Thiazole Units Research Articles

Conjugated Porous Organic Polymers Featuring Both Soft-Hard Combined Coordination Sites and Photoelectrochemical Properties for Palladium Capture and Subsequent Photocatalysis.

Palladium (Pd) capture from high-level liquid waste for subsequent photocatalytic applications is desirable for the development of nuclear energy and the reutilization of valuable resources. Herein, we approach our design with a unique porous organic polymer containing thiazolo[5,4-d]thiazole units (denoted as TzPOP-OH). It possesses two potential soft-hard (N-O and S-O) combined coordination sites for Pd(II) coordination and features strong donor-acceptor repeating units and high planarity of linkage enforced by hydrogen bonds for subsequent photocatalysis. Accordingly, TzPOP-OH with three hydroxyl groups on the linkage exhibits a high Pd(II) capacity of 369 mg g-1 at 3 M HNO3, considerably surpassing those of the controlled polymer TzPOP without hydroxyl groups and most other reported materials. Additionally, TzPOP-OH boasts other merits, including outstanding acid tolerance, extraordinary radiation stability, good reusability, and remarkable selectivity. After palladium adsorption, Pd@TzPOP-OH demonstrates impressive photodegradation efficiency to reduce the concentration of rhodamine B in contaminated urban water from 10 to less than 0.1 ppm. This work provides a feasible approach to designing materials with both suitable coordination microenvironments and semiconductor properties for metal separation and photocatalysis.

Isomers of n-Type Poly(thiophene-alt-co-thiazole) for Organic Thermoelectrics.

n-Type polythiophene represents a promising category of n-type polymer thermoelectric materials known for their straightforward structure and scalable synthesis. However, n-type polythiophene often suffers from a twisted backbone and poor stacking property when introducing high-density electron-withdrawing groups for a lower lowest unoccupied molecular orbital (LUMO) level, which is considered to be beneficial for n-doping efficiency. Herein, we developed two isomers of polythiophene derivatives, PTTz1 and PTTz2, by inserting thiazole units into the polythiophene backbone composed of thieno[3,4-c]pyrrole-4,6-dione (TPD) and thiophene-3,4-dicarbonitrile (2CNT). Although PTTz1 and PTTz2 share a similar polymer skeleton, they differ in thiazole configuration, with the nitrogen atoms of the thiazole units oriented toward TPD and 2CNT, respectively. The insertion of thiazole units significantly planarizes the polythiophene backbone while largely preserving low LUMO levels. Notably, PTTz2 exhibits a more coplanar backbone and closer π-stacking compared to PTTz1, resulting in a greatly enhanced electron mobility. Both PTTz1 and PTTz2 can be easily n-doped due to their deep LUMO levels. PTTz2 demonstrates superior thermoelectric performance, with an electrical conductivity of 50.3 S cm-1 and a power factor of 23.8 μW m-1 K-2, which is approximately double that of PTTz1. This study highlights the impact of the thiazole unit on n-type polythiophene derivatives and provides valuable guidelines for the design of high-performance n-type polymer thermoelectric materials.

Molecular engineering strategy and optoelectronic properties of diaminobenzene-thiazole π-conjugated small donor molecules for high-performance organic solar cells

In this current study, the π-conjugated oligomers based on Thiazole units have been designed to understand the interaction of molecular orbitals and the influence of the substituents on the energetic HOMO-LUMO gap to build highly π-conjugated nanostructures. Their strong π-conjugated insight was also evidenced in gas phase through the photovoltaic properties using B3LYP/6-31G(d,p) level of theory for potential applications in organic electronic devices. Our research indicates geometries optimized structures, FMOs and chemical parameters were determined to predict optical properties of all oligomers. The results demonstrate that thiazole unit’s addition improved absorption above 400 nm at first excited states. The open-cicruit voltage Voc have been decreased from 2.22 V to 1.26 V in M1-a to M1-d. Whereas, LHE values was increased from 0.404 to 0.986 in M2-a to M2-d. All designed molecules have shown the enhanced optoelectronic characteristic that is plausible reason for their potential photoactive use in Organic Photovoltaics (OPVs) devices efficiencies.

