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ÖgeHighly sensitive OFET based room temperature operated gas sensors using a thieno[3,2-b]thiophene extended phthalocyanine semiconductor(Royal Society of Chemistry, 2024)Over the past decades, organic field-effect transistor (OFET) gas sensors have maintained a rapid development. However, the majority of OFET gas sensors show insufficient detection capability towards oxidizing and hazardous gases such as nitrogen dioxide (NO2) and sulfide dioxide (SO2). In this report, a sustainable approach toward the fabrication of OFET gas sensors, consisting of a thieno[3,2-b]thiophene (TT) and phthalocyanine (Pc) based electron rich structure (TT-Pc) for the detection of both nitrogen dioxide (NO2) and sulfide dioxide (SO2) is disclosed for the first time. Khaya gum (KG), a natural, biodegradable biopolymer is used as the gate dielectric in these OFET-based sensors. Thin film properties and surface morphology of TT-Pc were investigated by UV-Vis, SEM, AFM and contact angle measurements, which indicated a uniform and smooth film formation. The UV-Vis properties were supported by computational chemistry, performed using density functional theory (DFT) for optimizing geometry and absorption of TT-Pc models. Sensitive and selective responses of 90% and 60% were obtained from TT-Pc OFET-based sensors upon exposure to 20 ppm of NO2 and SO2, respectively, under ambient conditions. One of the lowest limits of detection of ∼165 ppb was achieved for both NO2 and SO2 using a solution-processed TT-Pc sensor with a natural, biodegradable dielectric biopolymer. The sensors showed excellent long-term environmental and operational stability with only a 7% reduction of the sensor's initial response (%) upon exposure to NO2 and SO2 over nine months of operation in air.
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ÖgeImide-yne click polymerization: a new and versatile tool for the toolbox of X-yne click polymerization(Royal Society of Chemistry, 2024)The Michael reaction, a cornerstone in organic chemistry, continues to revolutionize the field with its unparalleled versatility in forming carbon–carbon, carbon–oxygen, carbon–nitrogen, and carbon–sulfur bonds, paving the way for groundbreaking advancements in complex molecule and macromolecule construction. In this study, imide-yne reaction was employed at the macromolecular level for the first time to prepare linear poly(imide ester)s. A wide range of bisimides and dipropiolates were reacted through imide-yne click polymerization in the presence of 1,4-diazabicyclo[2.2.2] octane (DABCO) at room temperature. The polymerizations proceed in an anti-Markovnikov fashion, yielding the E-isomer as the major product. Polymers were obtained in high yields and their molecular weights were found to be in the range of 5.64–12.67 kDa. The remaining unreacted double bonds in the linear polymers were found to undergo further functionalization with thiols using a strong organocatalyst 1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD), which was also supported by a model study. Post-polymerization modification study prompted us to prepare imide-yne monomers that can react with dithiols to synthesize poly(imide thioether)s through nucleophilic thiol–ene click reaction using TBD as the catalyst. The obtained polymers displayed a wide range of glass transition temperatures and thermal stability. Thus, it can be said that the proposed method enables the synthesis of new polyimide-based structures with tailorable thermal properties. It is believed that the proposed strategy will make a significant contribution to expanding the versatility of active alkyne chemistry at the macromolecular level.
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ÖgeA thienothiophene and anthracene based functional hyperbranched polymer: synthesis, photophysical properties and photocatalytic studies(Royal Society of Chemistry, 2024)Conjugated polymer photocatalysts have been receiving extensive attention in the field of photocatalytic hydrogen evolution, owing to their tunable molecular structures and electronic properties. Herein, we report a hyperbranched conjugated polymer, containing thienothiophene and anthracene units (TT-Ant), synthesized via Pd(0) catalyzed Suzuki coupling. Its structural, photophysical and electrochemical features were investigated by using UV-vis and fluorescence spectroscopy, cyclic voltammetry (CV) and X-ray photoelectron spectroscopy (XPS). Photocatalytic hydrogen evolution tests, combining the material with two different additives, resulted in high hydrogen production rates from water. A steady state production rate of around 286 μmol g−1 h−1 for its hybridization with TiO2 was recorded, which is more than 3 times that for pristine TiO2 under the same conditions. Moreover, the combination of the polymeric material with platinum (1% wt) resulted in a maximum rate value of 700 μmol g−1 h−1. The surface properties of the latter combination before and after the reaction were studied by scanning electron microscopy (SEM) and transmission electron microscopy (TEM), which demonstrated successful Pt deposition on the surface of the polymer. This work may provide a new strategy to construct stable photocatalysts with thienothiophene and anthracene cores as active sites for efficient catalytic reactions in energy conversion applications.
