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Pd/TiO <sub/>2</sub> -Photocatalyzed Self-Condensation of Primary Amines To Afford Secondary Amines at Ambient Temperature
摘要： Symmetric secondary amines were synthesized by the self-condensation of primary amines over a palladium-loaded titanium dioxide (Pd/TiO2) photocatalyst. The reactions a?orded a series of secondary amines in moderate to excellent isolated yields at ambient temperature (30 °C, in cyclopentyl methyl ether). Applicability for one-pot pharmaceutical synthesis was demonstrated by a photocatalytic reaction sequence of self-condensation of an amine followed by N-alkylation of the resulting secondary amine with an alcohol.
关键词： secondary amines,Pd/TiO2,self-condensation,primary amines,photocatalysis
更新于2025-09-23 15:21:21
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Organic Amines as Targeting Stabilizer at the Polymer/Fullerene Interface for Polymer:PC <sub/>61</sub> BM Solar Cells
摘要： Herein, it is demonstrated that a small amount (0.05% in weight ratio) of polyethyleneimine (PEI) can effectively suppress the “burn-in” degradation of both PTB7-Th:PC61BM and P3HT:PC61BM cells, similar to the piperazine derivatives, suggesting that organic amines can serve as universal stabilizer in polymer:PC61BM solar cells. Light-induced electron spin resonance (LESR) spectroscopy measurement shows a higher ESR signal intensity of PC61BM anions in 0.2% PEI-doped film than in 1% piperazine-doped film. Moreover, no piperazine is detected in a 10% (w/w) piperazine-doped film by gas chromatography–mass spectrometry (GS─MS). These results suggest that the residual piperazine in the blend film is very low, which can be understood by the high volatility of piperazine. Quantum calculations are performed on the intermolecular binding energy (EB) between polymer (using model repeating units), PC61BM, and piperazine molecules. Results reveal that piperazine prefers to localize at the polymer:fullerene interface by complexing with PC61BM (in P3HT:PC61BM) or PTB7-Th (in PTB7-Th:PC61BM system), which indicates that the photo dimerization of PC61BM which causes the “burn-in” degradation of polymer:fullerene solar cells mainly happens at the donor/acceptor interface, and the organic amine serves as the targeting stabilizer at the interface.
关键词： quantum calculations,polymer solar cells,organic amines,stabilizers
更新于2025-09-23 15:21:01
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Aromatic amine passivated TiO2 for dye-sensitized solar cells (DSSC) with ~9.8% efficiency
摘要： In this work, the e?ciency of dye-sensitized solar cells (DSSC) was improved by capping TiO2 with simple aromatic amines as a complexing agent. The aromatic amines, aniline and o-phenylenediamine capped TiO2 composites were synthesized via hydrothermal route and used as scattering layer in dye-sensitized solar cell (DSSC). Markedly, the maximum photo-conversion e?ciency of 9.84% was achieved with o-phenylenediamine capped-TiO2 composite as o-phenylenediamine capped-TiO2 showed higher re?ectivity than the pristine TiO2, which is highly bene?cial for re?ecting the photons back to photoanode. In addition, the average life time of carriers in o-phenylenediamine capped-TiO2 was found to be 9.8 ms, which was 2 times higher than the pristine TiO2 (4.29 ms).
关键词： Aromatic amines,DSSC,Scattering layer,Electron injection,TiO2,Lifetime
更新于2025-09-23 15:21:01
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Conjugated HCl-doped polyaniline for photocatalytic oxidative coupling of amines under visible light
摘要： HCl-Doped polyaniline (PANI-ES) and PANIs of different oxidation states were prepared by a typical oxidative polymerization and subsequent redox reaction, respectively. The photocatalytic performance of PANIs towards selective benzylamine oxidation reactions under visible light was investigated. PANI-ES containing a polaron structure exhibited the highest light-induced activity (54.9%). The results show that the formation of the surface complex between PANI-ES and adsorbed amine should be responsible for the enhanced visible light activity. The newly formed polaron band in PANI-ES has a greater number of delocalized electrons, which can facilitate electron transfer and thus improve the photoactivity. These results indicate that conjugated conducting polymers can be efficient visible light-responsive nonmetal photocatalysts for green synthesis.
关键词： Conjugated polyaniline,Amines,Visible light,Oxidative coupling,Photocatalysis
更新于2025-09-19 17:15:36
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CO2-Triggered Reversible Phase Transfer of Graphene Quantum Dots for Visible Light-Promoted Amines Oxidation
摘要： Emerging as novel photoluminescent nanomaterials, carbon dots have attracted increasing attentions in photocatalytic application such as hydrogen evolution, carbon dioxide reduction, pollutants degradation and organic synthesis. However, it is always a cumbersome process to seperate the carbon dots from the reaction system, which may limit their application in photocatalysis. Here, we report a graphene quantum dot with CO2-switchable reversible phase transfer performance via a facile surface functionlization approach. The mechanism of this hydrophilicity and hydrophobicity alteration involves protonation-deprotonation transformation and reversibly formation of hydrophilic bicarbonates salts when bubbling and removal of CO2. Afterwards, the obtained graphene quantum dot is utilized as a visible light photocatalyst for oxidative coupling of amines. Our photocatalyst demonstrates an excellent catalytic efficiency with both high reaction conversion and selectivity being achieved. Furthermore, graphen quantum dot could be recycled via a simple CO2 bubbling method.