Understanding the impact of thiazole unit sequence in π-bridge on the performance of small molecule donor materials

Energy level regulation and crystallization optimization of materials are the key ideas to improve the performance of organic solar cells. In this work, based on clarifying small molecule structure, we introduce thiazole into different positions of π-bridge and investigate its effect on the properties of small molecule donors (SMDs) and related device performance. As thiazole gradually moves towards BDT, the electron clouds of these three SMDs (BTTTzR, BTTzTR and BTzTTR) tend to be divided on the framework, gradually deepened the energy level, and enlarged band gaps. In terms of device performance, the BTTzTR:Y6 device shows good inhibition of charge recombination and phase separation performance, and the efficiency of the related OSCs is 7.87 %. Morphological analysis shows that BTTTzR is prone to form nanoscale microcrystals after thermal annealing treatment, with slightly decreased performance of 6.79 %. BTzTTR is affected by difficult intramolecular charge transfer and weak intermolecular interactions, shows the worst performance of 5.77 %. This work is conducive to a deeper understanding of the electron-deficient substitution of the π-bridge in SMDs.

The insertion of thiazolo[5,4-d]thiazole unit in covalent triazine framework for boosting the photocatalytic capacities in both selective aerobic oxidation of sulfides and amines

Recently, covalent triazine frameworks (CTFs) have realized versatile applications in the field of photocatalysis. Herein, two CTFs photocatalysts were designed and synthesized with or without thiazolo[5,4-d]thiazole (TzTz), an electron deficient unit, to highlight the introduction of an additional acceptor unit on the photocatalytic aerobic oxidation reaction of triazine based CTFs. Specifically, CTF-TZDA was prepared by a condensation reaction between terephthalimidamide and 4,4′-(thiazolo[5,4-d]thiazole-2,5-diyl) dibenzaldehyde (TzTz aldehyde), and similarly, CTF-FPBA was prepared between terephthalimidamide and [1,1′-biphenyl]-4,4′-dicarbaldehyde. CTF-TZDA showed high photocatalytic activities towards aerobic oxidation of both benzyl sulfides and benzyl amines to benzyl sulfoxides and benzyl imines, respectively, and the reaction was powered by blue light. A wide range of substrates can be aerobically oxidized with high yield (about 99%) and high selectivity over CTF-TZDA photocatalyst. The insertion of the TzTz unit lowered that band gap, accelerated the delocalization of π electrons, and elevated the LUMO levels of CTF-TZDA, which are beneficial to extend the light absorption range, and to promote the separation and transfer of photo-induced charge carriers. This work indicates that the insertion of an additional electron deficient unit rich in heteroatoms is considered as a feasible approach towards enhancing the photocatalytic activity of CTFs.

Synthesis of iodine-povidone-co-thiazole nanoporous membrane with antibacterial activity and application in water treatment

In order to prevent the spread of the epidemics caused by pathogenic microorganisms, it is very important to explore antimicrobial materials. In this paper, a novel antimicrobial polymer materials with dual active centers, iodine-povidone-co-thiazole nanoporous membrane (IPoTaNm), was successfully synthesized by one-pot emulsion polymerization followed by iodine complexation. The micromorphology and composition were characterized by scanning electron microscope (SEM), Fourier transform infrared spectra (FT-IR), dynamic light scattering (DLS), X-ray photoelectron spectroscopy (XPS), X-ray powder diffraction (XRD) and contact angle test. Then, its antimicrobial performance was measured by using Escherichia coli and Staphylococcus aureus as test strains. It indicated that IPoTaNm exhibits excellent antibacterial activity, which the inhibition rate got to 99.9 % after 48 h. It also presented sustaining bactericidal activity, which the antimicrobial activity maintained 99.9 % even after >7 days. The synergistic antimicrobial mechanism of thiazole units (AcT) and iodine in IPoTaNm was discussed, and some facters for their inhibitory effects in the water column were investigated. In summary, the obtained IPoTaNm with dual active centers was an excellent candidate for minimizing bacteria-infection in different functional materials, which has potential applications in wastewater treatment to reduce bacterial infections.

