Triphenylamine Derivatives Research Articles

Strong nonlinear optical response in star-shaped push–pull triphenylamine derivatives

Strong nonlinear optical response in star-shaped push–pull triphenylamine derivatives

Bimodal Array-Based Fluorescence Sensor and Microfluidic Technology for Protein Fingerprinting and Clinical Diagnosis.

Proteins play a crucial role in determining disease states in humans, making them prime targets for the development of diagnostic sensors. The developed sensor array is used to investigate global proteomic changes by fingerprinting multifactorial disease states in model urine simulating phenylketonuria and in serum from preeclamptic pregnant women. Here, we report a fluorescence-based chemical sensing array that exploits the host-guest interaction between cucurbit[7]uril (CB[7]) and fluorescent triphenylamine derivatives (TPA) to detect a range of proteins. Using linear discriminant analysis, we identify fluorescence fingerprints of 14 proteins with over 98% accuracy in buffer and human serum. The array is optimized on an automated droplet microfluidic-based platform, for high-throughput sensing with controlled composition and lower sample volumes. This sensor enables the discrimination of proteins in physiological buffer and human serum, with promising applications in disease diagnosis.

Artificial light-harvesting system with sequential energy transfer in photocatalytic C[sbnd]P coupling based on supramolecular organic framework of triphenylamine

Porous structures exhibit an increased access surface area, thereby promoting the efficient transportation of active oxygen species. Reinforcing the development of artificial light-harvesting systems (LHSs) with porous structured supramolecular organic frameworks (SOFs) as the energy donor can significantly enhance its photocatalytic performance, thereby facilitating efficient organic transformation via photocatalysis. In this investigation, we have successfully fabricated a supramolecular organic framework (MT-SOF) composed of cucurbit[8]uril (CB[8]) and triphenylamine derivative (MeTPPA). Because of the framework structure and large ring restriction in MT-SOF, its fluorescence emission shows a significant increase when compared to that of the individual MeTPPA molecule. By harnessing the remarkable fluorescence emission characteristics of MT-SOF, it was employed as an energy donor in conjunction with Sulforhodamine 101 (SR101) and Cyanine 5 (Cy5) as acceptors to fabricate sequential energy transfer LHS. MT-SOF-SR101-Cy5 has the ability to act as a photosensitizer, facilitating the CP bond coupling with broad applicability. It is important to mention that when compared to MeTPPA, MT-SOF and MT-SOF-SR101, the photocatalytic performance of MT-SOF-SR101-Cy5, featuring continuous two-step energy transfer, shows significant improvement, which can be attributed to the porous structure of MT-SOF and the increased efficiency in generating superoxide anion radical (O2−).

A water-soluble aggregation-induced emission luminogen for NIR-I/NIR-II fluorescence imaging of breast cancer bone metastases

Advanced breast cancer is prone to bone metastasis, which is the most common bone metastatic tumor. Current clinical methods for diagnosing breast cancer bone metastases rely on serological markers, computed tomography and magnetic resonance imaging. However, these technologies cannot meet patients' needs due to the delayed screening, complex procedures and expensive equipment. Optical imaging currently exhibits inexhaustible and vigorous vitality in the field of diagnosis thanks to its advantages of simplicity, good controllability and high resolution. Nevertheless, the development of prominent chromophores for the diagnosis of breast cancer bone metastases is an appealing yet significantly challenging task. In this contribution, we rationally designed and synthesized three water-soluble aggregation-induced emission (AIE) luminogens, named PEGTPA-BTD, PEGTPA-NTD, and PEGTPA-NSD, by introducing different moieties as electron acceptors and PEGylated triphenylamine derivatives as electron donors and hydrophilic moieties. In vitro experiments showed that PEGTPA-NSD has a longer absorption and emission wavelength, where the emission wavelength can extend into NIR-II region. Besides, PEGTPA-NSD could self-assemble into stable nanoparticles in aqueous solution. Cell experiments showed that PEGTPA-NSD had no obvious dark toxicity to tumor cells or normal cells, and were easily taken in by tumor cells for cell imaging. What's more, PEGTPA-NSD NPs possessed excellent fluorescence imaging performance and biocompatibility in vivo for breast cancer bone metastases in NIR-I and NIR-II region, respectively. In summary, PEGTPA-NSD is the first reported aggregation-induced emission luminogens (AIEgens) that can self-assemble to nanoparticles in aqueous solution for NIR-I/NIR-II fluorescence imaging of breast cancer bone metastases. These findings would provide new strategies for optical diagnostic imaging of breast cancer bone metastases to better advance clinical technology development.

