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Retrosynthetically designed and syntheses of three unprecedented core modified N‐confused porphyrinoids exhibiting vis‐NIR absorption with tunable aromaticity is reported. Controlled modification of types of oxidants (chloranil vs. DDQ) has led to the isolation of 18π‐aromatic porphyrinoid 7 (upon chloranil oxidation) while DDQ oxidation has led to 18 e σ‐aromatic porphyrinoids 8 and 9. All the three SN3 hybrid N‐confused porphyrinoids 7–9 have been thoroughly characterized via solution state spectroscopic measurements and in‐depth DFT studies for concluding π‐aromaticity of 7 and σ‐aromaticity of 8 and 9. While 7 could recognize the fluoride anion with high selectivity via deprotonation rather than an anion recognition based mechanism, acetate anion binding studies clearly revealed NH⋅⋅⋅AcO− H‐bonding interaction in the host‐guest complex [7‐AcO−] supporting an anion recognition based mechanism. Porphyrinoids 8 and 9 remain unsusceptible to anion recognition. The conformational preorganization and anion induced deprotonation leading to conformational reorganization have been extensively studied by solution state spectroscopic techniques and in depth DFT level theoretical calculations. [ABSTRACT FROM AUTHOR]

The study includes an accurate, rapid, simple method to determine the pure and pharmaceutical preparation (DAPSONE 100 mg) of dapsone at Schiff Base (Dapsone). This procedure is based on forming a charge transfer complex between dapsone Schiff base and chloranil reagent, which indicates maximum absorption at 374 nm. The optimal conditions for the complex formation were studied, including the type and volume of the reagent, the effect of acid and base, temperature, time, and preference of the suitable solvent, The linearity of the assay for the resulting complex ranged from 5.0 to 40.0 µg ml–1, with a Sandell sensitivity of 0.0409 µg/cm² and a molar absorptivity coefficient of 6.0337 × 10³ l/mol cm. The study evaluated the detection limit as 0.1086 µg/ml, while the quantitation limit is 0.3292 µg/ml. In contrast, the recovery percentage (Rec%) varied from 97.695 to 102.693%, with a relative standard deviation (RSD%) of less than 1.830%. Both direct and standard addition methods were used to determine dapsone in its pharmaceutical preparation, and the method was effectively applied. [ABSTRACT FROM AUTHOR]

Pentachlorophenol (PCP) is a widely used pesticide. However, whether PCP and its metabolite chloranil have endocrine-disrupting effects by inhibiting placental 3β-hydroxysteroid dehydrogenase 1 (3β-HSD1) remains unclear. The study used in vitro assays with human and rat placental microsomes to measure 3β-HSD activity as well as human JAr cells to evaluate progesterone production. The results showed that PCP exhibited moderate inhibition of human 3β-HSD1, with an IC 50 value of 29.83 μM and displayed mixed inhibition in terms of mode of action. Conversely, chloranil proved to be a potent inhibitor, demonstrating an IC 50 value of 147 nM, and displaying a mixed mode of action. PCP significantly decreased progesterone production by JAr cells at 50 μM, while chloranil markedly reduced progesterone production at ≥1 μM. Interestingly, PCP and chloranil moderately inhibited rat placental homolog 3β-HSD4, with IC 50 values of 27.94 and 23.42 μM, respectively. Dithiothreitol (DTT) alone significantly increased human 3β-HSD1 activity. Chloranil not PCP mediated inhibition of human 3β-HSD1 activity was completely reversed by DTT and that of rat 3β-HSD4 was partially reversed by DTT. Docking analysis revealed that both PCP and chloranil can bind to the catalytic domain of 3β-HSDs. The difference in the amino acid residue Cys83 in human 3β-HSD1 may explain why chloranil is a potent inhibitor through its interaction with the cysteine residue of human 3β-HSD1. In conclusion, PCP is metabolically activated to chloranil as a potent inhibitor of human 3β-HSD1. [Display omitted] • Pentachlorophenol is a moderate inhibitor of human and rat placental 3β-HSDs. • Pentachlorophenol is converted to chloranil that is a potent inhibitor of human 3β-HSD1. • Chloranil inhibits progesterone production by human JAr cells. • DTT can completely or partially antagonize chloranil-mediated inhibition of 3β-HSDs. [ABSTRACT FROM AUTHOR]

