Quinone Structure Research Articles

SuFEx-Functionalized Quinones via Ruthenium-Catalyzed C-H Alkenylation: A Potential Building Block for Bioactivity Valorization.

Herein, we describe the Ru-catalyzed C-H alkenylation of 1,4-naphthoquinones (1,4-NQs), resulting in 1,4-naphthoquinoidal/SuFEx hybrids with moderate to good yields. This method provides a novel route for direct access to ethenesulfonyl-fluorinated quinone structures. We conducted mechanistic studies to gain an in-depth understanding of the elementary steps of the reaction. Additionally, we evaluated the prototypes against trypomastigote forms of T. cruzi, leading to the identification of compounds with potent trypanocidal activity.

Deciphering the key drivers of oxidative potential during ammonium nitrate-mediated aqueous-phase photoreaction of methoxyphenols

Methoxyphenols are released in abundance from lignin pyrolysis during biomass burning. Apart from being atmospheric brown carbon components that absorb solar radiation and warm the climate, methoxyphenols also undergo photoreaction in the atmospheric aqueous phase and form secondary organic aerosols (aqSOA). While efforts have been devoted to understanding chemical evolutions and climate-related optical properties of aqSOA, their potential health impacts also require timely investigations. Herein, we used the dithiothreitol (DTT) assay to investigate oxidative potential of the aqSOA formed during the 8-hr aqueous-phase photoreaction of two typical methoxyphenols, vanillin and vanillic acid, under pH 2 or 8, and with or without ammonia nitrate. The highest DTT consumption rates (RDTT) were observed for vanillin aqSOA formed in the presence of ammonia nitrate and at pH 8. At pH 2, although RDTT increased rapidly during early photoreaction, it reduced after prolonged illumination. High resolution mass spectrometry and linear regression analyses were performed to correlate the photoreaction products with the observed RDTT. Results showed that three products that present quinone, lactone and dimer structures, respectively, should be the key drivers of elevated RDTT for aqSOA formed during photoreaction of vanillin and vanillic acid alone, whereas it shifted to the nitrogen-containing aromatic compounds during their photoreaction with ammonia nitrate. Our results have revealed the role of nitrogen-containing aromatic compounds in the oxidative potential and health effects of aqSOA from biomass burning, which was rarely recognized before and warrants immediate assessments.

Synthesis and Magnetic Property of 4,4′‐(2,6‐Anthracenediyl)bis(2,6‐di‐tert‐butylphenoxyl) Diradicaloids

AbstractAnthracene based phenoxyl diradicaloids are synthesized. The UV–vis spectra of them give absorption maxima around 700 nm attributes to the extended quinone structure. The diradical characters y of them are estimated as ∼0.6 from their static magnetic susceptibility and absorption maxima. The extended π‐conjugated anthracene‐linker enhances the diradical characters compared to the phenylene linker. It is noteworthy that these enhanced diradical characters are accomplished without steric effects.

Electrochemical identification of reductive enantiomers in wood channels: A low-cost and scalable platform for chiral sensing

Chirality, an inherent characteristic of natural substances (such as sugars, peptides, proteins, and nucleic acid), plays a vital role in human metabolism and exerts substantial impacts. In general, chiral drugs can display diverse pharmacological and pharmacokinetic properties. One enantiomer may exhibit therapeutic effects, while the other could cause adverse reactions. Selective recognition of enantiomers is thus a significant task in the biomolecular and pharmaceutical fields. Despite the development of several chiral identification techniques, low-cost enantioselective sensing methods remain highly desirable. Here, we designed and developed an electrochemical sensing device for reductive enantiomer identification using natural wood channels as the substrate. The wood channels were endowed with oxidase-like activity through the in-situ growth of cerium oxide nanoparticles (CeO2). Chiral recognition capability was further introduced by incorporating a layer of chiral ZIF-8 (L-ZIF) as the chiral selector. To demonstrate the enantioselective sensing performance, 3,4-dihydroxyphenylalanine (DOPA) enantiomers were employed as model analytes. Due to the oxidase-like activity and the confinement effect of the proposed channels, the captured DOPA enantiomers were effectively oxidized to their quinone structure, and the Ce(IV) in CeO2 was reduced to Ce(III). These changes led to alterations in the surface charge of the channels, thereby modulating their ionic transport properties. This sensing mechanism also proved useful for the identification of other reductive enantiomers. The limits of detection for l-DOPA and d-DOPA were determined as 2.41 nM and 1.56 nM, respectively. The resulting wood channel-based sensing device not only can be used for the recognition and detection of reductive enantiomers, but also is expected to be applied to the non-electochemically active substances. Moreover, this study offers a novel type of solid-state channel material with low cost, reproducibility, and easy accessibility for electrochemical chiral sensing.

