Azo Group Research Articles

Phenolic -OH-Induced Fluorescence and Chemoselectivity in a Triptycene-Based trans-Azo Oligomer for Sensing Applications.

A novel triptycene-based trans-azo fluorescent oligomer exhibiting phenolic groups has been designed. The presence of phenolic -OH in conjugation with the azo group rendered the oligomer fluorescence active by keto-enol tautomerism, which was evidenced by quenching the fluorescence intensity of TP1 in 1 M aq. NaOH. A green synthetic protocol was employed to synthesize this oligomer as a dark-brown solid, and it was characterized by using diverse analytical tools such as FTIR, 13C-CPMAS NMR, GPC, FESEM, EDS, TGA, and PXRD techniques. FESEM and PXRD confirmed its existence as amorphous nanoclusters. The oligomer displayed efficient chemosensing properties toward the detection of picric acid with the LOD value of 391 nM. The specific recognition of PA in the presence of other explosives and the results of real water sample analysis further indicated the high efficacy of the TP1 as a chemosensor.

Hypoxia-Activated Biodegradable Porphyrin-Based Covalent Organic Frameworks for Photodynamic and Photothermal Therapy of Wound Infection.

Wound infections have gradually become a major threat to human health. Recently, covalent organic frameworks (COFs) have shown great potential in antibacterial and wound healing; however, difficult biodegradability and long-time in vivo retention limit their further application. Herein, biodegradable COFs containing porphyrin backbones and hypoxia-sensitive azobenzene group, namely, HRCOFs, are fabricated for photodynamic therapy (PDT) and photothermal therapy (PTT) of wound infection. Due to the introduction of a porphyrin molecule, HRCOFs can produce singlet oxygen (1O2) under 660 nm laser irradiation. The prepared HRCOFs can also generate thermal energy under 808 nm NIR laser irradiation. HRCOFs show excellent synergetic antibacterial ability against Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli) in vitro. The in vivo experiments also demonstrate synergistic PDT and PTT effects of HRCOFs against wound infection. Importantly, HRCOFs are response to wound microenvironment, can be degraded for clearance, and avoid some adverse effects caused by long-time retention in vivo, exhibiting good biocompatibility. In general, the obtained biodegradable HRCOFs with both photodynamic and photothermal effects can be used for antibacterial infections and provide great value for promoting wound healing.

Isoreticular Contraction in Dicopper Paddle-Wheel-Based Metal-Organic Frameworks to Enhance C2H2/CO2 Separation.

Achieving a balance between high selectivity and uptake is a formidable challenge for the purification of acetylene from mixtures with carbon dioxide, particularly when seeking to maximize both C2H2 adsorption capacity and C2H2/CO2 separation selectivity in crystalline porous materials. In this study, leveraging the principles of reticular chemistry, we selected two tetracarboxylate-based linkers and combined them with Cu2+ ions to synthesize two isoreticular dicopper paddle-wheel-based metal-organic frameworks (MOFs): Cu-TPTC (terphenyl-3,3',5,5'-tetracarboxylic acid , H4TPTC) and Cu-ABTC (3,3,5,5-azobenzenetetracarboxylic acid, H4ABTC). The structural and sorption analyses revealed that Cu-ABTC, despite having slightly smaller pores due to the strategic replacement of a phenyl ring with an azo group between two tetratopic ligands, maintains high porosity compared to Cu-TPTC. Furthermore, Cu-ABTC outperforms Cu-TPTC in terms of C2H2 adsorption capacity (196 cm3 g-1 at 298 K and 1 bar) and C2H2/CO2 separation selectivity (16.5~5.6). These findings were corroborated by dynamic breakthrough experiments and computational modeling. This research highlights the potential of the isoreticular contraction strategy in enhancing MOFs for sophisticated gas adsorption and separation processes.

