Explore the vast range of titles available.

Shift current is a steady-state photocurrent generated in non-centrosymmetric single crystals and has been considered to be one of the major origins of the bulk photovoltaic effect. The mechanism of this effect is the transfer of photogenerated charges by the shift of the wave functions, and its amplitude is closely related to the polarization of the electronic origin. Here, we report the photovoltaic effect in an organic molecular crystal tetrathiafulvalene- p -chloranil with a large ferroelectric polarization mostly induced by the intermolecular charge transfer. We observe a fairly large zero-bias photocurrent with visible-light irradiation and switching of the current direction by the reversal of the polarization. Furthermore, we reveal that the travel distance of photocarriers exceeds 200 μm. These results unveil distinct features of the shift current and the potential application of ferroelectric organic molecular compounds for novel optoelectric devices. The bulk photovoltaics refers to an effect whereby electrons move directionally in non-centrosymmetric crystals upon light radiation. Here, Nakamura et al. observe this effect in a ferroelectric organic charge-transfer complex, which shows large diffusion distance of photogenerated electrons over 200 µm.

A straightforward and efficient spectrum technique was created using Ortho- chloranil as the electron acceptor (-acceptor) in a charge transfer (CT) complex formation reaction to determine the concentration of famotidine (FMD) in solutions. Compared to the double-distilled blank solution, the reaction result detected a definite violet colour at a maximum absorption wavelength of 546 nm, For concentrations range 2—28 µg/ml, the technique demonstrated excellent compliance with Beer-Law and Lambert's, as evidenced by its molar absorptivity of 2159.648 L mol −1 cm –1 . Lower detection limits of 0.3024 µg/ml and 1.471 µg/ml, respectively, were discovered. The complexes of famotidine and Ortho- chloranil were found to have a 2:1 stoichiometry. Additionally, the suggested approach effectively estimated famotidine concentrations in pharmaceutical formulations, particularly in tablet form.

Aqueous rechargeable metal batteries are intrinsically safe due to the utilization of low-cost and non-flammable water-based electrolyte solutions. However, the discharge voltages of these electrochemical energy storage systems are often limited, thus, resulting in unsatisfactory energy density. Therefore, it is of paramount importance to investigate alternative aqueous metal battery systems to improve the discharge voltage. Herein, we report reversible manganese-ion intercalation chemistry in an aqueous electrolyte solution, where inorganic and organic compounds act as positive electrode active materials for Mn 2+ storage when coupled with a Mn/carbon composite negative electrode. In one case, the layered Mn 0.18 V 2 O 5 ·nH 2 O inorganic cathode demonstrates fast and reversible Mn 2+ insertion/extraction due to the large lattice spacing, thus, enabling adequate power performances and stable cycling behavior. In the other case, the tetrachloro-1,4-benzoquinone organic cathode molecules undergo enolization during charge/discharge processes, thus, contributing to achieving a stable cell discharge plateau at about 1.37 V. Interestingly, the low redox potential of the Mn/Mn 2+ redox couple vs. standard hydrogen electrode (i.e., −1.19 V) enables the production of aqueous manganese metal cells with operational voltages higher than their zinc metal counterparts. Multivalent metal batteries are considered a viable alternative to Li-ion batteries. Here, the authors report a novel aqueous battery system when manganese ions are shuttled between an Mn metal/carbon composite anode and inorganic or organic cathodes.

The acid-catalyzed reaction of benzo[ e ( g )] derivatives of 2,3,3-trimethylindolenines with o -chloranil leads to new 2-(benzo[ e ( g )]indolin-2-yl)-5,6,7-trichloro-1,3-tropolones and 2-(benzo[ e ( g )]indolin-2-yl)-4,5,6,7-tetrachloro-1,3-tropolones. Based on the results of PBE0/6-311+G(d,p) calculations, the structural and energetic characteristics of the tautomeric forms of the obtained 1,3-tropolones were determined. The structure of 2-(3,3-dimethyl-3 H -benzo[ g ]indolin-2-yl)-5,6,7-trichloro-1,3-tropolone was determined by X-ray diffraction analysis. The compounds obtained are capable of switching emission at 420–440 nm and 476–530 nm upon successive exposure to CN − and Hg 2+ ions in an acetonitrile solution. 2-(1,1-Dimethyl-1 H -benzo[ e ]indolin-2-yl)-5,6,7-trichloro-1,3-tropolone exhibited high in vitro cytotoxic activity against A431 skin cancer and H1299 lung cancer cell lines.

The properties of graphene nanoribbons (GNRs) -such as conductivity or semiconductivity, charge mobility and on/off ratio-depend greatly on their width, length and edge structure. Existing bottom-up methods used to synthesize GNRs cannot achieve control over all three of these parameters simultaneously, and length control is particularly challenging because of the nature of step-growth polymerization . Here we describe a living annulative π-extension (APEX) polymerization technique that enables rapid and modular synthesis of GNRs, as well as control over their width, edge structure and length. In the presence of palladium/silver salts, o-chloranil and an initiator (phenanthrene or diphenylacetylene), the benzonaphthosilole monomer polymerizes in an annulative manner to furnish fjord-type GNRs. The length of these GNRs can be controlled by simply changing the initiator-to-monomer ratio, achieving the synthesis of GNR block copolymers. This method represents a type of direct C-H arylation polymerization and ladder polymerization , activating two C-H bonds of polycyclic aromatic hydrocarbons and constructing one fused aromatic ring per chain propagation step.