Water-Writing Pattern on PEDOT:PSS Inverse Opal Films through the Synergistic Effect of Morphology/Conformation Transition.

Poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) has received tremendous attention in the energy field owing to its high conductivity, ease of processing, biocompatibility, and low cost-effectiveness. Combining PEDOT:PSS and photonic crystals (PCs) is expected to promote the development of high-performance optoelectronic devices. The conductivity of PEDOT:PSS at present can only be measured through specific equipment, and the visualization of optoelectronic integration still remains a challenge. In this study, various patterned PEDOT:PSS inverse opal (PEDOT:PSS-IO) films are constructed by associating the conductivity of PEDOT:PSS with the structural color of PCs based on the synergistic effect of morphology/conformation transition, which achieves the visualization of optoelectronic integration. Morphology transition of the PEDOT:PSS-IO film alters from the interconnected to gradual closure pore structure, accompanied by an unusual blueshift of the stopband, which can be attributed to the collapse/reconstruction of the frame of the PEDOT:PSS-IO film. Conformation transition of PEDOT chains converts from the benzene to quinone structure, accompanying an enhancement of conductivity, which resulted from PSS removal and secondary doping. Under the induction of a polar solvent, the PEDOT:PSS-IO film brings the changes in optical/electrical dual-signals based on the synergistic effect of morphology/conformation transition. This phenomenon can be developed for the creation of a conductive PC pattern by using a polar solvent (water) as an ink, which is beneficial for the visualization of optoelectronic integration. This work provides essential significance for the fabrication of functional optoelectronic devices.

Biochar derived from animal and plant facilitates synergistic transformation of heavy metals and phosphorus in sewage sludge composting

This study investigated the influence of plant-derived biochar (PB) and animal-derived biochar (AB) on behavior of heavy metals and phosphorus fractions during sewage sludge composting. PB was highly effective in reducing the bioavailability of Zn and Cu by 39% and 50%, respectively, while AB decreased the bioavailability of Pb (30%) and Cd (12%). Both biochar increased available phosphorus by over 38%. Acid extractable and bioavailable Pb in AB, and water-soluble, oxidizable and total Zn, acid extractable and oxidizable Cu in PB were positively correlated with moderately resistant organic phosphorus (MROP). Besides, in AB, Cd had strong and positive correlation with highly resistant organic phosphorus (HROP). This suggested biochar facilitated the formation of stable organometallic complexes through binding metal ions to phosphorus fractions, with notable differences based on biochar source. FT-IR showed biochar promoted humification, with PB enhancing carboxyl and polysaccharide formation, while AB encouraged quinone and aryl ether structures. These surface functional groups on the biochar likely contributed to heavy metals and phosphorus binding through chelation, adsorption, and electron shuttling.

Active Oxygenated Structure‐Intensified CO2 Capture Enables Efficient Electrochemical Ethylene Production Over Carbon Nanofibers

