DMF Solution Research Articles

Synthesis, crystal structures, Hirshfeld surfaces and DFT calculations of two isomers of oxaspirocyclic compound

Two isomers of oxaspirocyclic compound: 3-cyclopentyl-1,5-dioxaspiro[5.5]undecane-2,4-dione (Z-1) and 8-cyclohexyl-6,10-dioxaspiro[4.5]decane-7,9-dione (Z-2) were synthesized by the reaction of cycloalkanones with distinct dioxaspiro moieties in a formic acid-triethanolamine and DMF solution. Compound Z-1 was monoclinic, P 1 21/c 1 space group with lattice parameters: a = 10.2056(11) Å, b = 5.9697(5) Å, c = 21.7646(18) Å, β = 90.985(4) °, V = 1325.8(2) Å3, Z = 4, F(000) =544. Compound Z-2 was triclinic, P-1 space group with lattice parameters: a =5.761(2), b = 10.310(4), c = 12.377(5) Å, α =68.294(4) °, β = 79.837(5) °, γ = 87.492(5) °, V =672.1(4) Å3, Z = 2, F(000) = 272. The IR spectra were compared with the calculated vibrational frequencies using the DFT/B3LYP/ G-31(d, p) method. It was observed that the energy gaps of Z-1 and Z-2 were 7.075 eV and 7.073 eV, respectively, indicating lower chemical reactivity between the two molecules. Intermolecular interactions were investigated by Hirshfeld surface, showing predominant H···H interactions in the two molecules. In addition, the stabilization energy and the nucleophilic and electrophilic attack regions were studied by NBO and MEP analysis, respectively.

New electrodes based on composites of polyphenothiazine with carbon nanomaterials

The goal of this research is to obtain new electrode hybrid coatings for electrochemical devices applications. Nanocomposites based on unsubstituted polyphenothiazine (PPTA) and carbon nanomaterials (CNM) were prepared for the first time. Reduced graphene oxide (RGO), single-walled and multi-walled carbon nanotubes (SWCNT and MWCNT) were used as CNM. Hybrid nanocomposites were prepared by two methods: via oxidative polymerization of PTA in the presence of CNM (CNM/PPTA-1), or from pre-synthesized polymer solution in DMF containing CNM followed by solvent removal (CNM/PPTA-2). The structure and morphology of PPTA-derived nanocomposites were studied by means of FTIR spectroscopy, X-ray diffraction, and FE-SEM. The nanocomposite composition dependence of conductivity was demonstrated. Electrochemical behavior of the electrode coatings prepared on the basis of the said polymer and CNM/PPTA nanocomposites thereof was studied by CV methods. All the samples were found to be electroactive in 1 M sulfuric acid. An addition of carbon nanomaterials was shown to improve reversibility of the electrode processes that is related to formation of nanocarbon conductive framework in the composite with a highly developed surface filled with thin layers of the polymer. CNM/PPTA nanocomposites exhibit the electrocatalytic effect to the redox behavior of ferro/ferricyanide couple in 1 M H2SO4.

Cyclic Voltammetry of C.I. Disperse Orange 62 in an Aqueous Electrolyte.

Disperse dyes are an important group of colorants for dyeing polyester fibers. Approximately 30.000 tons of disperse dyes are released into the waste water annually from spent dyebaths. Therefore, methods for decolorizing such dyes are of general interest. The reductive after-treatment of disperse dyes using reducing agents, such as Na2S2O4, is a widely used process to improve rub fastness through dye reduction. Electrochemical dye reduction could be an alternative process for reductive dye treatment. In this work C.I. Disperse Orange 62 was used as a representative dye to study the direct cathodic reduction of a disperse dye with cyclic voltammetry. As anticipated for dispersed organic matter, relatively low current densities were observed, which strongly depend on the state of dispersion of the dye. The current density was increased by using dispersions prepared through dye precipitation from DMF solution and by the use of N-cetyl-N,N,N,-trimethyl-ammonium bromide as a cationic surfactant. The results demonstrate the successful cathodic reduction of a dispersed organic dye; however, the low solubility of the reaction products in the aqueous electrolyte hinders an efficient cathodic dye reduction.