Fast Production of Covalent Organic Frameworks for Covalent Enzyme Immobilization with Boosted Enzymatic Catalysis by Solar‐Driven Photothermal Effect

AbstractDeveloping new enzyme‐immobilization systems to stabilize their dynamic structures and meanwhile enhance their catalytic activity is of great significance but very challenging. Herein, we design and fabricate a class of robust mesoporous covalent organic frameworks (COFs) via Michael addition‐elimination reaction. It is found that highly crystalline COFs can be produced in 10 min, which is attributed to the promoting effect of the intramolecular hydrogen bond activation. The COFs rich in hydroxyl groups can be facilely post‐modified by epibromohydrin to covalently immobilize enzymes with both high loading and activity. Furthermore, we create a solar‐driven photothermal‐promoted strategy by introducing photoactive azo groups to COF carriers, which can boost the enzyme catalytic performance (lipase) with much higher conversion of various racemic substrates and chiral resolution upon solar light irradiation. The heterogeneous biocatalysts also demonstrate exceptional reusability and stability. This work provides a green and energy‐efficient approach to facilitate the scale application of enzyme‐immobilized biocatalysts.

Fast Production of Covalent Organic Frameworks for Covalent Enzyme Immobilization with Boosted Enzymatic Catalysis by Solar-Driven Photothermal Effect.

Developing new enzyme-immobilization systems to stabilize their dynamic structures and meanwhile enhance their catalytic activity is of great significance but very challenging. Herein, we design and fabricate a class of robust mesoporous covalent organic frameworks (COFs) via Michael addition-elimination reaction. It is found that highly crystalline COFs can be produced in 10 min, which is attributed to the promoting effect of the intramolecular hydrogen bond activation. The COFs rich in hydroxyl groups can be facilely post-modified by epibromohydrin to covalently immobilize enzymes with both high loading and activity. Furthermore, we create a solar-driven photothermal-promoted strategy by introducing photoactive azo groups to COF carriers, which can boost the enzyme catalytic performance (lipase) with much higher conversion of various racemic substrates and chiral resolution upon solar light irradiation. The heterogeneous biocatalysts also demonstrate exceptional reusability and stability. This work provides a green and energy-efficient approach to facilitate the scale application of enzyme-immobilized biocatalysts.

Photoinduced Anisotropy in Thin Films of Azobenzene-Containing Liquid Crystalline Supramolecular Complexes of Various Polymer Architecture.

Light patternable colorless liquid crystalline (LC) polymers are promising materials for functional photonic devices with broad applications in optical communication, diffractive optics, and displays. This work reports photoinduced optical anisotropy in thin films of azobenzene-containing (Azo) LC block copolymer supramolecular complexes, which can be decolorized after light patterning providing colorless patterned birefringent polymer films. The supramolecular complexes are prepared via intermolecular pyridine-phenol hydrogen bonding between a low-molecular-weight Azo phenol and host LC AB diblock and ABA triblock copolymers consisted of LC phenylbenzoate (PhM) blocks and poly(vinylpyridine) units. The molecular architecture of the host polymers and the morphological pattern formed by the complexes can affect orientational behavior of Azo groups under irradiation with linearly polarized light. Photoorientation of hydrogen-bonded Azo groups is accompanied by the cooperative orientation of non-photochromic PhM units, which form individual microphases and stabilize the orientation of Azo groups. This effect is specific for block copolymer complexes and it is absent for random copolymer complex, which is used as a reference sample. Optical anisotropy induced in films of the block copolymer complexes can be amplified by heating above the glass transition temperature and subsequent rinsing with diethyl ether allows colorless birefringent polymer films to be prepared.