Ceritinib (CER) is a potent drug that has been recently approved by the Food and Drug Administration for the treatment of patients with non-small cell lung cancer harboring the anaplastic lymphoma kinase mutation gene. The existing methods for the quality control of CER are very limited and suffer from limited analytical throughput and do not meet the requirements of the green analytical principles. This study presented the first-ever development and validation of three innovative green and high-throughput microwell spectrophotometric methods (MW-SPMs) for the quality control of CER in its dosage form (Zykadia® capsules). These MW-SPMs were based on the formation of colored N-vinylamino-substituted haloquinone derivatives of CER upon its reactions with each of chloranil, bromanil, and 2,3-dichloro-1,4-naphthoquinone in the presence of acetaldehyde. The optimized procedures of the MW-SPMs were established, and their analytical performances were validated according to the ICH. The linear range of the MW-SPMs was 5–150 µg/mL, with limits of quantitation of 5.3–7.6 µg/mL. The accuracy and precision of the MW-SPMs were proved, as the average recovery values were 99.9–101.0%, and the relative standard deviations did not exceed 1.8%. The three methods were applied to the determination of CER content in Zykadia® capsules and drug content uniformity testing. The greenness of the MW-SPMs was proved using three different metric tools. In addition, these methods encompassed the advantage of high-throughput analysis. In conclusion, the three methods are valuable tools for convenient and reliable application in the pharmaceutical quality control units for CER-containing capsules. [ABSTRACT FROM AUTHOR]

A ferrocene‐based capsule is spontaneously and quantitatively formed in water by the assembly of bent amphiphiles carrying two ferrocene units. The disassembly and assembly of the new organometallic capsule, with a well‐defined and highly condensed ferrocene core, are demonstrated by chemical redox stimuli in a fully reversible fashion under ambient conditions. In contrast to previously reported multiferrocene assemblies, only the present capsule efficiently encapsulates typical organic/inorganic dyes as well as electron‐accepting molecules in water. As a result, unusual host‐guest charge‐transfer (CT) interactions, displaying relatively wide absorption bands in the visible to near‐infrared region (λ=650–1350 nm), are observed upon the encapsulation of acceptors (i.e. chloranil and TCNQ). The resultant encapsulation‐induced CT interactions can be released by a redox stimulus through the disassembly of the capsule. [ABSTRACT FROM AUTHOR]

Vanadium oxide (V2O5) is intercalated by tetrachlorobenzoquinone (TCB) through a one-step solvothermal method in an N-methylpyrrolidone (NMP)/water solvent mixture. The insertion and synergy of TCB and NMP widen the lattice and expand crystal particles, promoting Zn2+ ion transfer and coordination, which endow s-NMP–TCB–V2O5 with an improved capacity of 452 mA h g−1 as well as outstanding capacity retention of 85.6% after 1500 cycles. [ABSTRACT FROM AUTHOR]

Herein, we report the impregnation of chloranil into activated carbon micropores using scCO2. The sample prepared under 105 °C and 15 MPa showed a specific capacity of 81 mAh gelectrode−1, except for the electric double layer capacity at 1 A gelectrode-Polytetrafluoroethylene (PTFE)−1. Additionally, approximately 90% of the capacity was retained even at 4 A gelectrode-PTFE−1. [ABSTRACT FROM AUTHOR]

[Display omitted] • Flowerlike Co-PTA-400(Ar) MOF could be used as efficient catalyst for TCBQ-H 2 O 2 CL reaction. • The catalysis mechanism of the CL reaction was illustrated. • The CL system was used for sensitive detection of TCBQ in the environmental waters. Tetrachlorobenzoquinone (TCBQ) as one of the most toxic quinones has potential risk of causing canceration, and the monitoring of TCBQ in the environment is of significant importance. In this study, a flowerlike Co-PTA-400(Ar) metal organic frameworks (MOF) catalyzed TCBQ-H 2 O 2 chemiluminescence (CL) system was established for sensitive determination of trace TCBQ in environmental waters. The reaction between TCBQ and H 2 O 2 can result in weak CL emission, and the CL signal was enhanced about 10-fold using flowerlike Co-PTA-400(Ar) as catalyst. The luminescence mechanism was investigated through kinetic studies and free radical scavenging experiments. The strong CL emission of TCBQ mainly relied on the generation of abundant •OH by the catalysis of Co-PTA-400(Ar). This strategy allows to develop a highly sensitive method for the determination of TCBQ in the linear range of 1 ∼ 50 μM, with a detection limit of 0.56 μM (3 σ). The proposed method was applied for analysis of three spiked water samples with recoveries ranging from 95.7% to 100.5%. This method offering the advantages of rapid analysis, low costs, and high sensitivity, is appealing for detection of TCBQ in environmental waters. [ABSTRACT FROM AUTHOR]

Oxidation of bis(ortho -stibinoaryl)amine with chloranil leads to a bis(stiborane) molecule that spontaneously undergoes irreversible transformation into an ionized, cyclized stibonium antimonate isomer. [Display omitted] Oxidation of a bis-stibinoaryl amine (2) with chloranil leads first to formation of a crystallographically observed bis-stiboranoraryl amine (3a) which then undergoes isomerization to an ionic tetraarylstibonium antimonate (3b). The isomerization proceeds at different rates in different solvents, but a univariate explanation of solvent effects is not evident. The antimonate anion in 3b can be exchanged for a fluoride, resulting in a neutral fluorostiborane (4), and further to a triflate in an ionic tetraarylstibonium triflate (5). Compound 5 displays strong binding of fluoride in tetrahydrofuran. Structures of 3a , 3b , 4 , and 5 were determined by single-crystal X-ray diffraction. [ABSTRACT FROM AUTHOR]

