Triphenylamine Derivatives Research Articles

Synthesis of Triphenylamine Derivative and Its Recognition for Hg2+ with “OFF-ON” Fluorescence Response Based on Aggregation-Induced Emission (AIE) Mechanism

Synthesis of Triphenylamine Derivative and Its Recognition for Hg²⁺ with “OFF-ON” Fluorescence Response Based on Aggregation-Induced Emission (AIE) Mechanism

AIE biofluorescent probe based on twisted cucurbit[14]uril for the detection of Fe(CN)63- anion in solutions and live kidney cells

The kidney is one of the important organs for removing metabolites to maintain the stability of the internal environment. In this study, an AIE effect supramolecular fluorescent probe (TPAPy@tQ[14]) was constructed based on twisted cucurbit[14]uril (tQ[14]) and a triphenylamine derivative (TPAPy) through host-guest interaction. TQ[14] could effectively inhibit the rotation of the TPAPy molecule, which triggered the AIE effect. This effect was manifested as the emission of bright yellow fluorescence. TPAPy@tQ[14] could ultrasensitively detect potential cyanide (K3[Fe{CN}6]) in an aqueous solution at a detection limit as low as 3.28 × 10−7 M. The unique nature of the positive charge of TPAPy@tQ[14] could rapidly cross the glomerular filtration barrier into HK-2 cells. In addition, this probe was successfully applied to distinguish excess Fe(CN)63− in HK-2 cells for cell imaging, providing a new detection method for early clinical identification of acute kidney injury (AKI).

Air-stable organic radicals in solid state from a triphenylamine derivative by UV irradiation

Spin-delocalization and steric protection are commonly used and effective strategies to realize stable organic radicals. A bisheptamido-functionalized triarylamines derivative(T1) can enhance the stability of TPA photo-generated radical cations in air by supramolecular self-assembly and “push-pull” dipole structure to expand conjugation, so as to obtain air-stable solid free radicals with a lifetime of more than 60 days, which is based on the best record of the air-stabilized solid TPA radical cations. The preliminary studies demonstrate that T1 may be a promising candidate for organic semiconductor radical materials.

Asymmetric cobalt porphyrins for oxygen reduction reactions: Boosted catalytic activity by the use of triphenylamine

Asymmetric metalloporphyrins have been rarely investigated in oxygen reduction reaction (ORR), which is probably due to the remaining unclear structural effects on electrocatalytic performance and the low synthetic yields. A remarkable feature of these molecules is their inherent large dipole moments, which can benefit the charge separation and electron density modification. Here we synthesize two asymmetric molecules A-Cb-CoPor and A-TPA-CoPor by substituting one of the meso-positions with carbazole and triphenylamine (TPA) derivatives, respectively, to coat on carbon black as ORR electrocatalysts. Density functional theory calculations suggest the well separation of electron density on the cobalt porphyrins. The electrochemical performances of the composites are performed in acid with comparing to a symmetric Co porphyrin-coated catalyst CoPor1/C. A-TPA-CoPor/C attains better ORR activity and selectivity than A-Cb-CoPor/C due to the structural merits of TPA unit. However, an identical electron transfer number of 3.6 is obtained by A-TPA-CoPor/C and CoPor1/C, which is possibly a trade-off result of the use of TPA from its structural advantage and deleterious electron-donating ability. Impressively, both asymmetric porphyrin-based composites exhibit greater limiting current densities than CoPor1/C, which mainly originates from the reduced charge transfer resistance as suggested by the impedance measurements. Our work demonstrates the promise of the asymmetric molecular approach as a viable strategy for efficient ORR catalysts.

Stimuli-Responsive Electrospun Fluorescent Fibers Augmented with Aggregation-Induced Emission (AIE) for Smart Applications.