Atomically dispersed Fe boosting elimination performance of g-C3N4 towards refractory sulfonic azo compounds via catalyst-contaminant interaction

Herein, an oxygen-doped porous g-C3N4 photocatalyst modified with atomically dispersed Fe (Fe1/OPCN) is successfully prepared and exhibits significant superiority in removing refractory sulfonic azo contaminants from water via catalyst-contaminant interaction. The elimination performance of Fe1/OPCN towards acid red 9, acid red 13 and amaranth containing similar azonaphthalene structure and increasing sulfonic acid groups increases gradually. The amaranth degradation rate of Fe1/OPCN is 17.7 and 6.1 times as that of homogeneous Fenton and OPCN, respectively. In addition, Fe1/OPCN also has more outstanding removal activities towards other contaminants with sulfonic acid and azo groups alone. The considerable enhancement for removing sulfonic azo contaminants of Fe1/OPCN is mainly ascribed to the following aspects: (1) The modified Fe could enhance the adsorption towards sulfonic azo compounds to accelerate the mass transfer, act as e- acceptor to promote interfacial charge separation, and trigger the self-Fenton reaction to convert in-situ generated H2O2 into •OH. (2) Fe(Ⅲ) could coordinate with —N=N— to form d-π conjugation, which could attract e- transfer to attack —N=N— bond. Meanwhile, the inhibited charge recombination could release more free h+ to oxidize sulfonic acid groups into SO4-•. (3) Under the cooperation of abundant multiple active species (•O2-, h+, e-, •OH, SO4-•) formed during the degradation reaction, sulfonic azo compounds could be completely mineralized into harmless small molecules (CO2, H2O, etc.) by means of —N=N— cleavage, hydroxyl substitution, and aromatic ring opening. This work offers a novel approach for effectively eliminating refractory sulfonic azo compounds from wastewater.

Synthesis and Study Biological Activity of Some New Substituted Thiazolidin-4-one Derivatives

The microwave (MW) method was used to create a series of new thiazolidin-4-one derivatives containing benzothiazole and azo groups. Azoaldehyde derivative A was synthesized via the coupling reaction of 2-aminobenzothiazole diazonium ions and 2-hydroxybenzaldehyde. The resultant azoaldehyde A was then subjected to condensation reactions with the primary aromatic amines using the MW method to give azoimines derivatives S1-S5. Finally, compounds S1-S5 were reacted with α-mercaptoacetic acid by the MW method to generate the thiazolidin-4-one derivatives T1-T5. The novel-produced compounds T1-T5 were identified by FT-IR, 1H NMR, and 13C NMR spectroscopy. The DPPH was used to determine the antioxidant activity of the novel-produced compounds T1-T5. The obtained results for T1 and T5 were excellent as antioxidants in comparison with ascorbic acid, while in the antibacterial study, it was discovered that T2, T3, and T5 were found to be more successful than Gentamycin as a control drug against Staphylococcus aureus in an antibacterial investigation, while T3 was found to be more effective than the reference drug against Escherichia coli.

Tetrafunctionalized Azocalix[4]resorcinarene Dye: A Chromogenic Supramolecule Used for the Selective Liquid-Liquid Extraction and Spectrophotometric Determination of Cu(II)

Background: The detection and extraction of trace metal ions, particularly copper(II), are critical for environmental monitoring and industrial processes. Calixresorcinarene, with its unique cavity structure, offers excellent platforms for designing selective chemosensors and extractants. Functionalization of calixresorcinarene with azo groups can enhance their chromogenic properties, enabling both extraction and detection in a single step. Objective: This study aimed to evaluate its (Azocalix[4]resorcinaren) efficacy as a selective chemosensor for the liquid-liquid extraction and spectrophotometric determination of Cu(II) ions. Methods: Application in Extraction and Detection: The ability of the dye to selectively extract Cu(II) ions from aqueous solutions was investigated via liquid-liquid extraction experiments. The dye-Cu(II) complex formation was monitored by UV-Vis spectrophotometry, with systematic optimization of experimental conditions, including pH, solvent system, and extraction duration. Results: The synthesized azocalix[4]resorcinarene dye exhibited a pronounced selectivity towards Cu(II) ions, forming a stable, colored complex. The complexation induced a distinct bathochromic shift in the absorption spectrum, allowing for precise spectrophotometric detection. Optimal extraction was achieved at a specific pH and solvent combination, with the method demonstrating a low detection limit and high sensitivity. The dye showed minimal interference from other metal ions, confirming its selectivity for Cu(II). Conclusion: The tetrafunctionalized azocalix[4]resorcinarene dye is a highly effective chromogenic agent for the selective extraction and detection of Cu(II) ions. Its robust performance in both extraction efficiency and spectrophotometric detection underscores its potential utility in environmental analysis and industrial applications where trace metal detection is crucial.

