Phenyl Research Articles

Tuning the Emission Properties of 2,1,3-Benzothiadiazoles via Regioselective Substitution.

The 2,1,3-benzothiadiazole (BTD) unit is a prominent building block commonly used in various research areas such as optoelectronics and bioimaging. Despite its great versatility, the development of strategies to elaborate BTD has been largely neglected, including exploring its reactivity and understanding how regioselective functionalization can be used to tune the fluorescence emission. Previous focus has primarily been on C4- or C4,C7-substitutions. Here, a series of unsymmetrical mono - and disubstituted BTDs was synthesized and characterized for their photophysical properties. The reaction scope includes all six possible substituent patterns on the BTD benzoid ring (C4-, C5-, C4,C5-, C4,C6-, C4,C7- and C5,C6-substitution), which comprise arrangements that previously been synthetically challenging to access. By introducing a methoxy and/or a phenyl group we demonstrate that the emissive behavior of BTD derivatives strongly depends on the position of the substituent (s). We show that regioselective substitution on BTD can engender long-lived fluorescence and circumvent strong fluorescence quenching in polar protic solvents, which is a limitation of many previously described BTD derivatives.

Synthesis of Aryl‐Functionalized Benzo[d,e]Benzo[4,5]İmidazo[2,1‐a]Isoquinolin‐7‐One Derivatives: DNA Intercalation Causing Cytotoxicity

AbstractThis study focuses on the cytotoxic effect properties of 4‐aryl‐functionalized benzo[d,e]benzo[4,5]imidazo[2,1‐a]isoquinolin‐7‐one (4‐X−Ar−BBI). The electron‐withdrawing and electron‐donating substituents located at the para position of the phenyl ring attached to the heterocyclic structure have altered the pi electron density within the structure. This change in electron density has influenced the intercalation ability of the heterocyclic structure and has impacted the intensity of its interaction with DNA. The 4‐aryl‐benzo[d,e]benzo[4,5]imidazo[2,1‐a]isoquinolin‐7‐one derivatives (4‐X−Ar−BBI) were prepared via the Suzuki–Miyaura cross‐coupling reaction. The optimum reaction conditions were determined to be 70 °C for 5 hours using catalyst 1 and K2CO3, resulting in a yield of 96 % of 4‐H−Ar−BBI. Characterization of all compounds (4‐X−Ar−BBI) was performed using Fourier Transform Infrared spectroscopy, mass spectrometry, and 1H‐ and 19F‐NMR spectroscopies. The cytotoxic activities of the compounds (4‐X−Ar−BBI) were investigated against cancer cell lines, specifically HeLa (human cervix adenocarcinoma epithelial), PC3 (human prostate), and MCF‐7 (human breast). The stability of 4‐CN−Ar−BBI and the binding modes between 4‐CN−Ar−BBI and DNA were investigated via 1H‐NMR spectroscopy and UV‐Vis spectroscopy, respectively. 4‐CH3−3‐NO2−Ar−BBI exhibited the most potent cytotoxic activity against MCF‐7, and 4‐F−Ar−BBI showed the highest activity against HeLa, with IC50 values of 3.675 and 7.370 μM, respectively.

Py-CoMFA, docking, and molecular dynamics simulations of Leishmania (L.) amazonensis arginase inhibitors

Leishmaniasis is a disease caused by a protozoan of the genus Leishmania, affecting millions of people, mainly in tropical countries, due to poor social conditions and low economic development. First-line chemotherapeutic agents involve highly toxic pentavalent antimonials, while treatment failure is mainly due to the emergence of drug-resistant strains. Leishmania arginase (ARG) enzyme is vital in pathogenicity and contributes to a higher infection rate, thus representing a potential drug target. This study helps in designing ARG inhibitors for the treatment of leishmaniasis. Py-CoMFA (3D-QSAR) models were constructed using 34 inhibitors from different chemical classes against ARG from L. (L.) amazonensis (LaARG). The 3D-QSAR predictions showed an excellent correlation between experimental and calculated pIC50 values. The molecular docking study identified the favorable hydrophobicity contribution of phenyl and cyclohexyl groups as substituents in the enzyme allosteric site. Molecular dynamics simulations of selected protein–ligand complexes were conducted to understand derivatives’ interaction modes and affinity in both active and allosteric sites. Two cinnamide compounds, 7g and 7k, were identified, with similar structures to the reference 4h allosteric site inhibitor. These compounds can guide the development of more effective arginase inhibitors as potential antileishmanial drugs.

