Atomically Engineered Chlorine Coordination of Iron in Active Centers for Selectively Catalytic HO Decomposition Toward Efficient Antitumor-Specific Therapy.

The intervention of endogenous HO via nanozymes provides a potential antitumor-specific therapy; however, the role of the nanozyme structure in relation to the selective decomposition of HO to hydroxyl radicals (•OH) is yet to be fully understood, which limits the development of this therapeutic approaches. Herein, an iron single-atom nanozyme (Fe─NCl─C SAzyme) is reported, which is prepared through precise Fe─Cl coordination based on the construction of a characteristic Fe-containing molecule. Fe─NCl─C exhibits efficient catalytic HO decomposition (2.

Theoretical investigation on triphenylamine coelenteramide for bioinspired OLED application using thiophene rings in π-bridge.

As light emitter of most marine organisms bioluminescence, coelenteramide (CLM) received much attention due to some exciting application in the field of bioinspired organic light-emitting devices (OLED). Nevertheless, native CLM only emit bright blue light. In order to obtain light of different colors, two CLM analogues, TPA-CLM and TPA-TP-CLM were designed by introduction of triphenylamine group and (thiophene) π-bridge.

Theoretical Study on the Formation and Decomposition Mechanisms of Coelenterazine Dioxetanone.

Bioluminescence has been drawing broad attention due to its high signal-to-noise ratio and high bioluminescence quantum yields, which has been widely applied in the fields of biomedicine, bioanalysis, and so on. Among numerous bioluminescent substrates, coelenterazine is famous for its wide distribution. However, the oxygenation reaction mechanism of coelenterazine is far from being completely understood.

An ultrastable La-MOF for catalytic hydrogen transfer of furfural: activation of the surface.

The poor stability of metal-organic frameworks (MOFs) severely limits their catalytic application. The activation of stable MOF catalysts not only simplifies the catalytic process, but also reduces energy consumption. Therefore, it is meaningful to explore the activation of the MOF surface in the actual reaction process.

Ultrahigh Metal Content Carbon-Based Catalyst for Efficient Hydrogenation of Furfural: The Regulatory Effect of Glycerol.

The development of high-content non-noble metal nanocatalysts is important for multiphase catalysis applications. However, it is a challenge to solve the agglomeration in the preparation of high-content metal catalysts. In this paper, a carbon-based catalyst (Co@CN-G-600) with 71.

Mechanistic Insight into the Chemiluminescent Decomposition of Dioxetanone and the Chemiluminescent, Fluorescent Properties of the Light Emitter of Bioluminescence.

bioluminescence has been increasingly used in bioimaging, bioanalysis, and biomedicine, due to high quantum yield and high signal-to-noise ratio. However, there is still no consensus regarding different aspects of the chemiluminescent mechanism of this system, which impairs the development of new applications. Herein, we have used a theoretical DFT and TD-DFT approach to (i) determine the identity of the dioxetanone species responsible for efficient chemiexcitation and (ii) identify the bioluminescent emitter and determine if light-emission occurs from the fluorescent or chemiluminescent state.

Bottom-Up Construction of Active Sites in a Cu-N-C Catalyst for Highly Efficient Oxygen Reduction Reaction.

Bottom-up construction of efficient active sites in transition metal-nitrogen-carbon (M-N-C) catalysts for oxygen reduction reaction (ORR) from single molecular building blocks remains one of the most difficult challenges. Herein, we report a bottom-up approach to produce a highly active Cu-N-C catalyst with well-defined Cu-N coordination sites derived from a small molecular copper complex containing Cu-N moieties. The Cu-N moieties were found to be covalently integrated into graphene sheets to create the Cu-N active sites for ORR.

Facile Synthesis, Characterization of Poly-2-mercapto-1,3,4-thiadiazole Nanoparticles for Rapid Removal of Mercury and Silver Ions from Aqueous Solutions.

Industrial pollution by heavy metal ions such as Hg and Ag⁺ is a universal problem owing to the toxicity of heavy metals. In this study, a novel nano-adsorbent, i.e.

Highly Productive Synthesis, Characterization, and Fluorescence and Heavy Metal Ion Adsorption Properties of Poly(2,5-dimercapto-1,3,4-thiadiazole) Nanosheets.

Poly(2,5-dimercapto-1,3,4-thiadiazole) (PBT) nanosheets were synthesized by chemical oxidative synthesis under mild conditions. The media, oxidant species, monomer concentrations, oxidant/monomer molar ratio, and temperature were optimized to achieve higher yields and better performance. The molecular structure, morphology, and properties of the nanosheets were analyzed by Fourier transform infrared (FT-IR), ultraviolet-visible (UV-Vis), and fluorescence spectroscopies, wide-angle X-ray diffraction (WAXD), matrix-assisted laser desorption/ionization/time-of-flight (MALDI-TOF) mass spectrometry, X-ray photoelectron spectroscopy (XPS), scanning electronic microscopy (SEM), transmission electron microscopy (TEM), and simultaneous thermogravimetry and differential scanning calorimetry (TG-DSC).