Luminescent MOFs Based on Thiazolo[5,4-d]thiazole as a Chemosensor for the Detection of Environmental Contaminants

Luminescent metal-organic frameworks (LMOFs) are considered special candidates for the sensation and detection of particular analytes. Thiazolo[5,4-d]thiazoles (TTZs) are an ideal type of heterocycles for fluorophores with π-bridge moieties demonstrating structure-function characteristics. LMOFs with excellent sensing properties can be constructed by incorporating heterocyclic aromatic thiazolo[5,4-d]thiazole into the framework. This study has elaborated on LMOFs containing thiazolo[5,4-d]thiazole unit for the detection of environmental contaminants, such as toxic anions, aromatic compounds, and heavy metal ions.

Three functional Cd(II) coordination polymers constructed by the thiazolothiazole extended viologen ligand

Expanding the π-conjugated structure of traditional viologens by incorporating thiazole units to the bipyridine skeleton has attracted more and more attention. In this work, a rigid thiazolothiazole extended viologen ligand (TTVP, 2,5-bis (pyridinium-4-yl) thiazolo [5,4-d] thiazole propionate) has been used to constitute three new functional Cd(II) coordination polymers (CPs), {[Cd(TTVP)0.5(HBTC)(H2O)2]·2H2O}n (1), {[Cd(TTVP)0.5(p-BDC)0.5(p-HBDC)(H2O)]·3H2O}n (2), {[Cd(TTVP)0.5(m-BDC)]}n (3) by introducing different benzenecarboxylic acids as auxiliary ligands (H3BTC = 1,3,5-benzenetricarboxylic acid; p-H2BDC = 1,4-benzenedicarboxylic acid; m-H2BDC = 1,3-benzenedicarboxylic acid). The crystal structures and photochromic capabilities of 1−3 are studied. Both compounds 1 and 2 own one-dimensional (1D) chain-like structure, while compound 3 owns two-dimensional (2D) layered structure. As expected, compounds 1−3 show reversible photochromism due to electron-transfer (ET). In addition, the photo-controlled luminescent properties and the potential application as inkless and erasable printing media are also explored.

Enhancing the Efficiency and Durability of Perovskite Solar Cells by Donor–Acceptor Covalent Organic Framework with Thiazolo[5,4- d ]thiazole Unit

Enhancing the Efficiency and Durability of Perovskite Solar Cells by Donor–Acceptor Covalent Organic Framework with Thiazolo[5,4- <i>d</i> ]thiazole Unit

Introducing thiazole units into small-molecule acceptors for efficient non-fullerene organic solar cells

The end-group modification engineering has been widely applied in non-fullerene acceptors (NFAs) to achieve high-performance organic solar cells (OSCs). Herein, we designed and synthesized a series of small-molecule acceptors (SMAs), namely ODTz-γ, ODTz-m, DTTz-γ and DTTz-m, which containing the electron-withdrawing thiazole units on the end groups at different position. These SMAs not only exhibited strong and broad absorption region from 500 nm to 900 nm, identical band gaps, but also the similar energy levels, indicating the position of thiazole units have trivial effect on their absorbance and energy levels. OSCs were fabricated by integrating an electron-donating polymer PBDB-T with these resultant electron-accepting materials. Devices based on ODTz-γexhibited an obviously higher power conversion efficiency over 12.0%, which outperformed those of obtained from devices based on other SMAs. Further characterization of the devices revealed that introducing the thiazole units into the γ position of end groups can enhance the charge transport mobility, suppress recombination, and improve the blend film morphology.