This review addresses the latest advancements in the integration of aggregation-induced emission (AIE) materials with polymer electrospinning, to accomplish fine-scale electrospun fibers with tunable photophysical and photochemical properties. Micro- and nanoscale fibers augmented with AIE dyes (termed AIEgens) are bespoke composite systems that can overcome the limitation posed by aggregation-caused quenching, a critical deficiency of conventional luminescent materials. This review comprises three parts. First, the reader is exposed to the basic concepts of AIE and the fundamental mechanisms underpinning the restriction of intermolecular motions. This is followed by an introduction to electrospinning techniques pertinent to AIE-based fibers, and the core parameters for controlling fiber architecture and resultant properties. Second, exemplars are drawn from latest research to demonstrate how electrospun nanofibers and porous films incorporating modified AIEgens (especially tetraphenylethylene and triphenylamine derivatives) can yield enhanced photostability, photothermal properties, photoefficiency (quantum yield), and improved device sensitivity. Advanced applications are drawn from several promising sectors, encompassing optoelectronics, drug delivery and biology, chemosensors and mechanochromic sensors, and innovative photothermal devices, among others. Finally, the outstanding challenges together with potential opportunities in the nascent field of electrospun AIE-active fibers are presented, for stimulating frontier research and explorations in this exciting field.

Vibration‐Regulated Multi‐State Long‐Lived Emission from Star‐Shaped Molecules

AbstractHow to utilize molecular vibration to tune triplet‐involved emissions in multiple states is highly challenging. Here, star‐shaped triphenylamine derivatives have been employed as model systems to understand how molecular vibration affects thermally activated delayed fluorescence (TADF) and room temperature phosphorescence (RTP) emissions in multiple states. Nonplanar, star‐shaped conformations allow molecules to generate appropriate vibrations in the solution state, facilitating vibronic coupling between their T1and T2states to generate effective TADF. More importantly, a relatively dispersed state can allow the molecules to efficiently vibrate in the solid state, and a crystalline environment further promotes a more efficient TADF. Lastly, by suppressing molecular vibration to inhibit the TADF, ultra‐long RTP was observed upon doping these molecules into polymers. These molecules can be used in information encryption and storage as well as bioimaging.

Vibration-Regulated Multi-State Long-Lived Emission from Star-Shaped Molecules.

How to utilize molecular vibration to tune triplet-involved emissions in multiple states is highly challenging. Here, star-shaped triphenylamine derivatives have been employed as model systems to understand how molecular vibration affects thermally activated delayed fluorescence (TADF) and room temperature phosphorescence (RTP) emissions in multiple states. Nonplanar, star-shaped conformations allow molecules to generate appropriate vibrations in the solution state, facilitating vibronic coupling between their T1 and T2 states to generate effective TADF. More importantly, a relatively dispersed state can allow the molecules to efficiently vibrate in the solid state, and a crystalline environment further promotes a more efficient TADF. Lastly, by suppressing molecular vibration to inhibit the TADF, ultra-long RTP was observed upon doping these molecules into polymers. These molecules can be used in information encryption and storage as well as bioimaging.

Optical properties, bioimaging and theoretical calculation of a Zn(II) complex based on triphenylamine derivative

A luminescent material with various optical properties based on a triphenylamine Zn(II) complex is described. The ultraviolet–visible absorption, one-photon excited fluorescence (OPEF) and two-photon excited fluorescence (TPEF) of the complex indicate that the material has good OPEF and TPEF properties. And the results of one- and two-photon HepG2 cells imaging experiments show the potential of the complex in fluorescence microscopy bioimaging. The experimental Stokes shift and the FWHM (full-width at half-maximum) in different solvents were correlated with the rMPI polarity of the solvent, and the perfect Boltzmann curves were obtained, where the Boltzmann correlation between Stokes shift and solvent polarity is reported for the second time. But the Boltzmann correlation between FWHM and solvent polarity is reported for the first time. In addition, the computational results indicate that, the covalent bond within the salt ZnBr2 is strengthened by the coordination, and the newly formed coordination bond Zn-N is stronger than the original covalent bond Zn-Br.

