Benzothiadiazole Derivatives Research Articles

Electrochromic conjugated polymers: The relationship of gradient band gap and electrochromic performance

In the pursuit of high-performance electrochromic materials, in this paper, six donor-acceptor type with different gradient band gaps electrochromic conjugated polymers, named PBTz-T, PBTz-TT, PBTz-DT, PTBTO8-T, PTBTO8-TT, and PTBTO8-DT, were synthesized via direct (hetero) arylation polymerization, employing two benzothiadiazole derivatives with varying electron-accepting capabilities and three thiophene derivatives with different electron-donating capacities. The structures, optical, electrochemical, and electrochromic properties of the six polymers were investigated. As the number of fused thiophene increases, enhancing the electron-donating ability, a growth trend of electrochemical stability is observed for all polymers. Meanwhile, enhance electron-accepting capabilities of acceptors (from benzotriazole to benzothiadiazole) significantly lower the electronic band gap and improve electrochemical stability. PBTz-DT boasts a bleaching time of 0.3 s, outperforming most reported electrochromic polymers. PBTz-T, at 530 nm, exhibits exceptionally high coloration efficiency, reaching 916 cm2 C⁻1, and demonstrates higher electron utilization and lower energy consumption, making it an excellent candidate for high-performance electrochromic devices. This work compared studies the relationship of gradient band gaps of electrochromic conjugated polymers and their electrochemical and electrochromic performance, offers new insights into enhancing the electrochemical stability and synthesizing high coloration efficiency electrochromic materials.

Buried interface management for FAPbI3-based perovskite solar cells via multifunctional benzothiadiazole derivatives

Attaining high efficiency in perovskite solar cells (PSCs) often necessitates effective interfacial passivation, which poses challenges, especially concerning the buried interface due to the dissolution of passivation agents during perovskite deposition. In this work, we report a multifunctional modification strategy by introducing the variations of benzothiadiazole (BTD) derivatives to function as interface-modified layers in PSCs. This buried interface modification mitigates oxygen vacancies on the SnO2 surface and fine-tunes the energy level of the electron transport layer, resulting in an improved alignment with the FAPbI3 layer. Furthermore, the introduced BTD derivatives led to the improved crystallinity of FAPbI3 films as well as suppressed the non-radiative recombination losses through passivating the interfacial defects. Consequently, a device with modified SnO2 exhibited an enhanced power conversion efficiency (PCE) of 25.04% along with an improved long-term device stability.

The Past, Present, and Future of Plant Activators Targeting the Salicylic Acid Signaling Pathway.

Plant activators have emerged as promising alternatives to conventional crop protection chemicals for managing crop diseases due to their unique mode of action. By priming the plant's innate immune system, these compounds can induce disease resistance against a broad spectrum of pathogens without directly inhibiting their proliferation. Key advantages of plant activators include prolonged defense activity, lower effective dosages, and negligible risk of pathogen resistance development. Among the various defensive pathways targeted, the salicylic acid (SA) signaling cascade has been extensively explored, leading to the successful development of commercial activators of systemic acquired resistance, such as benzothiadiazole, for widespread application in crop protection. While the action sites of many SA-targeting activators have been preliminarily mapped to different steps along the pathway, a comprehensive understanding of their precise mechanisms remains elusive. This review provides a historical perspective on plant activator development and outlines diverse screening strategies employed, from whole-plant bioassays to molecular and transgenic approaches. We elaborate on the various components, biological significance, and regulatory circuits governing the SA pathway while critically examining the structural features, bioactivities, and proposed modes of action of classical activators such as benzothiadiazole derivatives, salicylic acid analogs, and other small molecules. Insights from field trials assessing the practical applicability of such activators are also discussed. Furthermore, we highlight the current status, challenges, and future prospects in the realm of SA-targeting activator development globally, with a focus on recent endeavors in China. Collectively, this comprehensive review aims to describe existing knowledge and provide a roadmap for future research toward developing more potent plant activators that enhance crop health.

