanced electrocatalytic performance of 2D/2D MXene/reduced graphene oxide(RGO) heterostructures for paracetamol (APAP) degradation: The critical contributions of charge transfer and Ti-OH edges for active species generation

To improve electrocatalytic performance, 2D/2D MXene/ reduced graphene oxide (RGO) heterostructures was prepared by constructing of Ti-O-C connection between two layers. A Ti-O-C connection not only facilitates charge transfer from MXene to RGO but also creates active sites for active species generation. Through in-depth mechanism investigation, all 1O2, O2•− and active chlorine were identified as active species for APAP degradation by triggering raw MXene, RGO, and MXene/RGO. Explosive generation of O2•− and active chlorine was responsible for the excellent catalytic activity of MXene/RGO. Experimental and density functional theory calculation results demonstrated the critical contributions of charge transfer and Ti–OH edges for active chlorine generation. At Ti-OH edges, Cl− can seize electron from H in H2O (absorbed on MXene/RGO surface), and the Ti-OH edges withdraw electrons from O in H2O. Then, electrons captured by the Ti-OH edges were transferred from MXene to RGO, resulting in the electrostatic imbalance in the Ti-OH/H2O/Cl− region, electron deficiency in H2O, and ultimately active chlorine generation. The electron-rich properties of RGO simultaneously enhanced the production of O2•− radicals. This study provided deepen mechanism discussion for electrocatalytic performance improvement over stable 2D/2D MXene/RGO heterostructures.

Proton transfer triggered in-situ construction of C=N active site to activate PMS for efficient autocatalytic degradation of low-carbon fatty amine

Removal of low-carbon fatty amines (LCFAs) in wastewater treatment poses a significant technical challenge due to their small molecular size, high polarity, high bond dissociation energy, electron deficiency, and poor biodegradability. Moreover, their low Brønsted acidity deteriorates this issue. To address this problem, we have developed a novel base-induced autocatalytic technique for the highly efficient removal of a model pollutant, dimethylamine (DMA), in a homogeneous peroxymonosulfate (PMS) system. A high reaction rate constant of 0.32 min−1 and almost complete removal of DMA within 12 min are achieved. Multi-scaled characterizations and theoretical calculations reveal that the in situ constructed C=N bond as the crucial active site activates PMS to produce abundant 1O2. Subsequently, 1O2 oxidizes DMA through multiple H-abstractions, accompanied by the generation of another C=N structure, thus achieving the autocatalytic cycle of pollutant. During this process, base-induced proton transfers of pollutant and oxidant are essential prerequisites for C=N fabrication. A relevant mechanism of autocatalytic degradation is unraveled and further supported by DFT calculations at the molecular level. Various assessments indicate that this self-catalytic technique exhibits a reduced toxicity and volatility process, and a low treatment cost (0.47 $/m3). This technology has strong environmental tolerance, especially for the high concentrations of chlorine ion (1775 ppm) and humic acid (50 ppm). Moreover, it not only exhibits excellent degradation performance for different amine organics but also for the coexisting common pollutants including ofloxacin, phenol, and sulforaphane. These results fully demonstrate the superiority of the proposed strategy for practical application in wastewater treatment. Overall, this autocatalysis technology based on the in-situ construction of metal-free active site by regulating proton transfer will provide a brand-new strategy for environmental remediation.

Recent Advances in Organic Photovoltaic Materials Based on Thiazole-Containing Heterocycles.

Organic solar cells (OSCs) have achieved great progress, driven by the rapid development of wide bandgap electron donors and narrow bandgap non-fullerene acceptors (NFAs). Among a large number of electron-accepting (A) building blocks, thiazole (Tz) and its derived fused heterocycles have been widely used to construct photovoltaic materials, especially conjugated polymers. Benefiting from the electron deficiency, rigidity, high planarity, and enhanced intra/intermolecular interactions of Tz-containing heterocycles, some related photovoltaic materials exhibit proper energy levels, optimized molecular aggregation, and active layer morphology, leading to excellent photovoltaic performance. This review focuses on the progress of Tz-based photovoltaic materials in the field of OSCs. First, the Tz-based donor and acceptor photovoltaic materials are reviewed. Then, the materials based on promising Tz-containing heterocycles, mainly including thiazolo[5,4-d]thiazole (TzTz), benzo[1,2-d:4,5-d']bis(thiazole) (BBTz), and benzo[d]thiazole (BTz) are summarized and discussed. In addition, the new emerging Tz-fused structures and their application in OSCs are introduced. Finally, perspectives and outlooks for the further development of Tz-containing heterocycle-based photovoltaic materials are proposed.

Benzo[1,2-d:4,5-d']bis([1,2,3]thiadiazole) and Its Bromo Derivatives: Molecular Structure and Reactivity.

Benzo[1,2-d:4,5-d']bis([1,2,3]thiadiazole) (isoBBT) is a new electron-withdrawing building block that can be used to obtain potentially interesting compounds for the synthesis of OLEDs and organic solar cells components. The electronic structure and delocalization in benzo[1,2-d:4,5-d']bis([1,2,3]thiadiazole), 4-bromobenzo[1,2-d:4,5-d']bis([1,2,3]thiadiazole), and 4,8-dibromobenzo[1,2-d:4,5-d']bis([1,2,3]thiadiazole) were studied using X-ray diffraction analysis and ab initio calculations by EDDB and GIMIC methods and were compared to the corresponding properties of benzo[1,2-c:4,5-c']bis[1,2,5]thiadiazole (BBT). Calculations at a high level of theory showed that the electron affinity, which determines electron deficiency, of isoBBT was significantly smaller than that of BBT (1.09 vs. 1.90 eV). Incorporation of bromine atoms improves the electrical deficiency of bromobenzo-bis-thiadiazoles nearly without affecting aromaticity, which increases the reactivity of these compounds in aromatic nucleophilic substitution reactions and, on the other hand, does not reduce the ability to undergo cross-coupling reactions. 4-Bromobenzo[1,2-d:4,5-d']bis([1,2,3]thiadiazole) is an attractive object for the synthesis of monosubstituted isoBBT compounds. The goal to find conditions for the selective substitution of hydrogen or bromine atoms at position 4 in order to obtain compounds containing a (het)aryl group in this position and to use the remaining unsubstituted hydrogen or bromine atoms to obtain unsymmetrically substituted isoBBT derivatives, potentially interesting compounds for organic photovoltaic components, was not set before. Nucleophilic aromatic and cross-coupling reactions, along with palladium-catalyzed C-H direct arylation reactions for 4-bromobenzo[1,2-d:4,5-d']bis([1,2,3]thiadiazole), were studied and selective conditions for the synthesis of monoarylated derivatives were found. The observed features of the structure and reactivity of isoBBT derivatives may be useful for building organic semiconductor-based devices.