Benzothiadiazole Group Research Articles

Highly stable Tb(III) metal-organic framework derived from a new benzothiadiazole functionalized ligand for fluorescence recognition of ascorbic acid

Because ascorbic acid (AA) is one of the basic elements to maintain the normal physiological functions of human body, it is urgent to develop a material that can achieve efficient, rapid and in-situ detection for AA. A new fluorescence organic compound 4′,4′′′-(benzo[c][1,2,5]thiadiazole-4,7-diyl)bis([1,1′-biphenyl]-4-carboxylic acid) (H2BTBC) based on benzothiadiazole group has been synthesized, which can detect Fe3+ ions by fluorescence turn-off effect with a detection limit of 0.015 μM, as well as recognize linear amines by fluorescence turn-on effect. Moreover, a highly stable Tb(III) metal–organic framework has been solvothermally prepared with H2BTBC, namely {[(CH3)2NH2]2[Tb2(BTBC)4]∙solvents}n (JXUST-39), which can selectively detect AA among biological fluids by fluorescence enhancement effect with a detection limit of 0.077 μM. In addition, the mechanism for JXUST-39 detecting AA is possibly the cooperative effect of absorbance-caused enhancement and charge transfer between JXUST-39 and AA. Moreover, LED lamp beads, fluorescent films and fluorescent detection test paper based on JXUST-39 were prepared to achieve portable detection via fluorescence enhancement effect.

Thiadiazole-Functionalized Th/Zr-UiO-66 for Efficient C2H2/CO2 Separation.

Adsorptive separation technology provides an effective approach for separating gases with similar physicochemical properties, such as the purification of acetylene (C2H2) from carbon dioxide (CO2). The high designability and tunability of metal-organic framework (MOF) adsorbents make them ideal design platforms for this challenging separation. Herein, we employ an isoreticular functionalization strategy to fine-tune the pore environment of Zr- and Th-based UiO-66 by the immobilization of the benzothiadiazole group via bottom-up synthesis. The functionalized UPC-120 exhibits an enhanced C2H2/CO2 separation performance, which is confirmed by adsorption isotherms, dynamic breakthrough curves, and theoretical simulations. The synergy of ligand functionalization and metal ion fine-tuning guided by isoreticular chemistry provides a new perspective for the design and development of adsorbents for challenging gas separation processes.

Dendritic sp Carbon-Conjugated Benzothiadiazole-Based Polymers with Synergistic Multi-Active Groups for High-Performance Lithium Organic Batteries.

Green organic materials composed of C, H, O, and N elements are receiving more and more attention worldwide. However, the high solubility, poor electrical conductivity, and long activation time limit the development of organic materials in practice. Herein, two stable covalent organic materials with alkynyl linkage between benzene rings and benzothiadiazole groups with different amounts of fluorine atoms modification (defined as BOP-0F and BOP-2F), are designed for lithium-ion batteries. Both BOP-0F and BOP-2F can achieve superior reversible capacities of ≈719.8 and 713.5 mAh g-1 over 100 cycles on account of the redox activity of alkynyl (two-electron involved) and benzothiadiazole units (five-electron involved) in these organic materials. While BOP-2F electrodes exhibit much more stable cycling performance than BOP-0F electrodes, especially without pronounced capacity ascending during initial cycling. It can be assigned to the synergy effect of alkynyl linkage and fluorine atom modification in BOP-2F. The lithium storage and activation mechanism of alkynyl, benzothiadiazole, and fluorine groups have also been deeply probed by a series of material characterizations and theoretical simulations. This work could be noteworthy in providing novel tactics for the molecular design and investigation of high-efficiency organic electrodes for energy storage.

