Search Results (74)

Developing high-performance n-type polymer semiconductors is hindered by the scarcity of strong electron-deficient building blocks. Herein, we report a dual-functionalization strategy that integrates both quinoid and cyano groups into polythiophene backbones to construct n-type polymers. Two new polymers, PQTTCN and PQTVTCN, were synthesized via the Stille copolymerization of a thienoquinoid-based dibrominated monomer (TTD2T-Br) with cyano-functionalized bithiophene and thienylene-vinylene-thienylene distannyl monomers, respectively. Electrochemical and computational analyses confirm that both polymers exhibit low-lying LUMO levels of −4.07 eV and highly planar backbones. In organic field-effect transistors, PQTTCN and PQTVTCN show unipolar n-type charge transport, with electron mobilities of 0.036 and 0.002 cm² V⁻¹ s⁻¹, respectively, which are attributed to their deep frontier molecular orbitals and planar conformations. Upon doping, both polymers exhibit n-type thermoelectric performance, achieving an electrical conductivity and power factor values of 0.16 S cm⁻¹ and 0.75 μW m⁻¹ K⁻² for PQTTCN and 0.043 S cm⁻¹ and 0.17 μW m⁻¹ K⁻² for PQTVTCN, respectively. AFM and GIWAXS results demonstrate that PQTTCN has better dopant compatibility and higher crystallinity than PQTVTCN. This work highlights that the combination of quinoid and cyano units offers a promising strategy for developing high-performance n-type polymer semiconductors for organic electronics. Full article

Organic photovoltaic materials and nonlinear optical materials share inherent commonalities in molecular characteristics—such as strong light absorption, high charge carrier mobility, and tunable energy levels. Therefore, this study selects a bithiophene-fused ring system with photovoltaic application potential as the research subject. Using TTTTB6-2CHO (TB1) and IDTTB6-2CHO (TB2) as comparative molecules, their nonlinear optical properties in the near-infrared region were systematically investigated. Transient absorption spectroscopy results demonstrate that TB1 exhibits strong and persistent excited-state absorption within the spectral range of 650–900 nm, endowing it with excellent two-photon absorption performance (a cross-section of up to 5591 GM at 650 nm) and an ultralow optical limiting threshold (0.00147 J/cm² under 800 nm femtosecond laser irradiation). The findings of this study not only confirm the feasibility of developing nonlinear optical materials from photovoltaic candidate molecules but also highlight the effectiveness of the “thiophene-for-benzene substitution” strategy in significantly enhancing optical nonlinearity. These results provide valuable design principles for the development of multifunctional organic optoelectronic materials, particularly for application scenarios such as laser protection. Full article

The exceptional catalytic efficiency of [FeFe]-hydrogenases has driven intense efforts to reproduce their structure and function in synthetic models. A key structural feature governing the behavior of synthetic H-cluster analogs lies in the identity of the bridging dithiolato ligands that link the iron centers. These ligands play a pivotal role in tuning the electron density of the metal core, thereby dictating the complex’s redox characteristics and catalytic reactivity. In this context, we herein describe the synthesis and application of ferrocenyl bithiophene-2,2′-yl thioketone (1) as a proligand for assembling biomimetic models of the [FeFe]-hydrogenase active site. The obtained complexes were thoroughly examined using a suite of analytical methods, including NMR and IR spectroscopy, elemental analysis, and a single-crystal X-ray diffraction, affording comprehensive structural and chemical characterization. Furthermore, their electrochemical behavior toward proton reduction and hydrogen evolution was evaluated via cyclic voltammetry, enabling direct comparison with structurally related analogs. Full article

The extensive use of submicron emulsion systems, particularly those stabilized by nonionic surfactants, with their proven effectiveness and safety profile, provides a reassuring foundation for our research. Consequently, we designed and engineered new submicron emulsion formulations stabilized with a biocompatible surfactant polyoxyethylated cocoamine, whose nonionic character is due to a high degree of polyoxyethylation. We chose oleic acid as the oil phase, a fatty acid known for its beneficial properties. This led to novel biocompatible nanoemulsions with high stability and cosurfactant-free microemulsions. The dynamic light scattering studies confirmed that both formulations have a nanometric size and low polydispersity index values. Moreover, transmission electron microscopy verified the nanodroplets’ morphological homogeneity and spherical shape. The resulting nanoplatforms can be applied to carry bioactive agents in the pharmaceutical and cosmetic fields. For this reason, we solubilized newly synthesized 5-dimethylamino-5′-nitro-2,2′-bithiophene as a model hydrophobic cargo for delivering poorly water-soluble compounds. This dye was chosen due to its strong solvatochromic behavior and suitability for micropolarity analysis via UV–Vis spectroscopy. We also present a simple method for rapid micropolarity screening to assess the type of nanodispersion via solvatochromic shift as an alternative procedure for evaluating of the oils used to fabricate nanoformulations for pharmaceutical and cosmetic purposes. Full article