Thermodynamic Properties of 3- and 4-Ethoxyacetanilides between 80 and 480 K.

In this work, we present a comprehensive study of the thermodynamic properties of 3-and 4-ethoxyacetanilides. The heat capacities in crystalline, liquid, and supercooled liquid states from 80 to 475 K were obtained using adiabatic, differential scanning (DSC), and fast scanning (FSC) calorimetries. The fusion enthalpies at Tm were combined from DSC measurement results and the literature data. The fusion enthalpies at 298.15 K were evaluated in two independent ways: adjusted according to Kirchhoff's law of thermochemistry, and using Hess' law. For the latter approach, the enthalpies of the solution in DMF in crystalline and supercooled liquid states were derived. The values obtained by the two methods are consistent with each other. The standard thermodynamic functions (entropy, enthalpy, and Gibbs energy) between 80 and 470 K were calculated.

A new turn-on fluorescent probe for fast detection of diabetic biomarker beta-hydroxybutyrate in vitro

Beta-hydroxybutyrate (β-HB) serve as a valuable diagnostic biomarker for Diabetic Ketoacidosis (DKA). Here, a new Schiff base fluorescent probe T was designed and synthesized to detect β-HB level in aqueous solution in vitro. The probe T can detect β-HB sensitively and selectively in DMF solution (5.0 × 10−5 M) among other interfering species (cations, anions, amino acids, biomarkers). The detection limit of probe T for β-HB was calculated to be 0.154 μM. These results demonstrate that the probe T may provide a convenient method for rapid detection of β-HB to diagnose diabetic ketoacidosis.

New substituted pentazadienes as initiators of free-radical polymerization: synthesis, photochemical properties and perspectives for holographic media

The series of 4,4′-substituted 3-hydroxyethyl-pentaza-1,4-dienes were synthesized in the reaction of aromatic diazonium salts with an ethanol amine. Photolysis of pentaza-1,4-dienes was investigated by means of UV/Vis spectroscopy. Electron donating methyl and methoxy substituents were found to increase photosensitivity whereas electron withdrawing chloro-substituents cause higher photolytic stability. 3-hydroxyethyl-pentaza-1,4-dienes as a radical polymerization initiator has been successfully investigated in 10% methyl methacrylate solution in DMF. Gel permeation chromatography (GPC) and differential scanning calorimetry (DSC) were used for obtained polymers characteristics evaluation. The highest values of PMMA Mn and Đ can be obtained in the case of chloro-substituted derivative. The holograms of a plane wavefront were recorded in media based on obtained PMMA doped by azo-dye by a 532 nm laser in a ∼1-μm-thick sample. The diffraction efficiency values for parallel polarized acting light increased in Cl→Me→OMe series.

Isomorphic relationship between three solvates of a ferrocenyl-based chromenopyrimidine

Solvates of 4-((3-ferrocenylphenyl)amino)-5-(2-fluorophenyl)-8,8-dimethyl-5,7,8,9-tetrahydro-6H-chromeno[2,3-d]pyrimidin-6-one (I), a promising antiproliferative agent towards human breast cancer (MCF-7) cells, were formed from their respective acetone, DMSO‑d6, and DMF solutions. Isomorphic relationship exists between the solvates of I since all compounds crystallize in a P21/n space group with four molecular entities in their respective unit cells, with slight differences in their respective unit cell parameters. IR spectroscopy was used to distinguish the three solvates by monitoring the NH vibration frequency since they all have intermolecular NH…Osolvent hydrogen bonding patterns in the solid state. The solvent molecule's Hirshfeld surface helps distinguish the solvates based on the contribution of reciprocal H…O contacts. Molecular pairwise interaction energy calculations were done to determine the associated energies between solvent-I molecular pairs that are linked by the intermolecular NH…Osolvent hydrogen bond. Correlations between the geometric parameters of the NH…Osolvent hydrogen bond, NH vibration frequency, the contribution of reciprocal H…O contacts toward the solvent's Hirshfeld surface and pairwise interaction energies of the three solvates, are discussed in this work.

