Aromatic Ring Research Articles

Effects of clean fracturing fluids on coal microstructure and coalbed gas adsorption.

Nowadays, some fracking fluids can enable resourceful extraction of coalbed methane and reduce greenhouse gas emissions. However, their toxicity or corrosiveness will cause harm to downhole workers and pollute groundwater resources. Thus, five kinds of clean composite fracturing fluids were developed in this paper by using starch solution as the matrix and adding various preparations. The change rule of methane adsorption capacity by microstructure changes of coal samples was investigated systematically, and the optimal composite fracturing fluid was determined. The results showed that the new fracturing fluid increased the degree of aromatic ring condensation by 43.3% and the average pore size by 52.1%. Also, the adsorption constants of a value decreased by 11.6% and b value decreased by 23.9%, which can remarkably reduce the methane adsorption. The experimental results provide theoretical support for the clean production of coalbed methane.

Monoaromatic Compounds Biodegradation by Hydrocarbon-Oxidizing Actinobacteria

Monoaromatic substances belong to the most widespread and dangerous environmental pollutants. They are components of wastewater from oil refineries and the coal and chemical industries and are often found in soil, groundwater, and surface water. The use of actinobacteria for bioremediation of natural and industrial objects contaminated by these substances is an environmentally and economically advantageous alternative to physicochemical cleaning methods. Therefore, it is actual to search for new actinobacteria strains capable to assimilate of monoaromatic compounds for their further use in biotechnologies of purification of the environment polluted by these substances. Aim. To determine the ability of hydrocarbon-oxidizing strains of actinobacteria of the Ukrainian Collection of Microorganisms to assimilate monoaromatic compounds − derivatives of benzene and phenol. Methods. The strain cultivation was carried out in a liquid mineral medium at an initial concentration of monoaromatic compounds of 500 mg/L as the only source of carbon and energy. The expression activity of the catA gene encoding catechol 1,2-dioxygenase, the key enzyme at the initial stage of the monoaromatic compounds biodegradation, was assessed under culture growth conditions with phenol and glucose. Relative expression of the catA gene was evaluated using RT-qPCR. Fatty acid methyl esters were obtained by hydrolysis of cells in a 5 % solution of acetyl chloride in methanol, followed by extraction with an ether-hexane mixture. Methyl esters were identified using an Agilent 6800N/5973 inert GC/MS system (Agilent Technologies, US). Fatty acid content was determined by AgilentChemStation software. Results. It was established that the studied strains of actinobacteria belonging to the species Dietzia maris, Gordonia rubripertincta, Rhodococcus aetherivorans, and Rhodococcus erythropolis differ in their ability to assimilate monocyclic aromatic compounds − benzene and phenol derivatives. Most strains grew better in media with benzene and its derivatives. All strains well grew on a mixture of ethylbenzene, ortho-, meta-, and para-xylene (EX), most of them grew with different intensities on a mixture of benzene, toluene, and ortho-xylene (BTX), and on monosubstrates – benzene, benzotriazole, and benzoate. Toluene was used by 50 % of the studied strains, and only one of them (R. aetherivorans UCM Ac-602) grew on ortho-xylene. A smaller amount of strains grew in media with phenol derivatives. They did not assimilate ortho-cresol and hydroquinone but grew with different intensities on phenol, paranitrophenol, resorcinol, and catechol. Only a few strains grew in the presence of meta- and para-cresols. The widest range of monoaromatic substances was used by R. aetherivorans UCM Ac-602. It was shown that in the process of phenol assimilation by strain R. aetherivorans UCM Ac-602, the level of transcriptional activity of the catA gene encoding the key enzyme of an ortho-pathway of aromatic ring cleavage, catechol 1,2-dioxygenase, increased almost 2-fold after 48 h compared to 24 h of strain growth on this substrate and 3-fold compared to glucose. The obtained data indicate the ability of R. aetherivorans UCM Ac-602 strains to assimilate monoaromatic substances through theortho-cleavage way. During growth on benzene, toluene, BTX and EX substances, the fatty acid pool of cells of this strain was dominated by hexadecanoic C16:0 (32.73-39.81 %), hexadecenoic C16:1 cis-9 (5.66-15.11 %), and octadecenoic C18:1 cis-9 (7.09-11.83 %) acids, as well as 10-methyloctadecanoic 10-Me-C18:0 (29.88-34.76 %) acid. The composition of fatty acids of cells grown on aromatic compounds, unlike those grown on glucose, contained 2.4-4.0 times less unsaturated C18:1 cis-9 acid and 2.8-3.2 times more methyl-branched acid 10Me-C18:0. Conclusions. Assimilation of monoaromatic compounds − derivatives of benzene and phenol - is a strain-specific characteristic of the actinobacteria species. Using strain R. aetherivorans UCM Ac-602 as an example, it was shown that the assimilation of monoaromatic substances in studied actinobacteria occurs through the ortho-cleavage pathway. One of the adaptation mechanisms of strain R. aetherivorans UCM Ac-602 to the assimilation of these substances is a significant decrease in unsaturated fatty acids and an increase in methyl branched acids, which contributes to an increase in membrane rigidity and cell resistance to the toxic effect of these substrates. The data obtained indicate a high level of adaptation of actinobacteria to the assimilation of monoaromatic compounds and the prospects for their further study to be used in biotechnologies for environmental purification from these pollutants.