AbstractThe pursuit of high efficacy C−C coupling during the electrochemical CO2 reduction reaction remains a tremendous challenge owing to the high energy barrier of CO2 activation and insufficient coverage of the desired intermediates on catalytic sites. Inspired by the concept of capture‐coupled CO2 activation, we fabricated quinone‐grafted carbon nanofibers via an in situ oxidative carbonylation strategy. The quinone functionality of carbon nanofibers promotes the capture of CO2 followed by activation. At a current density of 400 mA cm−2, the Faradaic efficiency of ethylene reached 62.9 %, and a partial current density of 295 mA cm−2 was achieved on the quinone‐rich carbon nanofibers. The results of in situ spectroscopy and theoretical calculations indicated that the remarkable selectivity enhancement in ethylene originates from the quinone structure, rather than the electronic properties of Cu particles. The interaction of quinone with CO2 increases the local *CO coverage and simultaneously hinders the co‐adsorption of *H on Cu sites, which greatly reduces the energy barrier for C−C coupling and restrains subsequent *CO protonation. The modulation strategy involving specific oxygenated structure, as an independent degree of freedom, guides the design of functionalized carbon materials for tailoring the selectivity of desired products during the CO2 capture and reduction.

Active Oxygenated Structure-Intensified CO2 Capture Enables Efficient Electrochemical Ethylene Production Over Carbon Nanofibers.

The pursuit of high efficacy C-C coupling during the electrochemical CO2 reduction reaction remains a tremendous challenge owing to the high energy barrier of CO2 activation and insufficient coverage of the desired intermediates on catalytic sites. Inspired by the concept of capture-coupled CO2 activation, we fabricated quinone-grafted carbon nanofibers via an in situ oxidative carbonylation strategy. The quinone functionality of carbon nanofibers promotes the capture of CO2 followed by activation. At a current density of 400 mA cm-2, the Faradaic efficiency of ethylene reached 62.9 %, and a partial current density of 295 mA cm-2 was achieved on the quinone-rich carbon nanofibers. The results of in situ spectroscopy and theoretical calculations indicated that the remarkable selectivity enhancement in ethylene originates from the quinone structure, rather than the electronic properties of Cu particles. The interaction of quinone with CO2 increases the local *CO coverage and simultaneously hinders the co-adsorption of *H on Cu sites, which greatly reduces the energy barrier for C-C coupling and restrains subsequent *CO protonation. The modulation strategy involving specific oxygenated structure, as an independent degree of freedom, guides the design of functionalized carbon materials for tailoring the selectivity of desired products during the CO2 capture and reduction.

Improving the Performance of Si/PEDOT:PSS Hybrid Solar Cells with More Economical and Environmentally Friendly Alcohol Ether Solvents.

The photoelectric characteristics of poly(3,4-ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS) films significantly affect the power conversion efficiency and stability of Si/PEDOT:PSS hybrid solar cells. In this paper, we investigated PEDOT:PSS modification with alcohol ether solvents (dipropylene glycol methyl ether (DPM) and propylene glycol phenyl ether (PPH)). The reduction of PSS content and the transformation of the PEDOT chain from benzene to a quinone structure in PEDOT:PSS induced by doping with DPM or PPH are the reasons for the improved conductivity of PEDOT:PSS films. DPM and PPH doping improves the quality of silicon with the PEDOT:PSS heterojunction and silicon surface passivation, thereby reducing the surface recombination of charge carriers, which improves the photovoltaic performance of Si/PEDOT:PSS solar cells. Comparing the power conversion performance (PCE) and air stability of Si/PEDOT:PSS solar cells with DPM (13.24%), DPH (13.51%), ethylene glycol (EG, 13.07%), and dimethyl sulfoxide (DMSO, 12.62%), it is suggested that doping with DPM and DPH can replace DMSO and EG to enhance the performance of Si/PEDOT:PSS solar cells. The EG and DMSO solvents not only have a certain toxicity to the human body but also are not environmentally friendly. In comparison to DMSO and EG, DPM and DPH are more economical and environmentally friendly, helping to reduce the manufacturing cost of Si/PEDOT:PSS solar cells and making them more conducive to their commercial applications.