Green Synthesis and Electrochemical Study of Undoped and Doped Al<sub>2</sub>O<sub>3</sub> Nanoparticles Using <i>Hibiscus rosa-sinensis</i> Leaves Extract

In the present work, nanoparticles of Al2O3, Cu-Al2O3, and Ni-Al2O3 were prepared using Hibiscus rosa-sinensis plant leaf extract through co-precipitation method. The prepared nanomaterials were characterized through TGA, EDX, SEM, UV-Vis, XRD, and FTIR instruments. The electrochemical behavior of Al2O3, Cu-Al2O3, and Ni-Al2O3 has been studied in DMF solution in the potential ranges from −1.5 to 1.5 V. The nanoparticles are thermally stable, according to the TGA, and the XRD patterns revealed that all the Al2O3, Cu-Al2O3, and Ni-Al2O3 particles were crystalline, with the mean sizes of 12.44, 34.61, and 31.63 nm, respectively. The cyclic voltammogram showed a cathodic peak (Epc) at 0.49 V with an anodic counterpart (Epa) at 0.49 V [E1/2 = 1.748 V]. The optical band gaps of Al2O3, Cu-Al2O3, and Ni-Al2O3 were 3.8, 3.2 and 3.65 eV, owed a cathode. It is observed that the electrochemical behavior of Ni-Al2O3 was identical to that of Al2O3 and Cu-Al2O3. The anodic and cathodic peak values rise with the scan rate. The one-electron oxidation and reduction processes are reversible, as seen by the shifting cathodic peak value toward higher negative values. All cycles exhibit absorption has a constant anodic current. This result indicated the diffusion-based redox process.

Promoted Charge Separation and Long-Lived Charge-Separated State in Porphyrin-Viologen Dyad Nanoparticles.

Developing light-harvesting systems with efficient photoinduced charge separation and long-lived charge-separated (CS) state is desirable but still challenging. In this study, we designed a zinc porphyrin photosensitizer covalently linked with viologen (ZnP-V) that can be prepared into nanoparticles in aqueous solution. In DMF solution, the monomeric ZnP-V dyads show no electron transfer between the ZnP and viologen units. In contrast, the ZnP-V nanoparticles in aqueous solution show fast charge separation with a CS state lifetime of up to 4.3 ms. This can be attributed to charge hopping induced by aggregation or distance modification between the donor and acceptor induced by electronic interaction. Nevertheless, the lifetime of the CS state is orders of magnitude longer than for molecular aggregates reported previously. The ZnP-V nanoparticles show enhanced photocatalytic hydrogen production as compared to the ZnP nanoparticles and still hold promise for other applications such as photovoltaic devices and photoredox catalysis.

Thin film nanocomposite polyamide membrane doped with amino-functionalized graphene quantum dots for organic solvent nanofiltration

Thin film nanocomposite (TFN) organic solvent nanofiltration (OSN) membrane with improved separation performance was fabricated via interfacial polymerization reaction between amine-functionalized graphene quantum dots (af-GQDs) doped aqueous monomer solution of m-phenylenediamine (MPD) and n-hexane solution containing trimesoyl chloride (TMC) monomer. We emphasize the employment of extra-low content for both af-GQDs and MPD, so that we could maximize the function of these nanomaterials and eliminate their aggregation at the same time. The af-GQDs nanomaterials could regulate the interfacial polymerization process and could be strongly anchored in the polyamide film via covalent bonding, hence could prevent their loss while providing more channels for faster solvent penetration. As a result, the optimized OSN membrane, TFN-50, shows a super-smooth surface, with a surface roughness as low as 4.3 ± 0.2 nm, and excellent pure solvent permeances which reach 135.8, 112.7, and 69.8 L m−2 h−1 MPa−1 for methanol, DMF and ethanol, respectively, as well as a very high Rhodamine B (RDB, 479 Da) rejection of up to 99.2%, and an ethanol permeance of 61.4 L m−2 h−1 MPa−1. Furthermore, the TFN-50 OSN membrane still shows excellent filtration performance after being submerged in DMF for 336 h or continuous crossflow filtration with Rose bengal (RB, 1017 Da)/DMF solution for 136 h, demonstrating its excellent solvent resistance.