Rhodamine 6G-PAH probes for heavy metal: Fluorescence detection, bioimaging, and solid-phase sensing application

Four rhodamine 6G-PAH probes with pyrene (R6G-Pyr), anthracene (R6G-Ant), acenaphthene (R6G-Acp) or phenanthrene (R6G-PA) as fluorophore were designed and synthesized for Hg(II) detection. Probe R6G-PA, which had the lowest detection limit of 0.84 nmol/L, displayed the best fluorescence performance as compared to the other three probes. This type of probe had good anti-interference properties against most common metal ions except Cu(II). Metal Cu(II) had a certain quenching effect on the fluorescence generated by Hg(II), with a minimum detection limit of 0.31 nmol/L (for R6G-Acp), indicating its potential practicability for Cu(II) detection. The structure-fluorescence relationship was discussed based on density functional theory (DFT) calculations, and R6G-PA + Hg(II), which had the minimum dihedral angle between polycyclic aromatic rings and rhodamine spiro ring, produced the strongest π-π accumulation and provided the brightest fluorescence. Probe R6G-PA was successfully employed for fluorescence detection of Hg(II) in biological samples. Its solid-phase sensor PS@R6G-PA was developed by immobilizing R6G-PA on PS microspheres for the determination of Hg(II) in water and food samples, with excellent reproducibility and fluorescence “on/off” response. The relative error of the spiked recovery rate was less than 10 %.

Formation Mechanisms and Fluorescence Properties of Carbon Dots in Coal Burning Dust from Coal‐Fired Power Plants

Carbon dots (CDs) show great application potential with their unique and excellent performances. Coal and its derivatives are rich in aromatic ring structure, which is suitable for preparing CDs in microstructure. Coal‐burning dust from coal‐fired power plants can be utilized as a rich resource to separate and extract CDs. It is shown in the results that there are two main possible mechanisms for the formation of CDs in coal‐burning dust. One is the self‐assembly of polycyclic aromatic hydrocarbons contained in coal or produced by incomplete combustion of coal. The other mechanism is that the bridge bonds linking different aromatic structures in coal break, which will form CDs with different functional groups when the coals burn at high temperature. Under violet light excitation at 310–340 nm or red light at 610–640 nm, CDs extracted from coal‐burning dust can emit purple fluorescence around 410 nm. The mechanism of up‐conversion fluorescence emission of CDs is due to a two‐photon absorption process. The recycling of CDs from coal‐burning dust from coal‐fired power plants are not only good to protect environment but will also be helpful for mass production of CDs.