Dendritic sp Carbon‐Conjugated Benzothiadiazole‐Based Polymers with Synergistic Multi‐Active Groups for High‐Performance Lithium Organic Batteries

AbstractGreen organic materials composed of C, H, O, and N elements are receiving more and more attention worldwide. However, the high solubility, poor electrical conductivity, and long activation time limit the development of organic materials in practice. Herein, two stable covalent organic materials with alkynyl linkage between benzene rings and benzothiadiazole groups with different amounts of fluorine atoms modification (defined as BOP‐0F and BOP‐2F), are designed for lithium‐ion batteries. Both BOP‐0F and BOP‐2F can achieve superior reversible capacities of ≈719.8 and 713.5 mAh g−1 over 100 cycles on account of the redox activity of alkynyl (two‐electron involved) and benzothiadiazole units (five‐electron involved) in these organic materials. While BOP‐2F electrodes exhibit much more stable cycling performance than BOP‐0F electrodes, especially without pronounced capacity ascending during initial cycling. It can be assigned to the synergy effect of alkynyl linkage and fluorine atom modification in BOP‐2F. The lithium storage and activation mechanism of alkynyl, benzothiadiazole, and fluorine groups have also been deeply probed by a series of material characterizations and theoretical simulations. This work could be noteworthy in providing novel tactics for the molecular design and investigation of high‐efficiency organic electrodes for energy storage.

Molecular Recognition Process in Resorcinarene-based Coordination Capsules.

Cu and Ag capsules can take up various organic molecules. Their molecular recognition possibly involves partial dissociation and slippage. We investigated molecular recognition processes in the Cu and Ag capsules by CD and 1 H NMR spectroscopy and employed 4,4'-diacetoxy biphenyl carrying two benzothiadiazole groups as a probe. CD and 1 H NMR measurements reveal that the host-guest complexation proceeds under second-order reactions and that these capsules undergo the partial dissociation to take up the probe in [D1 ]chloroform and [D8 ]THF. The slippage also contributes to host-guest complexation for a Cu capsule that carries p-methoxyphenyl groups on the 2,2'-bipyridiyl arms. DFT calculations suggest that π/π stacking interactions between the electron-rich p-methoxyphenyl group and the electron-poor 2,2'-bipyridyl arm elongate the capsule, allowing the guest to access the cavity without the partial dissociation.

Bioimaging and detecting endogenous and exogenous cyanide in foods, living cells and mice based on a turn-on mitochondria-targeted fluorescent probe

A novel fluorescent probe, with advanced features including “turn-on” fluorescence response, high sensitivity, good compatibility, and mitochondria-targeting function, has been synthesized based on structural design for detecting and visualizing cyanide in foods and biological systems. An electron-donating triphenylamine group (TPA) was employed as the fluorescent and an electron-accepting 4-methyl-N-methyl-pyridinium iodide (Py) moiety was used as a mitochondria-targeted localization unit, which formed intramolecular charge transfer (ICT) system. The “turn-on” fluorescence response of the probe (TPA-BTD-Py, TBP) toward cyanide is attributed two reasons, one is the insertion of an electron-deficient benzothiadiazole (BTD) group into the conjugated system between TPA and Py, and the other is the inhibition of ICT induced by the nucleophilic addition of CN–. Two active sites for reacting with CN− were involved in TBP molecule and high response sensitivity were observed in tetrahydrofuran solvent containing 3 % H2O. The response time could be reduced to 150 s, the linear range was 0.25–50 μM, and the limit of detection was 0.046 μM for CN− analysis. The TBP probe was successfully applied to the detection of cyanide in food samples prepared in aqueous solution, including the sprouting potato, bitter almond, cassava, and apple seeds. Furthermore, TBP exhibited low cytotoxicity, clear mitochondria-localizing capability in HeLa cells and excellent fluorescence imaging of exogenous and endogenous CN– in living PC12 cells. Moreover, exogenous CN– with intraperitoneal injection in nude mice could be well monitored visually by the “turn-on” fluorescence. Therefore, the strategy based on structural design provided good prospects for optimizing fluorescent probes.

