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(Poly)terephthalates with Efficient Blue Emission in the Solid State
摘要： We prepared dimethyl and diaryl 2,5-dialkoxyterephthalates from dimethyl 2,5-dihydroxyterephthalate in good-to-high yields via alkylation or a sequence of alkylation, hydrolysis, chlorination, and condensation. The absorption spectra of the dialkoxyterephthalates contain a small band at 332–355 nm, which could be assigned to intramolecular charge-transfer transition from the alkoxy to alkoxycarbonyl groups on the basis of theoretical calculations using density functional theory. The dialkoxyterephthalates exhibited blue fluorescence with moderate-to-excellent quantum yields not only in solution but also in the solid state, such as a poly(methyl methacrylate) (PMMA) film and a powder. The solid-state quantum yields of the diisopropoxy-substituted terephthalates were similar or considerably higher than those of the dimethoxy-substituted counterparts. Copolymerization of 2,5-diisopropoxyterephthaloyl chloride and 1,4-butanediol with or without terephthaloyl chloride gave brilliantly blue fluorescent polymers, whose quantum yields were 0.72 and 0.71 in toluene and 0.46 and 0.40 in the neat film, respectively. Furthermore, white emission was achieved when a fluorescent yellow 2,5-diaminoterephthalate was doped into the thin film of the blue fluorescent polymer at 0.4 wt %.
关键词： materials science,arenes,donor-acceptor systems,conjugation,fluorescence
更新于2025-09-23 15:23:52
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Tertiary Amines Differentiated from Primary and Secondary Amines by Active Ester-Functionalized Hexabenzoperylene in Field Effect Transistors
摘要： Herein, we report two novel derivatives of hexabenzoperylene (HBP) that are functionalized with ester groups. Methyl acetate functionalized HBP (1) in single crystals self-assembles into a supramolecular nanosheet, which has a two-dimensional π-stack of HBP sandwiched between two layers of ester groups. With the same self-assembly motif, active ester-functionalized HBP (2) in field effect transistors has enabled differentiation of tertiary amines from primary and secondary amines, in agreement with the fact that active ester reacts with primary and secondary amines but not with tertiary amines to form amides.
关键词： sensors,organic field effect transistors,organic semiconductors,self-assembly,arenes
更新于2025-09-23 15:22:29
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The synthesis of water-soluble phosphate pillar[5]arenes functionalized graphene as a fluorescent probe for sensitive detection of paraquat
摘要： We describe a selective and sensitive fluorescence platform for the detection of paraquat (PQ) based on competitive host–guest recognition between phosphate pillar[5]arenes (PWP5) and probe (Safranine T, ST) with using PWP5 functionalized reduced graphene (PWP5-rGO) as the receptor. PQ is a positive charge molecule that is captured by PWP5 via electrostatic interactions. The host-guest interaction between PWP5 and PQ is studied by 1H NMR. Therefore, a selective and sensitive fluorescence sensing of detection PQ is developed. It has a linear response ranges of 0.01?2.0 and 2.0?50.0 μM and a low detection limit of 0.0035 μM (S/N=3) for PQ. The sensing platform is also used to test PQ in two water samples with satisfying results. It suggests that this approach has potential applications for the determination of PQ.
关键词： phosphate pillar[5]arenes,paraquat,reduced graphene,host–guest recognition
更新于2025-09-23 15:21:21
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Novel Competitive Fluorescence Sensing Platform for L-carnitine Based on Cationic Pillar[5]Arene Modified Gold Nanoparticles
摘要： Supramolecular host-guest interaction and sensing between cationic pillar[5]arenes (CP5) and L-carnitine were developed by the competitive host-guest recognition for the first time. The fluorescence sensing platform was constructed by CP5 functionalized Au nanoparticles (CP5@Au-NPs) as receptor and probe (rhodamine 123, R123), which shown high sensitivity and selectivity for L-carnitine detection. Due to the negative charge and molecular size properties of L-carnitine, it can be highly captured by the CP5 via electrostatic interactions and hydrophobic interactions. The host-guest mechanism between PP5 and L-carnitine was studied by 1H NMR and molecular docking, indicating that more affinity binding force of CP5 with L-carnitine. Therefore, a selective and sensitive fluorescent method was developed. It has a linear response of 0.1–2.0 and 2.0–25.0 μM and a detection limit of 0.067 μM (S/N = 3). The fluorescent sensing platform was also used to detect L-carnitine in human serum and milk samples, which provided potential applications for the detection of drugs abuse and had path for guarding a serious food safety issues.
关键词： L-carnitine,cationic pillar[5]arenes,host–guest recognition,Au nanoparticles
更新于2025-09-23 15:19:57
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Aromatic Charge Resonance Interaction Probed by Infrared Spectroscopy
摘要： Charge resonance is a strong attractive intermolecular force in aromatic dimer radical ions. For cations, this stabilization arises from sharing a positive charge between two identical or different molecules (A2 + or AB+) with comparable ionization energies within the π-stacked dimer. Despite its importance, this fundamental interaction has not been characterized at high resolution by spectroscopy of isolated dimers. Herein, we employ vibrational infrared spectroscopy of cold aromatic pyrrole dimer cations to precisely probe the charge distribution by measuring the frequency of the isolated NH stretch mode (νNH). We observe a linear correlation between νNH and the partial charge q on the pyrrole molecule in different environments. Subtle effects of symmetry reduction, such as substitution of functional groups (here pyrrole → N-methylpyrrole) or asymmetric solvation (here by an inert N2 ligand), sensitively shifts the charge distribution toward the moiety with lower ionization energy. This general approach provides a precise experimental probe of the asymmetry of the charge distribution in such aromatic homo- and heterodimer cations.
关键词： charge resonance,IR spectroscopy,cations,structure elucidation,arenes
更新于2025-09-10 09:29:36