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Based on the strong binding properties of hydroxylamino-1,3,5-triazine (BHT) for hard metal ions, a novel spectroscopically labelled triazine-hydroxylaminato ligand, N,N′-(6-(9H-carbazol-9-yl)-1,3,5-triazine-2,4-diyl)bis(N-methylhydroxylamine) (H2cbht), was synthesized. Reaction of H2cbht with FeIII, VV and UVI resulted in the synthesis of [UVIO2(cbht)(DMF)(MeOH)], 1, (PPh4)2([UVIO2(Hcbht)2]·2[UVIO2(Hcbht)(cbht)]), 2, (PPh4)2[(UVIO2)3(μ-cbht)2(cbht)2], 3, Na[VVO2(cbht)], 4, and (PPh4)[FeIII(cbht)2], 5. The complexes were characterized by X-ray crystallography showing strong chelation of the metal ions with the BHT chelating moiety H2cbht. The DMSO/DMF solutions of the complexes were characterized by NMR, UV-vis and electrochemistry, confirming the high affinity of H2cbht for FeIII, VV or UVI. The luminescence properties of the carbazole group were retained in the BHT adduct of the H2cbht ligand. Interaction of the metal ions with H2cbht resulted in quenching of the luminescence of H2cbht. Stern–Volmer plots of luminescence vs. concentration of the metal ions are linear and suitable for the determination of the concentration of metal ions in nM range concentrations. Benesi–Hildebrand plots show that the metal-to-ligand ratio is 1 : 1 while the formation of the metal complexes exhibits high association constants. [ABSTRACT FROM AUTHOR]

Elicitors have a substantial impact on the accumulation of phytochemical components in wild plants. The present study aimed to evaluate the impact of salicylic acid (SA) and methyl jasmonate (MJ) on the enrichment of carbazole alkaloids (CAs) in the leaves of Murraya koenigii under controlled environment. Effect of elicitors at 1.0, 1.5 and 2.0 mM and their time of exposition 6 h, 12 h, 24 h, 2 days and 5 days were evaluated. Methanolic extracts of the treated samples were subjected to UPLC-ESI-QTRAP LC-MS/MS analysis for the separation and subsequent quantification of seven identified CAs, viz. murrayamine A, koenigine, koenimbidine, koenimbine, mahanine, 8,8′-biskoenigine and mahanimbine. Accumulation of all the CAs was found to be enhanced with both the elicitors, but it was dependent on the type of elicitor, its concentration, and time of exposition. The data were analyzed through multivariate statistical models, like PCA, HCA and PLS-DA. The analysis revealed that 1.5 mM dose of MJ and SA had a significant influence on CAs accumulation at 24 and 12 h, respectively. Five marker CAs from both MJ and SA-treated samples were identified using VIP scoring. These findings suggest that MJ and SA with their specific concentration and exposition time could be used for the accumulation of particular CA to a substantial limit in this plant. [ABSTRACT FROM AUTHOR]

A twisted five-ring fused compound, N-(2-decyltetradecyl)-7H-benzo[4,5]thieno[2,3-b]carbazole-S,S-dioxide (i-BTOCz), was synthesized and characterized. By introducing i-BTOCz into the main chains of polyfluorene (PF) and polycarbazole (PCz), respectively, blue light-emitting polymers (PF-i-BTOCzs/PCz-i-BTOCzs) were synthesized. Excellent thermal stability was achieved, along with a strong intramolecular charge transfer (ICT) effect of i-BTOCz and the resulting polymers. For the polymers, as the content of i-BTOCz increased, the lowest unoccupied molecular orbital (LUMO) energy levels decreased slightly and the highest occupied molecular orbital (HOMO) energy levels were almost unchanged. The photoluminescence (PL) spectra showed slight broadening in solution and basically no change in film, which due to the twisted molecular structure suppressed the decrease in the energy levels and redshift of spectra. With the current density in the range of 100–500 mA cm−2, the electroluminescence (EL) spectra of the polymers were almost unchanged, indicating outstanding EL stability. As the content of i-BTOCz increased, a slight redshift of the EL spectra was observed for the PF-i-BTOCzs and PCz-i-BTOCzs, with basically unchanged Commission Internationale de L'Eclairage (CIE) coordinates of (0.16, 0.14) and (0.17, 0.16), respectively. The maximum luminous efficiency (LEmax) of PF-i-BTOCz20 and PCz-i-BTOCz20 was 1.11 cd A−1 and 1.41 cd A−1, while the LEmax of PF and PCz was 0.58 cd A−1 and 0.35 cd A−1, respectively, indicating that introducing the twisted unit into the main chains of PF or PCz could be a viable strategy for restraining the redshift of spectra and obtaining efficient blue light-emitting polymers. [ABSTRACT FROM AUTHOR]

Carbazole‐derived self‐assembled monolayers (SAMs) with excellent hole‐extraction and injection properties are promising hole‐transporting materials for perovskite optoelectronic devices, including perovskite solar cells (PSCs) and perovskite light‐emitting diodes (PeLEDs). The performance and thermal stability of these SAMs are heavily influenced by their chemical structure. Herein, the construction of fused carbazole‐based SAMs is proposed by expanding the π‐conjugation of the carbazole unit for application in PSCs and PeLEDs. Three proof‐of‐concept SAMs are designed and synthesized, termed XS8, XS9, and XS10, that feature highly rigid and planar fused carbazole as the donor and a conjugated alkene unit as the linker. This conjugated extension improves planarity, stability, and enhances the molecular dipole moment. Among these, XS10, with the highest degree of conjugation, demonstrated superior performance in perovskite‐based devices. The PSC device utilizing XS10 achieves a maximum power conversion efficiency (PCE) of 20.28%, surpassing the 17.19% PCE of the classic 2PACz‐based device. Similarly, the PeLED device with XS10 achieves a maximum external quantum efficiency (EQE) of 16.6%, compared to 14.5% for PEDOT‐based devices. This work provides a novel molecular design strategy for creating efficient and stable SAMs for perovskite optoelectronics and other organic electronic devices. [ABSTRACT FROM AUTHOR]

Comprehensive Summary Photoinitiators of the oxime ester (OXE) or ketoxime ester (OXE‐CO) type can rapidly undergo N—O bond cleavage and generate free radicals to initiate photopolymerization under LED excitation, occupying an important position in the field of photocuring. However, the commercial OXEs, e.g., OXE 01 and 02 with λmax's at 326 and 344 nm, respectively, still do not well match the emission spectra of LEDs. Developing novel OXEs/OXE‐COs with high photosensitivity for long‐wavelength LEDs has great significance. Here, four new OXEs/OXE‐COs with nitro‐carbazole‐styrene conjugated chromophore were designed, synthesized, and used as photoinitiators. Results demonstrated that all photoinitiators had strong absorption within the UV–vis range (λmax: 381—392 nm, εmax: 8200—11500 M−1·cm−1). Molecular design of the oxime ester cleavage to produce a small volume methyl group and a methacryl group with an unsaturated double bond brings high activity and low migration, respectively, in one‐photon polymerization under 365—450 nm LEDs excitation. Moreover, OXEs/OXE‐COs with PETA exhibited a wide processing window, high resolution (line accuracy~100 nm) and good nano‐patterning capability under 780 nm femtosecond laser irradiation in two‐photon polymerization, indicating their great potential in 2D/3D microfabrication technologies. [ABSTRACT FROM AUTHOR]

Efficient blue multi‐resonance thermally activated delayed fluorescence (MR‐TADF) materials are highly desired for the fabrication of organic light‐emitting diodes (OLEDs) with high color purity. But only very limited carbonyl‐nitrogen (CO‐N) blue MR‐TADF are well‐developed. Herein, two new blue CO‐N MR‐TADF molecules (tBuPQCZ and 2tBuPQCZ) are explored by introducing bulky substituents to a planar CO‐N MR‐TADF core constructed by fusing carbonyl groups with carbazole, and their thermal stability, electronic structures, and photophysical properties are investigated. They exhibit blue photoluminescence (PL) peaks at 451 and 447 nm, and narrow full width at half maximums (FWHMs) of 26 and 25 nm in toluene. In doped films, they exhibit strong blue emissions with PL peaks at 474 and 469 nm, FWHMs of 51 and 49 nm, and satisfactory PL quantum yields of 80% and 72%. Moreover, blue OLEDs using them as emitters exhibit excellent external quantum efficiencies (EQEs) of 20.4% and 21.5%, and the hyperfluorescence OLEDs based on them provide state‐of‐the‐art EQEs of 30.1% and 29.0% with small FWHMs of 34 and 32 nm and Commission Internationale de I'Eclairage coordinates of (0.136, 0.134) and (0.141, 0.105). The insights gained in this work should be valuble for the development of efficient blue CO‐N MR‐TADF materials. [ABSTRACT FROM AUTHOR]