Acenequinone-fused porphyrins show remarkable long wavelength absorption, low-lying LUMO orbital and uniform π,π-stacking, enabling the potential applications as opto-electronic materials and catalysts. At present, the synthesis of large quinone fused porphyrins remains challenging. To address this, the cycloaddition reactions of naphthoquinone-fused porphyrin (Ni4NQ), followed by oxidative aromatization, have been employed. Through Diels-Alder reaction with perylenes in the presence of chloranil, a series of perylenequinone-fused porphyrins (1Ni–4Ni) have been synthesized with an overall yield above 70 %. Later, the tri-adduct 3Ni underwent 1,3-dipolar cycloaddition with nitrile oxide and the following DDQ oxidation to outcome the unsymmetrical tetra-adduct 5Ni. Although the peripheral perylenequinones fusion in 1Ni – 4Ni has limited impact on the absorption with respect to the naphthoquinone-fused counterpart Ni4NQ , introduction of an isoxazole via 1,3-cycloaddition (5Ni) leads to a bathochromic Q band. This result has been rationalized by theoretical calculations. Additionally, the incorporation of perylenequinone units gives rise to intense intermolecular π,π-stacking and CH-π interactions within the crystal packing. The self-assembly behavior using a good/bad solvent strategy are structural dependence. The tri-perylenequinone-fused porphyrins 3Ni formed spherical architecture, while tetraperylenequinone-fused porphyrin 4Ni afforded cubic or petal-type assemblies. Bulky quinone-fused porphyrins: We have reported the construction of perylenequinone-fused porphyrin via programmed cycloaddition reactions (e.g. [4 + 2]- and 1,3-dipolar cycloaddition) of naphthoquinone-fused porphyrins. The bulky quinone units induce tight π,π-interactions with the nearby molecules. [Display omitted] • A series of bulky quinone-fused porphyrins were constructed via programmed cycloaddition reactions. • All synthesized compounds exhibited intense absorbance in the NIR region. • The bulky quinone units induce tight π,π-interactions. • The self-assembly behaviors showed structural dependence. [ABSTRACT FROM AUTHOR]

We propose a simple data-analysis scheme to determine the coupling constant and the asymmetry parameter of nuclear quadrupolar interactions in field-swept nuclear magnetic resonance (NMR) for static powder samples. This approach correlates the quadrupolar parameters to the positions of the singularities, which can readily be found out as sharp peaks in the field-swept pattern. Moreover, the parameters can be determined without quantitative acquisition and elaborate calculation of the overall profile of the pattern. Since both experimental and computational efforts are significantly reduced, the approach presented in this work will enhance the power of the field-swept NMR for yet unexplored quadrupolar nuclei. We demonstrate this approach in 33S in α-S8 and 35Cl in chloranil. The accuracy of the obtained quadrupolar parameters is also discussed. [ABSTRACT FROM AUTHOR]

Proton‐coupled electron transfer (PCET) is of key importance in modern synthetic chemistry. Redox‐active guanidines were established by our group as valuable alternatives to toxic high‐potential benzoquinones in a variety of different PCET reactions. In this work, the PCET reactivity of a series of 1,4‐bisguanidino‐benzenes varying in their redox potentials and proton affinities is evaluated. The relevant redox and protonation states are fully characterized, and the compounds sorted with respect to their PCET reactivity by comparative PCET experiments supplemented by quantum‐chemical calculations. Depending on the studied reactions, the driving force is either electron transfer or proton transfer; thereby the influence of both processes on the overall reactivity could be assessed. Then, two of the PCET reagents are applied in representative oxidative aryl‐aryl coupling reactions, namely the intramolecular coupling of 3,3"‐4,4"‐tetramethoxy‐o‐terphenyl to give the corresponding triphenylene, the intermolecular coupling of N‐ethylcarbazole to give N,N'‐diethyl‐3,3'‐bicarbazole, and in the oxidative lactonization of 2‐[(4‐methoxyphenyl)methyl]‐benzoic acid. Under mild conditions, the reactions proceed fast and efficient. Only small amounts of acid are needed, in clear contrast to the corresponding coupling reactions with traditional high‐potential benzoquinones such as DDQ or chloranil requiring a large excess of a strong acid. [ABSTRACT FROM AUTHOR]