Efficient Deep‐Blue (465 nm) Perovskite Quantum Dot‐Based Light‐Emitting Diodes via Triphenylamine Derivative Tailored Hole Transport Engineering

Efficient Deep‐Blue (465 nm) Perovskite Quantum Dot‐Based Light‐Emitting Diodes via Triphenylamine Derivative Tailored Hole Transport Engineering

Study of Two-Photon induced excited state absorption of Three-Branched triphenylamine Derivatives: Cooperative and Anti-Cooperative effect of electron transition in the excited state

For multi-branched molecules, intramolecular cooperative effect can significantly enhance the molecular nonlinear optical absorption. Three triphenylamine-cored compounds (N1, N2 and N3) with three branches are synthesized to study the cooperative and anti-cooperative effect of electron transition in the excited state on two-photon absorption (TPA) and excited state absorption (ESA). Molecular polarization of these multi-branched triphenylamine derivatives is regulated by changing the molecular symmetry and the planarity of peripheral branches, to regulate their charge distribution and electron transition characteristics in the excited state. Here, we show that due to electronic coupling and interaction between certain branches, the asymmetric distribution of electron clouds in the excited states of these multi-branched molecules will lead to an enhancement of their TPA and ESA cross-sections, which is known as the cooperative effect of electron transitions. On the contrary, electronic coupling and interaction among all branches will lead to a highly symmetric distribution of electron clouds in the excited states of these multi-branched molecules, which will cause anti-cooperative effects and result in significant attenuation of TPA and ESA cross-sections.

Novel donor-acceptor-donor type electrochromic polymers based on 1,3-indandione modified triphenylamine derivatives as new acceptor units

Two donor (D)-acceptor (A)-donor (D) type of conjugated monomers, ITPA and ICTPA, consisted of 1H-indene-1,3(2H)-dione (IN)- or 2-(3-oxo-2,3-dihydroinden-1-ylidene)-malononitrile (INCN)-substituted triphenylamine as the acceptor unit, were synthesized by Stille coupling reaction and Knovenagel condensation reaction, and their corresponding polymers (PITPA and PICTPA) were prepared by electrochemical polymerization. Both ITPA and ICTPA hade low initial oxidation potential of 0.70 V and 0.76 V, respectively, which was conducive to achieve high-quality polymer films. In comparison with FTPA which was not substituted by IN unit, ITPA and ICTPA exhibited the distinct red-shifted and dual absorption bands due to the stronger electron-withdrawing ability of IN and INIC units. Moreover, the electrochromic results demonstrated that PITPA possessed much higher optical contrast of 41 %, higher coloration efficiency (CE) of 445.5 cm2 C−1 at 1100 nm with extremely fast response time as low as 0.3 s, and a promising optical memory behavior compared with its counterpart without IN unit. These results suggested that the introduction of IN unit into triphenylamine could improve the electrochromic performance of the conjugated polymers and also provide a new strategy to develop novel and high-performance electrocheomic polymers.

Yellow-transmissive blue electrochromic polymers based on triphenylamine and ProDOT derivatives