In the past, considerable effort are focused on advancing blue organic light‐emitting diodes (OLEDs) based on 1,3‐bis(N‐carbazolyl)benzene (mCP). To enhance and stabilize the device performance in vacuum‐processed OLEDs, it is essential to optimize the thermally stable organic materials constituting the emitting layer. The proposed novel carbazole derivative, Ad‐mCP, is designed and synthesized as a host material for blue thermally activated delayed fluorescence OLEDs, which are ideal for vacuum processing. Ad‐mCP exhibits a high glass transition temperature and triplet energy (T1), making it highly compatible with the blue dopant 2,11,14‐tri‐tert‐butyl‐N,N,5‐tris(4‐(tert‐butyl)phenyl)−5H‐5,8b‐diaza‐15b‐borabenzo[a]naphtho[1,2,3‐hi]aceanthrylen‐7‐amine emitter. The incorporation of a rigid adamantane unit into the carbazole group modifies the molecular structure of mCP, preserving crucial photophysical properties, such as T1,while enhancing the morphological and thermal stability of the host material in its film state. Moreover, the spatially hindered molecular structure of Ad‐mCP improves the photoluminescent quantum yield of the emissive layer and enhances charge balance, crucially contributing to the overall efficiency of the OLEDs. As a result, the exceptional performance of Ad‐mCP as a host material for OLEDs resulted in a remarkably high maximum external quantum efficiency of 29.9%, demonstrating superior stability in efficiency even after thermal annealing compared to mCP devices. [ABSTRACT FROM AUTHOR]

To further explore the candidate materials for latent fingerprints detection, two triphenylamine‐based salicylaldimine compounds containing phenoxazine moiety (TPA‐PXZ) and carbazole unit (TPA‐Cz) were designed and successfully synthesized, respectively. They exhibited intramolecular charge transfer transitions and aggregation‐induced emission properties. Based on quantum chemical calculation results, it was found that compounds TPA‐Cz and TPA‐PXZ had twisted spatial configuration, which were responsible for aggregation‐induced emission. Meanwhile, the morphology of two compounds nano‐aggregates in the THF/water mixtures with 60 % and 80 % water content was tested. To our delight, the developers that prepared by compounds TPA‐Cz and TPA‐PXZ both were used for latent fingerprints detection on the surface of glasses, and they emitted purple fluorescence, as well as the distinct fingerprint imaging could be easily distinguished fingerprint level 1–3 details. We believe that TPA‐Cz and TPA‐PXZ both are the promising candidate for latent fingerprints detection. [ABSTRACT FROM AUTHOR]

Phosphorescent material with narrowband emission is crucial for advancing wide-color-gamut organic light-emitting diodes (OLEDs). In this work, two iridium(III) complexes, (PhthzICz)2Ir(tmd) and (thzICz)2Ir(tmd), using rigid 2-(benzothiazole-2-yl)indolo[3,2,1-jk]carbazole (PhthzICz) and 2-(thiazole-2-yl)indolo[3,2,1-jk]carbazole (thzICz) as cyclometalated ligands and 2,2,6,6-tetramethyl-3,5-heptanedione (tmd) as ancillary ligands, were synthesized. When these complexes were doped into the host material 3,3′-di(9H-carbazol-9-yl)-1,1′-biphenyl, the doped films exhibited yellow photoluminescence (PL) peaking at 537 and 531 nm, full width at half maximum (FWHM) bands of 35 and 60 nm, and PL quantum yields of 89.9% and 85.9%, respectively. OLEDs based on these two emitters display moderate performance characteristics with maximum external quantum efficiencies of 25.2% and 22.7%. Notably, the device based on (PhthzICz)2Ir(tmd) exhibits a narrow FWHM of 31 nm. Overall, the study highlights the practicality of incorporating rigid groups into the cyclometalated ligands of Ir(III) complexes as a viable strategy for achieving efficient Ir(III) complexes for OLEDs with narrow emission and high efficiency. [ABSTRACT FROM AUTHOR]

Murraya koenigii is an important medicinal plant for its diverse pharmacological activities. It has been utilized in various indigenous systems of medicine for preparing different herbal formulations. M. koenigii is a rich source of bioactive carbazole alkaloids, among which mahanimbine, koenimbine, mahanine, and girinimbine are the major carbazole alkaloids isolated from the leaves of this plant. Mahanimbine has been utilized to treat cancer and diabetes, playing an important role in the pharmacological effects of this plant. Standardization is an essential process in the pharmaceutical industry to maintain the purity, quality, efficacy, and, safety of herbal raw materials. Different analytical techniques, including HPTLC, HPLC, GC-MS, and LC-MS have been used for this purpose. In the present study, a simple, specific, and rapid semi-automated TLC method was developed to determine the mahanimbine content in leaf samples collected from three geographical regions of India. This study revealed that the ethyl acetate extract prepared from leaf samples collected from Andhra Pradesh contains the highest amount of mahanimbine (507.2 µg), which indicates that this sample can be utilized for further research or in the preparation of herbal formulations. [ABSTRACT FROM AUTHOR]

In this study, fully aromatic polyether sulfones were developed, bearing blue, yellow, and orange–red π-conjugated semiconducting units. Carbazole-, anthracene-, and benzothiadiazole-based fluorophores are copolymerized with a diphenylsulfone moiety. A diphenylpyridine comonomer was additionally utilized, acting as both a solubilizing unit and a weak blue fluorescent group. Using this rationale, fluorescent polyarylethers with high molecular weights, up to 70 kDa, were developed, showing film formation ability and high thermal stability, while preserving excellent solubility in common organic, nonvolatile, and nonchlorinated solvents. Fine-tuning of the emission color was achieved through subtle changes of the comonomers' type and ratio. Single-chromophore-bearing copolymers emitted in the blue or the yellow region of the visible spectrum, while the dual-chromophore-bearing terpolymers emitted throughout the visible spectrum, resulting in white light emission. Solutions of 20 wt% in polar aprotic solvents at ambient conditions allowed the deposition of fluorescent copolyethers and printing from non-chlorinated solvents. All polyethers were evaluated for their structural and optoelectronic properties, and selected copolymers were successfully used in the emitting layer (EML) of organic light-emitting diode (OLED) devices, using either rigid or flexible substrates. Remarkable color stability was displayed in all cases for up to 15 V of bias voltage. The Commission Internationale de L'Eclairage (CIE) of the fabricated devices is located in the blue (0.16, 0.16), yellow (0.44, 0.50), or white region of the visible spectrum (0.33, 0.38) with minimal changes according to the ratio of the comonomers. The versatile methodology toward semiconducting polyethersulfones for polymer light-emitting diodes (PLEDs) developed herein led to the scaled-up production of luminescent polymers of up to 25 g of high-molecular-weight single batches, demonstrating the effectiveness of this approach as a straightforward tool to facilitate the synthesis of flexible and printable EMLs for large-area PLED coverage. [ABSTRACT FROM AUTHOR]

In this Synpacts article, we describe the concept of cyclodimerization in the biosynthesis and biomimetic synthesis of natural products and unnatural products. We also discuss key details of our discovery and development of a biomimetic-like, selective, homo- and heterochiral cyclodimerization strategy for the construction of nonnatural dimeric carbazole frameworks by employing a formal [3+2] annulation. Our work also demonstrated a novel reactivity of 1-(indol-2-yl)pent-4-yn-3-ols, and their potential as new synthetic building blocks in organic synthesis. 1 Introduction: Chiral Cyclodimerization Reactions 2 Biomimetic Syntheses of Natural Products through Chiral Cyclodimerizations 3 Bioinspired Synthesis of Nonnatural Dimeric Carbazoles through Selective Chiral Cyclodimerizations 4 Future Perspectives and Conclusions [ABSTRACT FROM AUTHOR]