New Molecularly Flexible Self-Assembling Benzothiadiazole Derivatives: Mesomorphism And DFT Investigations

In the present study, we have synthesized symmetric/unsymmetrical BTD embedded self-assembling molecules and investigated for their mesomorphic properties. Two symmetrical series (BTDK-(2-18) and BTDC-(4-18)) comprises benzothiadiazole moiety as a central core unit which is connected to two different systematically varied end-groups, alkoxy ester and alkoxy coumaryl unit connected through ether and imine linkages. On the other hand, the asymmetric molecules have an alkoxy chalconyl unit at one end and a formyl group at the other. It was observed that, the mesomorphism is completely depends on the molecular flexibility. New molecules revealed mesomorphic behaviour with N (nematic), SmA (smectic-A) and SmC (smectic-C) mesophase with high thermal stability and greater range. Changes in mesogenic units (alkoxy ester & alkoxy coumaryl unit) and the impact of altering the alkoxy chain at both ends have been investigated. Interesting evaluation has been carried out on the molecular flexibility which resulted in different mesomorphic behaviour of molecules under study. Furthermore, the experimentally established values of the mesophase thermal stability (Tc) and mesophase temperature ranges (ΔTSmA, ΔTSmC, and ΔTN), as well as the type of the mesophase, were related to the calculated quantum chemical parameters (Frontier molecular orbitals (FMOs), Aspect Ratio, Polarizability, dipole moment, molecular and electrostatic potential (MEP)) that were obtained by using the DFT method of the investigated compounds.

The Biostimulation Activity of Two Novel Benzothiadiazole Derivatives in the Tomato Cultivation

Biostimulants are gaining more and more attention in modern agriculture. As follows from the definition, their role is aimed at influencing the plant’s metabolism, which results in increasing the quantitative and qualitative parameters describing the yield. Significant attention should be paid to biostimulants increasing the content of health-promoting substances contained in plants. Treatments with biostimulants should be properly incorporated into existing plant protection schemes, which, of course, requires detailed research in this area. However, reliable research on active substances contained in biostimulants should be made first, and the activity of a given biostimulant must be proven. This work presents the results of a field experiment in tomato cultivation for two new active substances belonging to the group of benzothiadiazoles. The results indicate a positive effect on plant yield and, above all, on the lycopene content in tomato fruits. Increasing the lycopene content in fruit is of key significance, as it opens up opportunities for these active substances to be incorporated into new plant protection programs.

A theoretical investigation of benzothiadiazole derivatives for high efficiency OLEDs.

It is of great importance and worthy of efforts to give a clear structure-property relationship and microscopic mechanism of fluorescence emitters with high quantum yield. In this work, we perform a detailed computational investigation to give an explanation to the high efficiency of a fluorescence emitter XBTD-NPh based TADF sensitized fluorescence (TSF) OLEDs, and construct a symmetry structure DSBNA-BTD. Theoretical calculations show that XBTD-NPh is a long-time phosphorescent material at 77 K and TADF is attributed to the RISC of T1 to S1 state. For DSBNA-BTD, excitons arrived at T1 state comes to a large rate of nonradiatively path to the ground state, meaning it is may not be an efficient TADF molecule. For both molecules, the fast IC between T2 and T1 state results in that the hot exciton channel T1-Tn-S1 makes no contribution to the TADF.

The impact of structural modification on the electrochromic and electroluminescent properties of D–A–D benzothiadiazole derivatives with a fluorene linker and (Bi)thiophene units

Two derivatives of benzothiadiazole (BTD) symmetrically functionalized with a dihexylfluorene units serving as a linker between the BTD core and the thiophene or bithiophene were designed, synthesized and comprehensively characterized.

Effect of Benzothiadiazole-Based π-Spacers on Fine-Tuning of Optoelectronic Properties of Oligothiophene-Core Donor Materials for Efficient Organic Solar Cells: A DFT Study.

In this work, five novel A-π-D-π-A type molecules D1-D5 were designed by adding unusual benzothiadiazole derivatives as π-spacer blocks to the efficient reference molecule DRCN5T for application as donor materials in organic solar cells (OSCs). Based on a density functional theory approach, a comprehensive theoretical study was performed with different functionals (B3LYP, B3LYP-GD3, B3LYP-GD3BJ, CAM-B3LYP, M06, M062X, and wB97XD) and with different solvent types (PCM and SMD) at the extended basis set 6-311+g(d,p) to evaluate the structural, optoelectronic, and intramolecular charge transfer properties of these molecules. The B3LYP-GD3BJ hybrid functional was used to optimize the studied molecules in CHCl3 solution with the SMD model solvent as it provided the best results compared to experimental data. Transition density matrix maps were simulated to examine the hole-electron localization and the electronic excitation processes in the excited state, and photovoltaic parameters including open-circuit photovoltage and fill factor were investigated to predict the efficiency of these materials. All the designed materials showed promising optoelectronic and photovoltaic characteristics, and for most of them, a red shift. Out of the proposed molecules, [1,2,5]thiadiazolo[3,4-d]pyridazine was selected as a promising π-spacer block to evaluate its interaction with PC61BM in a composite to understand the charge transfer between the donor and acceptor subparts. Overall, this study showed that adding π-spacer building blocks to the molecular structure is undoubtedly a potential strategy to further enhance the performance of donor materials for OSC applications.