A naphthol hydrazone Schiff base bearing benzothiadiazole unit for fluorescent detection of Fe3+ in PC3 cells

Naphthol hydrazone derivatives are recognized as efficient chelating agents for both qualitative and quantitative detection of metal ions. Here we design a naphthol hydrazine-based chemosensor with covalently linking a strong electron-withdrawing benzothiadiazole group to modulate the molecular electronic structure, nominated as NtHzBtd. The fluorescent probe performs excellent selectivity and sensitivity towards Fe3+ with 1:1 binding stoichiometry, while exhibiting a quick response at 55 s with a relatively low limit of detection of 0.036 µM. A series of spectroscopic measurements in tandem with theoretical calculations suggest that the probe undergoes both intramolecular charge transfer (ICT) and chelation enhanced quenching (CHEQ) processes. Successful color rendering of paper strips and bioimaging in PC3 cells demonstrate the promising applicability of NtHzBtd for portable Fe3+ detection in real samples and biosystems.

Synthetic Route to Conjugated Donor-Acceptor Polymer Brushes via Alternating Copolymerization of Bifunctional Monomers.

Alternating donor–acceptor conjugated polymers, widely investigated due to their applications in organic photovoltaics, are obtained mainly by cross-coupling reactions. Such a synthetic route exhibits limited efficiency and requires using, for example, toxic palladium catalysts. Furthermore, the coating process demands solubility of the macromolecules, provided by the introduction of alkyl side chains, which have an impact on the properties of the final material. Here, we present the synthetic route to ladder-like donor–acceptor polymer brushes using alternating copolymerization of modified styrene and maleic anhydride monomers, ensuring proper arrangement of the pendant donor and acceptor groups along the polymer chains grafted from a surface. As a proof of concept, macromolecules with pendant thiophene and benzothiadiazole groups were grafted by means of RAFT and metal-free ATRP polymerizations. Densely packed brushes with a thickness up to 200 nm were obtained in a single polymerization process, without the necessity of using metal-based catalysts or bulky substituents of the monomers. Oxidative polymerization using FeCl3 was then applied to form the conjugated chains in a double-stranded (ladder-like) architecture.

A Series of D–A–D Structured Disilane-Bridged Triads: Structure and Stimuli-Responsive Luminescence Studies

A series of σ-π extended octamethyltetrasilanes, which have phenothiazine, 9,9-dimethyl-9,10-dihydroacridine, or phenoxazine (1, 2, and 3) groups as donor moieties and thienopyrazine or benzothiadiazole (a and b) groups as acceptor fragments, has been prepared, and their optical properties have been studied as an extension of our work. All six compounds exhibited fluorescence in the solid state with maximum wavelengths centered in the range of 400 and 650 nm upon excitation by a UV lamp. Compound 2b showed apparent dual emission behavior in solution, which depends on solvent polarity, and a reversible photoluminescent change under mechanical and thermal stimuli in the solid state. Quantum chemical calculations suggest the contribution of a quasi-axial conformer of the 9,9-dimethyl-9,10-dihydroacridine moiety in 2b to the dual emission in solution and the mechanofluoroluminescence in the solid state, similarly to 1a. These studies provide new insight into the preparation of disilane-bridged triads capable of responding to multiple stimuli.

Dinuclear Ruthenium(II)‐Pyrrolide Complexes Linked by Different Organic Units as PDT Photosensitizers: Computational Study of the Linker Influence on the Photophysical Properties*

AbstractA new family of bis[pyrrolyl Ru(II)] triad scaffolds, consisting of two [Ru(bpy)2]2+ centers separated by a variety of organic linkers, has been recently reported as efficient compounds for in vitro photodynamic therapy (PDT). Among all the complexes, the one carrying the pyrenyl group in the organic linker, namely 4 h, has emerged as an extremely potent photosensitizer for in vitro PDT. Here, we present a computational study based on both DFT and TDA‐TDDFT methods, to investigate the photochemical properties of this promising complex. In order to evaluate the influence of the organic chromophore on the photochemical properties, our investigation was further extended to the complex 4 e, whose linker includes the benzothiadiazole group, which has yielded the longest‐wavelength absorption maxima overall (but with a reduced intensity compared to 4 h). Eventually, the role of the second [Ru(bpy)2]2+ moiety was evaluated by comparison with the mononuclear complex.

