- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
Thermal Stability of LED Molecules Triphenylamine-Based Aromatic Polyamides: Spectral and Electrochemistry Applications
摘要： By using the aromatic nucleophilic displacement reaction of 4-fluorobenzonitrile with three aniline-derivatives using sodium hydride as the base synthesized new dinitriles intermediates (A-CN), (B-CN) and (C-CN). After alkaline hydrolysis of these resultants three di acid monomers e.g., 4,4'-dicarboxy-4''-ethylenetriphenylamine (A-OH), 4,4'-dicarboxy-4''-isopentyl-triphenylamine (B-OH), 4'-dicarboxy-4''-phenoxy-triphenylamine (C-OH) were obtained. A series of poly(amine-amide)s were prepared by the phosphorylation poly-condensation reaction with different aromatic diamines. The chemical structures of all the resultant compounds and poly(amine-amide)s were identified by FTIR, 1H and 13C NMR techniques. These aromatic poly(amine-amide)s exhibited excellent thermal stability with high glass transition temperatures (Tg). Solutions diluted in N-methyl pyrrolidone of these polyamides appeared a strong UV-visible absorption in the blue region. These polymers exhibited cyclic voltammetry of the resulting polyamides films cast onto an ITO-coated glass substrate in dry acetonitrile containing 0.1 M of tetrabutylammonium perchlorate as an electrolyte exhibited one oxidation redox couples.
关键词： LED-molecules,Emitting diodes,Thin layer
更新于2025-11-19 16:56:42
-
Tuning Molecular Solar Thermal properties by modification of a promising norbornadiene photoswitch
摘要： Carefully targeted modifications to the norbornadiene-quadricyclane couple should give molecules with great potential for solar energy storage. Here we report the synthesis of derivatives of a well-studied compound, 2-cyano-3-anisyl norbornadiene (NBD5). The conjugation was extended by conversion of the nitrile into acrylonitrile and acrylate derivatives over two steps. Despite red-shifting the absorbance properties, the metastable quadricyclanes exhibited extremely short lifetimes. Meanwhile, treatment of NBD5 with acetyl halides in the presence of aluminum trihalides led to the formation of 7-acetyl norbornenes through a Meerwein-Wagner rearrangement. Subsequent transformations made it possible to synthesise norbornadienes with varying degrees of steric bulk at the 7-position of the molecular scaffold. It was found that the bulkier this group was, the more stable the quadricyclane form. This reaction sequence allows for the synthesis of norbornadiene derivatives which are more suited to molecular solar thermal applications in domestic heating despite providing a slightly lower energy density.
关键词： Meerwein-Wagner rearrangement,conjugation,strained molecules,photochromism,energy density
更新于2025-11-19 16:56:35
-
Highly selective detection of Fe3+, Cd2+ and CH2Cl2 based on a fluorescent Zn-MOF with azine-decorated pores
摘要： The design and synthesis of sensitive and selective luminescent materials as chemical sensing agents is a fundamental goal in fluorescence assays. Considering high porosity, large surface area, excellent photoluminescence property of metal-organic frameworks (MOFs), luminescent properties of a microporous azine-functionalized MOF, TMU-16, dispersed in different metal ions and solvents have been investigated systematically. The TMU-16 displays superb luminescence emission, and it can detect Fe(III) and Cd(II) ions with high selectivity, excellent sensitivity, and short response time (<1 min). The emission intensities of TMU-16 were quenched upon the addition of Fe3+ and increased upon the addition of Cd2+. The detection limits of TMU-16 for Fe3+/Cd2+ in DMF are estimated to be 0.2 and 0.5 μM, respectively. The effect of other metal ions on the fluorescence intensity of the MOF was also studied and other metal ions showed low interference response in recognition of Fe3+ and Cd2+. Furthermore, TMU-16 exhibits distinct solvent-dependent luminescent spectra with emission intensity significantly enhanced toward dichloromethane. More importantly, this is the first example of MOF-based luminescent sensor as efficient multifunctional fluorescence material which can use for selective sensing of Fe(III) and Cd(II) ions and small molecules such as CH2Cl2.