Highly Emissive Luminogens in Both Solution and Aggregate States

Highly Emissive Luminogens in Both Solution and Aggregate States

Triphenylamine derivatives functionalized di-ureasil hybrids for information encipherment

Realizing information protection in low cost and large-scale fabrication still casts tough challenges in various aspects primarily involving material synthesis and engineering. Herein, to circumvent these challenges, the method of reversible protonation reactions of triphenylamine (TPA) derivatives grafted with pyridyl groups is intentionally introduced into the di-ureasil hybrids to functionalize the materials with targeted features. The results reveal that the reversible protonation reactions are still observed after homogenously distributing the TPA derivatives into the di-ureasil hybrids because of the organic-inorganic skeleton structure supplying the channels for the penetrations of NH3·H2O and HCl molecules, leading to an obvious emission color switch between red and cyan-green. Moreover, by replacing the pyridyl group with the pyridinium group in a similar molecule structure, the TPA derivatives are able to achieve an eye-cheated optical performance with very closing UV-Vis and emission spectra but lose the stimuli responsive optical performance. Capitalizing on the special features, the strategies designed for information encipherment applications based on the TPA derivatives functionalized di-ureasil hybrids were estimated through direct coating or preparing the inks for the fountain pens to write. This work successfully endows values of the as-synthesized TPA derivatives for the particular application. To compare with the most analogous powder materials applied for information protection applications, the portable security inks show a bright future for commercial applications offering simple operation, easy visual detection, and large-scale fabrications. In addition, the di-ureasil hybrids doped with TPA derivatives also present good performance as warming white-light-emitting films, showing potential for light electronics’ displays.

Dopant-free small molecule hole transport materials based on triphenylamine derivatives for perovskite solar cells

In the past decade, perovskite solar cells have become a promising candidate in the photovoltaic industry owing to their high power conversion efficiency that surpasses 25%. However, there are certain limitations that have hindered the development and full-scale practical application of these cells, including the high cost and degradation of perovskite caused by the dopants. Hence, there is an urgent need to develop dopant-free hole transport materials (HTMs). In recent years, HTMs based on triphenylamine (TPA-HTMs) are receiving growing interest owing to their high hole mobility, excellent film formation, and suitable energy levels. The literature here covers work relevant to TPA-HTMs in the last five years. They have been classified according to different core types. The correlations between performance and structure are summarized, and the future development trend of TPA-HTMs is highlighted.

A novel mitochondria-targeted fluorescent sensor for the HOCl /ClO− detection and imaging application in living cells

Hypochlorous acid (HClO)/Hypochlorite (ClO−) is not only a natural by-product of cell metabolism and participates in various physiological processes, but also as an excellent fungicide, HClO/ClO− has also been widely used in daily life, providing a strong guarantee for human health. It can be seen that it is necessary to develop a reliable and efficient HClO/ClO− detection and imaging method in biomedical research and disease diagnosis. Thus, a novel reactive HClO/ClO− fluorescent probe TPAQ-ClO based on triphenylamine derivatives was prepared to detect HClO/ClO− in vivo and in vitro. Due to the HClO-triggered the effective chemical conversion of the quinoline salt group cleavage, probe TPAQ-ClO exhibited an outstanding selectivity (LOD = 20.7 nM) and quick response to HClO/ClO− in DMSO/PBS buffer (4/6, v/v) solution with large Stokes shift (205 nm). Benefiting from its excellent sensing properties, the probe TPAQ-ClO has been used in mitochondrial co-localization experiments to image endogenous and exogenous HClO/ClO−. In addition, due to its excellent water solubility, the probe TPAQ-ClO can also provide a new fluorescent detection idea to detect HClO/ClO− in real samples.