Polymorphism of 3-hydroxy-2-naphthoic acid: crystal structures, Hirshfeld surface analysis and properties

Polymorphs play an important role in mediating the physical properties of compounds. Therefore, a set of polymorphs based on 3-hydroxy-2-naphthoic acid (HA), namely, α-HA (1), β-HA (2) and γ-HA·DMF (3) (DMF = N,N-dimethylformamide), were obtained by slow evaporation method, which were the solution of HA in ethanol, acetone and DMF, respectively. These crystal morphologies of HA have been characterized by single–crystal X–ray diffraction, IR and UV–Vis, and powder X-ray diffraction. In these polymorphism, classical hydrogen bonds of O–H∙∙∙O can be obviously observed, through which a supramolecular architecture will be generated. Apart from the classical hydrogen bonds, the hydrogen bonds of C–H⋯O can be only found in form γ-HA. The luminescent maximal are 497, 504 and 510 nm for α-HA,β-HA andγ-HA·DMF, respectively. The order of the maximal peaks is listed as the following: 3>2>1. Single-crystal X-ray diffraction analysis results reveal that the order of the distances between the aromatic rings is 3>2>1. The Hirshfeld analysis further confirm that there exists the largest contribution of the H∙∙∙H and H∙∙∙O close contacts in compound 3, which is in a good agreement with of the luminescent maxima in compound 3.

Molecular weight fraction-specific transformation of natural organic matter during hydroxyl radical and sulfate radical oxidation

Aquatic natural organic matter (NOM) is one of the main scavengers of reactive species (e.g., •OH and SO4•−) during oxidation processes and undergoes complex transformations. Here, the organic content, optical properties, and redox state in various MW fractions and bulk Suwannee River NOM (SRNOM) were simultaneously evaluated during •OH and SO4•− oxidation processes for the first time. The SRNOM transformation pathways were specific to radical species and MW fractions, which was evidenced by a proportional decrease in electron-donating moieties and chromophores during •OH oxidation but a higher decrease in electron-donating moieties than chromophores during SO4•− oxidation, particularly in lower MW fractions (<3 kDa). The •OH decomposed reactive moieties mainly via aromatic ring opening or depolymerization in all MW fractions. SO4•− oxidation followed a similar pathway in higher MW fractions (>3 kDa) but mainly formed compounds with UV-absorbing properties (e.g., quinones) in lower MW fractions (<3 kDa). With competitive kinetics and depolymerization model, •OH was quantified as approximately 10 times more reactive towards MW fractions than SO4•−. However, the SO4•− concentrations were approximately 10 times those of •OH, resulting in comparable performance to •OH oxidation. SRNOM depolymerization by •OH and SO4•− resulted in formation of more precursors of disinfection byproducts than the parent constituents, especially for •OH. This work improves our understanding of the transformation of specific SRNOM fractions during radical oxidation processes.

Insight into carbon structures and pyrolysis behaviors of coal from the 13C CP/MAS NMR spectra

Carbon structures play an important role in the pyrolysis behavior of coal. Solid-state 13C nuclear magnetic resonance (NMR) spectroscopy is a powerful nondestructive technique for characterizing the carbon skeleton structures in coal. In this study, the carbon type distribution, lattice parameters, and chemical bond concentrations of six coal samples with different Vdaf values were investigated using 13C CP/MAS NMR spectra. Typical TGA and Py-GC-MS methods were utilized to obtain information on weight loss and pyrolysis products of the coals. The aromaticity of coal was determined by an adjustment of the apparent area ratio in the 13C CP/MAS NMR spectra, which shows promising potential for predicting key temperatures, characteristic index, and tar quality in coal pyrolysis. Results from the carbon fractions indicated that the total concentrations of chemical bonds in coal are approximately 150 mmol g−1, with more Car−Car and Car−H bonds present in highly mature coal samples, and fewer Cal−Cal, Cal−H, and CO bonds. The breaking behaviors of chemical bonds during coal pyrolysis depend on a combination of temperature and concentration. The breakage of Cal−Cal bond contributes significantly to the pyrolytic weight loss of coal, accompanied by the decrease of Cal−H bonds along with the removal of aliphatic groups. Furthermore, as coal maturity increases, tar from fast pyrolysis contains more polycyclic aromatic hydrocarbons with a higher average molecular weight. The average number of aromatic rings in tar components is notably lower than that of aromatic clusters in coal. These results will contribute to a better understanding of the relationship between coal structure and reactivity, and may provide valuable insights for the efficient and clean utilization of coal.