Electrochromic polymer with yellow hue is few relative to those with other two primary colors due to its optical absorption at short wavelength of ≈ 450 nm. Triphenylamine (TPA) and its derivatives (TPAs) as chromogenic groups are frequently used to construct neutral yellow electrochromic polymers, however, those polymers based on TPAs usually exhibit low transmittance at oxidation state due to the residual absorption at short wavelength. Here, three neutral yellow electrochromic polymers (PBBE-1, PBBE-2 and PBBE-3) with different content ratios of ProDOT-10, TPA-4 and benzene were synthesized by Suzuki coupling reaction. With ProDOT-10 content in polymeric chain increasing, the oxidation potentials of polymers decrease gradually. Due to the twisted molecular structure, the absorption peaks of polymers almost remain unchanged when ProDOT-10 content in polymer reaches critical value, which provide an effective method for preparing neutral yellow electrochromic polymers. During oxidation process, PBBE-1 turns to black; PBBE-2 turns to dark blue; PBBE-3 turns to light grey, further to light blue. Through optimizing TBA-4/ProDOT-10 ratio, the electrochromic properties of polymers have been improved, such as optical contrast, response time and coloration efficiency. Especially, PBBE-3 possesses 40 % optical contrast at 435 nm, which is higher than reported TPAs based polymers at short wavelengths.

Glycerol as Reaction Medium for Sonogashira Couplings: A Green Approach for the Synthesis of New Triarylamine-Based Materials with Potential Application in Optoelectronics.

This study focuses on the design, eco-friendly synthesis, and characterization of several novel three-legged triphenylamine derivatives. By performing Sonogashira couplings of functionalized aryl iodides with tris(4-ethynylphenyl)amine in glycerol, a readily available bio-derived solvent, we achieved the synthesis of target products in short times and high yields, up to 94 %, with consistently lower E-factors and reduced costs compared to standard conditions using toluene as the reaction medium. The target molecules possess a D-(π-A)₃ or D-(π-D)₃ structure, where an electron-donating core connects to three electron-donating (D) or electron-accepting (A) peripheral aromatic subunits through an acetylene spacer. Their main optical and electronic properties have been determined experimentally and by DFT simulations and suggest a possible implementation in energy conversion technologies such as luminescent solar concentrators (LSCs) and perovskite solar cells (PSCs).

Interfacial layer with a dibenzofulvene-bridged triphenylamine core for efficient and stable inverted perovskite solar cells

Considering the energy level cascade, introducing a hole transport layer (HTL) between the NiOx and perovskite layers has become a common and effective strategy to enhance the performance of inverted perovskite solar cells (PSCs). Herein, we designed and synthesized three hole-transporting interfacial layers (TPAD, TPAO, and TPAS) based on a dibenzofulvene-bridged triphenylamine (TPA) core to fabricate efficient and stable inverted NiOx-based PSCs. Dibenzofulvene, known for its sp²-hybridized structure, offers superior planarity and molecular stacking, and it easily bonds with triphenylamine derivatives, resulting in unique light-harvesting and charge mobility properties for optoelectronic applications. Specifically, diphenylamine, dimethoxy diphenylamine, and dimethylthio diphenylamine were used as end-capping units for TPAD, TPAO, and TPAS, respectively. The NiOx-based inverted PSC devices fabricated with TPAS as an interfacial layer effectively modified NiOx to improve energy level alignment, enhance film quality and crystallinity, and improve carrier transport, leading to a high-quality perovskite layer and superior interface contact behavior. Consequently, this device yielded a highly efficient cell performance of 20.30 %, surpassing those using TPAD (19.29 %) and TPAO (18.78 %) as interfacial layers, and significantly outperforming devices using only NiOx (17.69 %). Additionally, the champion cell exhibited negligible hysteresis and long-term stability. These findings demonstrate a facile approach to preparing multifunctional TPA-based hole transport materials and showcase the efficient performance of inverted cells based on a triphenylamine dibenzofulvene-based interfacial layer, contributing to the development of high-efficiency inverted PSCs.

Avoiding Photocyclized Degradation of Electrochromic Materials Based on Quantum Chemical Molecular Design.

Suppressing the photodegradation of organic electronic materials is crucial for their device applications. This study proposes a method to mitigate the photodegradation. With focus on the molecular design of triphenylamine derivatives commonly used in organic electronics, it was demonstrated that spin distributions of the derivatives would be a good quantum descriptor for predicting the photocyclization resistance to not give carbazole derivatives.

Conjugated Nitroxide Radical Polymer with Low Temperature Tolerance Potential for High-Performance Organic Polymer Cathode.