Precise Side Chain Engineering Enabling High‐Performance Wide‐Bandgap Polymer Donors

AbstractA series of wide bandgap (WBG) conjugated polymers PTFBDT‐C, PTFBDT‐O and PTFBDT‐S are designed and synthesized with alkyl, alkoxy and thioalkyl side chains. By selecting benzodithiophene derivatives as the donor units and benzothiadiazole derivatives as the acceptor units, PTFBDT‐C, PTFBDT‐O and PTFBDT‐S are all of wide optical bandgaps. Furthermore, low bandgap small molecule L8‐BO‐4F is used as the acceptor to fabricate organic solar cells (OSCs). According to the results, PTFBDT‐C:L8‐BO‐4F blend film displays appropriate phase separation, high hole and electron mobilities, etc. Thus, the power conversion efficiency (PCE) of PTFBDT‐C:L8‐BO‐4F based OSCs is 14.02%, which is much higher than those of PTFBDT‐O:L8‐BO‐4F based (9.06%) and PTFBDT‐S:L8‐BO‐4F based ones (10.45%). These results show that the side chain engineering is an effective strategy to improve photovoltaic performance of wide bandgap polymers.

Dual-state emission of D-A-D type benzothiadiazole derivatives for the sensitive detection of amine compounds

Organic light-emitting materials with dual-state emission (DSE) in both solution and solid states have attracted widely attention because of their promising applications in diverse areas. In this work, five benzothiadiazole-based D-A-D type luminogens BT2Ph, BT2Na, BT2Pa, BT2An and BT2Py were concisely synthesized by introducing different π–conjugated rigid groups (benzene, naphthalene, phenanthrene, anthracene and pyrene ring). As a result of their twisted conformation and effective conjugation structure, these five dual-state emission molecules exhibit intense photoluminescence in solution and solid state. The reason for these luminogens with DSE behavior was further explained by the twisted intramolecular charge-transfer mechanism based on the variable temperature fluorescence spectrum measurement and theoretical calculation with time-dependent density functional theory (TD-DFT). Moreover, these DSE luminogens which possess excellent photostability and obvious solvatofluorochromic properties were multifunctional fluorescent probes for the visual detection of amine compounds (aniline, cyclohexylamine, and ammonia). A charge transfer mechanism between luminogens and amine compounds was found to be the cause of fluorescence quenching. Thus, these DSE molecules may have applications in anti-counterfeiting and fluorescent sensors.

Intramolecular Palladium Catalyst Transfer on Benzoheterodiazoles as Acceptor Monomers and Discovery of Catalyst Transfer Inhibitors.

Intramolecular catalyst transfer on benzoheterodiazoles was investigated in Suzuki-Miyaura coupling reactions and polymerization reactions with tBu3PPd precatalyst. In the coupling reactions of dibromobenzotriazole, dibromobenzoxazole, and dibromobenzothiadiazole with pinacol phenylboronate, the product ratios of monosubstituted product to disubstituted product were 0/100, 27/73, and 89/11, respectively, indicating that the Pd catalyst undergoes intramolecular catalyst transfer on dibromobenzotriazole, whereas intermolecular transfer occurs in part in the case of dibromobenzoxazole and is predominant for dibromobenzothiadiazole. The polycondensation of 1.3 equivalents of dibromobenzotriazole with 1.0 equivalent of para- and meta-phenylenediboronates afforded high-molecular-weight polymer and cyclic polymer, respectively. In the case of dibromobenzoxazole, however, para- and meta-phenylenediboronates afforded moderate-molecular-weight polymer with bromine at both ends and cyclic polymer, respectively. In the case of dibromobenzothiadiazole, they afforded low-molecular-weight polymers with bromine at both ends. Addition of benzothiadiazole derivatives interfered with catalyst transfer in the coupling reactions.