The kinetics of the reaction of phenylnitroso oxide, para-CH3-, para-CH3O-, and para-Br-phenylnitroso oxides with benzoquinones in acetonitrile at room temperature was studied by flash photolysis. Both nitroso oxide isomers were involved in the reaction, the rate constants for the cis forms being higher than for the trans isomers for all compounds under study. The reactivity of arylnitroso oxides (ArNOO) with benzoquinones was found to be dual. The electron-donating substituents in the ArNOO molecule increase the reactivity of both conformers with 1,4-benzoquinone, 2-chloro-1,4-benzoquinone, and chloranil. Arylnitroso oxides exhibited electrophilic properties in the reaction with duroquinone, which was determined from the positive slope of the Hammett dependence for the trans isomers of ArNOO (ρ = 0.68 ± 0.08, r = 0.994). The constants ρ for the reaction of the cis isomers with 1,4-benzoquinone (–1.5 ± 0.2, r = 0.990), 2-chloro-1,4-benzoquinone (–2.0 ± 0.2, r = 0.995), and chloranil (–4.8 ± 0.6, r = 0.98) and for the reaction of trans isomers with chloranil (–2.8 ± 0.3, r = 0.990) increased in magnitude with the electron deficiency of the double bond. Along with the negative slope of the Hammett dependence, they suggest a nucleophilic attack of nitroso oxide on benzoquinone. For the reaction of trans-nitroso oxides with 2-chloro-1,4-benzoquinone and 1,4-benzoquinone, the Hammett dependence is nonlinear. [ABSTRACT FROM AUTHOR]

The neutral-to-ionic phase transition in the mixed-stack charge-transfer complex tetrathiafulvalenep-chloranil (TTF-CA) has been studied by pressure-dependent infrared spectroscopy up to p = 11 kbar and down to low temperatures, T = 10 K. By tracking the C=O antisymmetric stretching mode of CA molecules, we accurately determine the ionicity of TTF-CA in the pressure-temperature phase diagram. At any point, the TTF-CA crystal bears only a single ionicity; there is no coexistence region or an exotic high-pressure phase. Our findings shed new light on the role of electron-phonon interaction in the neutral-ionic transition. [ABSTRACT FROM AUTHOR]

Capsaicin and dihydrocapsaicin were modified at phenolic moieties and allylic of double-bond to provide seven capsaicin and dihydrocapsaicin derivatives. Their structures were assigned by spectroscopic techniques (1D-NMR and MS). All compounds were evaluated as histone deacetylase inhibitors via in vitro fluorometric assay at 100 µM. The results revealed that the chloranil derivatives were found to be best histone deacetylase inhibitors among the tested compounds with 86% and 87% inhibitions. In addition, molecular docking experiments of the active compounds with representatives of class I (HDAC1, HDAC2, HDAC3 and HDAC8), class IIa (HDAC4 and HDAC7) and class IIb (HDAC6) HDAC isoforms displayed potential isoform-selective HDAC inhibitors. Those data show a new method for providing the isoform-selective histone deacetylase inhibitors from common natural products. [ABSTRACT FROM AUTHOR]

Tetrathiafulvalene (TTF) and chloranil were introduced at the side chains of different cyclic tripeptides, which were self‐assembled into peptide nanotubes (PNTs). PNTs were used as scaffolds for alignment of the charge‐transfer complexes between TTF and chloranil, and they were prepared via two methods, one is that mixing a PNT comprising only TTF with a PNT comprising only chloranil (method 1), and the other is that one pot mixing of cyclic tripeptides with TTF and cyclic tripeptides with chloranil to be self‐assembled into PNTs (method 2). These PNTs naturally associated to form PNT bundles. The surface potentials of the PNT bundles became larger for the PNTs carrying charge‐transfer complexes along the PNT (method 2) than those between PNTs (method 1). This bundle of PNT carrying charge‐transfer complexes along the PNT (method 2) showed a hysteresis response in the piezoelectric force curve with varying bias voltages according to piezoelectric force microscope measurements. [ABSTRACT FROM AUTHOR]

Objective: Two simple, rapid and sensitive methods were developed for determination of Erdosteine (ERD) in pure form as well as in their pharmaceutical formulations. Methods: The methods were based on formation of colored charge transfer complexes with ERD with chloranil (CA) and 7,7,8,8-tetracyanoquinodimethane (TCNQ). The obtained charge-transfer complexes were measured at 454 and 843 nm for CA and TCNQ methods, respectively. Optimization of different experimental conditions were investigated. Results: Beer's plots were obeyed in a general concentration range of 10-500 µg mL-1 and 20-600 µg mL-1 for CA and TCNQ methods, respectively. The validity of methods in terms of specificity, linearity, accuracy, precision, limit of detection and limit of quantitation were evaluated. Conclusion: The methods were applied successfully in the determination of ERD in capsule dosage forms. Developed new spectrophotometric methods have been found to be very practical and practical. The lack of complex sample preparation increases the applicability of the method. [ABSTRACT FROM AUTHOR]