Low-temperature operation poses a significant challenge for current commercial rechargeable lithium-ion batteries (LIBs). Organic polymer electrode materials, exhibiting a nonintercalation redox mechanism, offer a viable solution to mitigate the decline in electrochemical performance at low temperatures in LIBs. Herein, a radical polymer P(DATPAPO-TPA) with a conjugated nitrogen-rich triphenylamine derivative as the backbone and high-density nitroxide pendants has been synthesized. Due to the large interstitial spaces between adjacent structural units and polymer chains, resulting from the significant torsion angle between the benzene rings in the P(DATPAPO-TPA) skeleton, ions could effectively transport. This structural feature demonstrated a notable discharge capacity of 143.3 mA h·g-1 and a high charge-discharge plateau at ∼3.75 V vs Li+/Li, outperforming most reported radical polymer cathode materials. In addition, its capacity retention could reach 83.1% after 2000 cycles at an ultrahigh current density of 50 C, showing excellent rate capability and promising cyclability. Also notable was P(DATPAPO-TPA)'s favorable low-temperature performance that maintains a high discharge capacity of 139.2 mA h·g-1 at 0 °C. The synthesized P(DATPAPO-TPA) is a tangible illustration of a viable design strategy for low-temperature electrode materials, thereby contributing to broadening applications for radical polymer electrode materials.

Multi Stimuli Responsive Dual Aggregation-Induced Emission and Photochromic Behavior of a Tetraphenyl Substituted Triphenylamine Derivative and its Application as Anti-counterfeiting Agent.

A multi-stimuli responsive tetraphenyl substituted tripehnylamine-based aggregation induced emissive (AIE) material coupled with spiropyran was prepared. Owing to the presence of AIE and photochromic moiety, the molecule exhibits emissive aggregates, photochromism, and acidochromism. The multiple stimuli sensitive behavior of the molecule was explored for anti-counterfeiting behavior on TLC plate and commercial banknotes. The fluorogenic and photogenic response under UV and visible light established the potential of the candidate as a new generation encryption material.

Solvent polarity dependent photo-induced excited state intramolecular proton transfer for triphenylamine centered bis unsymmetrical azine (TPOV): A computational study

The exquisite, regulated characteristics of triphenylamine (TPA) derivatives have served as a profound inspiration in the photochemical field. Herein, the novel TPA-centered bis unsymmetrical azine (i.e., 3-methoxysalicylaldehyde substituted 4-((E)-hydrazonomethyl)-N-(4-((E)-hydrazonomethyl)phenyl)-N-phenylaniline (TPOV)) is investigated regarding its photo-induced behaviors and excited state intramolecular proton transfer (ESIPT) mechanisms. Solvent polar-dependent hydrogen bonding interactions and charge recombination, which is induced by photoexcitation, can greatly promote the ESIPT reactions of the TPOV chemosensor. In order to unveil the detailed excited state reaction mechanism, we theoretically construct the S0-state and S1-state of potential energy surfaces (PESs). Based on the S1-state PESs for TPOV in toluene, chloroform, and acetonitrile solvents, we unveil the single ESIPT reaction of TPOV that happens along with alternative dual intramolecular hydrogen bonds (O1-H2···N3 and O4-H5···N6). The solvent polarity-regulated excited state might clear the path for the creation of innovative luminescent materials.

Adjustable optoelectronic properties of triphenylamine-ethylenedioxythiophene based hybrid electrochromic polymer with different electron-donating substituents

