Toluene Research Articles (Page 1)

Tabernaemontana divaricata (L.) R. Br. is a popular ornamental shrub. Each and every part of the plant is medicinally very significant. The floral metabolome of it remains largely uncharacterized. In this study, gas chromatography-mass spectrometry (GC-MS) analysis was performed on methanolic floral extracts from four genotypes leading to the identification of 68-99 metabolites out of which 30 metabolites based on notable peak area percentages from all 4 genotypes were taken to further study. The detected compounds included methyl salicylate, myo-inositol, cis-vaccenic acid, squalene, geraniol, phytol, n-hexadecanoic acid and benzene derivatives. The metabolites belong to diverse chemical classes such as esters, terpenoids, lactones, fatty acid derivatives and aromatic alcohols. These metabolites are well known for their antioxidant, antimicrobial and anti-inflammatory properties. Chemometric tools including principal component analysis (PCA), hierarchical clustering and Venn diagrams revealed clear genotype-specific variation and distinct grouping based on metabolite profiles. Whereas previous reports have focused on alkaloid-rich leaf and latex extracts, this study provides first characterization of the floral metabolite diversity and identifies genotype specific metabolic profiles of T. divaricata, thereby enhancing its chemotaxonomic understanding. Potential applications in breeding, fragrance or therapeutics are suggested as future avenues for research.

A photoinduced palladium-catalyzed carbonylative formal [2 + 2] cycloaddition of toluene derivatives and imines provides a direct access to β-lactams under mild conditions (35 °C, 455 nm LED, 2 bar CO) with up to 99% yields. This three-component reaction accommodates both aldimines and ketimines as well as diverse aryl substrates, including ethylbenzene derivatives. Mechanistic studies reveal a sequential process consisting of C-H bond activation, carbonylation, and in situ ketene formation. This atom-economical protocol offers a valuable synthetic route to pharmaceutically important β-lactam scaffolds directly from readily available starting materials.

Aromatic nitriles are extensively produced chemicals with a wide variety of applications. The high demand of these compounds justifies the search for sustainable synthesis alternatives using renewable energy. Here, an electrochemical oxidation of toluene and xylene derivatives to aromatic nitriles using NH3 and H2O under ambient conditions in a one‐pot, two‐step protocol is reported. In a first step, the toluene derivative is oxidized in the absence of a catalyst to the aldehyde. In the second step, ammonia is added together with LiI as an electrocatalyst to obtain the nitrile. The reaction network and mechanism are investigated using control experiments and cyclic voltammetry.

Integration of network toxicology, machine learning and single-cell sequencing reveals the effects of soil pollutants on prostate cancer.

Abstract We have developed iridium-catalyzed C–H borylation and silylation reactions using pyrazolonaphthyridine (PzNPy) ligands. The readily tunable PzNPy system provides easy control of the ligand characteristics, enabling selective functionalization at the least hindered positions. With the new catalytic system, 1,4-disubstituted and multi-substituted toluene derivatives preferentially underwent borylation at benzylic positions, whereas 1,3-disubstituted arenes favored the least hindered sp2 positions. The Ir/PzNPy system also showed applicability in the C–H borylation of heteroarenes and metallocenes. Furthermore, increasing steric bulk near nitrogen atoms of ligand enabled C–H silylation of five-membered heteroarenes. These results expand the toolbox of bidentate nitrogen ligands for the development of iridium-catalyzed C–H functionalization reactions, suggesting the potential of tailorable PzNPy ligands to extend beyond their applications in palladium catalysis.