A dispersive liquid-liquid microextraction combines with UV-V is spectrophotometry for the preconcentration and determination of Mefenamic acid in pharmaceutical preparation was developed and introduced. The proposed method is based on the formation of charge transfer complexation between mefenamic acid and chloranil as an n-electron donor and a p- acceptor, respectively to form a violet chromogen complex measured at 542 nm. The important parameters affecting the efficiency of DLLME were evaluated and optimized. Under the optimum conditions, the calibration graphs of standard and drug, were ranged 0.03 - 10 µg mL-1. The limits of detection, quantification and Sandell's sensitivity were calculated. Good recoveries of MAF Std. and drug at 0.05, 2.5, 7.5 and 10 µg mL-1 ranged 94.00 - 100.2%. The method was applied successfully to determine MFA in pharmaceutical preparation from different sources. [ABSTRACT FROM AUTHOR]

An oxidative annulation for the synthesis of 2,4-diarylquinolines from o -allylanilines is disclosed that uses recyclable reagent Chloranil- as the oxidant. The corresponding products are obtained in moderate to excellent yields. Furthermore, a one-pot access to 2,4-di-aryl-quinolines from easily available anilines and 1,3-diarylpropenes is described as a highly atom-efficient protocol that involves oxidative coupling, rearrangement, and oxidative annulation. [ABSTRACT FROM AUTHOR]

The early stages of the ring opening reaction of 1,3-cyclohexadiene to form its isomer 1,3,5-hexatriene, upon excitation to the ultrashort-lived 1 1B2 state, were explored. A series of one-color two-photon ionization/photoelectron spectra reveal a prominent vibrational progression with a frequency of 1350 cm-1, which is interpreted in a dynamical picture as resulting from the ultrafast wave packet dynamics associated with the ring opening reaction. Photoionization in two-color three-photon and one-color four-photon ionization schemes show an ionization pathway via the same ultrashort-lived 1 1B2 state, and in addition, a series of Rydberg states with quantum defects of 0.93, 0.76, and 0.15, respectively. Using those Rydberg states as probes for the reaction dynamics in a time-resolved pump-probe experiment provides a direct observation of the elusive 2 1A1 state that has been implicated as an intermediate step between the initially excited 1 1B2 state and the ground electronic state. The rise and decay times for the 2 1A1 state were found to be 55 and 84 fs, respectively. [ABSTRACT FROM AUTHOR]

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., (© 2024. The Author(s).)

A convenient, environmentally benign, metal- and catalyst-free protocol has been developed for the conversion of thioamides to the corresponding 1,2,4-thiadiazole derivatives with chloranil under ultrasound irradiation in water at room temperature. This paper describes a general procedure for the synthesis of different 1,2,4-thiadiazoles in excellent yield in short reaction time via sonochemistry. [ABSTRACT FROM AUTHOR]

It's highly desired to simultaneously immobilize enzymes and their electron mediators on electrode surface to fabricate integrated enzymatic electrodes for constructing enzyme-based bioelectrochemical devices. Herein, a facile and efficient immobilizing method has been developed using liquid-crystalline lipidic cubic phases (LCPs) coated on single-walled carbon nanotubes (SWCNTs) films as hostingmatrix. To demonstrate this, an integrated enzymatic electrode has been developed by co-hostingNAD+-dependent alcohol dehydrogenase (ADH) and the NADH-oxidizing electrocatalyst chloranil (2,3,5,6-tetrachloro-1,4-benzoquinone,TCBQ) into LCPs on CNTs for NADH detection and ethanol biosensing. In this study, TCBQ shows excellent electrocatalytic activity toward NADH electro-oxidation at a low overpotential of ca. 0.13 V (vs. Ag/AgCl) and the integrated enzymatic electrode displays fast response to ethanol oxidation. Under the optimal conditions, the built ethanol biosensor exhibits a wide linear dynamic range from 0.2 to 13 mM, low detection limit of 0.05 mM (S/N = 3), high sensitivity of 0.5188 µA mM-1, and high stability. Furthermore, the developed ethanol biosensor has been used to detect ethanol content in complex real samples including human blood, beer, red wine, and Chinese liquor with satisfactory results, suggesting its potential applications in analytical and biomedical measurements. [ABSTRACT FROM AUTHOR]

An effective, mild, and convenient method for the synthesis of 10 new substituted 9-methyl-6-aryl-[1,2,4]triazolo[4,3-a][1,8]naphthyridines (5a–j) by the oxidation of the corresponding 2-(2-ethylidenehydrazinyl)-3-aryl-1,8-naphthyridines (4a–j) using chloranil under conventional method has been described. The structures of synthesized compounds (5a–j) were established on the basis of their elemental analysis and spectral (IR, Mass, 13C- and1H-NMR) data. The new compounds were synthesized with the objective of studying their antibacterial activity. The reaction will be characterized by easy workup, good efficacy, simple purification of the products, and availability of catalyst. [ABSTRACT FROM AUTHOR]