A first application of 2-(methoxycarbonyl)thiophen-3-diazonium salts in the halothienylation of α,β-unsaturated functionalized compounds under Meerwein reaction conditions is presented. This process provides thiophene-containing building blocks that can then undergo cyclization reactions with bisnucleophiles to synthesize thiophene-3-yl-containing heterocyclic systems. In this way, substituted 2,3′-bithiophene compounds and thiophene-3-yl derivatives of 2-aminothiazole, 2-aminoselenazole, thiazolidine, and selenazolidine can be efficiently prepared. Full article

The reaction of rhodanine vinyl bithiophene (BTR) with molecular dibromine (Br₂) resulted in the formation of compound 1. Single-crystal X-ray diffraction analysis revealed bromination of the terminal thiophenyl ring and the formation of a 1:1 CT “spoke” adduct between the rhodanine thiocarbonyl group and a neutral dibromine (Br₂) molecule. Full article

In this study, we synthesized novel donor–π–acceptor (D–π–A) functional dyes bearing a carbonyl-bridged bithiophene as a π-conjugated spacer and evaluated the absorption and fluorescence properties as well as the photostability. The developed dyes 1-CO–3-CO possess an N,N-diphenylaminophenyl electron donor unit and an electron acceptor unit such as a formyl group (1-CO), an (N,N-diethylthiobarbituryl)methylene moiety (2-CO), or a (3-dicyanomethylidene-1-indanon-2-yl)methylene moiety (3-CO). The absorption spectra of 1-CO–3-CO in dichloromethane at room temperature showed absorption maxima at 569 nm, 631 nm, and 667 nm, respectively, and the stronger acceptors in 2-CO and 3-CO led to enhancement of the ICT character. In addition, 2-CO and 3-CO had a second absorption band in the visible region, showing panchromatic absorption properties. Electrochemical analyses of the developed dyes revealed that the carbonyl bridging group in the π-spacer contributes to stabilization of the frontier orbitals such as the highest occupied and lowest unoccupied molecular orbitals (HOMO and LUMO, respectively), in comparison with the referential dyes bearing a dibutylmethylene-bridged bithiophene spacer, 1-CBu₂–3-CBu₂. The HOMO/LUMO stabilization brought about high photostability in the doped poly(methyl methacrylate) film. Full article

Dipeptidyl peptidase III (DPP III) is a zinc-dependent enzyme that hydrolyses biologically active peptides by cleaving dipeptides from their amino terminus. While the fundamental role of this metallopeptidase remains incompletely understood, human DPP III (hDPP III) has been linked to several pathophysiological processes relevant to drug development. In this study, thirty-six amidino-substituted benzimidazole derivatives, including seven newly synthesized compounds, were examined for their activity against hDPP III by combining in vitro tests, in silico quantitative structure–activity relationship (QSAR) modelling, and molecular docking approaches. The experiments demonstrate that all compounds display inhibitory activity at a 30 µM concentration. A biochemical assay revealed that 2,2′-bithiophene, 4-trifluoromethylphenyl, 4-(N,N-diethylamino)phenyl, and 2,3,4-trihydroxyphenyl as substituents at position 2 of the benzimidazole core enhance inhibitor potency. Additionally, the type of substituent at positions 5(6) of the benzimidazole core influences enzyme inhibition, with effectiveness ranked as follows: 2-imidazolinyl > unsubstituted amidine > 2-tetrahydropyrimidine. A multiple linear regression QSAR model for hDPP III inhibition was developed using four Dragon descriptors (Rww, Mats3e, BELe4, and nCs), which can explain 82% of the inhibitory activity. Docking analysis of the semi-closed form of hDPP III in a complex with the most potent compounds indicates the structural features of the benzimidazole derivatives important for the binding at the hDPP III active site. Full article