Investigating the Role of Solvents in Modulating Glass Transition and Dynamic Mechanical Characteristics of Polystyrene Film

This study investigates how different solvents impact the glass transition and dynamic mechanical properties of polystyrene (PS) films. Using FTIR spectroscopy, it analyzes solvent-induced variations in molecular vibrations, particularly in the phenyl ring region. Results show solvent-specific effects on the 750 cm-1 peak, associated with the "meta-substituted aromatic ring," influencing phenyl ring vibrations. DSC analysis highlights solvent effects on the glass transition temperature (Tg), revealing complexities in PS films prepared with chloroform, tetrahydrofuran (THF), and toluene. Varied Tg behavior suggests solvent-driven structural modifications and gradual solvent removal. Dynamic Mechanical Analysis (DMA) demonstrates solvent-dependent changes in storage modulus, loss modulus, and tan δ, indicating solvent polarity's role in polymer chain dynamics. Toluene-induced plasticization reduces Tg and increases creep compliance, showcasing PS film sensitivity to solvents. These findings stress solvent selection importance in tailoring thermal and mechanical properties of polymer films for specific applications.

Development of 4′-Oxo-MLN4924 as potential neddylation inhibitors: Design, synthesis, anti-HCMV evaluation, and molecular docking

MLN4924 (1), a neddylation inhibitor, has shown promising anticancer and antiviral properties. In this study, we designed and synthesized new derivatives of 4′-oxo-MLN4924, inspired by the structures of MLN4924 and another known neddylation inhibitor, referred to as compound 2. Like compound 2, we used a specific type of sugar molecule but incorporated a modified building block known as 7-deazapurine for the nucleobase part. Additionally, we arranged the sulfamate and 2′-hydroxyl as key functional groups. We found that the 2′-OH group is essential for activity against human cytomegalovirus (HCMV) using luciferase reporter assay. Molecular docking and molecular dynamics (MD) studies revealed that the conformation of the sugar moiety plays a crucial role in protein–ligand interactions. These studies suggest that derivatives with a bulky aromatic ring at the 6-position of the nucleobase are likely to have enhanced binding, which is supported by experimental findings.

Optical properties of Makrofol under various alpha fluences

The optical properties of Makrofol samples are investigated under various fluences of alpha exposure (2 MeV at , , , , , , and alphas.cm2 alongside the unirradiated ones (pristine). Several analyses, including UV-visible, diffused reflectance spectroscopy (DRS), photoluminescence (PL), Fourier transform infrared/attenuated total reflectance (FTIR-ATR), X-ray photoelectron spectroscopy (XPS) and sessile drop technique, are carried out to reveal the subsequent variations in the optical features of the irradiated polymer foils. The optical transmittance of the irradiated samples notably increases against the pristine ones, while it undergoes a+ plateau over various fluences. Additionally, the scattering events are more prominent in pristine samples over UV (240-400 nm) and IR (900-1040 nm) compared to the irradiated ones. While there are negligible physical alterations on the polymer surface, the photoluminescence emission gradually decreases with increasing alpha fluences in the irradiated samples mainly due to the reduction in the population of the aromatic rings. The latter is also verified by means of the surface chemical analyses such as XPS, FTIR-ATR and sessile drop/contact angle measurements. XPS reveals that the alpha particles give rise to the successive scissions of C-C and C=O bonds and the consequent recombination events in the form of C-O bonds, evidenced by the changes in their abundance percentages. Concurrently, the surface hydrophilicity initially elevates up to a certain fluence and then reduces at higher fluences, indicating a couple of competitive mechanisms are involved in the context of the interactions of the alpha particles with the Makrofol polycarbonate (PC).