A novel mitochondria-targeted triphenylamine-based fluorescent chemo-sensors for fast detection of H2O2 in living cells and its imaging application

Herein, a novel reactive H2O2 fluorescent probe TPAQ-H2O2 based on triphenylamine derivatives was prepared to detect H2O2 in vivo and in vitro. Due to the H2O2-triggered the effective chemical conversion of the quinoline salt group cleavage, probe TPAQ-H2O2 exhibited an intense Stokes shift (239 nm), exhibited high selectivity (LOD= 2.5 µmol) and quick response to H2O2 in DMSO/PBS buffer (4/6, v/v) solution in the presence of other competing substances (such as K+, Ca2+, Na+, Mg2+, Fe3+, CO32−, HS−, SO42−, F−, AcO−, NO3−, NO2−, ONOO−, NO, O2−, GSH, Cys, Hcy, NaClO). Benefiting from its excellent sensing properties, the probe TPAQ-H2O2 has been used in mitochondrial co-localization experiments to image endogenous and exogenous H2O2. In addition, due to its excellent water solubility, the probe TPAQ-H2O2 can also provide a new fluorescent detection idea to detect H2O2 in real samples.

Design of new hole transport materials based on triphenylamine derivatives using different π-linkers for the application in perovskite solar cells. A theoretical study.

New organic molecules containing five different compounds, commonly called p-linkers, located between the triphenylamine units, were theoretically designed and analyzed in order to be proposed as new hole transport materials (HTMs) in perovskite solar cells, in total ten new molecules were analyzed. The electronic, optical and hole transport properties were determined, similarly, the relationship of these properties with their molecular structure was also investigated by Density Functional Theory (DFT) and Density Functional Tight Binding (DFTB) calculations. Eight of the ten analyzed compounds exhibited the main absorption band out of the visible region; therefore these compounds did not present an overlap with the absorption spectra of the typical methylammonium lead iodide (MAPI) hybrid-perovskite. The results showed that the Highest occupied molecular orbital (HOMO) levels of the compounds are higher than the perovskite HOMO level, and in some cases these are even higher than the Spiro-OMeTAD HOMO. The calculated electronic couplings and the reorganization energy values provided useful information in order to determine if the systems were hole or electron transport materials.

Synthesis and application of triphenylamine-based aldehydes as photo-initiators for multi-photon lithography

Three new triphenylamine derivatives bearing formyl groups were synthesized and tested for their suitability as photo-initiators for multi-photon lithography. The efficiency of the photo-polymerization was tested by two different setups and for a variety of applications. Based on their broad fabrication window, the well-defined 3D prints in the sub-micron range (resolution and aspect ratio), the solubility, we demonstrate these photo-initiators are a viable alternative to standard photo-initiators.

Supramolecular Polymeric Material Based on Twisted Cucurbit[14]uril: Sensitive Detection and Removal of Potential Cyanide from Water.

Potassium ferricyanide in an aqueous solution is easily decomposed into highly toxic substances (potassium cyanide and hydrogen cyanide) by light or alkaline action, which poses a major hazard to environmental and human health. Here, a reticulated aggregation-induced emission (AIE) supramolecular polymer material (TPAP-Mb@tQ[14]) was prepared by the supramolecular self-assembly of twisted cucurbit[14]uril (tQ[14]) and a triphenylamine derivative (TPAP-Mb). TPAP-Mb@tQ[14] not only recognizes Fe(CN)63- with sensitive specificity with a limit of detection (LOD) of 1.64 × 10-7 M but can also effectively remove and adsorb Fe(CN)63- from an aqueous solution with a removal rate as high as 97.38%. Meanwhile, an important component of the supramolecular polymer material (tQ[14]) can be reused. Thus, the tQ[14]-based supramolecular assembly has the potential to be used for applications addressing toxic anionic contaminants present in aqueous environments.

Fully organic electroactive monomers for electrochromic behaviors having high coloration efficiency and long cycle stability towards flexible Solid-State electrochromic device