π -Extended BTD derivatives: synthesis, photophysical properties, and applications in biological systemsimagingfor discriminating living and dead cells.

Benzothiadiazole (BTD) is one of the popular compounds for organic electronic devices, organic synthesis, and fluorescent probes. Here, benzothiadiazole derivatives were successfully synthesized by heck coupling reaction, which exhibited the the advantages of simplicity and efficiency, wild substrate csope, easily available substrates and high yield. The fluorescent probe BTDAr-PEG targeting lipid droplets was successfully prepared by the nucleophilic substitution reaction between the heck coupling reaction product 3h and Amino polyethylene glycol monomethyl ether (Mn=2000). BTDAr-PEG exhibited the advantages of high selectivity, good stability and pH resistance. The use of PEG as a substrate gave BTDAr-PEG good biocompatibility. It was worth mentioning that BTDAr-PEG could not only track LDs in cells under different physiological conditions, but also distinguish between living and dead cells in biological systems.

Growth of single-crystals and microstructures using benzothiadiazole derivatives for efficient optical waveguide and nonlinearity

Organic nanomaterials have been extensively studied for the applications of the electronic and photonic fields. The bottom-up fabrication through self-assembly provides a powerful strategy to construct the nanostructures. In this work, we synthesized a conjugated molecule, namely, 4-(1-phenyl-1H-1,2,3-triazol-4-yl)benzo[c][1,2,5]thiadiazole (BT-SC), based on benzothiadiazole and benzene moieties bridged by a triazole. Then, a simple solvent-vapor annealing technique was presented to drive the self-assembly of BT-SC into highly uniform microrods or microfibers. The morphology of the self-assembly could be controlled by simply changing the solution concentration. The compound also could be assembled into aligned nanowires by wetting into hard templates of anodic aluminum oxide (AAO). The fabricated microrods showed strong emitter and excellent optical waveguide behaviors excited with a UV laser. Moreover, the microrods displayed nonlinear optical responses of two-photon excited fluorescence and could therefore become building blocks for actual photonic devices.

Tailored Supramolecular Cage for Efficient Bio-Labeling.

Fluorescent chemosensors are powerful imaging tools used in a broad range of biomedical fields. However, the application of fluorescent dyes in bioimaging still remains challenging, with small Stokes shifts, interfering signals, background noise, and self-quenching on current microscope configurations. In this work, we reported a supramolecular cage (CA) by coordination-driven self-assembly of benzothiadiazole derivatives and Eu(OTf)3. The CA exhibited high fluorescence with a quantum yield (QY) of 38.57%, good photoluminescence (PL) stability, and a large Stokes shift (153 nm). Furthermore, the CCK-8 assay against U87 glioblastoma cells verified the low cytotoxicity of CA. We revealed that the designed probes could be used as U87 cells targeting bioimaging.

Finely regulated benzothiadiazole derivatives: Aggregation-induced emission (AIE), hypso- or bathochromic mechanofluorochromic behaviors, and multilevel information encryption applications

Six fluorescent dyes containing the same central benzothiadiazole skeleton were synthesized. Fluorogenic compounds 1 and 2 demonstrated typical aggregation-induced emission enhancement and aggregation-induced emission phenomena. These benzothiadiazole-modified dyes emitted different crystal-state fluorescence including green, yellow-green, yellowish brown, orange red and red colors, and these compounds displayed contrasting force-responsive fluorescence characteristics. More specifically, compound 1 exhibited red-shifted mechanofluorochromism behavior, and compounds 4–6 exhibited blue-shifted mechanofluorochromism phenomena, while compounds 2 and 3 showed no fluorescence change under mechanical stimulation. Among these benzothiadiazole derivatives, luminogens 1 and 6 presented mechanically triggered high-contrast bathochromic and hypsochromic fluorescence responses, respectively. Based on their various crystal fluorescence and force-sensitive emissive properties of fluorogenic molecules 1–6, an interesting multilevel information encryption system was successfully constructed. Indeed, this study not only provided a valuable reference for the preparation of luminophores possessing rich mechanoluminochromic natures, but also extended ideas for the development of advanced information encryption systems.