关键词： graphene quantum dot,reversible phase transfer,visible light photocatalysis,CO2-switchable,amines oxidation
更新于2025-09-19 17:13:59
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An approach to analysis of primary amines by a combination of thin‐layer chromatography and matrix‐assisted laser desorption ionization mass spectrometry in conjunction with post‐chromatographic derivatization
摘要： On-spot derivatization has been suggested for the modification of primary amine containing compounds for their analysis by thin-layer chromatography hyphenated with matrix-assisted laser desorption ionization mass spectrometry. The proposed approach was based on post-chromatographic treatment of separated analytes inside the chromatographic zones on the thin-layer chromatography plates by tris(2,6-dimethoxyphenyl)methilium reagent. The derivatives, containing permanent positive charge, reveal exceptionally intense peaks of their cationic moieties and high signal/noise ratio in mass spectra recorded directly from the plates. The method was tested on a series of aliphatic, aromatic, and amine-containing pharmaceuticals.
关键词： thin-layer chromatography,mass spectrometry,primary amines,matrix-assisted laser desorption/ionization,derivatization
更新于2025-09-19 17:13:59
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Robust, Scalable Synthesis of the Bulky Hagfeldt Donor for Dye‐Sensitized Solar Cells
摘要： The bulky triarylamine group commonly referred to as the “Hagfeldt donor” is a key building block found in many of the organic dyes used in dye-sensitized applications such as dye-sensitized solar cells (DSCs). This building block has gained popularity owing to its presence in many of the best-performing DSC devices reported to date, which use dyes containing this donor group. The Hagfeldt donor provides a desirable 3-dimensional structure that aids in surface protection of electrons injected into the semiconductor from oxidants in the electrolyte, allowing for record-setting cobalt- and copper-based redox shuttles to be utilized more frequently. However, the synthesis of this molecule has proven unreliable for many routes. This study concerns a novel, reliable and scalable five-step synthesis of the Hagfeldt donor.
关键词： dyes,amines,redox shuttles,Hagfeldt donor,solar cells
更新于2025-09-11 14:15:04
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Raman Characterization of Phenyl-Derivatives: From Primary Amine to Diazonium Salts
摘要： The objective of the present work is to use Raman spectroscopy for characterizing, the fate of phenyl-derivatives, from phenyl-amines to aryl-diazonium derivatives (ADD). Four ADD were investigated: (i) benzene diazoniumtetrafluoroborate (DS), (ii) 4-decyl benzene diazoniumtetrafluoroborate (DS-C10H21), (iii) 4-carboxybenzene diazoniumtetrafluoroborate (DS-COOH) and (iv) 4-(aminoethyl) benzene diazoniumtetrafluoroborate (DS-(CH2)2NH2). Raman investigation of the above ADD confirmed the existence of an N≡N bond stretching in the range of 2285-2305 cm-1. Moreover, the strong band related to CH in plane-bending and C-N-stretching modes in the 1073-1080 cm-1 range, is a signature of phenyl derivatives stemming from ADD. Furthermore, we analyzed and discuss the H-N-(ring) symmetric stretching modes and the ring-N, as well as the benzene-ring vibrational modes, the C-H related vibrations and the functions in para-position carried by the aromatic ring. The effect of structural changes, the conformational rearrangements from amines to ADD and the influence of the substituent located in the para-position on Raman modes, were examined as well. Finally, Raman experiments supported by Density Functional Theory (DFT) modeling allowed us to determine the crystalline structure of DS-COOH.
关键词： Raman,Diazonium salts,Synthesis and characterization,DFT calculations,Phenyl-amines
更新于2025-09-04 15:30:14
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Salicylic acid complexed with TiO2 for visible light-driven selective oxidation of amines into imines with air
摘要： The interplay of salicylic acid (SA) and reactive oxygen species (ROS) can modulate biotic and abiotic stress of plants, essential biological aerobic oxidation processes. Meanwhile, ROS plays a critical role in TiO2 photocatalytic system for the degradation of organic species. Herein, we developed a system consisted of SA and TiO2 aiming at the selective oxidation of organic molecules by ROS. Interestingly, SA complexed with TiO2 leads to ligand-to-metal charge transfer (LMCT) under visible light irradiation. The charge transfer from ligand (chemically adsorbed SA) to metal (conduction band of TiO2) activates O2 to ROS, superoxide (O2?). The positive charge located at ligand SA is connected with (2,2,6,6-tetramethylpiperidin-1-yl)oxyl (TEMPO) catalysis for direct two-electron oxidation of amines and later regenerated by O2. SA and its derivatives were screened as ligands of TiO2 for the selective aerobic oxidation of amines into imines under blue light-emitting diode (LED) irradiation in which 5-CH3O-SA (5-methoxysalicylic acid, 0.8 mol%) complexed with anatase TiO2 and coupled with TEMPO (5 mol%) confers significantly better results than the others. By this visible light LMCT route, both primary amines and secondary amines can be selectively oxidized into corresponding imines with atmosphere O2 as the terminal oxidant. Importantly, the desired product of N-benzylidenebenzylamine can be isolated in 92% yield.
关键词： Salicylic acid,Titanium dioxide,Amines,Photocatalysis,Surface complex
更新于2025-09-04 15:30:14