Copper(II)-flavonolate complexes of 2N ligands as functional models for quercetin 2,4-dioxygenase enzymes: The role of axially coordinated water and ligand substitution on dioxygenase activity

Three new copper(II)-flavonolate complexes of the type [Cu(L)(fla)(ClO4)] 1–3, where L is the 2N ligand N-(pyridin-2-ylmethyl)aniline (L1), 2,6-dimethyl-N-(pyridin-2-ylmethyl)aniline (L2) and 2,6-diisopropyl-N-(pyridin-2-ylmethyl)aniline (L3), and H(fla) is 3-hydroxyflavonone, have been isolated as functional models for Cu(II)-containing quercetin 2,4-dioxygenase (2,4-QueD). Single crystal X-ray structure of 3 contains a CuN2O2Oʹ chromophore with a slightly distorted square pyramidal geometry (TBDSP, τ = 0.03). The pyridyl N1 and the tertiary amine N2 nitrogens of the 2N ligand occupy the two corners of the basal plane. The O1 (enolate) and the carbonyl O2 atoms of deprotonated 3-hydroxyflavanone (fla−) occupy the remaining corners while the O3 of perchlorate anion (ClO4−) occupies the axial position at a longer distance. The molecular structures of the complexes 1–3, their aquated species [Cu(L)(fla)(H2O)]+1a–3a and the square planar species [Cu(L)(fla)]+1c–3c have been computed by using DFT method. While 1–3 contain axially coordinated perchlorate 1a–3a contain axially coordinated water molecule with a slightly distorted square pyramidal geometry (CuN2O2Oʹ) with varying trigonality (τ, 0.03–0.05). The significantly high g|| (2.305) and low A|| (150 × 10−4 cm−1) values observed for 1–3 are consistent with π–back bonding of Cu(II) with the conjugated carbonyl group of coordinated fla− and are typical of type-II copper enzymes. The electrochemical reduction of CuII to CuI and oxidation of fla− occur upon dissociation of axially coordinated water molecule in 1a–3a formed in DMF solution to give 1c–3c. Upon exposure to dioxygen, all the Cu(II)-flavonolate adducts undergo oxygenative degradation in DMF solution, as seen from the disappearance of the LMCT band at 430 nm at 80 °C to produce CO and the corresponding acids. The rate of dioxygenation, kO2, of the complexes decrease in the order, 1 (3.31 ± 0.53) > 3 (2.59 ± 0.36) > 2 (1.52 ± 0.13 × 10−1 M−1 s−1), due to electron-donating substituents on the primary ligand.

Synthesis, characterization and antiproliferative activity of platinum(II) complexes with 3-(2-pyridyl)-N1,2-methyl-1,2,4-triazoles

The present work describes the synthesis, investigation and in vitro cytotoxicity of Pt(II) complexes with 3-(2-pyridyl)-N1-methyl-1,2,4-triazole (L1) and 3-(2-pyridyl)–N2-methyl-1,2,4-triazole (L2). The crystal structures of PtL1Cl2 and PtL2Cl2 were established using X-Ray analysis, which revealed the square-planar PtN2Cl2 coordination geometry for the central metal ion. High-resolution mass spectrometry (HRMS), as well as one- and two-dimensional nuclear magnetic resonance (NMR) spectroscopy showed stability of the investigated complexes in DMF solution, in contrast to DMSO, where species were shown to partially dissociate. The cytotoxicity of the investigated compounds was determined by the colorimetric MTT assay against two human cancer cell lines, including cisplatin-sensitive human ovarian adenocarcinoma A2780 cells (IC50 = 26 ± 5 and 6.1 ± 0.6 for PtL1Cl2 and PtL2Cl2 correspondingly) and their cisplatin-resistant A2780cis analogue (IC50 = 24 ± 2 and 20 ± 3 for PtL1Cl2 and PtL2Cl2 correspondingly).