Methacrylate-Containing <i>n</i>-Derivatives of <i>N</i>,<i>N</i>-Diethyl-4-(Phenyldiazenyl)Aniline as Initiators in Two-Photon Polymerization

The possibility of using a number of methacrylate-containing N,N-diethyl-4-(phenyldiazenyl)anilines with various para-substituents with respect to the azo group (-H, -Br, -NO2) as photoinitiators of radical polymerization is considered. The electrochemical and photoluminescent properties of these compounds have been studied. In the presence of azo dyes, two-photon photopolymerization of pentaerythritol triacrylate was carried out by focused radiation from a femtosecond laser with a wavelength of 780 nm. Structures with minimum linear element sizes of 94 ± 5 nm were obtained by DLW nanolithography, as well as 3D microstructures of complex architecture.

Efficient Cleavage of pUC19 DNA by Tetraaminonaphthols.

In an attempt to create models of phosphodiesterases, we previously investigated bis(guanidinium) naphthols. Such metal-free anion receptors cleaved aryl phosphates and also plasmid DNA. Observed reaction rates, however, could not compete with those of highly reactive metal complexes. In the present study, we have replaced the guanidines by ethylene diamine side chains which accelerates the plasmid cleavage by compound 13 significantly (1 mM 13: t1/2=22 h). Further gains in reactivity are achieved by azo coupling of the naphthol unit. The electron accepting azo group decreases the pKa of the hydroxy group. It can also serve as a dye label and a handle for attaching DNA binding moieties. The resulting azo naphthol 17 not only nicks (1 mM 17: t1/2~1 h) but also linearizes pUC19 DNA. Although the high reactivity of 17 seems to result in part from aggregation, in the presence of EDTA azo naphthol 17 obeys first order kinetics (1 mM 17: t1/2=4.8 h), reacts four times faster than naphthol 13 and surpasses by far the former bis(guanidinium) naphthols 4 and 5.

Reversible MOF-Based mixed matrix membranes for SO2/N2 separation: A photo-responsive approach

Fuel consumption for industrial development, SO2 gas emissions are increasing year by year and have become a focal point of air pollution. Membrane separation method photo-responsive materials and MOFs have attracted more and more attention in a variety of fields. This is because the membrane separation method uses less energy and is an uncomplicated process; MOFs have superior gas adsorption capabilities; and the photo-responsive materials are controllable. In this study, mixed matrix membranes are prepared using Uio-66-NH2 and photo-responsive materials CE-Azo-Uio-66 as fillers and Pebax as base membranes. By improving the dissolution-diffusion mechanism for SO2 gas molecules, SO2/N2 gas separation is accomplished. More channels for the mass transport of SO2 gas through the membrane can be created by MOFs increased porosity and larger specific surface area. Secondly, the SO2 adsorption and dissolution-diffusion mechanism of the mixed matrix membrane are strengthened by the grafted SO2 affinity groups on the MOF. Moreover, Pebax/CE-Azo-Uio-66 membranes is not only significantly more permeation selective than Pebax/Uio-66-NH2 membranes, but also shows photo-responsive characteristic. The SO2 permeability and selectivity of Pebax/CE-Azo-Uio-66 mixed matrix membranes at CE-Azo-Uio-66 content of 20 % are increased by 191 % and 179 %, respectively, compared to pure Pebax membranes. It is also found that the SO2 permeability and SO2/N2 selectivity of the membranes show regularly reversible changes at the UV–Vis photoconversion conditions of Pebax/CE-Azo-Uio-66-20 % membranes, indicating the photo-responsive characteristics of mixed matrix membranes that include Azo groups. The SO2 permeability of the Pebax/CE-Azo-Uio-66 membrane is increased by 1300 Barrer and the SO2/N2 selectivity is increased by 350 when the light source is changed from UV to Vis light, achieving a controlled separation of SO2/N2. Besides, the addition of MOF particles significantly enhances the mechanical properties and stability of the membrane.