Adsorption of CO2/CH4 on the aromatic rings and oxygen groups of coal based on in-situ diffuse reflectance FTIR

The adsorption mechanisms of CH4 and CO2 on the coal surface is the theoretical basis for CO2 sequestration with enhanced coalbed methane recovery (CO2-ECBM). Molecular simulation is the main method to study the adsorption mechanism at present, but the model used in the process of molecular simulation could not accurately characterize the coal macromolecular structure. Therefore, we used in-situ diffuse reflectance Fourier-transform infrared spectroscopy (FTIR) to study the adsorption of CO2/CH4 on the aromatic rings and oxygen groups of coal. The results showed that CO2 and CH4 were physisorbed on the aromatic rings, and the aromatic rings represented the primary competitive adsorption sites for CO2 and CH4, CO2 was preferentially adsorbed at the top of the aromatic ring compared to CH4. Both carboxyl and carbonyl groups were beneficial for CO2 adsorption but not for CH4 adsorption. Compared to aromatic rings, the adsorption affinity of carboxyl groups for CO2 were stronger. The results of this study revealed the adsorption mechanisms of CO2 and CH4 on the aromatic rings and oxygen groups, as well as the impact of oxygen groups on the gas adsorption capacity, providing a theoretical basis for applying CO2-ECBM in the medium-volatile bituminous coal reservoirs.

Peripheral Fusion of Carbon-based Aromatic Rings to B4N4-Heteropentalene Leading to Close π-Stacking in the Solid State.

π-Electronic molecules with a BN-heterocyclic and carbon-based aromatic hybrid ring system (h-CBN) are interesting in that they potentially exhibit synergistic properties arising from the two different π-systems. Here we report the synthesis and properties of a h-CBN-type molecule (1) having a bicyclic B4N4-heteropentalene core fused with extended aromatic rings. This molecule exhibits excellent chemical stability despite the absence of bulky substituents for kinetic protection, which in turn provides effective stacking of the π-system upon crystallization. Depending on the crystallization solvent, 1 forms two polymorphs, i.e., the α- and β-phases. While both phases have one-dimensional columnar structures, the π-stacking geometries associated with the transfer integrals of the frontier orbitals are different, resulting in a twofold difference in the electrical conducting properties. We also found that upon thermal vacuum deposition, 1 gives an amorphous film, which serves as a host material for a red phosphorescent OLED device (maximum external quantum efficiency: 15.5 and 13.3% at 0.1 and 2.5 mA, respectively).

Vibrational Energy Transfer in Energetic Ionic Liquid 4-Amino-1H-1,2,4-triazolium Nitrate: Ab Initio Molecular Dynamics Simulations.

Energetic ionic liquids (EILs) represent a distinctive class of energetic materials with substantial research significance and promising energetic applications. In this work, we delved into the vibrational energy transfer mechanism within the EILs, specifically focusing on 4-amino-1H-1,2,4-triazolium nitrate (ATN), utilizing ab initio molecular dynamics simulations. Our work illustrates distinct energy transfer patterns for different vibrational modes. Upon exciting the stretching vibration of the NH group in the cationic group, vibrational energy preferentially migrates to the neighboring CH bond within the aromatic ring on the femtosecond to picosecond time scales and notably in an in-phase coherent energy transfer fashion. In contrast, exciting the stretching vibration of the N9H11 bond triggers the transfer of vibrational energy to its neighboring N9H10 bond in an out-of-phase coherent fashion. Conversely, exciting the stretching vibration of the N9H10 bond leads to energy transfer predominantly through intermolecular pathways due to the hydrogen-bonding interaction between this bond and the anion. The vibrational energy of the excited N9H10 stretch is shown to dissipate very rapidly, displaying a fast component (with a time constant as short as ca. 7 fs) and a slow component (ca. 230 fs).

Photophysical properties of donor (D)-acceptor (A)-donor (D) diketopyrrolopyrrole (A) systems as donors for applications to organic electronic devices.

Fourteen substituted diketopyrrolopyrrole (DPP) molecules in a donor (D)-acceptor (DPP)-donor (D) arrangement were designed. We employed density functional theory, time-dependent DFT, DFT-MRCI and the ab initio wave function second-order algebraic diagrammatic construction (ADC(2)) methods to investigate theoretically these systems. The examined aromatic substituents have one, two, or three hetero- and non-hetero rings. We comprehensively investigated their optical, electronic, and charge transport properties to evaluate potential applications in organic electronic devices. We found that the donor substituents based on one, two, or three aromatic rings bonded to the DPP core can improve the efficiency of an organic solar cell by fine-tuning the highest occupied molecular orbital/lowest unoccupied molecular orbital levels to match acceptors in typical bulk heterojunctions acceptors. Several properties of interest for organic photovoltaic devices were computed. We show that the investigated molecules are promising for applications as donor materials when combined with typical acceptors in bulk heterojunctions because they have appreciable energy conversion efficiencies resulting from their low ionization potentials and high electron affinities. This scenario allows a more effective charge separation and reduces the recombination rates. A comprehensive charge transfer analysis shows that D-A (DDP)-D systems have significant intramolecular charge transfer, further confirming their promise as candidates for donor materials in solar cells. The significant photophysical properties of DPP derivatives, including the high fluorescence emission, also allow these materials to be used in organic light-emitting diodes.