Benzothiadiazole‐Based Green Hybridized Local and Charge‐Transfer (HLCT) Fluorophores as Solution‐Processed Non‐Doped Emitters for Simple Structured Electroluminescent Devices

AbstractHerein, two new solution‐processable HLCT fluorophores (CBzF and CBzFC) based on benzothiadiazole (Bz) derivatives were designed and synthesized (HLCT=hybridized local and charge transfer). Their optical and photophysical properties were experimentally and theoretically studied and verified by the solvatochromic effect and density functional theory calculations. The two molecules demonstrate high solubility, HLCT features, and an intense green fluorescence with solid‐state photoluminescence quantum yields of 63–72 %. Both fluorophores are effectively applied as non‐doped emitters for solution‐processed double‐layered OLEDs, which produce intense green emission colors with low turn‐on voltages (3.0–3.2 V). Specifically, the CBzFC‐based solution‐processed device achieves a high maximum luminescence (24400 cd m−2), high maximum efficiencies (EQEmax=5.59 %, CEmax=12.24 cd A−1, and PEmax=10.54 lm W−1), and decent efficiency low‐off.

Triphenylamine, Carbazole or Tetraphenylethylene-Functionalized Benzothiadiazole Derivatives: Aggregation-Induced Emission (AIE), Solvatochromic and Different Mechanoresponsive Fluorescence Characteristics.

The development of mechanochromic fluorophors with high-brightness, solid-state fluorescence is very significant and challenging. Herein, highly solid-state emissive triphenylamine, carbazole and tetraphenylethylene-functionalized benzothiadiazole derivatives were developed. These compounds showed remarkable aggregation-induced emission and solvatochromic fluorescence characteristics. Furthermore, these fluorogenic compounds also displayed different mechanically triggering fluorescence responses.

One-step assembly of Pd-Keggin-polyoxometalates for catalytic benzothiadiazole generation and derived cell-imaging probe application

One-step assembly of organic-ligand modified Pd-Keggin-POMs has been rarely reported, so as for their applications in catalytic benzothiadiazole generation and derived cell-imaging probing. Herein, three Pd-Keggin-POMs (compounds 1–3) have been successfully synthesized via a one-step assembly strategy. Thus-obtained Pd-Keggin-POMs with well-defined structures and heterogeneous properties enable highly efficient catalytic benzothiadiazole generation. Specifically, compound 3 showed outstanding catalytic activities in Suzuki-Miyaura coupling reactions for the generation of benzothiadiazole derivatives (yields, 90%-97%) and was represented as one of the best catalysts reported to date. Consequently, the obtained benzothiadiazoles were used as the bio-probe for tracking lipid droplets in living-cells and exhibited large Stokes shifts (130 nm), low cytotoxicity and good targeting, which could be also applied to mark the distribution of LDs in living HeLa cells. Systematic investigations clearly decipher the functions of Pd-Keggin-POMs toward finding novel bio-probe materials, highlighting a new insight into the generation of sustainable materials in life-science.

Near‐Infrared Colorimetric and Ratiometric Fluorescence Sensor for Fluoride Ions

AbstractTwo novel benzothiadiazole derivatives were prepared. Clear color changes from orange‐red to blue (DPCN) and pink to green (DPTPE) were observed after the addition of fluoride ions (F−). DPCN and DPTPE displayed ratiometric fluorescence changes in the presence of F−. 1H‐NMR titration and DFT calculations confirmed deprotonation in the presence of F−. Compared with DPTPE, the hydrogen proton of the imine group in DPCN had higher activity due to the influence of the strong electron‐withdrawing cyano group, such that it was more easily deprotonated and the detection limit for F− was much lower. This work provided guidance for the further design and preparation benzothiadiazole based colorimetric and ratiometric fluorescence sensor for F−.

Amphiphilic benzothiadiazole derivatives: synthesis, self-assembly and applications as light-emitting liquid crystal display and switchable anisotropic scattering device

Series of benzothiadiazole based amphiphilic mesogens consisting of a rigid 4,7-diphenyl-2,1,3-benzothiadiazole core with three lipophilic flexible alkoxy chains at one end and a polar glyceryl group at the other end were synthesized. The influence of the type of the linking groups in the rigid core and the length of terminal alkoxy chain on their self-assembly behavior and photophysical properties was investigated. These compounds can self-assemble into luminescent liquid crystals (LCs) with columnar/p6mm and CubI/Im3m lattices as well as luminescent organo gels with different morphologies. Furthermore, the applications of these compounds as light-emitting liquid crystal display (LE-LCD) as well as electrically switchable anisotropic scattering device were realized.