关键词： Small molecules,Metal ions,Luminescent,Sensing,Metal-organic frameworks,Detection
更新于2025-11-19 16:46:39
-
Reproduction of surface-enhanced resonant Raman scattering and fluorescence spectra of a strong coupling system composed of a single silver nanoparticle dimer and a few dye molecules
摘要： The spectral changes in surface-enhanced resonant Raman scattering (SERRS) and surface enhanced fluorescence (SEF) of single silver nanoparticle dimers adsorbed by near-single dye molecules are reproduced under strong coupling regimes. For the reproduction, the enhancement and quenching factors in SERRS and SEF are derived from the Purcell factors including both radiative and nonradiative plasmon modes. The Purcell factors are estimated using the coupling energies obtained by analyzing the spectral changes in plasmon resonance during SERRS and SEF decay processes on the basis of a classical hybridization model. The model is composed of a plasmon and a molecular exciton with phonon replicas accurately representing the molecular multi-level system. The reproduced SERRS spectral changes are consistent with the experimental ones. Furthermore, the calculated SEF spectral changes can reproduce the experimental ones by phenomenologically assuming transitions from ultra-fast SEF to conventional SEF with decreasing coupling energies.
关键词： strong coupling,hybridization model,silver nanoparticle dimer,dye molecules,Purcell factors,surface enhanced fluorescence,surface-enhanced resonant Raman scattering
更新于2025-09-23 15:23:52
-
Diketopyrrolopyrrole based small molecular semiconductors containing thiazole units for solution-processed n-channel thin-film transistors
摘要： In this work, three diketopyrrolopyrrole-based conjugated small molecular semiconductors characterized by the combination of a diketopyrrolopyrrole (DPP) central core, thiazole π-conjugated moiety, and dicyanovinyl end group with different alkyl side chain substituents, 2TzDPPA1-2DCV, 2TzDPPA2-2DCV, and 2TzDPPA3-2DCV were synthesized. These small molecules have a similar narrow band gap of about 1.50 eV and deep LUMO energy level at -4.30 eV. Under ambient conditions, electron mobilities of 0.28 cm2 V-1 s-1, 0.13 cm2 V-1 s-1, 0.25 cm2 V-1 s-1 for solution processed thin films of 2TzDPPA1-2DCV, 2TzDPPA2-2DCV, and 2TzDPPA3-2DCV were obtained, due to high crystallinity and well-organized molecular stacking. Compared with the other two materials, thin films of 2TzDPPA1-2DCV enable the best OFET performance with desirable Ion / Ioff rates exceeding of 107, attribute to the coefficient of smoother film morphology and stronger crystallinity. These results reveal that introducing the thiazole unit into the DPP-based conjugated skeleton is conducive to enhance the crystallinity and tailor LUMO energy levels which ensure good performance and excellent stability of these molecules as active materials for n-channel electronic devices.
关键词： small molecules,solution-processed n-channel thin-film transistors,thiazole unit,diketopyrrolopyrrole,air stability
更新于2025-09-23 15:23:52
-
Molecular-beam resonance method with Zeeman-decelerated samples: Application to metastable helium molecules
摘要： We use a multistage Zeeman decelerator to generate slow beams (v ≈ 100 m/s) of translationally cold, spin-polarized metastable a 3Σ+u He2 molecules and perform a precision measurement of their spin-rotation fine structure. The spin polarization results from the elimination of the high-field-seeking J = N spin-rotational component of each rotational level (rotational quantum number N) by the Zeeman deceleration process. By repopulating the J = N component from the J = N ± 1 low-field-seeking components using radio-frequency radiation, we measured the spin-rotation fine structure of 13 rovibrational levels with v = 0, 1 and N = 1–21. The low beam velocity and the resulting long interaction times with the radio-frequency radiation were exploited to determine the transition frequencies with a precision of 300 Hz.
关键词： metastable helium molecules,precision spectroscopy,molecular-beam resonance,Zeeman deceleration,spin-rotation fine structure
更新于2025-09-23 15:23:52
-
THz spectroscopy and first ISM detection of excited torsional states of <sup>13</sup> C-methyl formate
摘要： Context. An astronomical survey of interstellar molecular clouds needs a previous analysis of the spectra in the microwave and sub-mm energy range of organic molecules to be able to identify them. We obtained very accurate spectroscopic constants in a comprehensive laboratory analysis of rotational spectra. These constants can be used to predict the transitions frequencies very precisely that were not measured in the laboratory. Aims. We present the experimental study and its theoretical analysis for two 13C-methyl formate isotopologues to detect these two isotopologues for the first time in their excited torsional states, which lie at 130 cm?1 (200 K) in Orion-KL. Methods. New spectra of HCOO13CH3 (13C2) methyl formate were recorded with the mm- and submm-wave spectrometer in Lille from 50 to 940 GHz. A global fit for vt = 0 and 1 was accomplished with the BELGI program to reproduce the experimental spectra with greater accuracy. Results. We analysed 5728 and 2881 new lines for vt = 0 and 1 for HCOO13CH3. These new lines were globally fitted with 846 previously published lines for vt = 0. In consequence, 52 parameters of the RAM Hamiltonian were accurately determined and the value of the barrier height (V3 = 369.93168(395) cm?1) was improved. We report the detection of the first excited torsional states (vt = 1) in Orion-KL for the 13C2 and 13C1 methyl formate based on the present analysis and previously published data. We provide column densities, isotopic abundances, and vibrational temperatures for these species. Conclusions. Following this work, accurate prediction can be provided. This permits detecting 135 features of the first excited torsional states of 13C-methyl formate isotopologues in Orion-KL in the 80?280 GHz frequency range, without missing lines.