Synthesis and crystal structures of three organoplatinum(II) complexes bearing natural arylolefin and quinoline derivatives

Three organoplatinum(II) complexes bearing natural arylolefin and quinoline derivatives, namely, [4-methoxy-5-(2-methoxy-2-oxoethoxy)-2-(prop-2-en-1-yl)phenyl](quinolin-8-olato)platinum(II), [Pt(C13H15O4)(C9H6NO)], (I), [4-methoxy-5-(2-oxo-2-propoxyethoxy)-2-(prop-2-en-1-yl)phenyl](quinoline-2-carboxylato)platinum(II), [Pt(C15H19O4)(C10H6NO2)], (II), and chlorido[4-methoxy-5-(2-oxo-2-propoxyethoxy)-2-(prop-2-en-1-yl)phenyl](quinoline)platinum(II), [Pt(C15H19O4)Cl(C9H7N)], (III), were synthesized and structurally characterized by IR and 1H NMR spectroscopy, and by single-crystal X-ray diffraction. The results showed that the cycloplatinated arylolefin coordinates with PtII via the carbon atom of the phenyl ring and the C=Colefinic group. The deprotonated 8-hydroxyquinoline (C9H6NO) and quinoline-2-carboxylic acid (C10H6NO2) coordinate with the PtII atom via the N and O atoms in complexes (I) and (II) while the quinoline (C9H7N) coordinates via the N atom in (III). Moreover, the coordinating N atom in complexes (I)–(III) is in the cis position compared to the C=Colefinic group. The crystal packing is characterized by C—H...π, C—H...O [for (II) and (III)], C—H...Cl [for (III) and π–π [for (I)] interactions.

Trifluoromethanesulfonate salt of 5,10,15,20-tetrakis(1-benzylpyridin-1-ium-4-yl)-21H,23H-porphyrin and its CaII complex

The synthesis, crystallization and characterization of a trifluoromethanesulfonate salt of 5,10,15,20-tetrakis(1-benzylpyridin-1-ium-4-yl)-21H,23H-porphyrin, C68H54N8 4+·4CF3SO3 −·4H2O, 1·OTf, are reported in this work. The reaction between 5,10,15,20-tetrakis(pyridin-4-yl)-21H,23H-porphyrin and benzyl bromide in the presence of 0.1 equiv. of Ca(OH)2 in CH3CN under reflux with an N2 atmosphere and subsequent treatment with silver trifluoromethanesulfonate (AgOTf) salt produced a red–brown solution. This reaction mixture was filtered and the solvent was allowed to evaporate at room temperature for 3 d to give 1·OTf. Crystal structure determination by single-crystal X-ray diffraction (SCXD) revealed that 1·OTf crystallizes in the space group P21/c. The asymmetric unit contains half a porphyrin molecule, two trifluoromethanesulfonate anions and two water molecules of crystallization. The macrocycle of tetrapyrrole moieties is planar and unexpectedly it has coordinated CaII ions in occupational disorder. This CaII ion has only 10% occupancy (C72H61.80Ca0.10F12N8O16S4). The pyridinium rings bonded to methylene groups from porphyrin are located in two different arrangements in almost orthogonal positions between the plane formed by the porphyrin and the pyridinium rings. The crystal structure features cation...π interactions between the CaII atom and the π-system of the phenyl ring of neighboring molecules. Both trifluoromethanesulfonate anions are found at the periphery of 1, forming hydrogen bonds with water molecules.

Homochiral and Heterochiral Self-Sorting Assemblies of Antiaromatic Ni(II) Norcorrole Dimers.