Steroids, Tri- and Meroterpenoids with a Quinone Structure—A Review

Steroids, Tri- and Meroterpenoids with a Quinone Structure—A Review

Effect of tannic/gallic acid-iron dyeing treatment on surface color and light fastness of bamboo veneer

Currently, the quest for bamboo materials with high color fastness, rich colors and environmental friendliness is rapidly rising due to its potential applications in construction, furniture and decoration. However, finding an easy-to-operate and environmentally friendly dye for bamboo is a necessary task because of the difficulty in treating the dyeing waste liquid of acid dyes and the complexity of the production process of reactive dyes.Five formulations involving metal polyphenol complexes were employed to straightforwardly produce eco-friendly dyed bamboo and the impact of various formulations on the light aging resistance of the dyed veneers was examined. The results indicated that the light resistance of bamboo veneer dyed with the solution containing only FeSO4·7H2O and tannic acid reached level 4, surpassing the undyed bamboo veneer by three levels. The mechanism of enhanced lightfastness of dyed bamboo veneer was elucidated by XPS analysis. The polyphenol iron complex serves a dual purpose: it absorbs ultraviolet rays and scavenges free radicals within the system. Additionally, it reduced the oxidation of phenolics in the substrate, transforming them into dark-colored quinone structures. This process enhanced the light-aging resistance of the finishing materials. Therefore, this work provides a simple and environmentally friendly method for changing the color of bamboo and provides a new idea for the selection of dyes for bamboo dyeing in actual production.

Light-induced quinone conformation of polymer donors toward 19.9% efficiency organic solar cells

UV-light illumination converts the aromatic conformation of polymer donors into a rigid quinone structure, resulting in compact fibrillar aggregation of the active layer to achieve a maximum efficiency of 19.9% of single-junction organic solar cells.

Recognition of Oligonucleotide C by Polydopamine-Coated Solid-State Nanopores.

Selective recognition of short oligonucleotides at the single-molecule level is particularly important for early disease detection and treatment. In this work, polydopamine (PDA)-coated nanopores were prepared via self-polymerization as a solid-state nanopore sensing platform for the recognition of oligonucleotide C (PolyC). The PDA coating possesses abundant active sites, such as indole, amino, carboxyl, catechol, and quinone structures, which had interactions with short oligonucleotides to slow down the translocation rate. PDA-coated nanopores selectively interact with PolyC20 by virtue of differences in hydrogen bonding forces, generating a larger blocking current, while polyA and polyT demonstrated very small blockings. At the same time, PDA-coated nanopores can sensitively distinguish PolyC with different lengths, such as 20, 14, and 10 nt. The functionalization of PDA on the solid-state nanopore provides an opportunity for the rational design of the recognition surface for biomolecules.

Secondary interfacial reaction of p-aminodiphenylamine enables polyamide reverse osmosis membrane with enhanced and regenerative chlorine resistance

Developing polyamide (PA) reverse osmosis (RO) membrane with chlorine resistance is of great significance for simplifying pretreatment processes and saving operating costs. Herein, we constructed an active layer capable of highly chlorine stability and regenerative chlorine resistance by introducing p-amino diphenylamine (p-ADA) with redox activity via a facile secondary interfacial reaction (s-IR) on PA membrane surface. The calculation of resistance-in-series model indicated that the introduction of p-ADA facilitated the increase of NaCl transmembrane resistance without sacrificing membrane permeance. Chlorination experiments under acid conditions proved the protection effect of p-ADA grafted layer due to its oxidation resistance, avoiding the direct attack by free chlorine to amide bonds of polyamide membrane. By virtue of the convertible modality of the p-ADA molecule between the quinone and benzene structures during redox process, modified membranes presented the capability of regenerative chlorine resistance. After the “chlorination-reduction” cycle experiments, the normalized flux of modified membranes remained 0.522 while contrasted PA membranes showed a flux of 0.278; and the corresponding normalized NaCl rejection of modified membranes maintained at 0.998 significantly higher than that of PA membranes (0.963). This study presents a straightforward and efficient approach to enhance the chlorine resistance of PA RO membranes.

Model-Driven Design of Redox Mediators: Quantifying the Impact of Quinone Structure on Bioelectrocatalytic Activity with Glucose Oxidase.