Introducing thiophene and benzothiadiazole groups in triphenylamine-based organic dyes with rigidly fused π-bridge to design high-efficiency solar cells: A theoretical investigation

The influence of different types of π-bridges in triphenylamine-based organic sensitizers on their photophysical and photovoltaic properties is investigated by using sophisticated first-principles calculations and reliable theoretical models. Two well-designed strategies, namely the cyclization between separate benzothiadiazole and bithiophene as well as the insertion of electron-rich/deficient groups between the rigidly fused π-bridge and anchor moieties are proposed. It is found that the calculated photophysical and photovoltaic parameters of the dye with an unfused π-bridge reproduce very well the available experimental data, ensuring the rationality of present theoretical methods and models. The designed dye featuring a rigidly fused π-bridge shows a remarkable decrease of power conversion efficiency (PCE), with respect to the dye with an unfused π-spacer (6.36% vs. 11.18%), which implies that simply cyclizing separate aromatic heterocyclic groups is unfavorable for improving the photoelectrical performance. However, the PCE can be increased to 14.20% when an electron-rich thiophene group is introduced between the fused π-bridge and the anchor units. More importantly, replacing the thiophene moiety with an electron-deficient benzothiadiazole group can further improve the photovoltaic performance, and consequently a PCE as high as 23.81% is achieved, which is a significant theoretical improvement for triphenylamine-based organic dyes. To sum up, this study theoretically elucidates the effect of unfused and fused π-bridges as well as the introduction of electron-rich/deficient groups in organic dyes on their photophysical and photoelectric properties and provides a useful guidance for further designing highly-efficient dye sensitizers by molecular engineering.

Development of a Fluorophore with Enhanced Unorthodox Chalcogen Bonding for Highly Sensitive Detection of Trimethyl Arsine Vapor

In this work, we report the design of novel fluorophores that bear three benzothiadiazole and benzoselenadiazole groups, respectively, for sensitive detection of trimethyl arsine vapor. In particular, the fluorophore with the benzoselenadiazole groups can form stronger chalcogen bonding with trimethyl arsine than the fluorophore with the benzothiadiazole groups, which in turn triggers much faster and more sensitive fluorescence responses. On the basis of this novel mechanism, fluorescence detection of trimethyl arsine vapor with rapid response (∼3 s), high sensitivity (the theoretical LOD is 0.44 ppb), and high selectivity is achieved on bundled nanofibers from the fluorophore with the benzoselenadiazole groups. Here, the new fluorescence sensor may find wide applications in health and environmental monitoring, arsenic distribution recognition in soil, and arsenic mines exploration.

Investigating the effect of diverse structural variation of conjugated polymer electrolytes as the interlayer on photovoltaic properties

The effect of the diverse structural variation of conjugated polymer electrolytes (CPEs) as an interlayer on the photovoltaic properties was investigated. We found that the CPE with a strong electronegative BT group in the backbone and OH salt group in the side chain offers the highest PCEs among CPEs. • Diverse structural variation of conjugated polymer electrolytes (CPEs). • Step-by-step improvement in efficiency of solar cells based on diverse CPEs as interlayer. • Optical simulations of solar cells using transfer matrix formalism. A series of conjugated polymer electrolytes (CPEs) based on dimethylamino propyl fluorene (FN), thiophene (T), benzothiadiazole (BT), and dithienyl benzothiadiazole (TBT) were synthesized by the Suzuki coupling reaction. Quaternarized polyelectrolytes were obtained from the post-polymerization treatment of the amino-terminal group. The incorporation of electron-rich (T), electron-deficient moiety (BT), and their combination (TBT) in the polymer backbone represent the different effects of polarity. Conjugated backbones are substantially strengthened by varying their electron affinity and conjugated planarity. We systematically investigated the effect of applying CPEs with different backbones and functionalities in the side chain. Different backbones produce different molecular dipoles, and the side chain functionality induces an interfacial dipole. Inverted polymer solar cells (iPSCs) based on a bulk heterojunction (BHJ) were fabricated with the ITO/ZnO/CPE/PTB7-Th:PC 71 BM/MoO 3 /Ag structure. The device performance enhancement was achieved by inserting CPEs as the interlayer. Modifying the polymer backbone leads to improved efficiency and modifying the side chain functionality improves the performance compared with that of the interlayered neutral polymer.