Dual-Modality Imaging with a Zwitterionic Fluorescent Probe for Reversible Monitoring of Mitochondrial Membrane Potential Dynamics.

Traditional fluorescence intensity-based probes face challenges in accurately measuring mitochondrial membrane potential (MMP) due to intramolecular fluorescence quenching. In this work, we introduce a novel approach by incorporating quenching moieties within the zwitterionic probe to eliminate self-quenching interference, thus, enabling real-time and precise visualization of reversible MMP changes. We synthesized a zwitterionic fluorescent probe consisting of silicon-rhodamine (SiR) that was hydroxyl-substituted on the bay position of perylene diimides (PDIs) connected via a polyethylene glycol (PEG) linker. The lipophilic cationic SiR facilitates the entry of the PDI into the mitochondria, where the alkaline pH environment (pH = 8.0) ionizes the hydroxyl to a negatively charged species, affecting the quenching efficiency of SiR depending on the distance between the PDI and SiR moieties regulated by the MMP. The rigid aromatic ring of the PDI and strong hydrophobic interactions with the lipid bilayer, along with the inhibitory effect of the negatively charged hydroxyl on internalization, ensure the retention of PDI within the mitochondria. As the MMP decreases, SiR shifts outward, reducing quenching by phenolic anions and restoring fluorescence. Conversely, as the MMP increases, SiR moves inward, intensifying quenching by phenolic ions and reducing fluorescence, enabling reversible visualization monitoring of the MMP. This strategy overcomes the limitations of traditional intensity-based probes, providing a new avenue for reversible monitoring of the MMP.

Maximizing the toughness of polymer nanocomposites based on the radial strength of carbon nanotubes

Similarity in the mechanical properties of a matrix and an inclusion is key to designing tough nanocomposites. Matching the matrix and inclusions with similar mechanical strengths prevents stress perturbation at the interface, enabling nanocomposites to withstand higher loads as a homogeneous material. We tabulate the chirality-dependent radial buckling properties of multi-walled carbon nanotubes (MWCNTs) and present a design methodology for providing optimal strengthening properties for poly(p-phenylene terephthalamide) matrices. The structural orientation effect of the aromatic rings of polymer chains surrounding MWCNTs provides a strong support against transverse loading. The effect of the interfacial area of different materials on the toughness of the entire continuum system is characterized through a nonlinear finite element model. MWCNT buckling and polymer yielding occur simultaneously under conditions selected by the proposed methodology, thereby maximizing the reinforcing effect of the nanocomposites by creating a continuous stress field at the interface.

Exploring boratrane's potential to enhance the thermal stability of phenol-formaldehyde resins by borate bridge as a crosslinker and the mechanistic formation of boron species in carbonaceous materials: A comprehensive study

In advanced material science, we explore the potential of boratrane, a promising agent for enhancing thermal stability. By combining rigorous Density Functional Theory (DFT) calculations with groundbreaking experimental analyses, we reveal the intricate interplay of radical intermediates and mechanisms underlying the thermal evolution of boratrane-infused materials. Our innovative approach illuminates dynamic structural transformations and elucidates boratrane's pivotal role in fortifying thermal resilience. The DFT calculations identify radical intermediates and mechanisms of thermal degradation, highlighting the role of borate bridges in delocalizing π-electrons in aromatic rings through Gibbs free energy (∆GRXN), Highest Occupied Molecular Orbital (HOMO), Lowest Unoccupied Molecular Orbital (LUMO), and electrostatic potential (ESP) analyses. Fukui function analysis provides insights into the reactivity of these structures towards free radical attacks. Our findings demonstrate that boratrane-modified resins exhibit a stable BO4- structure, which prevents self-condensation of boratrane to B2O3 and enhances the thermal stability of oxygenated resins. This improvement is due to the formation of intramolecular hydrogen bonds, contributing to helix-like structures that strengthen the resin. The mechanism by which the BO4- structure terminates radical agents and transforms into carbonaceous material is elucidated through thermodynamic values, revealing the plausible reactions and chemical structure of boron in the resulting material.