Bound excited electronic states are observed in the anions of 7,7,8,8-tetracyanoquinodimethane (TCNQ), 2,5-dimethyl-N,N’-dicyanoquinodiimine (Me2–DCNQI), chloranil, and hexacyano-butadiene using electron photodetachment spectroscopy. Intensity dependence studies and two color experiments are consistent with a two-photon detachment mechanism. A mechanism is proposed to explain the observed photodetachment. The nature of the electronic state responsible for these excited states is discussed and other anions are suggested which should possess bound excited electronic states. [ABSTRACT FROM AUTHOR]

Resonance Raman spectra of o-chloranil were obtained by exciting the energetically lowest π–π* transition. Raman signals of three totally symmetric stretching modes (C=C, C=O, and C–C) showed pronounced intensity alterations. The intensity changes of these modes were analyzed using a dispersion formula which is based on the Kramers–Heisenberg–Dirac equation. Three-dimensional Franck–Condon integrals were calculated with the algorithm of Kupka and Cribb. The mathematical fitting of the experimentally derived spectra yielded the displacements of the potential curves along the considered normal coordinates and data of the Duschinsky mode mixing. The geometrical shifts along directions of ground-state normal coordinates were transformed to bond-length changes with the use of the eigenvector matrix L of the ground-state vibrations. L was obtained by a complete force field analysis. The excited-state geometry of o-chloranil is characterized by the contraction of the di-keto system accompanied by a weakening of the acrolein unit. The largest changes appear in the butadiene subsystem, where a conversion of bond order occurs between the double bonds and the single bond. [ABSTRACT FROM AUTHOR]

The crystal structure and the optical data of the (1:1) charge-transfer (CT) complex of tetrathiafulvalene (TTF) with 2,5-dichloro-p-benzoquinone (2,5Cl2BQ) are reported, yielding a full characterization of the ground state properties. The complex crystallizes in the triclinic space group P1, Z=1. TTF and 2,5Cl2BQ form mixed regular stacks along the b axis. The degree of ionicity ρ is ∼0.18, and the CT integral ∼0.22 eV. A detailed analysis of the optical data yields estimates of the strength of electron–molecular vibration coupling and of intersite electron–electron interactions. The latter has also been computed in the atom-in-molecule fractional charge approximation. The TTF-2,5Cl2BQ structure and microscopic parameters at ambient conditions are found to be rather similar to those of the extensively studied complex of TTF with tetrachloro-p-benzoquinone (CA). The different behavior of the two complexes under pressure (both exhibit a neutral–ionic phase transition, but ρ changes discontinuously for TTF–CA and continuously for TTF-2,5Cl2BQ) is ascribed to the competitive role of the Madelung energy and of the CT integral. [ABSTRACT FROM AUTHOR]

Raman and single crystal polarized reflectance spectra (from 400 to 10 000 cm-1) of the tetramethylparaphenylenediamine–chloranil (TMPD–CA) charge transfer complex are reported. A careful interpretation of the data leads one to estimate for TMPD–CA a degree of ionicity of 0.64 at room temperature, indicating a quasi-ionic ground state. Moreover, we show that the mixed stack formed by TMPD and CA is dimerized at all temperatures. The latter finding is substantiated by an a priori calculation of the infrared conductivity spectrum polarized along the stack axis. The calculation is based on a model taking into account the coupling of the molecular vibrations with the charge transfer excitations through the modulation of both on-site energies and charge transfer integrals; moreover the intrinsic intensity of the infrared active modes is introduced semiempirically. The spectral simulation finds a further application in interpreting the subtle spectral changes observed in correspondence with the TMPD–CA 250 K phase transition: it is suggested that the phase transition is a disorder–order, orientational one. An extensive comparison with the results previously obtained by other experimental techniques allows one to solve early contradictions and definitely clear up the nature of the ground state of this key charge transfer crystal. [ABSTRACT FROM AUTHOR]

Presents a study that examined the electron lifetime at the surface of several insulators. Methodology; Analysis of the current-voltage characteristics of the α-sulfur samples; Comparison of the electron lifetime in p-chloranil and red mercury iodide insulators.

Diagrammatic valence bond (DVB) theory is applied to charge–transfer (CT) excitations in ion–radical organic solids that, like TTF–chloranil, are close to the neutral–ionic (n–i) interface. Small but finite Mulliken integrals |t| in mixed regular donor–acceptor stacks lead to charge resonance among segments containing 2r adjacent ions and to a linear lowering of the CT absorption. Finite t and long range Coulomb interactions also lead, up to a critical value, to an ionicity jump Δq=qi-qn <1 between the neutral and ionic phases. The TTF–chloranil ionicities and CT absorption are fit with |t|=0.23 eV. Neither attractive nor repulsive interstrand Coulomb interactions affect the CT spectra at fixed ionicity in the mean field approximation. Direct DVB solutions to finite (2N≤18) donor–acceptor strands yield the n–i interface while 2N≤16 strands suffice for the CT absorption and intensity. [ABSTRACT FROM AUTHOR]