Study of Electronic and Steric Effects of Different Substituents in Donor–Acceptor Molecules on Multilevel Organic Memory Data Storage Performance

AbstractTo study the influence of different types of substituent moieties onto the molecular backbones of conjugated donor–acceptor (D–A) molecules on the thin‐film morphology and performance of their memory devices, three new molecules X‐TBT were synthesized, which consist of the same backbone of two triphenylamine (T) groups and benzothiadiazole (BT) group, but have different substituents (X) with different electronic effects, that is, cyano group (CN), tert‐butyl group (tBu), and methoxy group (OMe). Nonvolatile ternary write‐once‐read‐many‐times (WORM) data storage behavior is achieved for the CN‐TBT and tBu‐TBT based devices as compared to the binary memory characteristic of TBT (X = H). In contrast, OMe‐TBT based device still maintains binary WORM behavior due to its unfavorable molecular packing motif and weak intermolecular charge transfer effect, but exhibits the lowest operating voltage (1.4 V) as a result of the lowest energy barrier between electrode and active layer. Notably, the tBu‐TBT based device displays the highest ION2/ION1/IOFF ratio of 107:103:1. Altering the substituents in D–A molecules can adjust the molecular packing, thin film morphology, and electron trap depth of the active layer, which then significantly influence the memory performance.

Panchromatic Ternary Polymer Dots Involving Sub-Picosecond Energy and Charge Transfer for Efficient and Stable Photocatalytic Hydrogen Evolution.

Panchromatic ternary polymer dots (Pdots) consisting of two conjugated polymers (PFBT and PFODTBT) based on fluorene and benzothiadiazole groups, and one small molecular acceptor (ITIC) have been prepared and assessed for photocatalytic hydrogen production with the assistance of a Pt cocatalyst. Femtosecond transient absorption spectroscopic studies of the ternary Pdots have revealed both energy and charge transfer processes that occur on the time scale of sub-picosecond between the different components. They result in photogenerated electrons being located mainly at ITIC, which acts as both electron and energy acceptor. Results from cryo-transmission electron microscopy suggest that ITIC forms crystalline phases in the ternary Pdots, facilitating electron transfer from ITIC to the Pt cocatalyst and promoting the final photocatalytic reaction yield. Enhanced light absorption, efficient charge separation, and the ideal morphology of the ternary Pdots have rendered an external quantum efficiency up to 7% at 600 nm. Moreover, the system has shown a high stability over 120 h without obvious degradation of the photocatalysts.

Photocatalytic Microporous Polymer-Hydrogel Composites for the Removal of a Dye in Water

Photocatalytic hydrogel composites were prepared by using multifunctional microporous polymer particles as a reinforcing agent and also as a catalytic species. A benzothiadiazole-based conjugated microporous polymer (BTCMP) was synthesized by the Sonogashira-Hagihara reaction between 4,7-dibromo-2,1,3-benzothiadiazole and 1,3,5-triethynylbenzene as insoluble particles. BTCMP particles were functionalized with acryl groups via the thiol-yne click reaction with 2-aminoethanethiol and subsequent reaction with acryloyl chloride. Acrylated BTCMP particles were polymerized with acrylamide in a glass mold to yield a highly elastic hydrogel composite sheet. The tensile test results showed that covalently incorporated BTCMP particles significantly enhanced the mechanical properties of the hydrogels compared with a pure polyacrylamide hydrogel. A possible application of the hydrogel composites for the removal of a dye in water was studied using methylene blue as an exemplary dye. The maximum methylene blue adsorption capacity of the hydrogel composite containing 2 wt% of BTCMP particles was 2.6 times higher than that of the pure Polyacrylamide hydrogel. The hydrogel composite with photocatalytic activity originated from benzothiadiazole groups degraded adsorbed methylene blue molecules in an aqueous solution upon UV irradiation. The hydrogel composite could be reused for the methylene blue removal without any significant decrease in adsorption capacity and catalytic activity.