Exploration of Deep UV-NLO Responses of Non-Conjugated Crystal Systems by Harnessing Aprotic Solvents: DFT vs Experimental

This study introduces a newly found form of a non-conjugated crystal called 1,3,5-triazine-2,4,6-triamine polymorph (TT), which demonstrates a well-rounded UV nonlinear optical (NLO) behavior. By employing solvent-assisted Tauc bandgap adjustment, the crystal's structure was altered, leading to improved optical characteristics. The material's monoclinic polymorph displays adjustable bandgaps that are impacted by the choice of solvent during the crystallization process. When evaluated against a chemical potential of -2.61 eV, its characteristics were forecasted. Charge displacement across the aromatic ring is observed in the solvent stage, while molecular electrostatic potential (MEP) surfaces highlighted the nitrogen atoms as nucleophilic. The comparative examination of its energy gaps (Egaps) offers significant perspectives on their prospective uses. Understanding these energy differences is crucial for choosing materials for specific applications like electronic devices, sensors, or catalysis. Moreover, comprehending charge distributions and nucleophilic tendencies can influence the creation of new materials with customized attributes for diverse uses in fields such as chemistry, materials science, and beyond.

Flurbiprofen clubbed schiff's base derivatives as potent anticancer agents: In Vitro and In Silico approach towards breast cancer

In this work, we are reporting nineteen hydrazone-Schiff base derivatives (2a-2l and 3a-3g), containing flurbiprofen drug nucleus. The synthesized products were structurally elucidated through 1H, 13C-NMR and HR-ESI-MS spectroscopic techniques and finally tested for in vitro anti-cancer activity. Among the synthetic series, 2f, 2g, 3g, 3b, and 2e attributed the higher inhibitory potential against the breast cancer cell line (MDA-MB-231) having IC50 values of 21.0 ± 0.4, 21.8 ± 0.2, 27.1 ± 0.3, 28.8 ± 0.3, and 29.6 ± 0.3 µM respectively. However, the remaining derivatives attributed good to less active. DFT was used to calculate frontier molecular orbital of (2a-h, j-l, and 3a-d) including HOMO which concentrated on the substituents aromatic ring, and LUMO focused over flurbiprofen and hydrazide fragments, that indicate the charge transfer from molecule to biological media. The reactivity indices suggested the most active 2f (IC50 = 21.0 ± 0.4 µM) and 2g (IC50 = 21.8 ± 0.2 µM) showed higher indices reactivity namely σ, χ, and ω than lowest active 2g; this relation inversely for Eg, η, and IP. 2a-l had more electrophilic character and higher acceptance ability for biological targets than compounds (3a-g). The MEP map indicated the electron density distribution of 2a-l was more dispersed than that of 3a-g, indicating potential biological activities and are chemically reactive zone suitable for drug action. The docking study contributed to the analysis of cytotoxicity for investigated compounds.

The possible aromatic conjugation via the different edges of (car)borane clusters - Can the relationship between 3D and 2D aromatic systems be reconciled?

The possible aromatic conjugation between 3D and 2D aromatic units is in the focus since the synthesis of benzocarborane. It has been showed that in the 3D aromatic icosahedral 1,2-dicarba-closo-dodecaborane systems fused with 2D aromatic rings a global 3D/2D aromaticity does not exist. Despite this fact during the last years several studies propose interactions between 2D and 3D moieties. Herein, while tuning the size and the effective charge of the (car)borane systems, we demonstrate that global aromatic character can be excluded in any investigated cases, and the detectable conjugative properties can be explained the effect of the well-known negative hyperconjugation.