In this work, floating-gate organic field-effect transistor memory using the n-type semiconductor poly-{[N,N′-bis(2-octyldodecyl) naphthalene-1,4,5,8-bis (dicarbo- ximide)-2,6-dili]-alt-5,5′-(2,2′-bithiophene)} (N2200) as a charge-trapping layer is presented. With the assistance of a technology computer-aided design (TCAD) tool (Silvaco-Atlas), the storage characteristics of the device are numerically simulated by using the carrier injection and Fower–Nordheim (FN) tunneling models. The shift in the transfer characteristic curves and the charge-trapping mechanism after programming/erasing (P/E) operations under different P/E voltages and different pulse operation times are discussed. The impacts of different thicknesses of the tunneling layer on storage characteristics are also analyzed. The results show that the memory window with a tunneling layer thickness of 8 nm is 16.1 V under the P/E voltage of ±45 V, 5 s. After 1000 cycle tests, the memory shows good fatigue resistance, and the read current on/off ratio reaches 10³. Full article

Currently, photothermal (PT) polymers are gaining increasing attention in water evaporation, photocatalysis and photothermal therapy. However, high-performance PT polymers often require conjugated backbones and/or large fused units, which can impede non-radiative decay and lead to suboptimal PT performance. The development of general strategies for preparing high-performance PT polymers remains a significant challenge. In this paper, the high-performance donor–acceptor (D–A) random copolymers, named PBT4T-BBT-x (x = 0, 5, 10, 20 and 100), were fabricated by cross-mixing bithiophene donors with benzothiadiazole (BT) and benzodithiadiazole (BBT) acceptors. Notably, when the ratios of BT and BBT are finely tuned, the polymers exhibit significantly controllable open-shell radical effects and twisted intermolecular charge transfer (TICT) states. The synergistic effects of radicals and TICT states notably enhanced the PT performance of random copolymers. Specifically, when the proper ratios of BBT units are used, the photothermal conversion efficiency (PTCE) is remarkably increased from 21.7% to 58.5%, and the PT temperature obviously increases from 150 °C to 232 °C under 808 nm laser irradiation. Furthermore, the random copolymers exhibit good water evaporation rates. We propose that this strategy provides a valuable synthesis pathway for generating high-performance photothermal therapy and water evaporation materials. Full article

We synthesized n-type polymers poly{[N,N′-bis(2-octyldodecyl)-naphthalene-1,4,5,8-bis(dicarboximide)-2,6-diyl]-alt-5,5′-(2,2′-bithiophene)} [P(NDI2OD-T2)] and poly{[N,N′-bis(3-(4-cardanol)propyl)-naphthalene-1,4,5,8-tetracarboxylic diimide]-alt-[5,5′-bis(2-thienyl)-2,2′-bithiophene]} [P(NDICL-T2)] with cardanol-based side chains via Stille coupling to enhance electron mobility. Replacing the 2-octyldodecyl side chain with cardanol in P(NDICL-T2) improved electron mobility due to increased chain flexibility and ordered packing. Lower glass transition temperature (t_g), red-shifted UV-vis absorption, results from crystalline structure analysis, indicating tighter lamellar spacing and enhanced molecular ordering, and smoother surface morphology confirmed the enhanced intermolecular interactions and uniform film formation. Full article

A group of bithiophenyl compounds comprising the cyanoacrylate moiety were designed and successfully synthesized. The optical, (spectro)electrochemical, and aggregation-induced emission properties were studied. DFT calculations were used to explain the reaction’s regioselectivity and to determine the molecules’ energy parameters (i.e., band gaps, HOMO levels, and LUMO levels). The aggregation-induced emission of compounds has been studied in the mixture of DMF (as a good solvent) and water (as a poor solvent), with different water fractions ranging from 0% to 99%. It has been shown that there are differences in the physicochemical properties of the obtained compounds due to the length of the alkyl chain in the ester group. Investigated derivatives were tested for their potential use in visualizing latent fingerprints and electrochromic materials. Full article