Recently, π-π stacked antiaromatic π-systems have received considerable attention because they can exhibit stacked-ring aromaticity due to substantial intermolecular orbital interactions. Here, we report three antiaromatic norcorrole dimers that self-assemble to form supramolecular architectures through chiral self-sorting. A 2,2'-linked norcorrole dimer with 3,5-di-tert-butylphenyl groups forms a π-stacked dimer both in solid and solution states via homochiral self-sorting. Its association constant in solution is (3.6±1.7)×105 M-1 at 20 °C. In the solid state, 3,3'-linked norcorrole dimers with 3,5-di-tert-butylphenyl and phenyl groups afford macrocyclic and helical supramolecular assemblies via heterochiral and homochiral self-sorting, respectively. Notably, the subtle modification in the substituent resulted in a complete change in the structure of the aggregates and the chiral self-sorting mode. The present findings demonstrate that structural manipulation in antiaromatic monomer units leads to the formation of various supramolecular assemblies on the basis of the attractive interactions between antiaromatic π-systems.

Monomer-Recyclable Polyester from CO2 and 1,3-Butadiene.

Synthesis of monomer-recyclable polyesters solely from CO2 and bulk olefins holds great potential in significantly reducing CO2 emissions and addressing the issue of plastic pollution. Due to the kinetic disadvantage of direct copolymerization of CO2 and bulk olefins compared to homopolymerization of bulk olefins, considerable research attention has been devoted to synthesis of polyester via the ring-opening polymerization (ROP) of a six-membered disubstituted lactone intermediate, 1,2-ethylidene-6-vinyl-tetrahydro-2H-pyran-2-one (𝜹-L), obtained from telomerization of CO2 and 1,3-butadiene. However, the conjugate olefin on the six-membered ring of 𝜹-L leads to serious Michael addition side reactions. Thus, the selective ROP of 𝜹-L, which can precisely control the repeating unit for the production of polyesters potentially amenable to efficient monomer recycling, remains an unresolved challenge. Herein, the first example of selective ROP of 𝜹-L is reported using a combination of organobase and N,N'-Bis[3,5-bis(trifluoromethyl)phenyl]urea as the catalytic system. Systematic modifications of the substituent of the urea show that the presence of electron-deficient 3,5-bis(trifluoromethyl)-phenyl groups is the key to the extraordinary selectivity of ring opening over Michael addition. Efficient monomer recovery of oligo(𝜹-L) is also achieved under mild catalytic conditions.

DFT Calculations Rationalize Unconventional Regioselectivity in PdII-Catalyzed Defluorinative Alkylation of gem-Difluorocyclopropanes with Hydrazones.

Density functional theory (DFT) calculations have been conducted to gain insight into the unique formation of the branched alkylation product in the PdII-catalyzed defluorinative alkylation of gem-difluorocyclopropanes with hydrazones. The reaction is established to occur in sequence through oxidative addition, β-F elimination, η1-η3 isomerization, transmetalation, η3-η1 isomerization, 3,3'-reductive elimination, deprotonation/N2 extrusion, and proton abstraction. The rate-determining step of the reaction is identified as the β-F elimination, featuring an energy barrier of 28.6 kcal/mol. The 3,3'-reductive elimination transition states are the regioselectivity-determining transition states. The favorable noncovalent π-π interaction between the naphthyl group of gem-difluorocyclopropane and the phenyl group of hydrazone is found to be mainly responsible for the observed regioselectivity.

Comprehensive investigations of four ratiometric fluorescent chemosensors based on 4-(1H-imidazol-2-yl)benzaldehyde skeleton for malononitrile detection

Malononitrile is a very important chemical material and has wide application fields in production of medicines, pesticides, and extraction of gold. However, its nonnegligible hypertoxicity inspired researchers to develop more efficient analysis techniques to sensitively and selectively detect malononitrile. Nopinone derivatives initiated by our research group have been developed as a class of organic fluorescent chemosensors for identifying multiple analytes in recent years. Different heterocyclic compounds based on nopinone were designed and synthesized to be applied in the fields of environmental analysis, food detection and bioimaging. Nevertheless, the comparison research on the optical properties of fluorescent compounds containing the nopinyl matrix with other structural analogs including alkyl, cyclohexyl and phenyl groups was deficient. Herein, four 4-(1H-imidazol-2-yl)benzaldehyde-based ratiometric fluorescent chemosensors based on o-dimethyl cyclohexyl, phenyl and nopinyl units for recognizing malononitrile were designed and developed, and their differences in the optical properties and detection performances were investigated by using spectral analysis combined with theoretical calculations. Moreover, the nopinone-based 4-(1H-imidazol-2-yl)benzaldehyde fluorescent chemosensor NMZQ was successfully applied in the dual channel fluorescence bioimaging of malononitrile in living HeLa cells and zebrafish, which attributed to its outstanding spectral property and detection performance.