New wide bandgap conjugated D-A copolymers based on Benzo[d]thiazole for efficient photovoltaics

Two wide bandgap copolymers based on benzo[d]thiazole unit, named PBTz-F and PBTz-Cl, containing benzo[1,2-b:4,5-b′]dithiophene (BDT) as electron donor units are developed. The resulting polymers lower the highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) energy levels via substituting halogen atoms (fluorine or chlorine atoms) on the thiophene side chain of the BDT unit. However, the chlorine atom in the copolymers has a stronger capacity to downshift energy levels than the fluorine atom. PBTz-Cl:Y6-BO-based OSC delivers a higher PCE of 12.36% with simultaneously enhanced VOC of 0.90 V, JSC of 22.78 mA cm−2, and FF of 0.61 when compared to that based on PBTz-F:Y6-BO (PCE = 11.38%, JSC = 22.48 mA cm−2, VOC = 0.88 V, and FF = 0.58) due to its stronger absorption, higher charge mobilities, deeper HOMO energy level, and favorable blend film morphology. These results emphasized that chlorination is a practical strategy to obtain high PCE and BTz-based polymers are potential donor candidates for high-performance OSCs.

Intramolecular nitrogen-sulfur interaction to enhance electron-accepting properties of end groups in small molecule donors

In organic solar cells (OSCs), it is very important to investigate the relationship between the structure and performance of materials by rational design of small molecule donors (SMDs). In this work, we use thiazole replace a thiophene unit in the π bridge, which could strengthen the connection between π bridges and end groups (EGs). Due to the N–S non-covalent interaction between EG and thiazole unit, the negative charge region of SMDs is expanded, the electron-withdrawing ability of EGs is also enhanced, and the corresponding molecular framework is twisted into a unique linear type. This can effectively enhance intermolecular interaction, promote molecular crystallization, and help to improve hole mobility of related SMDs. This work enriches design strategy that strengthens the interaction between π bridges and EGs, and provides a reference for studying the relationship between molecular structure and crystallinity.

Regioselective Direct C-H Bond Heteroarylation of Thiazoles Enabled by an Iminopyridine-Based α-Diimine Nickel(II) Complex Evaluated by DFT Studies.

Direct C-H bond arylation is a highly effective method for synthesizing arylated heteroaromatics. This method reduces the number of synthetic steps and minimizes the formation of impurities. We report an air- and moisture-stable iminopyridine-based α-diimine nickel(II) complex for direct C5-H bond arylation of thiazole derivatives. Under a low catalyst loading and performing the reactions at lower temperatures (80 °C) under aerobic conditions, we produced mono- and diarylated thiazole units. Competition experiments and density functional theory calculations revealed that the mechanism of C-H activation in 4-methylthiazole involves an electrophilic aromatic substitution.

Design and Synthesis of BODIPY-Hetero[5]helicenes as Heavy-Atom-Free Triplet Photosensitizers for Photodynamic Therapy of Cancer.

Designing heavy-atom-free triplet photosensitizers (PSs) is a challenge for the efficient photodynamic therapy (PDT) of cancer. Helicenes are twisted polycyclic aromatic hydrocarbons (PAHs) with an efficient intersystem crossing (ISC) that is proportional to their twisting angle. But their difficult syntheses and weak absorption profile in the visible spectral region restrict their use as heavy-atom-free triplet PSs for PDT. On the other hand, boron-containing PAHs, BODIPYs are highly recognized for their outstanding optical properties. However, planar BODIPY dyes has low ISC and thus they are not very effective as PDT agents. We have designed and synthesized fused compounds containing both BODIPY and hetero[5]helicene structures to develop red-shifted chromophores with efficient ISC. One of the pyrrole units of the BODIPY core was also replaced by a thiazole unit to further enhance the triplet conversion. All the fused compounds have helical structure, and their twisting angles are also increased by substitutions at the boron centre. The helical structures of the BODIPY-hetero[5]helicenes were confirmed by X-ray crystallography and DFT structure optimization. The designed BODIPY-hetero[5]helicenes showed superior optical properties and high ISC with respect to [5]helicene. Interestingly their ISC efficiencies increase proportionally with their twisting angles. This is the first report on the relationship between the twisting angle and the ISC efficiency in twisted BODIPY-based compounds. Theoretical calculations showed that energy gap of the S1 and T1 states decreases in BODIPY-hetero[5]helicene as compared to planar BODIPY. This enhances the ISC rate in BODIPY-hetero[5]helicene, which is responsible for their high generation of singlet oxygen. Finally, their potential applications as PDT agents were investigated, and one BODIPY-hetero[5]helicene showed efficient cancer cell killing upon photo-exposure. This new design strategy will be very useful for the future development of heavy-atom-free PDT agents.