The electrochromic phenomenon of conducting polymer is mainly dominated by the π-π* band transition. The π conjugation is influenced by the coplanarity between polymer units, deviations from which can lead to an increased ionization potential and band gap values. In order to investigate the effect of plane distortion angle on electrochromic color in the main chain structure of polymerization, high-performance poly(3,3′-dimethyl-2,2′-bithiophene) (PDMeBTh) with a large plane distortion angle is successfully synthesized in boron trifluoride diethyl etherate (BFEE) by the electrochemical anodic oxidation method. The electrochemical and thermal properties of PDMeBTh prepared from BFEE and ACN/TBATFB are compared. The electrochromic properties of PDMeBTh are systematically investigated. The PDMeBTh shows a different color change (orange-yellow in the neutral state) compared to poly (3-methylthiophene) (light-red in the neutral state) due to the large torsion angle between thiophene rings of the main polymer chain. The optical contrast, response time, and coloring efficiency (CE) of the prepared PDMeBTh are also studied, which shows good electrochromic properties. For practical applications, an electrochromic device is fabricated by the PDMeBTh and PEDOT. The color of the device can be reversibly changed between orange-yellow and dark blue. The light contrast of the device is 27% at 433 nm and 61% at 634 nm. The CE value of the device is 403 cm² C⁻¹ at 433 nm and 577 cm² C⁻¹ at 634 nm. The constructed device also has good open circuit memory and electrochromic stability, showing good potential for practical applications. Full article

Antimony (Sb) is currently a widespread element with key roles in telecommunication, sustainable energy, and military industries, among others. Its significant toxicity determines the need to realize sensors for water, air, and soil and the industrial process monitoring of Sb species. Unfortunately, no antimony sensors exist so far, and just laboratory analysis methods are in use. We aimed to contribute to the development of optical sensors for the metalloid by tailoring, for the first time, luminescent Ru(II) and Re(I) polypyridyl complexes to probe and quantify the presence of Sb(III). The molecular design of the complexes includes the multifunctional Sb-binding 2-(2,2′-bithien-5-yl)-1H-imidazo[4,5-f]-1,10-phenanthroline (btip) ligand that ensures the molecular binding of Sb(III) in organic media. The Ru(II)-btip complex is additionally endowed with one 2,2′-bipyrazine (bpz) or two 1,4,5,8-tetraazaphenanthrene (tap) ligands, namely [Ru(bpz)(btip)₂]²⁺ and [Ru(tap)₂(btip)]²⁺, that boost the excited state oxidation potential of the probe, leading to an intramolecular photoinduced electron transfer from btip to the Ru(II) core. The latter is suppressed upon interaction with Sb(III), leading to an 11-fold increase in both the luminescence intensity and lifetime of [Ru(bpz)(btip)₂]²⁺ in the presence of ca. 50 μmol L⁻¹ of SbCl₃ in organic medium. The fluorescence intensity of [Re(CO)₃(H₂O)(btip)]⁺ also increases upon interaction with Sb(III) but to a much lesser extent due to the intraligand π*→π nature of its emission compared to the Ru(II) ligand-to-metal excited state deactivation. However, the weak π*→d emission band in the red spectral region of the former is quenched by the semimetallic element. The sensing mechanisms of the Ru(II)- and Re(I)-btip probes that allow luminescence intensity (Ru, Re), ratiometric (Ru), and lifetime measurements (Ru) are compared and discussed in this initial solution sensing study. Full article

A systematic investigation of optical, electrochemical, photophysical, and electrooptical properties of printable green color-emitting polymer (poly(9,9-dioctylfluorene-alt-bithiophene)) (F8T2) and spiro-copolymer (SPG-01T) was conducted to explore their potentiality as an emissive layer for wearable polymer light-emitting diode (PLED) applications. We compared the two photoactive polymers in terms of their spectral characteristics and color purity, as these are the most critical factors for wearable lighting sources and optical sensors. Low-cost, solution-based methods and facile architecture were applied to produce rigid and flexible light-emitting devices with high luminance efficiencies. Emission bandwidths, color coordinates, operational characteristics, and luminance were also derived to evaluate the device’s stability. The tuning of emission’s spectral features by layer thickness variation was realized and was correlated with the interplay between H-aggregates and J-aggregates formations for both conjugated polymers. Finally, we applied the functional green light-emitting PLED devices based on the two studied materials for the detection of Rhodamine 6G. It was determined that the optical detection of the R6G photoluminescence is heavily influenced by the emission spectrum characteristics of the PLED and changes in the thickness of the active layer. Full article