Data mining of arsenic-based small molecules geometrics present in Cambridge structural database

Arsenic, ubiquitous in various industrial processes and consumer products, presents both essential functions and considerable toxicity risks, driving extensive research into safer applications. Our investigation, drawing from 7182 arsenic-containing molecules in the Cambridge Structural Database (CSD), outlines their diverse bonding patterns. Notably, 51% of these molecules exhibit cyclic connections, while 49% display acyclic ones. Arsenic forms eight distinct bonding types with other elements, with significant interactions observed, particularly with phenyl rings, O3 and F6 moieties. Top interactions involve carbon, nitrogen, oxygen, fluorine, sulfur, and arsenic itself. We meticulously evaluated average bond lengths under three conditions: without an R-factor cut-off, with R-factor ≤0.075, and with R-factor ≤0.05, supporting the credibility of our results. Comparative analysis with existing literature data enriches our understanding of arsenic's bonding behaviour. Our findings illuminate the structural attributes, molecular coordination, geometry, and bond lengths of arsenic with 68 diverse atoms, enriching our comprehension of arsenic chemistry. These revelations not only offer a pathway for crafting innovative and safer arsenic-based compounds but also foster the evolution of arsenic detoxification mechanisms, tackling pivotal health and environmental challenges linked to arsenic exposure across different contexts.

Multi‐azo Photoswitches for Improved Molecular Solar Thermal Energy Storage

AbstractMolecular solar thermal energy storage (MOST) based on photoisomerization represents a novel approach for the capture, conversion and storage of solar energy. Azo photoswitches can store energy by isomerization from their thermodynamically stable E isomers to higher energy metastable Z isomers. The energy density of azo photoswitches is crucial as it directly determines the storage capacity, but it is relatively low (160 J g−1). Therefore, enhancing the energy density through molecular structural design represents a central research focus in the field of MOST. A straightforward approach to enhance the energy density is to design multi‐azo photoswitches. This allows multiple azobenzene units to share a common framework while keeping the molecular weight as small as possible. In particular, when two azobenzene units are connected via a phenyl ring in a meta orientation, it facilitates efficient isomerization, thereby maximizing the energy density of the azo photoswitches (392 J g−1). This paper provides a brief overview of the development of multi‐azo photoswitches and highlights their outstanding performance as a MOST system. It also offers prospects for their future advancements in the field. We propose that, to further improve the energy density of multi‐azo photoswitches, one approach is to design wide spectrum of light photoisomerization of multi‐azo photoswitches. Additionally, introducing photo‐induced phase changes to multi‐azo photoswitches enables the simultaneous storage of both photon energy and ambient heat.

Application of the Photo‐Fries Reaction as a Key Step in the Preparation of Valuable Aryloxyethyl Selenocyanates

AbstractA multistep sequence leads to the preparation of a series of aryl selenocyanate WC‐9 homologues, which are interesting compounds with potential biological activity against Trypanosoma cruzi, the etiological agent of Chagas disease. The synthetic sequence involves the application of the photo‐Fries rearrangement reaction as a key step for the preparation of a series of 2‐hydroxyphenones bearing alkyl chains of different length and a phenyl group. These intermediates are obtained upon direct irradiation (254 nm) of 4‐phenoxyphenyl esters in different solvents at room temperature. Then, reaction of the 2‐hydroxyphenones with 2‐(2‐bromoethoxy)tetrahydro‐2H‐pyran followed by acid deprotection, tosylation (or mesylation) reaction and, finally, nucleophilic attack with potassium selenocyanate provides the target aryloxyethyl selenocyanate homologues in good yields.

Synthesis, crystal structure and Hirshfeld surface analysis of 1-[3-(2-oxo-3-phenyl-1,2-dihydroquinoxalin-1-yl)propyl]-3-phenyl-1,2-dihydroquinoxalin-2-one

In the title compound, C31H24N4O2, the dihydroquinoxaline units are both essentially planar with the dihedral angle between their mean planes being 64.82 (4)°. The attached phenyl rings differ significantly in their rotational orientations with respect to the dihydroquinoxaline planes. In the crystal, one set of C—H...O hydrogen bonds form chains along the b-axis direction, which are connected in pairs by a second set of C—H...O hydrogen bonds. Two sets of π-stacking interactions and C—H...π(ring) interactions join the double chains into the final three-dimensional structure.