Cyclic-nucleotide phosphodiesterases (PDEs) represent a superfamily of enzymes playing a pivotal role in cell signaling by controlling cAMP and cGMP levels in response to receptor activation. PDE activity and expression are linked to many diseases including inflammatory diseases. In light of their specific biochemical properties, PDE inhibition has attracted the interest of several researrs In this context, PDE4 inhibition induces anti-inflammatory effects. Piclamilast and rolipram, well-known PDE4 inhibitors, are endowed with common side effects. The selective phosphodiesterase 4B (PDE4B) inhibitors could be a promising approach to overcome these side effects. In the present study, six potential PDE4B inhibitors have been investigated. Through this study, we identified three PDE4B inhibitors in human macrophages activated by lipopolysaccharide. Interestingly, two of them reduced reactive oxygen species production in pro-inflammatory macrophages. [ABSTRACT FROM AUTHOR]

[Display omitted] Perovskite light-emitting diodes (PeLEDs) exhibit remarkable potential in the field of displays and solid-state lighting. However, blue PeLEDs, a key element for practical applications, still lag behind their green and red counterparts, due to a combination of strong nonradiative recombination losses and unoptimized device structures. In this report, we propose a buried interface modification strategy to address these challenges by focusing on the bottom-hole transport layer (HTL) of the PeLEDs. On the one hand, a multifunctional molecule, aminoacetic acid hydrochloride (AACl), is introduced to modify the HTL/perovskite interface to regulate the perovskite crystallization. Experimental investigations and theoretical calculations demonstrate that AACl can effectively reduce the nonradiative recombination losses in bulk perovskites by suppressing the growth of low- n perovskite phases and also the losses at the bottom interface by passivating interfacial defects. On the other hand, a self-assembly nanomesh structure is ingeniously developed within the HTLs. This nanomesh structure is meticulously crafted through the blending of poly-(9,9-dioctyl-fluorene-co-N-(4-butyl phenyl) diphenylamine) and poly (n-vinyl carbazole), significantly enhancing the light outcoupling efficiency in PeLEDs. As a result, our blue PeLEDs achieve remarkable external quantum efficiencies, 20.4% at 487 nm and 12.5% at 470 nm, which are among the highest reported values. Our results offer valuable insights and effective methods for achieving high-performance blue PeLEDs. [ABSTRACT FROM AUTHOR]

Herein, we have designed and synthesized two novel BODIPY dimer-based small molecules, denoted as ZMH-1 and ZMH-2, covalently linked and functionalized with triphenylamine (TPA) (ZMH-1) and carbazole (CZ) (ZMH-2) units as the electron donor at the 3- and 5-positions of the BODIPY core, respectively. Their optical and electrochemical properties were investigated. We have fabricated all small molecule bulk heterojunction organic solar cells using these BODIPY-based small molecules as electron donors along with fullerene derivative (PC71BM) and medium bandgap non-fullerene acceptor IDT-TC as electron acceptors. The optimized OSCs based on ZMH-1:PC71BM, ZMH-2:PC71BM, ZMH-1:IDT-IC, and ZMH-2:IDT-IC attain overall PCEs of 8.91%, 6.61%, 11.28%, and 5.48%, respectively. Moreover, when a small amount of PC71BM as guest acceptor is added to the binary host ZMH-1:IDT-TC and ZMH-2:IDT-TC, the ternary OSCs based on ZMH-1 and ZMH-2 reach PCEs of 13.70% and 12.71%, respectively. [ABSTRACT FROM AUTHOR]

A series of poly(ethylene glycol)‐block‐poly(propylene glycol) (PEG/PPG)‐ and 5,6‐di(9H‐carbazol‐9‐yl)isoindoline‐1,3‐dione (2CZPImide)‐based crosslinked rubbery polymer membranes, denoted as PEG/PPG‐2CZPImide (x:y), are prepared from the norbornene‐functionalized PEG/PPG oligomer (NB‐PEG/PPG‐NB) and 2‐(bicyclo[2.2.1]hept‐5‐en‐2‐ylmethyl)‐5,6‐di(9H‐carbazol‐9‐yl)isoindoline‐1,3‐dione (2CZPImide‐NB) via ring‐opening metathesis polymerization (ROMP). The molar ratio (x:y) of the NB‐PEG/PPG‐NB (x) to 2CZPImide‐NB (y) monomers is varied from 10:1 to 6:1. X‐ray diffraction (XRD), scanning electron microscopy‐energy dispersive X‐ray spectroscopy (SEM‐EDS), and pure gas permeability studies reveal that the comonomer 2CZPImide‐NB successfully increases the d‐spacing among the crystalline PEG/PPG segments, hence enhancing the diffusivity of gases through the membranes. The synthesized membranes exhibit good CO2 separation performance, with CO2 permeabilities ranging from 311.1 to 418.1 Barrer and CO2/N2 and CO2/CH4 selectivities of 39.4–52.0 and 13.4–16.0, respectively, approaching the 2008 Robeson upper bound. Moreover, PEG/PPG‐2CZPImide (6:1), displaying optimal CO2 permeability and CO2/N2 and CO2/CH4 selectivities, shows long‐term stability against physical aging and plasticization resistance up to 20 days and 10 atm, respectively. [ABSTRACT FROM AUTHOR]

The incorporation of fluorescent properties into spin‐crossover (SCO) materials, aiming at controlling fluorescence via spin‐state transitions for applications in magneto‐optical switching and information processing, represents an appealing research direction. In this study, we prepared two examples of one‐dimensional cyclic chain‐like Fe(II) coordination polymers, denoted as [Fe(DPPC)2(NCS)2]⋅CH3OH⋅o‐C6H4Cl2 (1, DPPC=3,6‐di‐4‐pyridinyl‐9‐[4‐(4‐pyridinyl)phenyl]‐9H‐carbazole) and [Fe(PDPC)2(NCS)2] (2, PDPC=3,6‐di(pyridin‐4‐yl)‐9‐phenyl‐9H‐carbazole). Analyses through single‐crystal X‐ray studies and magnetic measurements validate the two‐step SCO behavior of 1 within the temperature range of 50~200 K. Additionally, when combined with temperature‐dependent fluorescence emission spectroscopy, the results demonstrate the coexistence of SCO and fluorescence in 1. [ABSTRACT FROM AUTHOR]

Electrochemiluminescence (ECL) featuring thermally activated delayed fluorescence (TADF) properties has attracted considerable interest, showcasing their potential for 100 % exciton harvesting, which marks a significant advancement in the realm of organic ECL. However, the challenge of elucidating the precise contribution of TADF to the enhanced ECL efficiency arises due to the lack of comparative studies of organic compounds with or without efficient TADF properties. In this study, we present four carbazole‐benzonitrile molecules possessing similar chemical structures and comparable exchange energy (ΔEST). Despite their comparable properties, these compounds exhibited varying TADF efficiencies, warranting a closer examination of their underlying structural and electronic characteristics governing the optical properties. Consequently, intense ECL emission was only observed from 4CzBN with a remarkable TADF efficiency, underscoring the substantial difference in the ECL signal among molecules with comparable ΔEST and similar spectral properties but varying TADF activity. [ABSTRACT FROM AUTHOR]

