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- 实验方案
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Phase-dependent photoluminescence of non-symmetric 2,1,3-benzothiadiazole liquid crystals
摘要： In order to understand the effect of disubstitution on calamitic liquid crystals, a series of non-symmetric 2,1,3-benzothiadiazole compounds were synthesized and characterized. These specific molecular architectures without the C2 axis were prepared to investigate their mesomorphism and physical properties and to compare them with symmetric molecules. Their liquid crystalline behavior was studied by differential scanning calorimetry, polarized optical microscopy and X-ray diffraction. The thermal properties evidenced the influence of non-symmetric design on the formation of liquid crystalline phases. Photophysical studies were performed in solution and with films, where these materials displayed intense photoluminescence between 500–650 nm, high quantum yields (ΦF = 0.62 – 0.96) and strong solvatochromism. Photoluminescence was measured as a function of temperature, displaying a strong dependence on the phase.
关键词： Heterocycles,Liquid crystals,Luminescence,2,1,3-Benzothiadiazole
更新于2025-09-23 15:23:52
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Azaindolo[3,2,1-jk]carbazoles: New Building Blocks for Functional Organic Materials
摘要： The preparation and characterization of twelve azaindolo[3,2,1-jk]carbazoles is being presented. Ring closing C-H activation allowed for the convenient preparation of six mono and six twofold nitrogen substituted indolo[3,2,1-jk]carbazole derivatives whereupon ten of the materials have not been described in literature before. The photophysical and electrochemical characterization of the developed materials revealed a significant impact of the incorporation of pyridine like nitrogen into the fully planar indolo[3,2,1-jk]carbazole backbone. Furthermore, the nitrogen position decisively impacts intermolecular hydrogen bonding and thus the solid state alignment. Ultimately, the versatility of the azaindolo[3,2,1-jk]carbazoles scaffold suggests this class of materials as an attractive new building block for the design of functional organic materials.
关键词： heterocycles,functional organic materials,C-H activation
更新于2025-09-23 15:22:29
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Control of excited state conformation in B,N-acenes
摘要： Herein we show a new concept to control conformation in molecules through harvesting negative hyperconjugation. The strategy was realized with the 2,3,1,4-benzodiazadiborinane scaffold that was prepared by a new synthetic protocol. Photochemical studies identify dual light emission that can be assigned to originate from well-defined conformers. The emission at longer wavelength can be switched off by restricting the rotational degrees of freedom in the solid-state as well as by controlling the energy level of the excited states through solvent polarity.
关键词： B,dual fluorescence,azobenzene,N heterocycles,azaborine,synthetic methods
更新于2025-09-23 15:22:29
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Control of excited state conformation in B,N-acenes
摘要： Herein we show a new concept to control conformation in molecules through harvesting negative hyperconjugation. The strategy was realized with the 2,3,1,4-benzodiazadiborinane scaffold that was prepared by a new synthetic protocol. Photochemical studies identify dual light emission that can be assigned to originate from well-defined conformers. The emission at longer wavelength can be switched off by restricting the rotational degrees of freedom in the solid-state as well as by controlling the energy level of the excited states through solvent polarity.
关键词： dual fluorescence,azobenzene,B,N heterocycles,azaborine,synthetic methods
更新于2025-09-23 15:22:29
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The impact of replacement of nitrogen with phosphorus atom in the pyromellitic diimides on their photophysical and electrochemical properties
摘要： Exploration of optoelectronic properties of novel phosphorus-embedded π-conjugated compounds would provide us with fundamental information about the design of hitherto unknown electroactive organic materials. Herein, detailed photophysical and electrochemical profiles of a series of benzene-cored diketophosphanyl compounds were investigated with steady- and time-resolved spectroscopic and spectroelectrochemical techniques. The comparative studies revealed the impact of phosphorus and nitrogen atoms on their triplet energies and on the behaviour of electrochemical processes to form radical species.
关键词： photophysics,phosphorus heterocycles,π-conjugated compounds,radical,electrochemistry
更新于2025-09-23 15:21:21
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Synthesis of Chalcogenides and Metal Complex of 2-Phenylbenzo[ 1,3,2]dioxophosphinin-4-one
摘要： The chalcogenides and the metal complexes of 2-phenyl-benzo[1,3,2]dioxophosphinin-4-one are prepared by single step reaction of 2-phenyl-benzo[1,3,2]dioxophosphinin-4-one (1) with DMSO, elemental S, Se and W(CO)5CH3CN.
关键词： P-heterocycles,Salicylic acid,Phosphorous-chalcogenides,Triethylamine
更新于2025-09-23 15:21:01
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Silvera??chitosan nanocomposite as a plasmonic platform for SERS sensing of polyaromatic sulfur heterocycles in oil fuel
摘要： Herein, a silver-chitosan nanocomposite for applications in surface enhanced Raman spectroscopy (SERS) sensing was proposed. It was shown that optically transparent chitosan coatings with 0.8 μm thickness allow penetration of target analytes to silver nanoparticles and the analysis in both polar and nonpolar solvents. Under the chosen conditions, chitosan formed continuously smooth films and coatings stabilizing rough nanostructured metallic surfaces and served as a suitable matrix for immobilization, uniform spreading, and preconcentration of the analytes. Polycyclic aromatic sulfur heterocycles were chosen as target analytes being one of the most important fuel quality markers, hazardous components and the hardest-to-remove impurities. For the most effective immobilization and even distribution of the analytes onto a nanostructured metallic surface, an additional polymer layer of chitosan was found to be needful. The presence of thin films of chitosan resulted in higher reproducibility of SERS spectra as compared to bare nanostructured silver substrates. Additionally, the developed nanocomposite SERS sensors provided the rapid determination of dibenzothiophene and its derivatives in isooctane with the threshold of detection better than 0.1 μM. This approach was successfully applied in the analysis of real fuel samples and the results agreed well with independently measured FTIR and GC-MS data.