ABSTRACTAn amide‐pyridine‐monophosphine ligand, {(o‐PPh2)C6H4C(O)N(H)CH2(C5H4N)} (1), was employed for the synthesis of CuI and CuII complexes. Reaction of ligand 1 with CuX (X = Cl, Br, I) in 1:1 molar ratio afforded bidentate dinuclear P,N‐chelated CuI complexes of the type [(CuX)2{(o‐PPh2)C6H4C(O)N(H)CH2(C5H4N)}2‐κ2‐P,N] (2–4; X = Cl, Br, I). In contrast, treatment of 1 with CuCl2 under aerobic conditions in a CH2Cl2/CH3CN (1:1) mixture yielded the tridentate mononuclear pincer complex {CuCl2(o‐OPPh2)C6H4C(O)N(H)CH2(C5H4N)‐κ3‐O,N,N} (5), while reaction with CuCl in a C2H4Cl2/CH3CN (1:1) solvent system gave the dinuclear analogue [(CuCl)2{{(o‐OPPh2)C6H4}C(O)NCH2(C5H4N)}2‐κ3‐O,N,N] (6). Notably, the CuI dinuclear complex 4 catalyzed acid and base free direct amidation of unactivated alkanes and toluene derivatives via C (sp3)‐N bond formation. This transformation proceeded efficiently through N‐alkylation of phthalimide, sulfonamide, and benzamide, as well as activation of challenging C (sp3)‐H bonds in cycloalkanes, alkenes, and benzylic substrates. The catalyst exhibited high activity at low loading, delivering excellent yields under mild conditions within short reaction times.

We studied how decorating magnesium oxide (MgO) nanocages with nickel (Ni), palladium (Pd), and platinum (Pt) affects their ability to detect chlorobenzene (CB), a polluting organic compound. Using the DFT method, we examined how well these decorated structures bind to CB molecules and how close they get. The results showed that the bare MgO nanocage exhibits a HOMO of −8.49 eV and a LUMO of −0.92 eV, resulting in a wide HOMO-LUMO energy gap of 7.57 eV, which limits its chemical reactivity. To enhance the binding affinity toward CB, various adsorption sites for TM-decorated MgO were explored. Optimised configurations and vibrational frequency calculations confirm the stability of the TM-decorated systems. Pristine MgO shows weak interaction with CB (−10.2 kcal.mol−1), but TMs significantly improve stability, with Pt-MgO displaying the strongest interaction (E ads = −21.1 kcal.mol−1) and the closest contact distance of 2.43 Å. Natural bond orbital (NBO) analysis reveals minimal charge transfer between CB and the nanocages, and the interactions are particularly dependent on lone pair electrons from Cl interacting with Mg orbitals. Notably, Pt-MgO shows a significant decrease in energy gap (∼19.1%) upon CB adsorption, indicating enhanced electrical conductivity. Ni-decorated MgO might be suitable for designing and developing a different type of CB sensor design, i.e. Φ-type sensor. We also evaluated the recovery times for desorption using transition state theory in UV light, highlighting that Pt-MgO offers a favourable recovery time of 2.8 × 10−1 s. This research identifies Pt-MgO as a promising candidate for selective CB detection, demonstrating the potential of TM decoration in enhancing the reactivity of MgO nanocages. The selectivity of the Pt-MgO nanocage for CB detection was evaluated in the presence of interfering pollutants, including toluene (TL), phenol (PH), benzene (BZ), bromobenzene (BB), and fluorobenzene (FB) and it was revealed that the studied species do not significantly interfere with CB detection using the Pt-MgO nanocage.

Methylcyclohexane (MCH) has emerged as one of the most promising liquid organic hydrogen carriers (LOHCs) for H2 storage and long-distance transportation. Developing efficient, selective, and stable catalysts for MCH dehydrogenation is essential to make the process viable for practical applications. In this study, a platinum-iron-tin alloy supported on activated carbon (PtFeSn/AC) is reported, prepared via laser synthesis in liquid (LSL), exhibiting excellent dehydrogenation performance. The rapid crystallization and quenching inherent to the LSL process kinetically trap lattice distortions in the PtFeSn/AC catalyst due to atomic radius mismatches among Pt, Fe, and Sn. These distortions generate strain effects that create a local unsaturated coordination environment and downshift the d-band center of the catalyst, thereby enhancing the exposure of active sites and facilitating the desorption of toluene (TOL). As a result, the PtFeSn/AC catalyst demonstrates exceptional dehydrogenation performance, achieving a hydrogen evolution rate of 2625 mmolgPt -1min-1 under a weight hourly space velocity (WHSV) of 27.7 h-1. Notably, the catalyst exhibits remarkable stability, with only a 3.2% drop in conversion after 193 h of continuous reaction. Additionally, TOL selectivity remains extraordinarily high at 99.96%. This work provides critical insights into the design of high-performance catalysts via non-conventional synthesis methods for practical applications.