Mechanism of Sulfate Radical Formation on Activation of Persulfate Using Doped Metal Oxide and Its Role in Degradation of Tartrazine Dye in an Aqueous Solution.

Degradation of tartrazine dye (TZD) was performed in this study using sulfate radicals (SO4•-) generated from the activated sodium persulfate (SPS) using Fe3O4@PDA nanoparticles (NPs). The NPs were characterized by Fourier transform infrared (FTIR), vibrating sample magnetometer (VSM), X-ray diffraction (XRD), high-resolution scanning electron microscopy (HR-SEM), X-ray photoelectron spectroscopy (XPS), high resolution transmission electron microscopy (HRTEM), and energy-dispersive X-ray spectroscopy (EDX). The average particle size of the NPs was 17.49 nm from XRD analysis. The presence of the C-N group at 1129 cm-1 in FTIR and 2.54% of the nitrogen element identified from the EDX plot was evidence of successful doping of polydopamine (PDA). Superparamagnetic nature with a decrease in the Ms value to 42.015 emu/g after doping was determined. Doping was further confirmed by XPS analysis with binding energies at 399.68 and 400.99 eV. The average particle size from HRTEM analysis was 21.47 nm with a lattice spacing of 0.30 nm. Turnover number (TON) and turnover frequency (TOF) values for Fe3O4@PDA were determined to be 3.72 and 0.0248 min-1 with respect to different systems, respectively. Optimum conditions for the Fe3O4@PDA/SPS system were 50 ppm TZD, 0.9 g/L catalyst, 12 mM SPS, and pH 4 with 94.68% efficiency in 150 min. The inhibition effect of ions in TZD degradation followed the order humic acid <NO3- < Cl- < CO32. The kinetic model fitting the Fe3O4@PDA/SPS system has pseudo-second-order kinetics. Excess formation of SO4•- produced hydroxyl radicals (•OH) that were identified by a scavenging test. Reusability of the NPs was performed for five cycles and showed acceptable degradation performance up to 82.47%. The intermediates identified from gas chromatography-mass spectrometry (GCMS) proved the cleavage of azo and sulfonate groups of TZD with the formation of nontoxic intermediates. Finally, the phytotoxicity assessment was studied using Vigna radiata (Green grams). The % decrease of the root, shoot, and seedling length for the degraded dye solution was negligible. Hence, this study proved that the Fe3O4@PDA/SPS system could effectively degrade TZD with nontoxic intermediate formation.

Molecular Insights into the Potential Anticancer Property of a Diimine-Diazo Molecule: A Molecular Docking and Molecular Dynamics Simulations Perspective

Cancer is a disease in which cells grow abnormally and uncontrollably and destroy body tissue, and it is one of the most important threats to human health. In this study, the interaction of a molecule containing imine and azo groups (DIDA) with tumor growth-related VEGFR2 (PDB ID: 2XIR) and EGFR (PDB ID: 1M17) proteins was investigated by molecular docking and molecular dynamics simulation methods. The molecular docking study revealed that the best binding occurred between DIDA-2XIR with a binding energy of -12.4 kcal/mol. Molecular dynamics simulation was used to verify the stability of the DIDA-2XIR complex. RMSD, RMSF, SASA, Rg parameters and number of hydrogen bonds obtained during molecular dynamics simulations showed that the DIDA-2XIR complex was stable at the molecular level. Our findings have made an important contribution to the understanding of the mechanism of interaction of the DIDA with VEGFR2 and support its availability as a potential VEGFR2 inhibitor.