Diboron‐based multi‐resonance (MR) molecules featuring para‐B‐π‐B configuration represent a highly promising class of emitters for red and near‐infrared organic light‐emitting diodes (OLEDs). The emission spectra of the diboron‐based MR emitters can be fine‐tuned by modulating the carbazole/phenol resonant partners. However, beyond spectral tuning, a comprehensive understanding of the intricate relationship between molecular structure, and the overall properties of diboron‐based MR emitters remains elusive. In this work, through meticulous molecular design and precise material synthesis, the study has constructed three new MR emitters and completed the establishment of the diboron‐based MR molecular family involving a carbazole/phenol resonant counterpart. These emitters facilitate a systematic investigation into the comprehensive impact of resonant partners on critical properties beyond spectral tuning, such as thermally activated delayed fluorescence, full‐width at half‐maximum, and horizontal orientation ratio. Eventually, by employing these emitters, high‐performance narrowband emitting OLEDs with maximum external quantum efficiencies (EQEmaxs) of 30.2%, 33.0%, and 37.0% are fabricated for the green, yellow, and red devices, respectively, together with exceptional operational lifetimes. In particular, both yellow and red OLEDs exhibit unprecedented low‐efficiency roll‐off, maintaining high EQEs over 30% and 25% at the ultrahigh brightness levels of 10 000 and 100 000 cd m−2, respectively. [ABSTRACT FROM AUTHOR]

The document is the contents list for an issue of the journal Chemical Communications. It includes highlights, cover images, and a list of articles and authors featured in the issue. The journal is published by The Royal Society of Chemistry and aims to connect the world with the chemical sciences. The articles cover a range of topics including asymmetric synthesis, solid-electrolyte interface layers, metal selenides, and various catalytic applications. [Extracted from the article]

The first carbazole-embedded p-benziporphyrinoid is synthesized by a [3+1] acid-catalyzed condensation between appropriate coupling partners. The macrocycle 1 exhibited orange emission and showed a large Stokes shift of 5831 cm−1. Intriguingly, it shows a selective affinity towards Hg2+ ions over other metal-ions in a reversible manner. Job's plot confirmed the 1 : 1 stoichiometry with unambiguous confirmation of both 1 and 1-Hg by single crystal X-ray analysis. [ABSTRACT FROM AUTHOR]

Polyhedral oligomeric silsesquioxane (POSS) is an organic‐inorganic hybrid molecule with two structural variations, closed‐ and open‐cage configurations, referred to as completely condensed POSS (CC‐POSS) and corner‐opened POSS (CO‐POSS), respectively. In this study, we synthesized 12 dimers by combining CC‐ and CO‐POSS variants decorated with isobutyl or phenyl substituents to explore their structure‐property relationships. The choice of substituents, both at the cage vertices and open sites, significantly affected the thermal and optical properties of the materials. Modifying the substituents on CO‐ and CC‐POSS, which are isomers, led to significant alterations in the material properties. Notably, isomer‐bearing carbazole substituents exhibited a substantially higher quantum yield (0.32) than its counterpart isomer (0.13), underscoring the crucial role of structural nuances in determining material performance. These results offer valuable insights for the design of novel silsesquioxane‐based materials. [ABSTRACT FROM AUTHOR]

The multiple resonance thermally activated delayed fluorescence (MR‐TADF) materials can meet the requirement of a high color gamut of displays due to their narrowband emission. However, most reported organic light‐emitting diodes (OLEDs) based on MR‐TADF materials suffer from severe efficiency roll‐off. Herein, three green MR‐TADF emitters, p‐ICz‐BNCz, m‐ICz‐BNCz, and dm‐ICz‐BNCz, are obtained by introducing bulky indolo[3,2,1‐jk]carbazole (ICz) units into the classical DtBuCzB skeleton at the para or meta positions relative to the boron‐substituted phenyl ring. Compared with the para‐substitution of ICz, the meta‐substitution not only increases the reverse intersystem crossing rate constants of m‐ICz‐BNCz and dm‐ICz‐BNCz by nearly three times, but also makes their configurations more twisted. The two factors work together to improve the utilization of triplet excitons of the emitters, showing photoluminescence quantum yields exceeding 90%. As a result, the two corresponding OLEDs exhibit maximum external quantum efficiency (EQEmax) values of 28% and 32.9%, respectively, with low‐efficiency roll‐off. At the high brightness of 1000 cd m−2, the EQE values of the two devices still maintain at 19.3% and 25.0%, respectively. In addition, green emissions with Commission Internationale de l'Eclairage coordinates of (0.20, 0.70) and (0.30, 0.67) are also observed. [ABSTRACT FROM AUTHOR]

The efficacy of aniline and carbazole‐based sensitizers used in dye‐sensitized solar cells (DSSCs) is correlated with the trends in density functional theory (DFT) based charge transfer (CT) and non‐linear optical (NLO) properties since both DSSC and NLO properties highly rely on CT properties. The aniline‐based donors showed a higher degree of planarity over carbazole‐based donor sensitizers. This improved planarity in aniline‐based sensitizers is attributed to efficient charge transfer and higher dipole moment. The efficient CT within the sensitizers is confirmed with bond‐length alternation (BLA), bond order alternation (BOA), and quinoid character (QC). A direct correlation of band‐gap (EG) with μ, ω, η, and Γ is witnessed. Time‐dependent DFT (TD‐DFT) results of vertical excitation demonstrated similar trends that are observed practically. Indeed, we observed a direct correlation between α and β and the experimentally observed DSSC efficiency. DFT and TD‐DFT methods, linear, employed for computing the CT and linear and DSSC properties as implemented in Gaussian 09. NLO properties were simulated through single‐point polar calculations. B3LYP and PBE1PBE functionals were used for geometry optimization. The linear and NLO properties were determined in various functionals, that is, global hybrid and range‐separated hybrid functionals. A polarizable continuum model (PCM) was used for solvation studies. To understand the realistic picture of the dye@TiO2 cluster, dye bound on TiO2 clusters were optimized using a LANL2DZ basis set specifically for the Ti atom. [ABSTRACT FROM AUTHOR]

Three novel conjugated molecules have been synthesized: 2‐(fluoranthen‐3‐yliminomethyl)‐3,4‐ethylenedioxythio‐phene (EIF), 2‐(fluoranthen‐3‐yliminomethyl) thiophene (TIF), and 2‐(fluoranthen‐3‐yliminomethyl) fluorene (FIF). Optical properties were obtained from electronic absorption and emission spectra in DMSO solution. The solvatochromic properties of the molecules have been studied in different solvents. Electrochemical properties were studied by cyclic voltammetry in a Bu4NBF4 (0.1 M)/MeCN organic solution. As part of investigations to explain the nature of electronic transition process, we have performed geometry optimization of both the ground and the vertical excitation states, using the DFT B3LYP/6‐311G (d, p) and TD‐DFT (CPCM)/B3LYP/6‐311G (d, p) approaches, respectively. Theoretical calculations closely match the experimental findings. Results show that EIF, TIF and FIF are potential candidates to be used as electron transport layer in Organic Light‐Emitting Diodes (OLEDs). [ABSTRACT FROM AUTHOR]

π‐Conjugated chiral nanorings with intriguing electronic structures and chiroptical properties have attracted considerable interests in synthetic chemistry and materials science. We present the design principles to access new chiral macrocycles (1 and 2) that are essentially built on the key components of main‐group electron‐donating carbazolyl moieties or the π‐expanded aza[7]helicenes. Both macrocycles show the unique molecular conformations with a (quasi) figure‐of‐eight topology as a result of the conjugation patterns of 2,2',7,7'‐spirobifluorenyl in 1 and triarylamine‐coupled aza[7]helicene‐based building blocks in 2. This electronic nature of redox‐active, carbazole‐rich backbones enabled these macrocycles to be readily oxidized chemically and electrochemically, leading to the sequential production of a series of positively charged polycationic open‐shell cyclophanes. Their redox‐dependent electronic states of the resulting multispin polyradicals have been characterized by VT‐ESR, UV/Vis‐NIR absorption and spectroelectrochemical measurements. The singlet (ΔES‐T=−1.29 kcal mol−1) and a nearly degenerate singlet‐triplet ground state (ΔES−T(calcd)=−0.15 kcal mol−1 and ΔES−T(exp)=0.01 kcal mol−1) were proved for diradical dications 12+2⋅ and 22+2⋅, respectively. Our work provides an experimental proof for the construction of electron‐donating new chiral nanorings, and more importantly for highly charged polyradicals with potential applications in chirospintronics and organic conductors. [ABSTRACT FROM AUTHOR]