Why linear naphthopyran does not exhibit stable photochromism: A theoretical study

In the present work, we applied our recent hypothesis of intramolecular excimer formation to explain the lack of stable photochromism of linear naphthopyran. To clarify the influence of the stacking interaction between the non-aromatic naphthalene unit and aromatic phenyl ring, a comparative analysis of the results of identical TD-DFT/DFT calculations was performed for angular (3H–) and linear naphthopyrans. In contrary to linear naphthopyran, the open form of 3H-naphthopyran is very stable. The excitations of the closed forms of both naphthopyran isomers are quantitatively and qualitatively close to each other. Optimization of the excited states of the closed forms of both naphthopyran isomers from their FC points leads to the cleavage of C–O bonds and the formation of stacks between the phenyl rings and conjugated rings. The total interaction energy in the intramolecular excimer of 3H-naphthopyran is 17 kcal/mol higher in absolute value than for linear naphthopyran. This difference is due to the significantly greater overlap of rings during stacking in the intramolecular excimer of 3H-naphthopyran compared to linear naphthopyran, since the attraction between the aromatic and non-aromatic systems decreases very strongly with their longitudinal displacement. According to calculations, upon relaxation, 3H-naphthopyran retains the open form with residual stacking while in linear naphthopyran the stacking is destroyed completely, and the molecule returns to the closed form by C–O bond recovery.

Antioxidant and Antimicrobial Potential of 1,8-Naphthyridine Based Scaffolds: Design, Synthesis and in Silico Simulation Studies within Topoisomerase II.

A series of spiro β-Lactams (4 a-c, 7 a-c) and thiazolidinones (5 a-c, 8 a-c) possessing 1,8-naphthyridine moiety were synthesized in this study. The structure of the newly synthesized compounds has been confirmed by IR, 1H-NMR, 13C NMR, mass spectra, and elemental analysis. The synthesized compounds were tested in vitro for their antibacterial and antifungal activity against various strains. The antimicrobial data showed that most of the compounds displayed good efficacy against both bacteria and fungi. The structure-activity relationship (SAR) studies suggested that the presence of electron-withdrawing chloro (3 b, 4 b, and 5 b) and nitro groups (7 b, 8 b) at the para position of the phenyl ring improved the antimicrobial activity of the compounds. The free radical scavenging assay showed that all the synthesized compounds exhibited significant antioxidant activity on DPPH. Compounds 8 b (IC50=17.68±0.76 μg/mL) and 4 c (IC50=18.53±0.52 μg/mL) showed the highest antioxidant activity compared to ascorbic acid (IC50=15.16±0.43 μg/mL). Molecular docking studies were also conducted to support the antimicrobial and SAR results.

Polarity control of siloxane composite films for triboelectric nanogenerator based self-powered body temperature monitoring

Body temperature monitoring systems serve as key indicators for identifying potential patients with various illnesses such as influenza and COVID-19. Conventionally, these monitoring devices rely on batteries, limiting their long-term and widespread application. Self-powered thermometers are considered a sustainable solution that enable continuous monitoring. Among various self-charging power sources, triboelectric nanogenerators (TENGs) are a novel development, but suffer several critical drawbacks for medical applications. In this study, we present a high-performance TENG for self-powered body temperature monitoring systems by controlling the polarity of glass-fabric reinforced vinyl-thiol functionalized hybrid materials (GFR-VTHs) by varying the phenyl group contents. The effect of polarity modification on the performance of the developed TENG was confirmed by the high electrical output and stable operation under 10,000 cycles of repetitive pressing tests. Finally, self-powered body temperature monitoring systems were constructed by measuring human body temperature with a clinical thermometer powered by the GFR-VTH-based TENG, demonstrating device feasibility as a power source for self-powered healthcare systems.