Synthesis of Montmorillonite-Silica Nanocomposite Using Millet Husk and Montmorillonite Clay and Optimization of Adsorption Parameters for Congo Red Dye Adsorption

Dyes are substances that, when applied to a substrate provides color by a process that alters, at least temporarily, any crystal structure of the colored substances The discharge of these effluents into the receiving environments results in hazardous health problems as most of these dyes have carcinogenic effects on the living organisms. Generally, dyes are classified into three categories: a) anionic: direct, acid, and reactive dyes; b) cationic: basic dyes; and c) non-ionic: disperse dyes. The chromophores in anionic and non-ionic dyes mostly consist of azo groups or anthraquinone types. However, Congo red, are difficult to biodegrade due to their complex aromatic structures, which provide them with physico-chemical, thermal, and optical stability. This study is aimed at synthesizing Montmorillonite-silica nanocomposite, a cost effective adsorbent from millet husk and Montmorillonite-clay with the determination of its optimum adsorption parameters for Congo Red Dye adsorption. Here, synthesis of Montmorillonite-silica nanocomposite and optimization parameters were carried out using standard procedures. The unbiased result demonstrated that the percentage yield was found to be 94.51 %. The optimum adsorption parameters studied were adsorbent dose, adsorbate concentration, pH and Kinetics studies. The optimum adsorption parameters were found to be 8.0 g/L, 2.0 mg/L, 8 and 30 minutes, respectively. Hence, the synthesized Montmorillonite-silica nanocomposite obtained from montmorillonite clay and millet husk ash can serve as a cost-effective adsorbent for the removal of Congo Red Dye from waste waters.

Nano-organic polymers with rich redox sites as anode materials for dual-ion batteries

Organic electrode materials (OEMs) are considered one of the potential electroactive materials used in rechargeable batteries due to their high availability, low price, and sustainability. Nevertheless, the high solubility of their organic small molecules and their low electrical conductivity limit their practical applications. In this study, porous nanorods organic conjugated polymer were successfully prepared by a solvothermal method using 1,4,5,8-naphthalenetetracarboxylic anhydride and azodicarbonamide as precursors for dual-ion battery anodes. The successful synthesis of polymer extends the π-conjugated structure, effectively reducing its solubility in organic electrolytes. Moreover, the azo group (NN) in the polymer was easily conjugated with the adjacent aromatic ring, increasing the utilization of the active site, thereby improving the conductivity of the material so that the polymer has a high discharge capacity (90.5 mAh g−1 at 2 C, up to 96 % capacity retention). Even with a high rate of 10 C, the polymer still exhibits excellent electrochemical performance (50.0 mAh g−1 at 270 cycles). Moreover, reaction kinetics tests show that the electrode material was based on a pseudocapacitive storage mechanism influenced by diffusion and double-layer control. Therefore, the design strategy of such a material paves the way for the application of dual-ion batteries.

Electrochemical Determination of Tartrazine and Carmoisine Dyes from Aqueous Solutions on Modified Electrodes

Introduction: The recognition of the health hazards of azo dyes has highlighted the need to develop efficient, rapid, and reliable analytical methods for dye determination. Method: In this work, electrochemical probing of the azo group of Tartrazine (TZ) and Carmoisine (CR) in food dyes was carried out. Synthesized bismuth and zinc oxide nanoparticles were used to modify Graphite Electrode (GE). Results: Electrochemical analysis showed a much better electrochemical response using ZnO+Bi/GE as a modifier than individually nanoparticle-modified graphite electrodes. From the CV analysis, it was found that both the dyes exhibited irreversible electrochemical behavior, and the redox parameters were calculated. The Limit of Detection (LOD) values recorded for TZ and CR for ZnO+Bi/GEbased sensors were 0.84 uM and 2.80 uM, respectively. The obtained sensitivity values were 11.86 uA/uM/cm2 for TZ and 17.3 uA/uM/cm2 for CR. Conclusion: The sensor evidently demonstrated reliable simultaneous detection of both dyes, making it suitable for practical applications in food safety analysis.