Symmetry‐Broken Charge‐Transfer Excited State in Homoleptic Zinc(II) Imidazo[1,2‐a]pyridine Complexes

AbstractA series of four homoleptic cationic ZnII complexes (Zn1–Zn4) coordinated by two substituted bis‐imidazo[1,2‐a]pyridine (ImPy) ligands (L1–L4) is herein presented. The ligands are functionalized with either electron acceptor or donor functional groups at the C6 positions of the two ImPy moieties. In DMF solution, all of the complexes display intense near‐UV to blue emission (λem=379–450 nm) with high photoluminescence quantum yields (PLQY) up to 0.50 and short‐lived excited states. Additionally, complex Zn4, containing the ‐NPh2 functionalized ligand, displays an interesting solvatochromic behavior. The absorption spectrum is characterized by electronic transitions with mainly ligand‐centered (1LC) and intraligand charge‐transfer (1ILCT) character, which involves a symmetric electron density redistribution at Franck‐Condon (FC). In stark contrast, the subsequent excited‐state dynamics relaxes the molecular symmetry and allows symmetry‐breaking hole‐electron pair redistribution on the bichromophoric system. As a consequence, an efficient radiative de‐excitation process takes place that is ascribed to a singlet‐manifold excited state with symmetry‐broken charge transfer (1SBCT) character, as supported by an in‐depth photophysical, electrochemical and time‐dependent density functional theory (TD‐DFT) investigation. Remarkably, the 1SBCT nature provides structureless green photoluminescence in the solid state (λem up to 520 nm for Zn4), which is rather uncommon for ZnII complexes.

Thermodynamics of aggregation of poly(2-ethyl-2-oxazoline-b-4-vinylbenzoic acid) in water and colloidal stability of their aggregates in water/DMF mixtures

Block copolymer aggregates have attracted considerable interest due to their potential applications which vary from biomedicine to catalysis. Herein, the synthesis and the self-assembly behavior of poly(2-ethyl-2-oxazoline-b-4-vinylbenzoic acid) - P(EtOx-b-4VBA) - in aqueous medium were reported. A series of P(EtOx-b-4VBA) with different compositions were prepared by the sequential cationic ring-opening polymerization of EtOx and atom transfer radical polymerization of 4VBA, achieving molar dispersity indices below 1.3. Their critical aggregation concentration (c.a.c.) and the thermodynamics of their aggregation in water were studied by fluorescence spectroscopy using pyrene as a probe, revealing a strong dependence on temperature and on the 4VBA/EtOx molar ratio. P(EtOx-b-4VBA) presented a c.a.c. vs. temperature behavior different from that usually observed for low molar mass surfactants. The thermal properties were studied, and the relationship of the glassy P4VBA block (Tg > 143 °C) with the self-assembly in solution was discussed in terms of the stability of P(EtOx-b-4VBA) aggregates and the possible protocols that can be used to prepare them. The self-assembly promoted by solvent switch from a DMF solution with water and dialysis of this solution against water resulted in aggregates with different sizes and colloidal stability. The rate of water addition was determinant towards formation of kinetically stable aggregates as well as on their properties, as revealed by DLS, Zeta-potential measurements, and cryo-TEM images. Finally, the loading of a model hydrophobic molecule, Nile red, was studied, indicating that the aggregates display capacity for the encapsulation of hydrophobic compounds.

Nano copper (II) complex based on 2 -cyano-N'-((2-hydroxynaphthalen-1-yl) methylene) acetohydrazide: Synthesis, spectroscopic, electrospinning, DFT calculations and optical properties