Synthesis and Dynamic Behaviors of 5,7,8,10-Tetraphenyl-1,14-dianilinotripyrrins

Abstract5,7,8,10-Tetraphenyl-1,14-di(arylamino)tripyrrins have been synthesized via 5,7,8,10-tetraphenyltripyrrane. The structures and dynamic equilibrium between single helical monomer and double helical dimer were analyzed by 1H NMR spectra and X-ray diffraction analysis. Their dimerization association constants in CDCl3 are larger than those of previously reported dianilinotripyrrin derivatives. In DMSO, they exhibited luminescence around 700 nm as a consequence of restricted rotational relaxation by the phenyl groups installed at the 7,8-positions.

Enhanced solubility and oral bioavailability of niclosamide- sulfobutylether-β-cyclodextrin sodium inclusion complexes: An approach to improve its repurposing potential

Niclosamide monohydrate (NCL) displays promising efficacy across diverse medical conditions, but its limited solubility (1.6 µg/mL at 20°C) and oral bioavailability (10%) hinder its translational potential. In this study, we investigate the complexation of NCL with sulfobutylether-β-cyclodextrin sodium (SBECD) as a strategy to enhance its solubility, dissolution rate and oral bioavailability. Molecular docking studies revealed weak binding (∆Gbind < 2.0 kcal/mole) between NCl and SBECD. The nitrophenyl ring inserted into the SBECD cavity, while the phenyl ring, housing Cl and OH groups, prominently extended outside. Phase solubility studies confirmed a 1:1 inclusion complex formation with a stability constant of 186 M−1. Inclusion complexes, prepared via co-grinding, kneading, solvent evaporation, and spray drying, significantly improved NCL dissolution. Specifically, the spray dried and kneaded complexes achieved complete drug release within 60 min, unlike pure NCL exhibiting only 16% dissolution at 90 min. Microscopic analysis showcased reduced particle surface area in the spray dried complex. Oral bioavailability assessments demonstrated an approximately1.6-fold increase for the spray dried and kneaded complexes compared to pure NCL. Our findings support the scalability and efficacy of NCL-SBECD complexation as a strategic approach for enhancing the repurposing potential of NCL in therapeutic applications.

Large-scale and facile fabrication of phenyl-containing silicone foam materials with lightweight, wide-temperature flexibility and tunable pore structure for exceptional thermal insulation

Silicone foam materials with unique inorganic/organic molecular networks and porous structures are widely used in many emerging fields from aerospace to new energy fields. However, current silicone foam materials still show some limitations, such as the relatively high-density values of >200 mg cm−3, complex fabricating process and difficulty in tailoring pore structure. Herein, we report a large-scale and facile fabricating strategy to prepare phenyl-containing silicone foam materials (PhSiRF) with ultra-lightweight feature, tunable pore structure, and excellent wide-temperature mechanical flexibility. Interestingly, the presence of phenyl groups onto the Si–O–Si backbone tailors the chemical foaming rate probably due to the steric hindrance effect, thus producing tunable pore size distributions in the range of 180–500 μm. Typically, the PhSiRF with 50 % phenyl groups not only shows a very low density of ∼100 mg cm−3, superior to previous silicone foams and composites, but also exhibits wide-temperature flexibility (stable compressive strain of 80 % from −90 to 210 °C) and excellent thermal insulation performance, which outperforms those of conventional polymer foams including polyurethane, polyethylene and melamine foams. Based on the structure observation and theory analysis, the influence of different pore morphological structures on the thermal insulation performance is discussed and demonstrated. Clearly, this work provides a new yet simple method for developing high-performance silicone rubber foam materials for promising thermal insulation applications.

Turn-On Solid-State Fluorescent Determination of Zinc Ion by Quinoline-Based Covalent Organic Framework.

A new quinoline-based COF (covalent organic framework), obtained by Povarov reaction, containing 2,6-diisopropylphenyl moieties as substituents over the heterocyclic ring is described for detecting Zn2+ in aqueous solution. The introduction of the mentioned bulky phenyl rings into the network favors an increase of the distance between the reticular sheets and their arrangement, obtaining a new material with an alternating AB type stacking. The new material exhibits good selectivity to detect Zn2+ by fluorescence emission in aqueous solutions up to a concentration of 1.2 × 10-4m of the metal ion. In order to have a deeper insight into the interaction between the COF and the zinc cation, a thorough spectroscopical, microscopical, and theoretical study is also presented and discussed in this communication.