Comprehensive Analysis of Impurity Detection in Linear Alkyl Benzene–Based Liquid Scintillators Using Infrared Spectroscopy for Enhanced Neutrino Detection

Abstract We present a comprehensive analysis of infrared (IR) spectra for linear alkyl benzene (LAB)-based scintillation solutions, focusing on the detection and identification of impurities. Previous research primarily utilized ultraviolet-visible spectroscopy to investigate electronic structures and transitions, whereas our approach emphasizes vibrational transitions and IR spectral characteristics. We specifically examined the presence of common impurities, such as acetone, water, and three impurity compounds (IMP1, IMP2, and IMP3) identified by the JUNO Collaboration. Acetone, a common contaminant from cleaning procedures, was detected by its characteristic absorption peaks at 1200, 1360, and 1700 $\rm {cm}^{-1}$. Water, an inevitable by-product of Gd-loaded LAB using a neutralization reaction process, was identified through distinct O-H stretching and H-O-H bending vibrations at 3200–3600 $\rm {cm}^{-1}$ and 1600 $\rm {cm}^{-1}$, respectively. The IR spectra of IMP1, IMP2, and IMP3 were theoretically calculated, revealing unique absorption bands for key functional groups, including carbonyl (C=O), amide (C-N), sulfoxide (S=O), aryl chloride (Ar-Cl), azo (N=N), and ether (C-O-C) groups. The findings confirm the absence of these impurities in the LAB (+ 2,5-Diphenyloxazole [PPO] + 1,4-Bis(2-methylstyryl)benzene [bis-MSB]) sample, ensuring the high performance and accuracy of neutrino detectors. This study demonstrates the effectiveness of IR spectroscopy as a powerful analytical tool for quality assurance in liquid scintillation solutions, providing a robust framework for enhancing the reliability and precision of neutrino detection experiments.

Photoresponsive conductive polymer network based on azobenzene bridging crosslinked polycarbazole for boosting solar thermal storage

Azobenzene is one of the most extensively researched multifunctional chromophores and azobenzene including materials has a wide variety of applications due to their photoisomerization behavior. In this study, electroactive and light-harvesting carbazole and photoresponsive azobenzene units have been combined with a special macromolecular design. In this design the azo groups can be effectively isomerized in solid state, and free-standing films can be obtained by the electrochemical method. Thermal characterizations of both monomer and polymer have been performed and isomerization kinetics and solar-thermal properties have been investigated. The half-life at 60 °C and the gravimetric energy storage density of polymer was calculated as 103 min and 179.9 j g−1, respectively. Cross-linked polycarbazole structure causes dramatically increased solar thermal storage and half-life compared to respective monomer and brought unexpected mechanical and solvatochromic properties.

Rhodium(III)-Catalyzed B(4)-Azo Coupling of o-Carboranes with Aryl Diazonium Tetrafluoroborates.

Rh(III)-catalyzed B(4)-azo coupling reactions of o-carborane acids with aryl diazonium tetrafluoroborates have been developed, leading to the regioselective formation of B(4)-azo-coupled o-carboranes. Moreover, B(4)-azo-coupled o-carboranes can be further functionalized by introducing a second azo group, producing B(4)-C(1)-di(arylazo) o-carborane. The B(4)-azo group as an efficient directing group enables catalytic C-H amidation reactions, providing a new synthetic route for complex o-carborane derivatives.