2-cyano-N'-((2-hydroxynaphthalen-1-yl)methylene)acetohydrazide, (1) and its copper (II) chelate (2) were synthesized and characterized by elemental analyses, TGA, FT-IR and spectroscopic techniques. By using an X-ray diffraction approach, the structural characteristics of the produced powder chelating agent (1) and its copper (II) chelate (2) were identified. The transmission electron microscope technique was utilized to analyze the morphology of the isolated compounds (1 and 2). In DMF solutions at various molar concentrations, the electronic absorption spectra of the chelating agent (1) as well as its copper (II) chelate (2) was examined in the UV– Vis. area. In the area of maximal absorbance, the molar extinction coefficient of the ligand (1) and its copper (II) complex (2) were calculated. For the ligand (1) as well as its copper (II) complex (2) at various molarities, the optical transition type and optical energy band gap values were explored using the absorption coefficient. New electrospun fibers (3) and (4) which fabricated from the prepared ligand (1) and its copper (II) complex (2), respectively. Photoluminescence studies performed for the samples (1, 2, 3 and 4). In addition, computational analyses of the free ligand (1) and its copper complex (II) (2) were carried out using DFT calculations.

New Fe(III) Trichlorido Complex of a Bidentate N'-(thiophen-2-ylmethylene)isonicotinohydrazide Ligand: Synthesis, X-ray Structure, Spectral Characterization, and Electrochemistry Study

Fe(III) complex of the hydrazone from (E)-N'-(thiophen-2-ylmethylene)isonicotinohydrazide (HL) has been synthesized and characterized by elemental analysis, electrical conductance in non-aqueous solvents, FT-IR and electronic spectroscopies, room temperature magnetic measurement, electrochemistry study as well as by X-ray diffraction structure determination. In the complex, the ligand acts in its neutral bidentate form, coordinating through the carbonyl oxygen and azomethine nitrogen. A high spin octahedral geometry assigned to the Fe(III) complex were further confirmed by room temperature magnetic moment data. Elemental analysis showed that Fe(III) complex is composed of metal and ligands in a molar ratio of 1:1. This complex of Fe(III) is a neutral electrolyte in DMF solution. The electrochemistry study shows that a one electron process determined the electrochemical reaction is governed by an electron transfer with an irreversible process. The structure of the complex has also been determined by X-ray diffraction revealing an octahedral environment around the Fe(III) ion.

ТЕРМООКИСЛИТЕЛЬНАЯ УСТОЙЧИВОСТЬ ПРОТОНООБМЕННЫХ МЕМБРАН НА ОСНОВЕ СОПОЛИМЕРОВ СТИРОЛСУЛЬФОКИСЛОТЫ И N-ВИНИЛИМИДАЗОЛА

The differential scanning colorimetry (DSC) thermooxidative stability of new copolymers of styrene-sulfonic acid and N-vinylimidazole obtained by radical copolymerization in a DMF solution in an argon atmosphere has been studied

Advanced Electrode Coatings Based on Poly-N-Phenylanthranilic Acid Composites with Reduced Graphene Oxide for Supercapacitors.

The electrochemical behavior of new electrode materials based on poly-N-phenylanthranilic acid (P-N-PAA) composites with reduced graphene oxide (RGO) was studied for the first time. Two methods of obtaining RGO/P-N-PAA composites were suggested. Hybrid materials were synthesized via in situ oxidative polymerization of N-phenylanthranilic acid (N-PAA) in the presence of graphene oxide (GO) (RGO/P-N-PAA-1), as well as from a P-N-PAA solution in DMF containing GO (RGO/P-N-PAA-2). GO post-reduction in the RGO/P-N-PAA composites was carried out under IR heating. Hybrid electrodes are electroactive layers of RGO/P-N-PAA composites stable suspensions in formic acid (FA) deposited on the glassy carbon (GC) and anodized graphite foil (AGF) surfaces. The roughened surface of the AGF flexible strips provides good adhesion of the electroactive coatings. Specific electrochemical capacitances of AGF-based electrodes depend on the method for the production of electroactive coatings and reach 268, 184, 111 F∙g-1 (RGO/P-N-PAA-1) and 407, 321, 255 F∙g-1 (RGO/P-N-PAA-2.1) at 0.5, 1.5, 3.0 mA·cm-2 in an aprotic electrolyte. Specific weight capacitance values of IR-heated composite coatings decrease as compared to capacitance values of primer coatings and amount to 216, 145, 78 F∙g-1 (RGO/P-N-PAA-1IR) and 377, 291, 200 F∙g-1 (RGO/P-N-PAA-2.1IR). With a decrease in the weight of the applied coating, the specific electrochemical capacitance of the electrodes increases to 752, 524, 329 F∙g-1 (AGF/RGO/P-N-PAA-2.1) and 691, 455, 255 F∙g-1 (AGF/RGO/P-N-PAA-1IR).