A new homologous series 4-(4’-n-alkoxy cinnamoyloxy) Azo 4”-bromo-3”-methyl benzene was synthesized with a view to understand and establish the relation between mesogenic properties and structure of molecules. Ethyl to hexadecyl all twelve homologues are enantiotropically nematogenic. None of the homologues exhibited a smectogenic mesophase. No odd–even effect was observed in the transition curve. The average thermal stability was observed to be 127.9°C and the nematogenic mesophase ranged from 8.0°C to 16.0°C. Thus, the series was found to be of a low ordered melting type with moderate nematogenic range. Analytical data confirmed the structure of the compounds, and the mesomorphism was identified by optical microscopy. The mesogenic properties were compared with structurally similar compounds.

The selective oxidation of benzylic C(sp3)-H bonds with a high bond dissociation energy (BDE) remains challenging. Copper-based metal-organic coordination polymers are promising mimics of Cu enzymes but suffer from limited selectivity. Herein, two Cu-based coordination polymers with precisely tuned coordination environments are synthesized to emulate enzymatic benzylic oxidation. Their unique hexagonal structures enhance substrate adsorption and energy transfer (EnT). Under visible light, the coordination polymers exhibit prolonged fluorescence lifetimes and high-energy excited states, enabling efficient oxygen activation via energy transfer. The optimized Cu-pbhc framework interacts with hydroquinone (HQ) to demonstrate selective benzylic oxidation, achieving an 84% yield with over 90% selectivity toward a toluene derivative. This study proposes a systematic design strategy for developing high-performance catalysts for benzylic oxidation, achieved through the synergistic regulation of redox properties and excited-state dynamics.

Biomass-derived activated carbons play an important role in H2 storage applications since their structural and chemical properties can be modulated by adjusting the activating methods and experimental parameters as well as by functionalization with heteroatoms. However, unfavorable reaction conditions are usually required, which may compromise the carbonaceous framework, negatively impacting on the hydrogen storage performance. In this context, this work investigates the potential modification effects of different solvents on activated carbons (ACs) under mild conditions, with a focus on structural and textural rearrangements. ACs were treated, among others, with solvents such as toluene (TOL), tetrahydrofuran (THF), and isopropyl alcohol (IPA) at 353 K for a variable amount of time. Structural and textural analyses revealed that solvents might have a significant impact on the microporosity, chemical functionalization, and specific surface area (SBET) of ACs, thus potentially affecting their further chemical functionalization. TOL and IPA treatments demonstrated the solvent's role in framework reorganization, enhancing microporosity and storage capacity over reaction time. In contrast, THF exposure led to a decrease in textural properties and thermal stability, attributed to disruptive reaction conditions above the solvent's boiling point. Furthermore, the presence of atmospheric oxygen was found to induce the formation of oxygenated functional groups in the graphitic carbon structure, which contributed to structural instability even if facilitating the framework reordering during prolonged treatments. Although treated samples exhibited reduced hydrogen uptake compared to the parent AC, selected treatments with toluene and IPA demonstrated promising improvements in adsorption efficiency (i.e., H2 uptake/SBET). This study opens the possibility of an effective biomass-derived AC modification, without the need to employ high-energy-consuming thermal treatments, thus maximizing the potential of greener processes.

Selective oxidation of C(sp3)─H bonds via photoelectrocatalytic (PEC) strategy provides a promising approach to synthesize valuable oxygenates, but the efficiency of this process is still unsatisfactory due to the stable nature of hydrocarbon molecules. Herein, we report the PEC oxidation of toluene to benzaldehyde (BA) over a subnanometric PtOx cluster-loaded TiO2 (PtOx/TiO2) photoanode, achieving BA production rate of 1.75µmol cm‒2 h‒1 with selectivity of 83.5% in aqueous medium, which is 4.4-fold higher than that of pristine TiO2. The strategy is also effective for the selective oxidation of toluene derivatives. As a proof-of-concept, we fabricate a self-powered PEC tandem device with S-shaped flow channels for the oxidation of toluene, producing BA with a productivity of ∼170µmol under light irradiation. Experimental studies combined with density functional theory (DFT) results demonstrate that the toluene oxidation over PtOx/TiO2 photoanode follow an electrophilic hydroxyl species (OH*)-mediated pathway, which can suppress the over-oxidation of BA. Moreover, we reveal that subnanometric PtOx clusters promote toluene adsorption and OH* species generation, leading to the high efficiency of toluene oxidation. This work is expected to broaden the avenue toward the activation of C(sp3)─H bond under mild conditions in aqueous solution via a sustainable way.