Benzothiadiazole Aryl-amine Based Materials as Efficient Hole Carriers in Perovskite Solar Cells.

Four hole transport materials (HTMs) based on a benzothiadiazole (BT) central core have been synthesized and successfully employed in triple-cation mixed-halide perovskite solar cells (PSCs), reaching 18.05% solar to energy conversion efficiency. The synthesis of these HTMs follows the push-and-pull approach to modulate the HOMO energy level by combining the BT group as an electron acceptor and diphenyl- and triphenyl-amines as electron donors. Here we show that despite adjusting the HOMO energy level to that of the perovskite is a believed requisite to achieve efficient interfacial hole transfer, additional factors must be taken into account to design novel and efficient HTMs, such as a high hole mobility, solubility in organic solvents, and thermal stability.

Effect of charge transport channel and interaction of IDT type dyes on photoelectric characteristics

In this work, four indacenodithiophene (IDT) dyes (L348-L351), with the same brominated triphenyl amine donor and phenylcarboxylic acid unit acceptor as well as different auxiliary acceptors, have been investigated. The photoelectric properties of molecules were analyzed by density functional theory (DFT), including electronic structure, absorption spectra, intramolecular charge transfer (ICT), dye activity and photoelectric parameters (JSC and VOC). ICT is mainly evaluated by parameters such as charge density difference (CDD), DCT, Δr, Sr, Δq and coulomb attraction (EC). The photoelectric parameters are mainly evaluated by factors, such as excitation lifetime (t), electron injection lifetime (τ), adsorption energy (Eads), vertical dipole moment (μnormal) and the internal reorganization rate calculated by the Marcus theory. The calculation results show that molecule L350 (introducing benzothiadiazole group) has good charge separation and excellent electron transfer ability. It is hoped that the theoretical simulation can be used to improve the efficiency of screening and optimizing dyes, which provides a reference for improving the performance of photovoltaic materials.

Efficiency enhancement of pyridinium ylide dye-sensitized solar cells by introduction of benzothiadiazolyl chromophore: A computational study

Organic pyridinium ylide sensitizers NO108-NO111 with different anchoring groups show attractive applications in dye-sensitized solar cells. To elucidate the intrinsic sensitization mechanism of this series of dyes, theoretical calculations of electrochemical and spectroscopic properties for free and adsorbed ylides have been performed. Moreover, to prescreen and optimize suitable candidates for pyridinium ylide cells, the benzothiadiazole (BTD) group is introduced in the best-performing ylide NO111, and the afforded dye is coded as NO111-1. Comparing pyiridine-N-oxide in NO108, diethylmalonate in NO111 shows superior properties in terms of interfacial charge transfer, anti-aggregation, and long-term stability. It also demonstrates that the novel designed NO111-1-sensitized film possesses higher average theoretical maximum limit of short-circuit photocurrent density (JSCmax≈ 23 mA/cm2), and slower parasitic recombination than NO111 one. This result is expected to further reveal the effects of anchoring groups on properties of dyes, and is helpful for the design of more efficient pyridinium ylide dyes.

New organic materiel based on benzothiadiazole for Photovoltaic application Solar Cells

Abstract In this work, we have studied conjugated polymers based on benzothiadiazole. the quantum chemical calculations on the structure and electronic and optics properties using the density functional theory (DFT), for the ground- and excited-state properties, respectively, using CAM-B3LYP and the 6-31G(d, p) basis set. These results will be devoted to the influence of the substitution benzothiadiazole on the electronic and optoelectronic properties of the polymer. The highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) levels of these compounds were calculated and compared to LUMO of fullerenes,C60 [6,6]-phenyl- C61-butyric-acid methyl ester to estimate the effectiveness of these molecules as electron donors in bulk heterojunction (BHJ) small molecules-fullerene solar cells. The absorption energies have been obtained from TD-DFT calculations performed on the excited-state optimized S geometries. Finally, the theoretical results suggest that both the introduction of benzothiadiazole groups contribute significantly to the electronic and optoelectronic properties of the alternating donor–acceptor–donor conjugated systems studied.