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ÖgeDrug encapsulation and release with a nonionic amphiphilic calix[4]pyrrole(Royal Society of Chemistry, 2024)A polyethylene glycol-tethered amphiphilic calix[4]pyrrole compound (C4P-PEG) was synthesized via an esterification reaction between the corresponding alcohol-functionalised calix[4]pyrrole and carboxylic acid ended polyethylene glycol. The structure of C4P-PEG was confirmed by means of NMR spectroscopy and high-resolution mass spectrometry. The complexation ability of the control compound octamethylcalix[4]pyrrole and C4P-PEG with chemotherapeutic cancer drug, doxorubicin-HCl, was shown with the aid of various NMR techniques in DMSO, containing 1.5% (wt) water. Nonionic amphiphilic calix[4]pyrrole compound C4P-PEG was then shown to produce stable micelles in water. The title compound was also used to encapsulate doxorubicin-HCl in aqueous medium and its concurrent drug release ability was illustrated under acidic and basic conditions. While the characterizations of drug-free and drug-loaded micelles were carried out with dynamic light scattering experiments and transmission electron microscopy, the drug loading capacity, encapsulation efficiency and in vitro drug release profiles were studied with the aid of UV-vis spectrophotometry.
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ÖgeAnionic starch-based hybrid cryogel-embedded ZnO nanoparticles: tuning the elasticity and pH-functionality of biocomposites with dicarboxylic acid units(Royal Society of Chemistry, 2024)Weakly anionic semi-interpenetrating polymer network (semi-IPN) biocomposites based on starch (ST)-incorporated poly(acrylamide-co-itaconic acid)/ZnO (ST-PAI/ZnO) were synthesized by a simple one-pot method via free radical aqueous polymerization. Hybrid biocomposites exhibited lower equilibrium swelling compared with neat copolymer gel. For both hydrogels and cryogels, swelling followed a decreasing order as copolymer PAI > starch-free PAI/ZnO > ST-PAI/ZnO gels. With the addition of 9% ST and ZnO, the swelling ratio of gels decreased from 898 to 68.3, resulting in a significant increase in elastic modulus. Compared with a fixed amount of ST, biocomposite cryogels exhibited significantly higher modulus than hydrogels. With the addition of 9% ST, the elastic modulus of cryogels reached 22.2 kPa while it was 2.7 kPa for the hydrogels. An equation expressing the effective cross-linking density of semi-IPNs presented by a cubic polynomial as a function of starch was obtained. As pH increased with the presence of dicarboxylic acid units, a gradual increase in swelling occurred at two different pH values. A gradually reproducible swelling change of semi-IPNs was depicted with pH ranging from 2.1 to 11.2. Biocomposite cryogels showed rapid swelling in a buffer solution of pH 11.2 and rapid shrinking in pH 2.1. Salt-induced swelling testing showed that the ability to reduce the degree of swelling and solubility of starch was Br− > Cl− > NO3− > SO42− for anions consistent with the Hofmeister series. Adsorption efficiency for the removal of methyl violet (MV) dye was analyzed using Langmuir, Freundlich, Dubinin–Radushkevich and Temkin isotherm models. The results confirmed that the Langmuir isotherm and pseudo-second-order model are suitable for describing MV adsorption on semi-IPN biocomposites. The synthesized biocomposites with good swelling/deswelling kinetics in different pH-buffer solutions, high saline absorbency, desirable adsorption efficiency, and acceptable pH-dependent swelling reversibility can be considered as smart hybrid materials for the adsorption of the dye in water purification tasks.
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