The first catalytic asymmetric cross‐dehydrogenative coupling of 2H‐chromenes with aldehydes using o‐chloranil (3,4,5,6‐tetrachloro‐1,2‐ benzoquinone) as an oxidant has been described. The organocatalytic process is tolerated with a broad range of structurally and electronically varied 2H‐chromenes and aldehydes with good yield and high enantiocontrol. The first catalytic asymmetric cross‐dehydrogenative coupling of 2H‐chromenes with aldehydes using o‐chloranil as an oxidant has been described. The organocatalytic process is tolerated with a broad range of structurally and electronically varied 2H‐chromenes and aldehydes with good yield and high enantiocontrol. [ABSTRACT FROM AUTHOR]

Abstract 2,3,7,8-Tetrachlorobenzo- p -dioxin (TCDD) exposure in utero had been shown to affect ovarian development and functions. However, its mechanism remained unknown. In this study, to investigate the effect of maternal exposure to TCDD on ovaries, the pregnant Sprague Dawley (SD) rats were treated with TCDD (100 ng/kg or 500 ng/kg) or only vehicle and corn oil on the day 8–14 of gestation through the gavage with a stainless-steel feeding needle (once a day). The vaginal opening and estrous cycle of female offspring rats (F1) were monitored twice a day. The ovarian histology, follicle counts, real-time PCR, western blotting and DNA methylation analysis about Gdf9 and Bmp15 were carried out in F1 rats. The results showed that exposure to TCDD (especially the dose of 500 ng/kg) in utero on GD8-14 might change the ovary weight, the concentration of E2 and FSH, the estrous cycles and the numbers of primordial and secondary follicles of the offspring rats. In addition, the mRNA and protein expression of GDF9 and BMP15 was down-regulated, while the methylation patterns of Gdf9 and Bmp15 were not affected. In conclusion, maternal exposure to TCDD could affect the ovary development and functions which were possibly associated with down-regulation of mRNA and protein expression of GDF9 and BMP15. However, the down-regulation was not related to the pattern of methylation of Gdf9 and Bmp15. [ABSTRACT FROM AUTHOR]

The first examples of stable phlorin analogues of dithiacorrphycene were synthesized by treating appropriate tetrapyrranes with two equivalents of trifluoroacetic acid in CH2Cl2 followed by oxidation with p‐chloranil. The oxidative coupling of tetrapyrrane resulted in the formation of two unexpected phlorin analogues of dithiacorrphycenes that differed from each other at the meso‐sp3‐carbon, and the two macrocycles were easily separated and isolated by column chromatography. The novel macrocycles were confirmed by X‐ray crystallography and characterized by HRMS, 1D and 2D NMR spectroscopy, absorption spectroscopy, cyclic voltammetry, and time‐dependent DFT studies. X‐ray structure analysis revealed the highly strained and distorted nature of the macrocycles. The macrocycles showed one ill‐defined absorption band at λ≈315 nm and a broad band at λ≈530 nm. Because both macrocycles possess two thiophene and two pyrrole rings with one ionizable inner NH, the cation‐sensing properties of the phlorin analogues of dithiacorrphycenes have been investigated. The phlorin analogues of dithiacorrphycenes act as specific chemodosimetric sensors for Fe3+ ions by converting phlorin analogues of dithiacorrphycenes into dithiacorrphycene. Making macrocycles: The first examples of the synthesis of phlorin analogues of dithiacorrphycenes are reported. Because both macrocycles possess two thiophene and two pyrrole rings with one ionizable inner NH, the cation‐sensing properties have been investigated found to act as chemodosimetric sensors for Fe3+ ions (see figure). [ABSTRACT FROM AUTHOR]

A theoretical approach is used to calculate wavelength dependence of displacement and velocity resolution in the technology of laser Doppler vibrometry (LDV). Mathematical description of a typical LDV system in the heterodyne arrangement is considered in this regard. Thermal noise and shot noise are assumed as the primary source of noise. Minimum target displacement and velocity which produce noise equivalent signal are considered as displacement and velocity resolution respectively. A theoretical linear relationship between laser wavelength and the mentioned resolutions is obtained when all other operational parameters of the LDV system are kept constant. The results of the present research are in good agreement with the earlier experimental researches conducted by others. [ABSTRACT FROM AUTHOR]

A colorimetric visual detection for melamine in milk, based on tetracyclopentyl calix[4]pyrrole-tetrachlorobenzoquinone assembly, was demonstrated. Color changes from purple to yellow occurred when a melamine-tetrachlorobenzoquinone complex was formed under optimized conditions. The formation and stability of the complex in a borate buffer was studied in detail. A 1:1 stoichiometric ratio was verified with UV-vis spectrometry, and a stability constant of 1.78 × 104 M-1 was calculated using nonlinear fitting. The colorimetric visual detection was demonstrated for melamine in pure solution and in a spiked milk sample, with respective sensitivities as low as 25 and 50 ppb. [ABSTRACT FROM AUTHOR]