关键词： chitosan,nonpolar solvents,polycyclic aromatic sulfur heterocycles,silver nanoparticles,surface enhanced Raman spectroscopy
更新于2025-09-23 15:19:57
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Comparison of 1-Propyl-5H-tetrazole and 1-Azidopropyl-5H-tetrazole as Ligands for Laser Ignitable Energetic Materials
摘要： Laser ignitable explosives are potential candidates in future applications for replacing toxic and very sensitive primary explosives, which are used in current devices. In this study, the literature unknown ligand 1-azidopropyl-5H-tetrazole (APT, 1) was synthesized for the first time and applied in energetic coordination compounds (ECC). The complexes are based on different 3d transition metals (Mn2+, Fe2+, Cu2+, and Zn2+) as well as various oxidizing anions (NO3?, ClO4?, ClO3?) and were tested towards their capability as laser ignitable explosives. Furthermore, analogous complexes based on the literature known ligand 1-propyl-5H-tetrazole (PT, 2) were investigated, for comparing the influence of the additional azide group towards the performance of the ECC. Toxicity measurements using Vibrio fischeri and the decreased sensitivities prove their usability as safer laser ignitable explosive with lower toxicities compared to currently used explosives.
关键词： tetrazole ligands,laser ignition,nitrogen heterocycles,structure elucidation,energetic coordination compounds
更新于2025-09-23 15:19:57
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Molecular engineering of an electron-transport triarylphosphine oxide-triazine conjugate toward high-performance phosphorescent organic light-emitting diodes with remarkable stability
摘要： Organic electron-transport materials are an essential component to boost performances and stability of organic light-emitting diodes. We present a robust organic electron-transport compound 3-(6-(3-(4,6-bis(4-biphenylyl)-1,3,5-triazin-2-yl)phenyl)pyridin-2-yl)phenyldiphenylphosphine oxide by facilely coupling the triphenylphosphine oxide moiety to the 2-phenyl-4,6-bis(4-biphenylyl)-1,3,5-triazine unit via a 2,6-pyridinylene linker. It is well soluble in weakly polar solvents and possesses a high Tg of 123 °C with an exceptional Td≈470 °C at 1% weight loss and deep HOMO/LUMO levels of ca. ?6.45/?3.06 eV. The phosphorescent spectrum measured in solid state at 77 K reveals a notable triplet energy of 2.88 eV. n-Doping with 8-hydroxyquinolatolithium (Liq) produces the electron mobility value of 4.66×10?5–3.21×10?4 cm2 V?1 s?1@(2–5)×105 V cm?1. Moreover, the contrasting solubility of the bromo reaction intermediate and the new compound in alcoholic solvents facilitates separation. The characterizations of bottom- and top-emission green phosphorescent OLEDs involving this single Liq-doped electron-transport layer reveal long stability. In particular, the latter provides outstanding performances with 77.4 cd A–1 (corresponding to an EQE of 18.7%) and 86.8 lm W–1@ca. 1000 cd m?2, based on the green emitter bis(2-phenylpyridine)(2-(4-methyl-3-phenylphenyl)pyridine)iridium(III). Moreover, driven by a constant current for ca. 640 h, the initial luminance of 1000 cd m–2 appears almost no decay.
关键词： halogen impurities,heterocycles,electron-transport materials,lifetime,phosphine oxides
更新于2025-09-19 17:13:59
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Synthesis and characterization of vinazene end capped dipyrrolo[2,3-b:2′,3′-e]pyrazine-2,6(1H,5H)-dione small molecules as non-fullerene acceptors for bulk heterojunction organic solar cells
摘要： Two dipyrrolo[2,3-b:2',3'-e]pyrazine-2,6(1H,5H)-dione (PzDP)-based small molecules DPDV and DPEV with PzDP as the core building block and 4,5-dicyano-2-vinylimdazole (vinazene) as end-cap units were synthesized by Heck coupling reaction. The photophysical, electrochemical properties of DPDV and DPEV were investigated and applied as non-fullerene acceptors (NFAs) for solution-processed bulk heterojunction (BHJ) organic solar cells (OSCs). Theoretically evaluated optical and electrochemical properties were well matched with experimental values. Solution processed BHJOSCs employing poly[(4,8-bis[(2-ethylhexyl)oxy]benzo[1,2-b:4,5-b′]dithiophene-2,6-diyl)-alt-(3-fluoro-2-[(2-ethylhexy)carbonyl]thieno[3,4-b]thiophene-4,6-diyl)] (PTB7) as the donor polymer and DPDV/ DPEV as NFAs exhibited short-circuit current density (JSC) of 2.23/ 2.44 mA cm-2, open-circuit voltage (VOC) of 0.54/ 0.55 V, fill factor (FF) of 36.97/ 38.62 and power conversion efficiency (PCE) of 0.45/0.52%, respectively.
关键词： heterocycles,cyclic voltammetry,bulk heterojunction organic solar cells,non-fullerene acceptors materials,organic semiconductors
更新于2025-09-11 14:15:04