Tandem synthesis and antibacterial screening of new thieno[2,3-b]pyridine-fused pyrimidin-4(3H)-ones linked to thiazole or oxazole units

New two series of thieno[2,3-b]pyridine-fused pyrimidinones 1 and 2 linked to thiazole or oxazole units were prepared utilizing a three-component tandem protocol. Therefore, a mixture of 1 equiv. of 3-aminothieno[2,3-b]pyridine-2-carboxylate was first microwave irradiated with 1.5 equiv. of dimethylformamide-dimethylacetal in toluene was at 110 °C for 15 min. Next, the crude enamine was dissolved in dioxane and 1 equiv. of the respective 4-arylazole-based amines was added. The mixture was microwaved at 100 °C for 20–30 min, resulting in a 74–89% yield of the target pyrimidinones. The new products showed a wide spectrum of antibacterial activity. In general, oxazole-linked pyrimidinones 2 exceeded their analogs 1 attached to thiazole units in antibacterial activity. Hybrids 2d, and 2e, with 4-(p-tolyl)oxazole and 4-(4-methoxyphenyl)oxazole units, demonstrated the best antibacterial potency among the new products with MIC/MBC values of 4.4/8.8 and 4.2/8.5 µM, respectively. According to SwissADME, all new pyrimidinones could be classified as drug-like.

Tuning the Intermolecular Electrostatic Interaction toward High‐Efficiency and Low‐Cost Organic Solar Cells

AbstractOrganic solar cells (OSCs) have achieved much progress with rapidly increasing power conversion efficiencies (PCEs). It should be noted that the top‐performance OSCs are generally consisted of active materials with complex chemical structures, resulting in high costs. Here, combining the material design and morphology control, high‐efficiency OSCs are fabricated by a low‐cost donor: acceptor blend. A completely non‐fused electron acceptor named Tz is designed and synthesized via introducing thiazole units on both sides of a bithiophene core, which shows an outstanding PCE of 13.3% with a typical polythiophene donor. More importantly, optimization guidelines are presented to get excellent morphology for low‐cost donor:acceptor systems. Three polythiophenes are selected, poly(3‐hexylthiophene) and its two derivatives with electron‐withdrawing substitutions (PDCBT and PDCBT‐2F), as donors to fabricate the cell devices. The computational and experimental data reveal that decreasing the electrostatic interaction between polythiophene and Tz is the key to getting a suppressed miscibility and thus a high phase purity. This study provides insight into the molecular design and donor:acceptor matching requirements for high‐efficiency and low‐cost OSCs.

Two-Dimensional Benzobisthiazole-Vinylene-Linked Covalent Organic Frameworks Outperform One-Dimensional Counterparts in Photocatalysis