Developing economical and high‐performing sensitizers is crucial in advancing dye‐sensitized solar cells (DSSCs) and optoelectronics. This research paper explores the potential of novel red light‐absorbing organic dyes based on Indolo[3,2‐b]carbazole (ICZ) as the donor applied in co‐sensitizer‐free DSSCs for breakthroughs in photovoltaic (PV) applications. DFT and TD‐DFT based computational methods were employed to calculate the conduction band levels, electron injection capabilities, and power conversion efficiency (PCE) of metal‐free organic dyes (ICZ1–ICZ9) having D‐A‐π‐A architecture. Comprehensive analyses included NBO, DOS, FMO, ICT, MEP, binding energy, and TDM analysis. Quantum chemical calculations of the structural, photochemical, and electrochemical properties, as well as the key parameters, reveals that all the designed dyes could be an excellent candidate for high‐efficiency DSSCs due the small energy gap (2.130–1.947 eV), longer wavelength absorption (759.47–520.63 nm), longer lifetimes (15.65–6.67 ns), a lower ΔGreg (0.29–0.14 eV), a significant dipole moment changes (31.489–16.195D), LHE (0.95‐0.46), the large qCT (0.962–0.689), small DCT (7.657, 4.897 Å), and VOC (1.13–0.86 eV). This quantum simulation showed that, when compared to reference D8, the photovoltaic dyes ICZ8, ICZ2, and ICZ7 are recognized as being eye‐catching. Furthermore, dye@(TiO2)9 cluster model results demonstrate promising prospects for enhancing the photovoltaic (PV) performance of ICZ1–ICZ9 dyes by electron injection and conduction band (CB) engineering. This study will help the experimentalists for developing ICZ‐based PVs as more efficient and sustainable energy solutions. [ABSTRACT FROM AUTHOR]

A series of five 3,6‐divinyl‐N‐arylcarbazoles‐bridged diruthenium complexes with a general formula of [{Ru(CO)Cl(PiPr3)2}2(μ‐(CH=CH)2‐(N‐arylcarbazole)‐3,6); aryl = 4‐anisyl; [1a], 4‐tolyl; [1b], phenyl; [1c], 4‐(trifluoromethyl)phenyl; [1d], and 4‐nitrophenyl; [1e]] were successfully synthesized. These new square‐pyramidal bis(ruthenium‐vinyl)‐type complexes were characterized in their neutral state via classical NMR, UV/Vis, and IR spectroscopic techniques and in their three various accessible oxidized states via electrochemical techniques and ESR spectroscopy along with UV/Vis/NIR and IR spectroelectrochemistry as well as with DFT calculations. Our obtained results were compared with the closely related bis(ruthenium‐vinyl)‐appended N‐(4‐anisyl)diphenylamine TAARu2 counterpart of [1a]. Electrochemical studies on complexes [1a]–[1e] revealed three consecutive, chemically and electrochemically, well‐separated, reversible one‐electron oxidation processes at low and well‐accessible potentials. Their half‐wave potential separations ΔE½ between the individual redox waves and the derived comproportionation constants Kc1–Kc3 attribute to noteworthy stability of every oxidized intermediate state. The concert electrochemical and UV/Vis/NIR/IR spectro(electro)scopic results on these rotationally restricted N‐arylcarbazoles‐bridged bis(ruthenium‐alkenyl)‐type complexes [1a]–[1e] confirmed the relative weakness influence of altering the para‐substituent on the peripheral aryl ring. This is most probably due to the sizable torsion with nearly 55° between the co‐planarity of the carbazole heterocycle core and the peripheral N‐bound aryl ring. In their mixed‐valent (MV) radical states [1a]+–[1e]+, the observed pattern of two well‐separated Ru(C≡O) bands mirrors the uneven distribution of the uni‐positive charge over the two chemically equivalent bis(ruthenium‐vinyl) moieties as indicated by classical class II of Robin–Day classification of MV states. [ABSTRACT FROM AUTHOR]

Comprehensive Summary: We report herein an unprecedented N‐heterocyclic carbene‐catalyzed formal [3 + 3] annulation of ynals with N‐Ts indolin‐3‐ones under the oxidation condition affording the functionalized pyrano[3,2‐b]indol‐2‐ones. The alkynyl acylazoliums via the combination of a carbene with ynals in the presence of oxidate proved to be the important intermediates for the success of this transformation. This method features a broad substrate scope and mild conditions, including axially chiral skeletons with suitable substitutions. [ABSTRACT FROM AUTHOR]

Since the early days of time of flight secondary ion mass spectrometry (ToF-SIMS), increasing the ion signal has been crucial. It is even more crucial when performing tandem mass spectrometry experiments. To achieve this goal, many developments have been made over the years, which are divided into two categories: instrumental development and sample modification. The latter involves sample metallization, matrix deposition, or changing the temperature of the measurement. In this study, the possibility of using matrices to enhance the signals of organic light emitting device (OLED) molecules was explored. Seven molecules commonly used in OLEDs were separately deposited on Si wafers: Alq3, 2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane, 1,4,5,8,9,11-hexaazatriphenylenehexacarbonitrile, Ir(mppy)3, N,N′-bis(naphthalene-1-yl)-N,N′-bis(phenyl)benzidine, 2,2′,7,7′-tetra(N,N-ditolyl)-amino-spiro-bifluor (STTB), and tris(4-carbazoyl-9-ylphenyl)amine. Using the same solvent, three different matrices with different thicknesses, common in matrix assisted light desorption ionization time of flight mass spectrometry, α-cyano-4-hydroxycinnamic acid, 2,5-dihydrobenzoic acid (DHB), and dihydrochloride N-(1-Naphthyl)ethylenediamine, were sprayed on these surfaces. Spectra were acquired for all compounds and spraying conditions in static ToF-SIMS experiments for Alq3 chemical imaging and depth profiling were performed. This allowed the investigation of the fragmentation pattern of the chosen matrices in ToF-SIMS and, thus, obtained a reference for these molecules. The results show that matrices can enhance the signal of fragments of the studied molecules, for example, the signal of STTB is increased with DHB spraying. Samples sprayed only with the solvent were also prepared to verify the impact of the matrices on the signal. Spraying with the solvent alone can enhance the signal even more than the matrices up to four times in the case of Alq3. This result opens new possibilities in the field of matrix-enhanced ToF-SIMS in terms of applications and matrix choices. [ABSTRACT FROM AUTHOR]

Comprehensive Summary: We report herein an unprecedented N‐heterocyclic carbene‐catalyzed formal [3 + 3] annulation of ynals with N‐Ts indolin‐3‐ones under the oxidation condition affording the functionalized pyrano[3,2‐b]indol‐2‐ones. The alkynyl acylazoliums via the combination of a carbene with ynals in the presence of oxidate proved to be the important intermediates for the success of this transformation. This method features a broad substrate scope and mild conditions, including axially chiral skeletons with suitable substitutions. [ABSTRACT FROM AUTHOR]

Thermoplastic polyimides (TPIs) can meet the requirements of advanced electronic packaging such as flexible copper clad laminate (FCCL) applied under extreme conditions, attributed to their excellent thermal stability, mechanical properties, electrical insulation and chemical resistance. With the increasing demands for electronic devices, such as applications in high‐frequency communication, it is highly desirable to develop high‐performance TPI with good thermoplasticity, thermal stability, mechanical properties and dielectric properties. However, there is a trade‐off between thermoplasticity and other properties. Herein, we introduce an effective strategy to afford TPIs with good performance by copolymerization of a diamine monomer consisted of a coplanar aromatic carbazole group and a short flexible linkage methylene group. On the one hand, short flexible linkages help improve the flexibility of polymer chains and are not too much to enable small‐scale molecular motions below Tg. On the other hand, coplanar aromatic donor groups benefit to strong charge transfer complex (CTC) interaction and π‐π stacking interaction. Based on this strategy, the resultant TPI possesses good thermoplasticity with a proper Tg of 348 °C. Meanwhile, it preserves a low coefficient thermal expansion of 48 ppm K−1, low dielectric constant/dielectric loss factor of 3.27/0.0073 at 10 GHz, and tensile strength of ca. 78 MPa. [ABSTRACT FROM AUTHOR]