Successful application of emerging bioelectrocatalysis technologies depends upon an efficient electrochemical interaction between redox enzymes as biocatalysts and conductive electrode surfaces. One approach to establishing such enzyme-electrode interfaces utilizes small redox-active molecules to act as electron mediators between an enzyme-active site and the electrode surface. While redox mediators have been successfully used in bioelectrocatalysis applications ranging from enzymatic electrosynthesis to enzymatic biofuel cells, they are often selected using a guess-and-check approach. Herein, we identify structure-function relationships in redox mediators that describe the bimolecular rate constant for its reaction with a model enzyme, glucose oxidase (GOx). Based on a library of quinone-based redox mediators, a quantitative structure-activity relationship (QSAR) model is developed to describe the importance of mediator redox potential and projected molecular area as two key parameters for predicting the activity of quinone/GOx-based electroenzymatic systems. Additionally, rapid scan stopped-flow spectrophotometry was used to provide fundamental insights into the kinetics and the stoichiometry of reactions between different quinones and the flavin adenine dinucleotide (FAD+/FADH2) cofactor of GOx. This work provides a critical foundation for both designing new enzyme-electrode interfaces and understanding the role that quinone structure plays in altering electron flux in electroenzymatic reactions.

Further revealing reaction mechanism on the oxidation behavior of the vanillyl alcohol

Theoretical investigation on the oxidation reaction of vanillyl alcohol is accomplished by density functional theory. The three oxidation reaction pathways were identified, and the three reactive sites on the vanillyl alcohol are H on phenolic hydroxyl group, H on hydroxymethyl group, and H on methoxyl group. Theoretical calculation and analysis were carried out about the twenty-nine possible reaction channels. The potential energy surface information of every reaction channels was obtained at the B3LYP/6–311 + G(d,p) level, including geometry structure optimization and frequency calculation of the stationary point. The oxygen reaction mechanism of vanillyl alcohol is further revealed in detail at molecular and atomic levels. The calculation results show that the H on phenolic hydroxyl group is easier to be oxidized to phenoxy radical among three reactive sites. Vanillin can produce vanillyl alcohol through a reversible process. The reaction channel of addition by oxygen on one para-position of quinone structure of phenoxy radical is more kinetically favorable than that of the two ortho-positions. Revealing the oxidation mechanism of vanillyl alcohol will provide a new understanding of the catalytic oxidation of lignin model materials and a theoretical basis for the process optimization of efficient utilization of biomass energy.

Double redox-active quinone molecules functionalized a three-dimensional graphene network for high-performance supercapacitor

As a well-known two-dimensional material, graphene is widely used as an electrode material in energy storage devices. However, the tendency of the agglomeration or restacking of graphene sheets limit the properties. To overcome this issue, redox-active molecules can be introduced that inhibit the stacking of graphene sheets and impart excellent pseudocapacitance properties. In this study, we design a three-dimensional (3D) graphene network anchored with redox-active 2,5-(di-p-phenylenediamine)-1,4-benzoquinone (DBP) and hydroquinone (HQ) (DFGN) using a facile one-step hydrothermal process. The covalent binding and absorption between redox-active molecules and graphene sheets reduce restacking and enable promising pseudocapacitance through reversible faradic reactions of quinone and aniline structures. Among all the samples, DFGN-1 shows the best specific capacitance (667.3 F/g at 1 A/g), high-rate capability (89.2 % even up to 50 A/g), and good cycling stability. Furthermore, DFGN-1 is also employed as an electrode material to construct flexible solid-state supercapacitors (FSSCs), which exhibit great specific capacitance (441 F/g at 0.5 A/g), excellent cycling stability (90.6 % after 10,000 cycles at 10 A/g) and high-energy density of 9.29 Wh/kg at a power density of 96.22 W/kg. Interestingly, FSSCs also display great mechanical flexibility in bending and twisting states and extraordinary mechanical durability even after being bent 5000 times. Overall, double redox-active quinone molecules functionalized 3D graphene network provides a novel tactic to construct promising potential electrodes in energy storage applications.

Simple and rapid detection of tyrosinase activity with the adjustable light scattering properties of CoOOH nanoflakes.