Abstract Selective oxidation of C(sp3)─H bonds via photoelectrocatalytic (PEC) strategy provides a promising approach to synthesize valuable oxygenates, but the efficiency of this process is still unsatisfactory due to the stable nature of hydrocarbon molecules. Herein, we report the PEC oxidation of toluene to benzaldehyde (BA) over a subnanometric PtOx cluster‐loaded TiO2 (PtOx/TiO2) photoanode, achieving BA production rate of 1.75 µmol cm‒2 h‒1 with selectivity of 83.5% in aqueous medium, which is 4.4‐fold higher than that of pristine TiO2. The strategy is also effective for the selective oxidation of toluene derivatives. As a proof‐of‐concept, we fabricate a self‐powered PEC tandem device with S‐shaped flow channels for the oxidation of toluene, producing BA with a productivity of ∼170 µmol under light irradiation. Experimental studies combined with density functional theory (DFT) results demonstrate that the toluene oxidation over PtOx/TiO2 photoanode follow an electrophilic hydroxyl species (OH*)‐mediated pathway, which can suppress the over‐oxidation of BA. Moreover, we reveal that subnanometric PtOx clusters promote toluene adsorption and OH* species generation, leading to the high efficiency of toluene oxidation. This work is expected to broaden the avenue toward the activation of C(sp3)─H bond under mild conditions in aqueous solution via a sustainable way.

The methylcyclohexane-toluene-hydrogen (MTH) cycle is one of the most promising liquid organic hydrogen carrier (LOHC) systems. Despite the good performance of carbon-supported Pt nanoparticles, the drawbacks of noble metals, such as high cost and limited availability, hinder the industrial applications of these catalyst technologies. Herein, a ruthenium single-atom/nanoparticle (Ru SA/NP) dual-site electrocatalyst is developed with low metal loadings and notable electrochemical hydrogenation (ECH) efficiency of toluene (TL) to methylcyclohexane (MCH) in an electrochemical microreactor. The results reveal that within a wide potential window (∆V = 500mV), the optimal catalyst Ru4-CN exhibits ≈100% Faraday efficiency (FE), high MCH selectivity, and significant inhibition of the hydrogen evolution reaction (HER). At a cell voltage of 2.0V, the yield of MCH reaches 657.12µmol h-1 mgRu -1, which is ≈28 times higher than that of commercial Ru/C catalyst. Experimental and theoretical analyses indicate that TL preferentially adsorbs on Ru NP, while hydrogen atoms adsorb on Ru-SA to form H*, which is then delivered to Ru-NP to hydrogenate TL. This work brings forth a special design of Ru SA/NP dual-sites on the electrochemical hydrogenation of organic substrates and sheds light on the structure-activity relationships for future studies.

Printable planar carbon electrodes present a cost‐effective and highly promising alternative to thermally evaporated metals, serving as the rear contact for stable perovskite solar cells (PSCs). However, the power conversion efficiencies (PCEs) of the carbon‐based PSCs (C‐PSCs) are notably lower compared to those of state‐of‐the‐art PSCs. The inferior contact between the carbon electrode and the underlying layer contributes to the performance loss. Here, we developed scalable doctor‐bladed carbon electrode by simultaneously incorporating 4 wt% carbon black and utilizing toluene (TLE) solvent engineering to a commercial carbon paste, resulting in improved flexibility and conductivity while yielding reduction of resistivity by 50% measured via a 4‐point probe. Consequently, the carbon sheet can efficiently adhere the underlying hole‐transporting layer by a simple pressing technique, significantly boosting charge transfer across the interface. The TLE device achieves a champion PCE of 15.77% with an ultralow hysteresis index (HI) of 0.027, compared to the solvent‐free device which has a HI of 0.176. The developed carbon‐based device exhibits notably improved long‐term stability when subjected to dark conditions and 40‐50% RH, sustaining 82% of its initial efficiency after 24 days without encapsulation with minimal declines in Jsc and Voc.