Due to the good optoelectronic properties of triphenylamine (TPA) and its derivatives-based organic conjugated polymers, they have been widely used in various organic electronic devices. They are easy to lose electrons to form stable cationic free radicals with color change under electrochemical oxidation conditions. Therefore, TPA derivatives-based electrochromism materials have attracted the widely attentions of researchers. In this work, a series of TPA derivatives were successfully obtained by Stille coupling reactions, and their basic optical and electrical properties were investigated in detail. Their corresponding polymer films (P(TPA-EDOT), P(PhTPA-EDOT), and P(OCH3TPA-EDOT)) were also prepared on transparent ITO glass by electrodeposition method and their electrochromic properties were further studied. Due to the relatively strong electron donating ability of OCH3– group on the TPA unit, the intramolecular charge transfer peak of OCH3TPA-EDOT is obvious red-shifted and its initial oxidation potential is relatively low, which is beneficial for it to get high-quality electrochromic polymers. Electrochemical analysis shows that all these three polymer films show reversible redox reaction with excellent redox stability. Spectroelectrochemistry shows that all of them have good electrochromic properties and show multi-electrochromic behavior with strong color change. The dynamic study show that all these three polymers have relatively fast switching time (as low as 0.8 s), high coloration efficiency (up to 206.2 C−1 cm2) and obvious optical contrast change. Especially in the near infrared region, the optical contrast is relatively high (P(TPA-EDOT) is 45.3 % at 1100 nm, P(PPhTPA-EDOT) is 53.1 % at 1100 nm, and P(OCH3TPA-EDOT) is 57.2 % at 1100 nm). All these results show that the different substituents on the TPA unit have a certain influence on the resultant monomers’ optoelectronic performances, and they also can adjust the optical band gap of the corresponding polymers with different electrochromic properties.

Near-infrared polarity fluorescent probe for wash-free imaging lipid droplets and the application in the diagnosis of non-alcoholic fatty liver tissue

Lipid droplets (LDs), as primary cellular energy storage organelles, play essential roles not only in energy conservation but also in inflammatory responses, apoptosis, and the progression of diseases such as non-alcoholic fatty liver disease (NAFLD). Studies indicate that alterations in the polarity of LDs are closely linked to pathological factors like oxidative stress, ferroptosis, and lipophagy. Therefore, developing biological probes for precisely monitoring LDs polarity is crucial for understanding these biological phenomena and devising new therapeutic strategies. In this context, we synthesized four fluorescent probes (CNL1-CNL4) to precisely monitor the polarity of LDs using triphenylamine and carbazole derivatives as electron donors and isophorone and benzopyranonitrile units as electron acceptors, employing intramolecular charge transfer (ICT) mechanism. Our findings demonstrated that all four probes exhibited high sensitivity and specificity for polarity changes. Probes CNL2 and CNL4 were sensitive to polarity, and their maximum fluorescence intensity and maximum emission wavelength demonstrated a good linear relationship with polarity parameters within a certain range. Biological experiments demonstrated that both CNL2 and CNL4 possess excellent wash-free imaging capabilities and superior LDs targeting abilities but also enable dynamic monitoring of LDs and respond well to changes in LDs polarity under varying concentrations of oleic acid stimulation. Due to its longer emission wavelength (>650 nm), boasting excellent photostability, and featuring a larger Stokes shift (≈168 nm in acetonitrile), probe CNL4 was selected for further studies. Furthermore, probe CNL4 effectively monitors changes in LDs polarity under conditions of ferroptosis and oxidative stress. It has shown potential in the diagnosis of NAFLD tissue and during the process of lipophagy, highlighting its value in disease diagnostics and biological research. These findings not only deepen our understanding of the mechanisms underlying NAFLD progression but also provide new tools for diagnosing and treating related diseases.

Supramolecular Chiral Aggregation of Porphyrin Induced by Photo-Generated Triphenylamines Radical Cations.

Here, it is shown that photoirradiation triggered chiral J-aggregates formation of an achiral anionic porphyrin, TPPS (tetrakis(4-sulfonatophenyl) porphyrin), in the presence of chiral triphenylamine (TPA) derivatives. A series of chiral triarylamines linked with aromatic rings is designed through urea or amide bonds. UV-irradiation of self-assembled urea-linked triphenylamine derivatives causes the formation of persistent radical cations in the chlorinated solvents, which subsequently induces the aggregation of TPPS. Transferring chirality of TPA derivatives to achiral TPPS J-aggregates leads to the chiral assemblies with remarkable chiroptical signals. The experimental results demonstrate that, TPA derivatives linked by the urea bond can effectively promote the aggregation of TPPS rather than those with the amide bond although the photo-generated radical cations are both produced. It is suggested that the urea-linked TPA derivatives are more favorable to stable radical cations and thus cause the formation of TPPS chiral J-aggregation. This work may open up an avenue for designing photo-modulated chiral supramolecular assemblies.