The combination of a microcavity and a microsphere has been proposed in this work to manipulate light in terms of emission wavelength and propagation direction. A microcavity with a layer of molecular photoswitch between two one-dimensional photonic crystals of polyvinyl carbazole and cellulose acetate has been designed. To tune the microcavity, the molecular photoswitch has been excited taking into account its cyclization upon irradiation at 313 nm and its cycloreversion at 450 nm. In this way, the emission peak of the microcavity switches from 508.5 nm to 525 nm. A polystyrene microsphere with a radius of 1 μ m is placed near the microcavity. With the detector at an angle of 8°, the emission at 525 nm is 1.73 times higher with respect to the emission at 508.5 nm, while at 10.8°, the emission at 508.5 nm is 1.45 times higher with respect to the emission at 525 nm. The value of these findings is that they offer the experimentalists a ready means to compare the optical data of these types of composites with theory. [ABSTRACT FROM AUTHOR]

Abstract Background Carbazoles are an important class of heterocyclic aromatic compounds that contain nitrogen atom in the ring. They have a large-conjugated system, attractive “electrical and charge-transport properties”, and the ability to efficiently incorporate different functional groups into the structurally inflexible carbazolyl ring. Main text Carbazole derivative ECCA acts as an anticancer agent by reactivating the P53 molecular signaling pathway; similarly, some other derivatives of carbazole show antifungal activity by acting on the RAS-MAPK pathway. Carbazole derivatives also show their effect on inflammation by inhibiting the p38 mitogen-activated protein kinase signaling pathway by stopping the conversion of DAXX protein into ASK-1. By modifying the AKT molecular signaling pathway through boosting protein phosphatase activity in the brain, they show anti-Alzheimer’s activity and also by translocating the GLUT4 these are effective against diabetes. Conclusion After exploring the literature on carbazole, it was found that carbazole has an immeasurably great potential for the treatment of various diseases as the carbazole nucleus leads to various synthesized derivatives which are used for their pharmacological activities. So there is a need to explore carbazole for some newer drugs.

Abstract Background Carbazole-based molecules containing thiosemicarbazide functional groups are recognized for their diverse biological activities, particularly in enhancing therapeutic anticancer effects through inhibiting crucial pathways. These derivatives also exhibit noteworthy antioxidant properties. Objectives This study aims to synthesize, characterize, and evaluate the antioxidant and anticancer activities of 18 novel carbazole derivatives. Methods The radical scavenging capabilities of the compounds were assessed using the 2,2-diphenyl-1-picrylhydrazyl assay. Antiproliferative activities were evaluated on MCF-7 cancer cell lines through viability assays. Additionally, the modulation of the PI3K/Akt/mTOR pathway, apoptosis/necrosis induction, and cell cycle analysis were conducted for the most promising anticancer agents. Results nine compounds showed potent antioxidant activities with IC50 values lower than the positive control acarbose, with compounds 4 h and 4y exhibiting the highest potency (IC50 values of 0.73 and 0.38 µM, respectively). Furthermore, compounds 4o and 4r displayed significant anticancer effects, with IC50 values of 2.02 and 4.99 µM, respectively. Compound 4o, in particular, exhibited promising activity by targeting the PI3K/Akt/mTOR signaling pathway, inhibiting tumor survival, inducing apoptosis, and causing cell cycle arrest in MCF-7 cell lines. Furthermore, compound 4o was showed significant antimicrobial activities against S. aureus and E. coli, and antifungal effect against C. albicans. Its potential to overcome drug resistance through this pathway inhibition highlights its promise as an anticancer agent. Molecular docking simulations supported these findings, revealing favorable binding profiles and interactions within the active sites of the enzymes PI3K, AKT1, and mTOR. Moreover, assessing the druggability of the newly synthesized thiosemicarbazide derivatives demonstrated optimal physicochemical properties, further endorsing their potential as drug candidates.

Thin films of carbazole (Cz) derivatives are frequently used in organic electronics, such as organic light-emitting diodes (OLEDs). Because of the proximity of the Cz units, the excited-state relaxation in such films is complicated, as intermolecular pathways, such as singlet–singlet annihilation (SSA), kinetically compete with the emission. Here, we provide an investigation of two benchmark systems employing neat carbazole and 3,6-di-tert-butylcarbazole (t-Bu-Cz) films and also their thin film blends with poly(methyl methacrylate) (PMMA). These are investigated by a combination of atomic force microscopy (AFM), femtosecond and nanosecond transient absorption spectroscopy (fs-TA and ns-TA) and time-resolved fluorescence. Excitonic J-aggregate-type features are observed in the steady-state absorption and emission spectra of the neat films. The S1 state shows a broad excited-state absorption (ESA) spanning the entire UV–Vis–NIR range. At high S1 exciton number densities of about 4 × 1018 cm−3, bimolecular diffusive S1–S1 annihilation is found to be the dominant SSA process in the neat films with a rate constant in the range of 1–2 × 10−8 cm3 s−1. SSA produces highly vibrationally excited molecules in the electronic ground state (S0*), which cool down slowly by heat transfer to the quartz substrate. The results provide relevant photophysical insight for a better microscopic understanding of carbazole relaxation in thin-film environments.

Zerovalent magnesium (Mg(0)) nanoparticles are prepared in the liquid phase (THF) by reduction of MgBr2 either with lithium naphthalenide ([LiNaph]) or lithium biphenyl ([LiBP]). [LiBP]‐driven reduction results in smaller Mg(0) nanoparticles (10.3±1.7 nm) than [LiNaph]‐driven reduction (28.5±4 nm). The as‐prepared Mg(0) nanoparticles are monocrystalline (d101=245±5 pm) for both types of reduction. Their reactivity is probed by liquid‐phase reaction (THF, toluene) in suspension near room temperature (20–120 °C) with 1‐bromoadamantane (AdBr), chlortriphenylsilane (Ph3SiCl), trichlorphenylsilane (PhSiCl3), 9H‐carbazole (Hcbz), 7‐azaindole (Hai), 1,8‐diaminonaphthalene (H4nda) and N,N'‐bis(α‐pyridyl)‐2,6‐diaminopyridine (H2tpda) as exemplary starting materials. The reactions result in the formation of 1,1'‐biadamantane (1), [MgCl2(thf)2]×Ph6Si2 (2), [Mg9(thf)14Cl18] (3), [Mg(cbz)2(thf)3] (4), [Mg4O(ai)6]×1.5 C7H8 (5), [Mg4(H2nda)4(thf)4] (6) and [Mg3(tpda)3] (7) with 40–80 % yield. 1 and 2 show the reactivity of Mg(0) nanoparticles for C−C and Si−Si coupling reactions with sterically demanding starting materials. 3–7 represent new coordination compounds using sterically demanding N−H‐acidic amines as starting materials. The formation of multinuclear Mg2+ complexes with multidentate ligands illustrates the potential of the oxidative approach to obtain novel compounds with Mg(0) nanoparticles in the liquid phase. [ABSTRACT FROM AUTHOR]

Background: Carbazoles are an important class of heterocyclic aromatic compounds that contain nitrogen atom in the ring. They have a large-conjugated system, attractive "electrical and charge-transport properties", and the ability to efficiently incorporate different functional groups into the structurally inflexible carbazolyl ring. Main text: Carbazole derivative ECCA acts as an anticancer agent by reactivating the P53 molecular signaling pathway; similarly, some other derivatives of carbazole show antifungal activity by acting on the RAS-MAPK pathway. Carbazole derivatives also show their effect on inflammation by inhibiting the p38 mitogen-activated protein kinase signaling pathway by stopping the conversion of DAXX protein into ASK-1. By modifying the AKT molecular signaling pathway through boosting protein phosphatase activity in the brain, they show anti-Alzheimer's activity and also by translocating the GLUT4 these are effective against diabetes. Conclusion: After exploring the literature on carbazole, it was found that carbazole has an immeasurably great potential for the treatment of various diseases as the carbazole nucleus leads to various synthesized derivatives which are used for their pharmacological activities. So there is a need to explore carbazole for some newer drugs. [ABSTRACT FROM AUTHOR]