The microwave spectrum of 3,5-dimethylanisole was recorded using a pulsed molecular jet Fourier transform microwave spectrometer, covering the frequency range from 2.0 to 26.5 GHz. Splittings from internal rotations of the syn-m and anti-m-methyl groups were observed, analyzed, and modeled using the XIAM and the ntop programs for a data set including 622 rotational lines. The torsional barriers of the syn-m and anti-m-methyl groups were determined to be 58.62367(53) cm-1 and 36.28449(69) cm-1, respectively. The low barriers to internal rotation of both methyl groups posed significant challenges for spectral analysis and modeling. The successful assignment was achieved using combination difference loops and separately fitting the five torsional components. Comparing the torsional barriers observed in various toluene derivatives with methyl groups at meta-positions supports the assumption that electrostatic effects contribute more significantly than steric effects in the low-barrier cases of aromatic molecules.

Abstract Fusarium verticillioides isolated from soil was found to produce extracellular cutinase under optimized culture conditions. The enzyme was purified using ion‐exchange and size‐exclusion chromatography, achieving a purification fold of 12.5 and a final yield of 62%. The molecular weight of the purified cutinase was determined to be 25 kDa using SDS‐PAGE. The purified enzyme exhibited stability over a temperature range of 30–60 °C and a pH range of 6.0–9.0 retaining more than 85% of its activity after 6 h of incubation. It was stable in the presence of various organic solvents (up to 30% v/v) and surfactants, whereas its activity was completely inhibited by the serine protease inhibitor, that is, phenyl methane sulfonyl fluoride (PMSF), confirming the presence of an active serine residue in the catalytic site. Cutinase was highly efficient in catalyzing the synthesis of butyl valerate ester, achieving a yield of 92% under optimized conditions: 0.25 M butanol, 0.25 M valeric acid, 30 mg of enzyme, and n ‐hexane as the organic solvent at 50 °C for 8 h. The ester yield and purity were confirmed by GCMS analysis. This study highlights the potential of cutinase as a robust biocatalyst for ester synthesis with demonstrated efficiency and high yields. Its application in the food industry as a sustainable alternative to chemically synthesized esters is promising especially for artificial flavoring and aroma production. However, future studies are needed to address scalability, long term storage stability, and the economic feasibility of large‐scale production to fully realize its industrial potential.

Both methyl groups and benzene rings are exceedingly common, and they lie near one another in many chemical situations. DFT calculations are used to gauge the strength of the attractive forces between them, and to better understand the phenomena that underlie this attraction. Methane and benzene are taken as the starting point, and substituents of both electron-withdrawing and donating types are added to each. The interaction energy varies between 1.4 and 5.0 kcal/mol, depending upon the substituents placed on the two groups. The nature of the binding is analyzed via Atoms in Molecules (AIM), Natural Bond Orbital (NBO), Symmetry-Adapted Perturbation Theory (SAPT), nuclear magnetic resonance (NMR) chemical shifts, and electron density shift diagrams. While there is a sizable electrostatic component, it is dispersion that dominates these interactions, particularly the weaker ones. As such, these interactions cannot be categorized unambiguously as either H-bonds or tetrel bonds.

Support-facet-mediated metal-support interaction regulation of Pt-based catalyst for efficient dehydrogenation

We report a novel method for constructing an mRNA-displayed bicyclic peptide library cyclized through 1,3,5-tris(methyl)benzene by ribosomally incorporating N-acetyl-3,5-bis(chloromethyl)benzylthio-L-alanine, enabling the selection of bicyclic peptides against specific targets. Using this method, we successfully identified bicyclic peptides that bind to human Trop2 and VEGF165, providing a new strategy for selecting bicyclic peptides cyclized by trimethylbenzene.