Phenyl-bridged N,N,N'N'-Tetrasubstituted bis(2-amino-5-thiazolyl) diamine: Synthesis and applications in electrochromism and photocatalytic nitrobenzene reduction

A novel type of triphenylamine derivatives, phenyl-bridged N,N,N′,N′-tetrasubstituted bis(2-amino-5-thiazolyl) diamine (4) and its cationic form (5) were synthesized via the Hantzsch reaction. The UV–Vis spectroscopy, cyclic voltammetry (CV) and density functional theory (DFT) calculation results showed that the diamine possesses excellent redox properties and a narrow optical energy gap (∼1.85 eV). As an electrochromic material, compound 4 exhibits a notable color change from colorless to blue. It maintains stable cycling performance for up to 175 cycles, even within a higher voltage range of −2.4 to 2.4 V. In addition, as a catalyst, compound 5 exhibits good substrate compatibility and an aniline conversion rate of up to 89 % during the photocatalytic reduction of nitrobenzene. These results would contribute to understand the synthesis of triphenylamine electrochromic materials and expand their applications in the field of photocatalysis.

Construction of multi‐decay pathways and realizing polymer‐regulated organic smart luminescent materials

AbstractThe construction of multi‐decay pathways of smart organic light‐emitting materials has drawn intensive research enthusiasm owing to their substantial promise in diverse optoelectronic applications. Nowadays, numerous chemical substances have been refined to extend and enhance their intriguing luminescent properties. Nowadays, plenty of chemicals have been adapted to amplify more interesting luminescent properties. How to utilize an easy way to tune multi‐decay pathways resulting in various emissions is still challenging. Here, we present a triphenylamine derivative, TPA3BP, which exhibits a variety of multi‐decay pathways in different states and can exhibit thermally activated delayed fluorescence in both the polydimethylsiloxane and crystalline state, but also achieve room temperature phosphorescence by embedding it into the poly (methyl methacrylate) (PMMA) and polyvinyl pyrrolidone matrix. The multi‐decay luminescence can be attributed to the dual effect arising from the n‐π* transition of TPA3BP and the regulation of molecular transition pathways within the matrix environment. This intriguing phenomenon highlights the combined influence of TPA3BP's electronic transitions and the influence of the polarity and rigidity of the surrounding matrix on the observed characteristics. This advancement has widened the structural possibilities for multi‐decay luminescent materials, enabling their targeted synthesis for future applications, such as information encryption and smart anti‐counterfeiting.

Polarity-sensitive fluorescent probe based on coumarin derivatives for imaging lipid droplets and diagnosis of non-alcoholic fatty liver

Aberrant alterations in the polarity of lipid droplets (LDs) are closely linked to disorders of lipid metabolism, which can result in LDs dysfunction and the onset of various diseases, including non-alcoholic fatty liver disease (NAFLD) and specific types of cancer. Therefore, it is imperative to comprehensively comprehend and accurately diagnose associated diseases by monitoring changes in LDs polarity in real time. In this paper, we designed and synthesized four novel fluorescent probes XOT1-XOT4 by using coumarin as a polarity-sensitive group and incorporate various triphenylamine derivatives as electron-donating groups, enabling specific targeting of LDs. All four probes possess high sensitivity towards minute polarity changes. Among them, XOT3 exhibited excellent photophysical properties and demonstrated a linear fluorescence change (R2 = 0.98596) within the polarity range of Δf = 0.023496 ∼ 0.047464. Moreover, probe XOT3 could be effectively utilized for visualizing intracellular LDs by precisely targeting them without requiring any washing steps. Importantly, probe XOT3 has been successfully utilized to monitor alterations in the polarity of LDs during apoptosis and ferroptosis as well as the quantity, size, and fluorescence intensity of LDs stimulated by oleic acid. Furthermore, probe XOT3 was capable of effectively visualizing LDs in tissues and organs in mouse models of non-alcoholic fatty liver disease (NAFLD), which provides a powerful tool for the early diagnosis of NAFLD.