Theoretically obtained insight into the mechanism and dioxetanone species responsible for the singlet chemiexcitation of Coelenterazine.

Coelenterazine is a widespread bioluminescent substrate for a diverse set of marine species. Moreover, its imidazopyrazinone core is present in eight phyla of bioluminescent organisms. Given their very attractive intrinsic properties, these bioluminescent systems have been used in bioimaging, photodynamic therapy of cancer, as gene reporter and in sensing applications, among others.

A Computational Investigation of the Equilibrium Constants for the Fluorescent and Chemiluminescent States of Coelenteramide.

In spite of recent advances in understanding the mechanism of coelenterate bioluminescence, there is no consensus about which coelenteramide specie and/or state are the light emitter. In this study, a systematic investigation of the geometries and spectra of all possible light emitters has been performed at the TD ωB97XD/6-31+G(d) level of theory, including various fluorescent and chemiluminescent states in vacuum, in a hydrophobic environment and in aqueous solution. To deduce the most probable form of the fluorescent and chemiluminescent coelenteramide emitter, the equilibrium constants for the fluorescent and chemiluminescent states connecting the various species have been calculated.

Catechol degradation on hematite/silica-gas interface as affected by gas composition and the formation of environmentally persistent free radicals.

Environmentally persistent free radicals (EPFRs) formed on a solid particle surface have received increasing attention because of their toxic effects. However, organic chemical fate regulated by EPFRs has rarely been investigated, and this information may provide the missing link in understanding their environmental behavior. Previous studies have suggested that the reduction of transition metals is involved in EPFRs formation.

The effect of micro-environment on luminescence of aequorin: the role of amino acids and explicit water molecules on spectroscopic properties of coelenteramide.

Despite the fact that the luminescence reaction mechanism of aequorin has been intensively investigated, details in luminescence such as the effect of important amino acids residues and explicit water molecules on spectroscopic properties of coelenteramide remain unclear. In this work, the effect of amino acids residues His16, Tyr82, Trp86, Phe113, Trp129, Tyr132, explicit water molecules Wat505 and Wat405 on the spectral properties of CLM(-) has been studied by CAM-B3LYP, TD M06L and TD CAM-B3LYP methods in hydrophobic environment and aqueous solution. In hydrophobic environment, the amino acids or water molecules have no significant effect on the absorption.

Poly(1-amino-5-chloroanthraquinone): highly selective and ultrasensitive fluorescent chemosensor for ferric ion.

Poly(1-amino-5-chloroanthraquinone) (PACA) was firstly synthesized by a chemically oxidative interfacial polymerization. The PACA has been developed as a fluorescent sensor for the determination of Fe(III) in semi-aqueous solution at pH 7.0.

Diaqua-bis-(4,4'-bipyridine-κN)bis-(2,4,5-trifluoro-3-hy-droxy-benzoato-κO)manganese(II).

In the title compound, [Mn(C(7)H(2)F(3)O(3))(2)(C(10)H(8)N(2))(2)(H(2)O)(2)], the Mn(II) ion, situated on a centre of inversion, has a distorted octa-hedral coordination geometry and is coordinated by two N atoms from two 4,4'-bipyridine ligands, two O atoms from two 2,4,5-trifluoro-3-hy-droxy-benzoate ligands and two water mol-ecules. Inter-molecular O-H⋯N hydrogen bonds link the mol-ecules into a chain along the a axis. Inter-actions between neighboring chains occur through O-H⋯O hydrogen bonds, which link the chains into a two-dimensional supra-molecular network parallel to the ac plane.

Theoretical investigation on the origin of yellow-green firefly bioluminescence by time-dependent density functional theory.

The question whether the emitter of yellow-green firefly bioluminescence is the enol or keto-constrained form of oxyluciferin (OxyLH(2)) still has no definitive answer from experiment or theory. In this study, Arg220, His247, adenosine monophosphate (AMP), Water324, Phe249, Gly343, and Ser349, which make the dominant contributions to color tuning of the fluorescence, are selected to simulate the luciferase (Luc) environment and thus elucidate the origin of firefly bioluminescence. Their respective and compositive effects on OxyLH(2) are considered and the electronic absorption and emission spectra are investigated with B3LYP, B3PW91, and PBE1KCIS methods.

A time-dependent density functional theory investigation on the origin of red chemiluminescence.

Is the resonance-based anionic keto form of oxyluciferin the chemical origin of multicolor bioluminescence? Can it modulate green into red luminescence? There is as yet no definitive answer from experiment or theory. The resonance-based anionic keto forms of oxyluciferin have been proposed as a cause of multicolor bioluminescence in the firefly. We model the possible structures by adding sodium or ammonium cations and investigating the ground- and excited-state geometries as well as the electronic absorption and emission spectra.