• Design and synthesis of three donor–acceptor-donor type monomers and electro-polymerization. • Naphthalene diimide as acceptor core and triphenylamine Derivatives as the donor moiety. • Electrochromic behaviors of the polymer films. • Enhancement of colouration efficiency. Constructing an electrochromic material with high switching stability as well as energy-saving property is really challenging with respect to the practical application which mainly depends on the lower response time, higher switching stabilities and higher colouration efficiencies. Herein, we have reported the design and synthesis of electroactive triphenylamine end capped to central pyromellitic dianhydride, naphthalenetetracarboxylic dianhydride, perylenetetracarboxylic dianhydride based three donor - acceptor - donor type monomers which are subsequently electropolymerized on conductive glass surface to have polymers which are subsequently explored by extensive cyclic voltammetry studies. Density functional theory (DFT) studies disclose that HOMO is localized solely on triphenylamine unit which accounts for the electropolymerization process upon oxidation. Besides, TD-DFT calculations unveil the responsible electronic transitions for electrochromism in the polymers. Three polymers exhibit the reversible multiple colour changes of colourless to brown to deep blue in the anodic region by applying voltage 0 to 1 to 1.2 V and also colourless to deep pink in the cathodic region (voltage window of 0 to −2 V) with attractive response times, optical contrast, switching stabilities, and coloration efficiencies. These polymers can be switched upto 10,000 cycles with the colouration efficiency 800 cm 2 /C in the anodic process and 600 cycles for the cathodic process in a three electrodes configuration. These values, to the best of our knowledge, are not reported for triphenylamine based fully organic electrochromic material till now. Finally, Solid-state devices made of three polymers have demonstrated the electrochromism operated at a potential range of 0 to 2.5 V. Among them, the large area (5 × 5 cm 2 ) of device coated with naphthalenetetracarboxylic diimide is electrochemically stable for 4000 switching cycles, suggesting its suitability as a potential electrochromic material for next-generation flexible EC display application.

Triphenylamine, Carbazole or Tetraphenylethylene-Functionalized Benzothiadiazole Derivatives: Aggregation-Induced Emission (AIE), Solvatochromic and Different Mechanoresponsive Fluorescence Characteristics.

The development of mechanochromic fluorophors with high-brightness, solid-state fluorescence is very significant and challenging. Herein, highly solid-state emissive triphenylamine, carbazole and tetraphenylethylene-functionalized benzothiadiazole derivatives were developed. These compounds showed remarkable aggregation-induced emission and solvatochromic fluorescence characteristics. Furthermore, these fluorogenic compounds also displayed different mechanically triggering fluorescence responses.

Photoinduced [6π]-Electrocyclic Reaction of Mono-, Di-, and Trisubstituted Triphenylamines in Acetonitrile. A Steady-State Investigation.

Direct irradiation of mono-, di-, and trisubstituted triphenylamine derivatives in acetonitrile as solvent with light of 254 nm has been systematically investigated, revealing that the exo/endo carbazole derivatives were formed as the main photoproducts from modest to good yields for triphenylamines substituted with electron-donor and neutral substituents. The kinetic profiles of the photoreaction were also recorded, and the consumption rate constants (k) were measured. These kinetic parameters show dependence on the nature of the substituents, and linear Hammett correlations were carried out to showcase the substituent effect. On the other hand, the spectroscopic behavior of the electron-rich substituted triphenylamines has been analyzed, suggesting that the fluorescence emission spectra display a mirror image of the lower energy absorption bands, while for those amines bearing electron-acceptor groups the formation of charge-transfer complexes and their fluorescence emissions constitute the main deactivation pathway of the photoreaction.

A simple AIE-active triphenylamine derivative for supersensitive detection of water in organic solvents with noticeable fluorescence color change

In this work, an extremely simple triphenylamine-based luminogen 1-(4-(diphenylamino)phenyl)-2-phenylethanone (TPACO) with aggregation-induced emission (AIE) and twisted intramolecular charge transfer (TICT) characteristic was readily synthesized as a super-sensitive fluorescent water sensor. TPACO exhibits remarkable solvatochromic effect and ultrahigh sensitivity to trace water in organic solvents with good linear“intensity-to-content” relationships. The detection limit of TPACO for water in tetrahydrofuran and 1,4-dioxane can be as low as 76 ppm (0.0068 vol%) and 31 ppm (0.0032 vol%), respectively. Under UV irradiation, the probe can signify water content in organic solvents with distinguishable fluorescence color change observable by naked eye. In addition, the emission of TPACO can be quenched by alkali via keto-enol isomerization.