To control presence of ionic species in excited state of a fluorophore is quite challenging task. Herein, we report the unusual excited‐state prototropism of an important photoacid carbazole dissolved in water in presence of small amount of added ionic liquids (ILs). We have observed that the excited state prototropic equillibria of carbazole dissolved in water can be affected by the presence of small amount of added ILs. More importantly, the excited‐state prototropism of carbazole can be controlled via the acidity of added ILs. More specifically, we found that the fluorescence emission from the neutral prototropic form of carbazole can be observed even under highly basic conditions (aqueous NaOH, pH 12.6) in presence of only small amount of any of the added ILs such as 1‐butyl‐3‐methyl imidazolium tetrafluoroborate ([bmim][BF4]), 1‐butyl‐1‐methylpyrrolidinium bis(trifluromethansulphonyl)imide ([bmpyrr][Tf2N]) and 1‐butyl‐3‐methyl imidazolium hexafluorophosphate ([bmim][PF6]). The observed fluorescence emission from the neutral form of carbazole can be attributed to excited state protonation of carbazole anion by taking proton from IL cation. In a true sense, the excited state carbazole does not transfer the proton; rather takes the proton from IL cation. The observed unusual excited state protonation of carbazole anion to neutral carbazole, in the excited state even in highly basic conditions can be attributed to the presence of acidic protons with the IL cations. Herein, we reports quite unusual results where the IL assisted excited state protonation of carbazole anion occured in an exclusive manner in which proton from the IL cation exclusively protonate carbazole anion surrounded by highly alkaline media (water, pH 12.6). ILs acidity controlled excited‐state properties of important photoacids can have a wide range of chemical and biological applications and the observed results can play important roles in chemical technology to control prototropic equillibra with the help of ILs for some specific application. These observations can open new windows to attract more applications for these alternative solvent media to applications in pH and pOH jump experiments, effective photo protecting agents and chemical lasers. [ABSTRACT FROM AUTHOR]

Developing efficient long‐wavelength thermally activated delayed fluorescence (TADF) emitters is a challenging issue due to inherent limitations of the energy‐gap law. In this contribution, a new molecular design of cyanobenzene‐decorated quinoxaline acceptor, combining two or four cyanobenzene acceptors and a rigid carbazole donor, is successfully utilized to construct long‐wavelength TADF emitters (tCzQx2CN and tCzQx4CN). The two additional cyanobenzene units at the 5‐ and 8‐positions of the quinoxaline acceptor are presumed to interlock the molecular rotations and improve the acceptor strength. Compared with tCzQx2CN, tCzQx4CN exhibits orange‐red emission with a considerable bathochromic shift (>35 nm), as expected. Owing to its enhanced charge transfer and well‐separated highest‐occupied and lowest‐unoccupied molecular orbitals, tCzQx4CN exhibits reduced singlet‐triplet energy splitting and improves reverse intersystem crossing. An organic light–emitting diode (OLED) of tCzQx4CN manifestes bright orange‐red emission (λEL ≈581 nm), a superior external quantum efficiency (EQE) of ≈23.7% (compared with that of tCzQx2CN), and a satisfactory operational lifetime. Furthermore, a tCzQx4CN‐sensitized red‐hyperfluorescent OLED device exhibits excellent performance with an EQE of 16.0% and a CIE(x,y) of (0.62, 0.37). This design would potentially pave the way for constructing red/deep‐red TADF emitters by using a diverse combination of donor/acceptor units. [ABSTRACT FROM AUTHOR]

The tetradentate ligand, merging a carbazole unit with high triplet energy and dimethoxy bipyridine, renowned for its exceptional quantum efficiency in coordination with metals like Pt, is expected to demonstrate remarkable luminescent properties. However, instances of tetradentate ligands such as bipyridine-based pyridylcarbazole derivatives remain exceptionally scarce in the current literature. In this study, we developed a tetradentate ligand based on carbazole and 2,3′-bipyridine and successfully complexed it with Pt(II) ions. This novel compound (1) serves as a sky-blue phosphorescent material for use in light-emitting diodes. Based on single-crystal X-ray analysis, compound 1 has a distorted square-planar geometry with a 5/6/6 backbone around the Pt(II) core. Bright sky-blue emissions were observed at 488 and 516 nm with photoluminescent quantum yields of 34% and a luminescent lifetime of 2.6 μs. TD-DFT calculations for 1 revealed that the electronic transition was mostly attributed to the ligand-centered (LC) charge transfer transition with a small contribution from the metal-to-ligand charge transfer transition (MLCT, ~14%). A phosphorescent organic light-emitting device was successfully fabricated using this material as a dopant, along with 3′-di(9H-carbazol-9-yl)-1,1′-biphenyl (mCBP) and 9-(3′-carbazol-9-yl-5-cyano-biphenyl-3-yl)-9H-carbazole-3-carbonitrile (CNmCBPCN) as mixed hosts. A maximum quantum efficiency of 5.2% and a current efficiency of 15.5 cd/A were obtained at a doping level of 5%. [ABSTRACT FROM AUTHOR]

The distinctive electron structures of luminescent radicals offer considerable potential for a diverse array of applications. Up to now, the luminescent properties of radicals have been modulated through the introduction of electron-donating substituents, predominantly derivatives of carbazole and polyaromatic amines with more and more complicated structures and redshifted luminescent spectra. Herein, four kinds of (N-carbazolyl)bis(2,4,6-tirchlorophenyl)-methyl (CzBTM) radicals, Ph2CzBTM, Mes2CzBTM, Ph2PyIDBTM, and Mes2PyIDBTM, were synthesized and characterized by introducing simple phenyl and 2,4,6-trimethylphenyl groups to CzBTM and PyIDBTM. These radicals exhibit rare blueshifted emission spectra compared to their parent radicals. Furthermore, modifications to CzBTM significantly enhanced the photoluminescence quantum yields (PLQYs), with a highest PLQY of 21% for Mes2CzBTM among CzBTM-type radicals. Additionally, the molecular structures, photophysical properties of molecular orbitals, and stability of the four radicals were systematically investigated. This study provides a novel strategy for tuning the luminescent color of radicals to shorter wavelengths and improving thermostability. [ABSTRACT FROM AUTHOR]

Four different carbazole‐based self‐assembled molecules (SAMs) with different terminal groups have been designed and synthesized as hole‐selective contacts for inverted perovskite solar cells to investigate their interfacial interactions and, consequently, the performance of the devices. Using the carbazole core as a reference, the effect of the thiophen‐2‐yl phenyl, or the hydroxymethyl phenyl attached to the core through a phenyl moiety, with that of the thiophene directly linked to the carbazole is compared. These new SAMs have been successfully synthesized using cost‐effective starting materials and a straightforward synthetic method, eliminating the need for expensive and complex purification processes. Subsequently, they have been applied as efficient hole‐selective contact in inverted perovskite solar cells, leading to an outstanding power conversion efficiency of 19.67% in the case of SAM5, containing a carbazole‐core substituted with double 2‐phenylthiophene side arms as functional group. The detailed characterization of the interface and the charge kinetics has allowed to determine the effect of each substituent. [ABSTRACT FROM AUTHOR]

Carbazole-based self-assembled monolayers have received considerable attention as hole-selective layers (HSLs) in inverted perovskite solar cells. As an HSL, the electron-blocking capability is important and directly related to electron affinity (EA). Low-energy inverse photoelectron spectroscopy (LEIPS) is the most reliable method for EA measurement. However, the intense electron-impact-induced fluorescence from carbazole interferes with their measurement. By improving the photon detector, we were able to measure 2PACz and MeO-2PACz LEIPS spectra and determine their respective EAs of 1.72 and 1.48 eV. These small EA values ensure effective electron-blocking capability of HSLs regardless of the type of perovskite layer. [ABSTRACT FROM AUTHOR]