Vinylene/olefin-linked two-dimensional covalent organic frameworks (v-2D-COFs), featured with vinylene-linked in-plane conjugations, high chemical stabilities, and designable chemical structures, are promising for optoelectronic/photocatalytic applications. Developing v-2D-COFs with superior π-conjugation and optoelectronic properties is meaningful but remains challenging. In this work, we present the crystalline benzobisthiazole-bridged unsubstituted v-2D-COF (v-2D-COF-NS1 and v-2D-COF-NS2) synthesized via a benzothiazole-mediated aldol-type polycondensation. Interestingly, the resultant v-2D-COF exhibits a high chemical stability under both strong acidic (12 M HCl) and basic conditions (saturated KOH) due to the robust vinylene-linked skeletons. Moreover, the electron-deficient thiazole units and 2D π-conjugations endow v-2D-COFs (i.e., v-2D-COF-NS1) a narrow band gap of ∼1.85 eV with a conduction band of −3.65 eV vs vacuum, which are desirable for photocatalytic hydrogen evolution. As such, the v-2D-COF-NS1-based photoelectrode gives a photocurrent up to ∼47 μA cm–2 at 0.3 V vs reversible hydrogen electrode (RHE), which is much higher than the value of the corresponding linear polymer (LP-NS1) and outstanding among the reported COF photoelectrodes. Under a continuous visible light irradiation, v-2D-COF-NS1 generates hydrogen gas with an excellent rate of ∼4.4 mmol h–1 g–1 over 12 h. This work demonstrates the synthesis of unsubstituted v-2D-COFs that intrinsically contain benzobisthiazole-based building blocks and shows great potential in photocatalytic reactions.

Thiazolo[5,4-d]thiazoles with a spirobifluorene moiety as novel D–π–A type organic hosts: design, synthesis, structure–property relationship and applications in electroluminescent devices

Novel D–π–A type organic small-molecules with thiazolo[5,4-d]thiazole and spirobifluorene units. Optoelectronical properties suggests their applications in materials. Electroluminescent devices containing the novel TzTz-based derivatives 4b, 5b show affinitive emission.

Synthesis, in vitro Toxicity, and Antitrypanosomal Activity of Arylated and Diarylated Thiazoles

Chagas disease is a relevant public health threat that affects over 6 million people worldwide, resulting in devastating social and economic consequences. Moreover, the therapeutic options are limited, highlighting the urgency in searching for novel active antitrypanosomal molecules. Compounds with either thiazole or biaryl units have been described as possessing anti-Trypanosoma cruzi activities. Therefore, here, we describe the synthesis of nine arylated and diarylated thiazole derivatives and the evaluation of their in vitro toxicity on mammalian cells as well as their anti-T. cruzi activity. The compounds were prepared in straightforward synthetic routes, using Hantzsch thiazole synthesis and cross-coupling reactions as key steps. A pyridylphenyl-thiazole (PPT) derivative (4c) presented 76% of T. cruzi growth inhibition in preliminary tests using a fixed concentration of 20 µM. This compound was used as a scaffold for the synthesis of two novel PPT analogs (4g and 4h). Dose-response assays on intracellular forms of T. cruzi demonstrated that these three compounds presented high antiparasitic potency (half maximal effective concentration (EC50) values ranging from 1.15 to 2.38 μM) and low toxic profile against L929 cell lines. Hence, these findings highlight the pyridyl-phenyl-thiazole backbone as a novel privileged scaffold in the search for active molecules against T. cruzi.

Thiazole Imide‐Based All‐Acceptor Homopolymer with Branched Ethylene Glycol Side Chains for Organic Thermoelectrics

Abstractn‐Type semiconducting polymers with high thermoelectric performance remain challenging due to the scarcity of molecular design strategy, limiting their applications in organic thermoelectric (OTE) devices. Herein, we provide a new approach to enhance the OTE performance of n‐doped polymers by introducing acceptor‐acceptor (A‐A) type backbone bearing branched ethylene glycol (EG) side chains. When doped with 4‐(2,3‐dihydro‐1,3‐dimethyl‐1H‐benzimidazol‐2‐yl)‐N,N‐dimethylbenzenamine (N‐DMBI), the A‐A homopolymer PDTzTI‐TEG exhibits n‐type electrical conductivity (σ) up to 34 S cm−1and power factor value of 15.7 μW m−1 K−2. The OTE performance of PDTzTI‐TEG is far greater than that of homopolymer PBTI‐TEG (σ=0.27 S cm−1), indicating that introducing electron‐deficient thiazole units in the backbone further improves the n‐doping efficiency. These results demonstrate that developing A‐A type polymers with EG side chains is an effective strategy to enhance n‐type OTE performance.