Tyrosinase (TYR), as an important biological enzyme, has been widely used in synthetic biology, medical hairdressing, environmental detection, biological sensors, and other fields. In clinical practice, tyrosinase activity is an important indicator for detecting melanoma. Therefore, the detection of tyrosinase activity is of great importance. Based on the polyphenol oxidase activity of tyrosinase, a simple and rapid detection method was proposed based on the adjustable light scattering properties of cobalt hydroxyl oxide nanoflakes (CoOOH NFs). It was found that the amount and size of CoOOH NFs decreased due to the redox reaction mediated by catechol (CC), resulting in a lower light scattering signal of CoOOH NFs. However, in the presence of tyrosinase, catechol was oxidized to a quinone structure, resulting in the reduced decomposition of CoOOH NFs and recovered light scattering signal, which was developed for the quantitative detection of tyrosinase activity. It was found that in the range of 10-400 U/L, the light scattering intensity wascorrelated linearly with tyrosinase activity, and the limit of detection was 6.71 U/L (3σ/k). To verify the feasibility of the proposed method in clinical samples, thespiked recovery experiments were carried out with human serum samples, which showed recovery rates between 93.0% and 104.6%, suggesting the high accuracy. The proposed assay provides a simple and rapid method for detection of a natural enzyme based on the adjustable light scattering properties of CoOOH nanoflakes, which lays the foundation for the development of various enzyme sensing applications in the future.

Identification of novel coenzyme Q10 biosynthetic proteins Coq11 and Coq12 in Schizosaccharomyces pombe

Coenzyme Q (CoQ) is an essential component of the electron transport system in aerobic organisms. CoQ10 has ten isoprene units in its quinone structure and is especially valuable as a food supplement. However, the CoQ biosynthetic pathway has not been fully elucidated, including synthesis of the p-hydroxybenzoic acid (PHB) precursor to form a quinone backbone. To identify the novel components of CoQ10 synthesis, we investigated CoQ10 production in 400 Schizosaccharomyces pombe gene-deleted strains in which individual mitochondrial proteins were lost. We found that deletion of coq11 (an S.cerevisiae COQ11 homolog) and a novel gene designated coq12 lowered CoQ levels to ∼4% of that of the WT strain. Addition of PHB or p-hydroxybenzaldehyde restored the CoQ content and growth and lowered hydrogen sulfide production of the Δcoq12 strain, but these compounds did not affect the Δcoq11 strain. The primary structure of Coq12 has a flavin reductase motif coupled with an NAD+ reductase domain. We determined that purified Coq12 protein from S.pombe displayed NAD+ reductase activity when incubated with ethanol-extracted substrate of S.pombe. Because purified Coq12 from Escherichia coli did not exhibit reductase activity under the same conditions, an extra protein is thought to be necessary for its activity. Analysis of Coq12-interacting proteins by LC-MS/MS revealed interactions with other Coq proteins, suggesting formation of a complex. Thus, our analysis indicates that Coq12 is required for PHB synthesis, and it has diverged among species.

Immobilizing Quinone-Fused Aza-Phenazine into π-d Conjugated Coordination Polymers with Multiple-Active Sites for Sodium-Ion Batteries.

The development of coordination polymers with π-d conjugation (CCPs) provides ide prospects for exploring the next generation of environmental-friendliness energy storage systems. Herein, the synthesis, experimental characterizations, and Na-ion storage mechanism of π-d CCPs with multiple-active sites are reported, which use quinone-fused aza-phenazine (AP) and aza-phenazin (AP) as the organic ligands coordinated with the metal center (Ni2+ ). Among them, NiQAP as the cathode material exhibits impressive electrochemical properties applied in sodium-ion batteries (SIBs), including the high initial/stable discharge specific capacities (180.0/225.6 mAh g-1 ) at 0.05 A g-1 , a long-term cycle stability up to 10,000 cycles at 1.0 A g-1 with a high reversible capacity of 100.1 mAh g-1 , and good rate capability of 99.6 mAh g-1 even at 5.0 A g-1 . Moreover, the Na-ion storage mechanism of NiQAP is also performed by the density functional theory (DFT) calculation, showing multiple-active sites of C≐O and C≐N (in the quinone and phenazine structure) and NiO4 (in the coordination unit) for Na-ion storage. These results highlight the importance of organic electrode material with the coordination units and provide a foundation for further studying the CCPs with multiple active sites for energy storage systems.