Luminescent materials with multiple emission centers are attracting more and more attentions due to their potential applications in multicolor displays, polychromatic imaging, information encryption, and ratiometric chemical sensing. Organic molecules with phosphorescence behavior at room temperature (RTP) provide idea candidate for constructing luminescent materials with multiple emission centers, which show great potentials for application in ratiometric chemical sensing owing to its long‐lived emission and high signal‐to‐noise ratio. However, developing RTP materials with multiple emission centers and their application in aqueous solutions remains a huge challenge. Herein, two chromophore isomers (p‐N‐DPC·(PF6)2 and m‐N‐DPC·(PF6)2) based on carbazole and naphthalene units are prepared by using pyridine quaternary ammonium salt as link to improve their solubility in water and form electron deficient centers to facilitate charge transfer (CT). p‐N‐DPC·(PF6)2 displayed multiple emissions behavior, including monomer fluorescence, dimer fluorescence, monomer phosphorescence, dimer phosphorescence, and CT phosphorescence. Especially, p‐N‐DPC·(PF6)2 exhibits monomer fluorescence, dimer fluorescence, and CT phosphorescence in an aqueous solution, which is successfully applied as self‐calibrated dual ratio luminescent sensor for phosphate detection. This study not only provides a strategy to construct luminophore with multiple emissions but also develops a fluorescence/ phosphorescence dual ratio luminescent sensor in an aqueous solution. [ABSTRACT FROM AUTHOR]

Due to side effects and drug resistance, cancer treatment choices are limited despite continued attempts. Topoisomerases are essential for several cellular processes and human topoisomerase I and topoisomerase II alpha inhibitors have proven to be an effective chemotherapeutic alternative for a wide range of cancers, due to its fast proliferating cells and the higher level of these enzymes in solid tumors relative to normal tissue. In this study, around 30 carbazole derivatives were designed using Chem Draw Ultra and their ability to inhibit topoisomerase II was investigated using in silico docking studies and molecular dynamics. The results revealed ligand 10 and ligand 25 held good binding energy scores of -9.21 and -9.50, Kcal mol-1 respectively, with good interaction. ADMET analysis assured the drug likeness and better GI absorption than the parent drug and dexrazoxane. Desmond module of Schrödinger Suite was used and it demonstrated the stability in ligand receptor complexes. [ABSTRACT FROM AUTHOR]

Three different iridium(III) complexes, labelled as Ir1–Ir3, each bearing a unique anchoring moiety (diethyl [2,2′-bipyridine]-4,4′-dicarboxylate, tetraethyl [2,2′-bipyridine]-4,4′-diylbis(phosphonate), or [2,2′-biquinoline]-4,4′-dicarboxylic acid), were synthesized to serve as photosensitizers. Their electrochemical and photophysical characteristics were systematically investigated. ERP measurements were employed to elucidate the impact of the anchoring groups on the photocatalytic hydrogen generation performance of the complexes. The novel iridium(III) complexes were integrated with platinized TiO2 (Pt–TiO2) nanoparticles and tested for their ability to catalyze hydrogen production under visible light. A H2 turnover number (TON) of up to 3670 was obtained upon irradiation for 120 h. The complexes with tetraethyl [2,2′-bipyridine]-4,4′-diylbis(phosphonate) anchoring groups were found to outperform those bearing other moieties, which may be one of the important steps in the development of high-efficiency iridium(III) photosensitizers for hydrogen generation by water splitting. Additionally, toxicological analyses found no significant difference in the toxicity to luminescent bacteria of any of the present iridium(III) complexes compared with that of TiO2, which implies that the complexes investigated in this study do not pose a high risk to the aquatic environment compared to TiO2. [ABSTRACT FROM AUTHOR]

A hierarchically porous sulfated geopolymer catalyst was prepared by three staged sequential treatments involving desilication, ion exchange, and sulfation steps. The first step helped generate hierarchical porosity through the selective removal of Si. The desilicated geopolymer was converted from basic Na-form to acidic H-form through ion exchange with ammonium chloride solution. The ion-exchanged geopolymer was then impregnated with sulfuric acid to produce a super-acidic sulfated geopolymer catalyst. The physicochemical characteristics of the catalyst were analyzed by XRD, FE-SEM, TEM, BET, XPS, NH3-TPD, and FTIR analysis. Three types of model fuels containing pyridine, indole, and carbazole were prepared to evaluate the performance of the catalyst. The influence of parameters affecting the oxidation of pyridine was assessed by conducting the reaction with varying amounts of catalyst, stirring speed, oxidant to nitrogen ratio, temperature, and initial nitrogen concentration. The reaction proceeded via nucleophilic attack by pyridine on the catalyst and followed pseudo first-order kinetics with a TOF and TON of 22.4 h−1 and 134.4, respectively. The oxidized products were removed from the model oil by extraction with aqueous solvents, and the effect of influencing parameters on the extraction efficiency was also studied. The efficiency of the coupled oxidation-extraction process for the three model fuels varied in the order: pyridine > indole > carbazole. [ABSTRACT FROM AUTHOR]

Context: Three donor (D)–acceptor (A)-type temperature-activated delayed fluorescent (TADF) molecules of 9-(2-(4,6-diphenyl-1,3,5-triazin-2-yl)phenyl)-9H-3,9′-bicarbazole (o-TrzDCz), 9-(3-(4,6-diphenyl-1,3,5-triazin-2-yl)phenyl)-9H-3,9′-bicarbazole (m-TrzDCz), and 9-(4-(4,6-diphenyl-1,3,5-triazin-2-yl)phenyl)-9H-3,9′-bicarbazole (p-TrzDCz) were designed in this paper, and the photophysical properties, including the intersystem crossing rate, the reorganization energies (λ), and the intersystem crossing/reverse intersystem crossing (ISC/RISC) rate, were simulated to explore the effect of substitution sites on their TADF character. The values of the twist angle between the D and A moieties in ground state and the molecular root-mean-square deviation (RMSD) of the S1 and T1 states referenced to the S0 state indicate that o-TrzDCz possess bigger steric hindrance and stabler molecular configuration. The λ values of the ISC/RISC process should be 0.06/0.04 eV for o-TrzDCz, which are much smaller than those of m-TrzDCz (0.51/0.41 eV) and p-TrzDCz (1.93/1.06 eV). At the same time, o-TrzDCz possess the biggest kRISC (7.28 × 106 s−1) and kr (3.12 × 106 s−1) values and the smallest kp (0.10 s−1) value among the three titled molecules. These data indicate that o-TrzDCz should have more excellent TADF character than m-TrzDCz and p-TrzDCz. In a word, this research presents that adjusting the molecular linking manner should be a charming way to explore novel high-efficient TADF molecules. Methods: Quantum chemical calculations were performed at PBE0/6-31G* level by Gaussian 09 and ORCA 4.1.0 software packages, and reorganization energies and Huang-Rhys were performed by the DUSHIN program and MOMAP 2019B software package based on the Gaussian 09 output files, while the phosphorescence rates were performed at B3LYP/6-31G* level by Dalton 2021. [ABSTRACT FROM AUTHOR]

Thin films of carbazole (Cz) derivatives are frequently used in organic electronics, such as organic light-emitting diodes (OLEDs). Because of the proximity of the Cz units, the excited-state relaxation in such films is complicated, as intermolecular pathways, such as singlet–singlet annihilation (SSA), kinetically compete with the emission. Here, we provide an investigation of two benchmark systems employing neat carbazole and 3,6-di-tert-butylcarbazole (t-Bu-Cz) films and also their thin film blends with poly(methyl methacrylate) (PMMA). These are investigated by a combination of atomic force microscopy (AFM), femtosecond and nanosecond transient absorption spectroscopy (fs-TA and ns-TA) and time-resolved fluorescence. Excitonic J-aggregate-type features are observed in the steady-state absorption and emission spectra of the neat films. The S1 state shows a broad excited-state absorption (ESA) spanning the entire UV–Vis–NIR range. At high S1 exciton number densities of about 4 × 1018 cm−3, bimolecular diffusive S1–S1 annihilation is found to be the dominant SSA process in the neat films with a rate constant in the range of 1–2 × 10−8 cm3 s−1. SSA produces highly vibrationally excited molecules in the electronic ground state (S0*), which cool down slowly by heat transfer to the quartz substrate. The results provide relevant photophysical insight for a better microscopic understanding of carbazole relaxation in thin-film environments. [ABSTRACT FROM AUTHOR]