关键词： astrochemistry,ISM: molecules,line: identification,ISM: individual objects: Orion KL,submillimeter: ISM,astronomical databases: miscellaneous
更新于2025-09-23 15:23:52
-
The efficient photodesorption of nitric oxide (NO) ices
摘要： The study and quantification of UV photon-induced desorption of frozen molecules furthers our understanding of the chemical evolution of cold interstellar regions. Nitric oxide (NO) is an important intermediate species in both gas-phase and solid-phase chemical networks. In this work, we present quantitative measurements of the photodesorption of a pure NO ice. We used the tunable monochromatic synchrotron light of the DESIRS beamline of the SOLEIL facility near Paris to irradiate NO ices in the 6–13.6 eV range and measured desorption by quadrupole mass spectrometry. We find that NO photodesorption is very efficient, its yield being around 10?2 molecule per incident photon for UV fields relevant to the diffuse and dense interstellar medium. We discuss the extrapolation of our results to an astrophysical context and we compare photodesorption of NO to previously studied molecules.
关键词： methods: laboratory: solid state,ISM: abundances,ultraviolet: ISM,astrochemistry,ISM: molecules,molecular processes
更新于2025-09-23 15:23:52
-
Signal enhancement in laser diode thermal desorption-triple quadrupole mass spectrometry analysis using microwell surface coatings
摘要： Laser diode thermal desorption (LDTD) is an ionization source usually coupled to triple quadrupole mass spectrometry (QqQMS) and specifically designed for laboratories requiring high-throughput analysis. It has been observed that surface coatings on LDTD microwell plates can improve the sensitivity of the analysis of small polar molecules. The objective of the present study is to understand and quantify the effect of microwell surface coatings on signal intensity of small organic molecules of clinical, environmental and forensic interest. Experiments showed that the peak areas of diclofenac, chloramphenicol, salicylic acid and 11-nor-9-carboxy-Δ9-tetrahydrocannabinol obtained by LDTD-QqQMS increased by up to 3 orders of magnitude when using microwells coated with ethylenediaminetetraacetic acid (EDTA). Tests with different chelating agents and polytetrafluoroethylene as microwell surface coatings showed that nitrilotriacetic acid gave significantly higher peak areas for five out of the nine compounds that showed signal enhancement using chelating agents as coatings. Scanning electron microscopy studies of EDTA-coated and uncoated microwells showed that analytes deposited in the former formed more uniform and thinner films than in the latter. The enhancement effect of surface coatings in LDTD-QqQMS was explained mainly by the formation of homogenous and thinner layers of nanocrystals of analytes that are easier to desorb thermally than the layers formed when the analytes dry in direct contact with the bare stainless steel surface. Chemisorption of some analytes to the stainless steel surface of the microwell plate appeared to be a minor factor. Surface coatings widen the number of compounds analyzable by LDTD-QqQMS and can also improve sensitivity and limits of detection.
关键词： pharmaceuticals,high-throughput,hormones,pesticides,x-ray photoelectron spectroscopy,scanning electron microscopy,stainless steel,small organic molecules,chelating agents
更新于2025-09-23 15:23:52
-
Design, synthesis and structural optimization of two click modified butterfly molecules: Aggregation induced ratiometric fluorescence change and ICT associated hydrogen bonding effect in solvatochromic analysis
摘要： Two click modi?ed butter?y molecules are designed and synthesized having presence and absence of the aggregative moiety to differ between aggregation induced ratiometric emission changes via excimer formation and ICT associated hydrogen bonding effect. These two distinct phenomena can be successfully employed in solvatochromic analysis. This is also supported by the theoretical study through the structural variation of the two butter?y molecules.
关键词： Hydrogen bonding,Butter?y molecules,Ratiometric,AIE,Solvatochromic
更新于2025-09-23 15:22:29