Microbes in contaminated environments often evolve new metabolic pathways for detoxification or degradation of pollutants. In some cases, intermediates in newly evolved pathways are more toxic than the initial compound. The initial step in the degradation of pentachlorophenol by Sphingobium chlorophenolicum generates a particularly reactive intermediate; tetrachlorobenzoquinone (TCBQ) is a potent alkylating agent that reacts with cellular thiols at a diffusion-controlled rate. TCBQ reductase (PcpD), an FMN- and NADH-dependent reductase, catalyzes the reduction of TCBQ to tetrachlorohydroquinone. In the presence of PcpD, TCBQ formed by pentachlorophenol hydroxylase (PcpB) is sequestered until it is reduced to the less toxic tetrachlorohydroquinone, protecting the bacterium from the toxic effects of TCBQ and maintaining flux through the pathway. The toxicity of TCBQ may have exerted selective pressure to maintain slow turnover of PcpB (0.02 s ⁻¹) so that a transient interaction between PcpB and PcpD can occur before TCBQ is released from the active site of PcpB.

A reproducible, critical and simple spectrophotometric method for assay of RNB was investigated is based on (charge transfer complex) formation reaction of RNB with O-Chloranil reagent in the presence of sodium bicarbonate in ethanol to give a highly coloured species with maximal absorption at 440 nm, As well Beer's law was obeyed in the range of (5-50) µg.mL with a molar absorptivity of 1.21×104 L.mol−1.cm−1 and the limit of detection and quantitation were 0.059 and 0.242 µg.mL respectively. The (average recovery rate) was 101.65% and relative standard deviation (RSD) was better than 0.55%. In addition, it was ratio of 1:1. The method was successfully applied to assay of RNB in Diyala river water and waterproof case.

A new simple method is proposed for the spectrophotometric estimation of trimethoprim drug (TMP), depending on the formation of an n-π charge transfer complex between TMP acting as n-donor and o-chloranil acting as π-acceptor in ethanolic medium. The complex has a maximum absorbance at 379 nm. Beer’s law is applied within the limits of concentration of 5–60 μg/mL. The method is accurate, precise, and sensitive, as the average recovery was 101.57%. The relative standard deviation (RSD) was less than 3.03%, and the molar absorptivity was 1.11×104 L/mol.cm. The limit of the quantitation (LOQ) was 0.2323 μg/mL, and the limit of detection (LOD) was 0.0697 μg/mL. The complex was formed at a ratio of 1:1. TMP is usually found mixed with sulfamethoxazole in its pharmaceutical preparations, so the uniqueness of this method over others is that TMP can be estimated alone in tablets containing sulfamethoxazole and other excipients after the simple extraction. The method was contrasted favorably with the British Pharmacopoeia by computing the t-exp and F-test and other literature methods.

Sinopodophyllum hexandrum is a perennial anti-cancer medicinal plant as unique phytochemical composition podophyllotoxin, and it has special effects on the treatments of pneumonic, cervical and testicular cancers. Besides the podophyllotoxin, phenolic substances play a key role in the clinical practice. However, few reports were available in terms of the phenolic compositions and antioxidant activity. In this work, main phenolic compounds were quantified by RP-HPLC in seven organs from S. hexandrum . Simultaneously, the sodium borohydride/chloranil-based (SBC) method and the Folin-Ciocalteau colorimetric method were used to determine total flavonoids and total phenols contents, respectively. The antioxidant activity of the different organs was further assessed by three methods (DPPH method, ABTS method and FRAP method). Phenolic compositions/total flavonoids contents/total phenols contents/antioxidant activity was observed to have significant differences among different organs ( P <0.05), but have a consistent changing rule viz. rhizome>root>fruit>flower>leaf>stem>petiole. Furthermore, a correlation analysis was employed and indicated that a positive correlation existed between phenolic compositions contents and antioxidant activity. Obviously, rhizome had high phenolic compositions contents and strong antioxidant activity with the low DPPH IC50 value of 23.52 μg/mL, high ABTS value of 1137.82 μmol equiv. Trolox/g and high FRAP value of 685.76 μmol equiv. Trolox/g. Therefore, rhizome is recommended as a preponderant medicinal part, and root is proposed as an alternative raw material resource for natural antioxidant agents in functional food, medicine and chemicals. This study can provide a new insight into the utilization extension of S. hexandrum resources.

Most chemiluminescence (CL) reactions usually generate only one-step CL, which is rarely dependent on the highly reactive and biologically/environmentally important hydroxyl radicals ( • OH). Here, we show that an unprecedented two-step CL can be produced by the carcinogenic tetrachloro-1,4-benzoquinone (also known as p -chloranil) and H 2 O 2 , which was found to be well-correlated to and directly dependent on its two-step metal-independent production of • OH. We proposed that • OH-dependent formation of quinone-dioxetane and electronically excited carbonyl species might be responsible for this unusual two-step CL production by tetrachloro-1,4-benzoquinone/H 2 O 2 . This is a unique report of a previously undefined two-step CL-producing system that is dependent on intrinsically formed • OH. These findings may have potential applications in detecting and quantifying • OH and the ubiquitous polyhalogenated aromatic carcinogens, which may have broad biological and environmental implications for future research on these types of important species.