Electrochemical behaviour of anthraquinone dyes in non-aqueous solvent solution. Part II. Controlled potential electrolysis of alizarin

This article is the second part of our already published research results (Caram, Banera, Martínez Suárez, Mirífico, 2017). The present work aims to characterise/identify reaction intermediates and final products of the cathodic electrolysis of alizarin (AH2) in solution of DMF and ACN with TBAP and NaClO4 as supporting electrolytes to corroborate the reaction mechanism previously published by us. Intermediates and reaction products are accumulated by controlled potential electrolysis (CPE) of AH2 performed at the potentials of the first, second, and third charge transfers. Progress of the electrolysis is followed by CV. The techniques employed for the characterisation/identification of the involved chemical species are CV, UV–Vis, FTIR, 1H and 13C NMR, ESR, elemental analysis, and quantum chemical computations based on density functional theory (DFT). Some aspects of the mechanism are corroborated, some details are modified, and new insights are obtained. Intermediates are detected by CV, and the structure of some of them (AH2● ─, AH3●, and AH─) is confirmed by ESR and by the identity of the isolated reaction products (1-hydroxy-2-methoxyanthracene-9,10-dione (AH-CH3) by adding an excess of CH3I at the end of the CPE in DMF/TBAP and NaClO4 as the electrolyte systems, and sodium 1-hydroxy-9,10-dioxo-9,10-dihydroanthracene-2-olate (AH-Na) in ACN/NaClO4). Ion pair formation between AH2● ─ semiquinone radical anion with Na+ is significant. The homogeneous dissociation equilibrium AH3─ ⇄AH22– + H+ does not occur, and AH2• – + AH2 ⇄ AH – + AH3• is a slow process more shifted to the right in DMF/TBAP electrolyte medium. AH-CH3 and AH-Na are clear evidence of the self-protonation reaction of AH2• –. Ca. 20 % of the initial moles of AH2 are converted into AH-CH3 in DMF/TBAP and NaClO4 as the electrolyte systems. CPE of AH2 in ACN/NaClO4 results in reaction products that are insoluble and are coating the electrode, ca. 80 % of the initial moles of AH2 are recuperated as pure AH-Na. AH-CH3 and AH-Na contain the carbonyl-quinone groups in their structures. The applied potential does not modify these results. AH-CH3 and AH-Na are electrochemically (CV) characterised. The acidity of the quinone dye, the homogeneous protonation/deprotonation equilibriums, the intramolecular hydrogen bonding, and the easy air oxidation and protonation of some of the intermediates have led to the obtained results.

Rationally designed a silent AIE oxidation platform based on pillar[5]arene for [formula omitted] and vitamin C (Vc) sensor

The benefits of Vc for the body's typical metabolism have received adequate attention. However, effective probes for analyzing specific Vc are currently lacking. To monitor Vc levels, we design and create a novel luminescence-silent oxidation AIE fluorescent probe (2BCP@Fe) by interacting between a coumarin dual-functionalized fluorescent pillar[5]arene derivative and Fe3+ to monitor largescale Vc. The morphological transformation was achieved by adding a certain amount of aqueous solution into the BCP DMF solution. A fluorescence ‘turn-on‘ phenomenon was observed, which was caused by restricting intramolecular rotation.Meanwhile, SEM measurements supported the importance of the cation-π interaction between Fe3+ and BCP in this supramolecular process. Additionally, the supramolecular system (2BCP@Fe) can monitor H2PO4- ions through competitive contact and can operate as a “turn-on” fluorescent probe for Vc detection through the process of redox reaction. As a result, such a novel fabrication strategy might offer a prospective strategy for preparing the metal-modified macrocyclic host functional materials for sensing, catalysis, and other fields.