Abstract: The crystal structure of [4‐damp])2[Cl4Q]3 (4‐damp=4‐dimethylamino‐N‐methylpyridinium, Cl4Q=tetrachloroquinone) salt is built up from slipped columnar stacks of quinoid rings composed of closely bound trimers with the intra‐trimer separation distance of 2.84 Å and total charge of −2 whereas the inter‐trimer distance is 3.59 Å. The individual rings exhibit partial negative charges that are distributed unevenly among the three Cl4Qs in the trimer. The strong interactions within a trimer (Cl4Q)32− have a partially covalent character with two‐electron/multicentered bonding, that is extended over three rings, plausibly termed as “pancake bonding”. The electron pairing within this multicentre bond leads to the fact that the crystals are diamagnetic and act as insulators. The studies of the structure and nature of bonding are based on X‐ray charge density analysis and density functional theory. [ABSTRACT FROM AUTHOR]

A new class of bioorthogonal reagents based on the cyclopentadiene scaffold is described. The diene 6,7,8,9-tetrachloro-1,4-dioxospiro[4,4]nona-6,8-diene (a tetrachlorocyclo-pentadiene ketal, TCK) is ambiphilic and self-orthogonal with remarkable stability. The diene reacts rapidly with a transcyclooctene and an endo-bicyclononyne, but slowly with dibenzoazacyclooctyne (DIBAC), allowing for tandem labeling studies with mutually orthogonal azides that react rapidly with DIBAC. TCK analogues are synthesized in three steps from inexpensive, commercially available starting materials. [ABSTRACT FROM AUTHOR]

The transition-metal-catalyzed C-H arylation of aromatic hydrocarbons represents a useful and ideal method for the production of biaryls and multiarylated aromatic compounds. We have previously reported the palladium-catalyzed direct C-H arylation of polycyclic aromatic hydrocarbons, such as phenanthrene, pyrene, and corannulene with various organosilicon, -borane, and -germanium compounds. In these reactions, o-chloranil proved to be an essential and unique promoter (stoichiometrically as an oxidant) and arylation occurred exclusively at the K-region. Herein, we report our mechanistic investigation of Pd/o-chloranil catalysis in C-H arylation of phenanthrene with trimethylphenylsilane by computational calculations. The results revealed that C-H arylation occurs through a sequence of transmetalation, carbometalation, and trans-β-hydrogen elimination steps. In addition, the triple role of o-chloranil as a ligand, oxidant, and base is also elucidated. [ABSTRACT FROM AUTHOR]

An attractive organic electrode material, poly (2-chloro-3,5,6-trisulfide-1,4-benzoquinone) (PCTB), as an active material for rechargeable lithium batteries was investigated. It was prepared by polymerization of chloranil through thioether bonds. Because the existence of C Cl in the product, PCTB exhibits a superior lithium-storage performance with high potential. A positive-electrode that incorporated PCTB showed a discharge capacity of 138.65 mAh/g at 30 mA/g with an average voltage of 2.72 V. [ABSTRACT FROM AUTHOR]

• Sulfuric acid modification was proposed to enhance WS 2 QDs' chemiluminescence. • Tetrachlorobenzoquinone boosted the chemiluminescence of modified WS 2 QDs-Na 2 SO 3. • A chemiluminescence platform was designed for tetrachlorobenzoquinone detection. As a representative intermediate in the migration and transformation of pentachlorophenol (PCP), tetrachlorobenzoquinone (TCBQ) is a carcinogenic halogenated quinone, which can threat human health. Chemiluminescence (CL) is a promising method in environmental analysis due to its high sensitivity, no background interference, and portable features. However, no CL platform for TCBQ determination was developed which may be owing to the weak CL intensity. Herein, a novel CL signal amplification strategy for tungsten disulfide quantum dots (WS 2 QDs) via sulfuric acid (SA) activation was proposed. The sulfuric acid-activated WS 2 QDs (SA-WS 2 QDs) exposed more active sites (W4+) and their CL emission with Na 2 SO 3 was 20 times stronger than that of untreated WS 2 QDs. More importantly, the CL emission was significantly enhanced with the introduction of TCBQ through generating electronically excited carbonyl species (λ em = 550 nm), and thus a sensitive and selective sensing method for TCBQ in practical water sample was established (linear range: 0.05–1 μM, the limit of detection: 2 nM). This study not only developed a simple, efficient, and sensitive method for TCBQ detection, but also proposed a green and feasible strategy to enhance the CL property of nanoparticles. [ABSTRACT FROM AUTHOR]

The new compound 1-(2-methoxyphenyl)piperazinium chloranilate (MPP.CA) was synthesized and studied by the single crystal X-ray diffraction method. Its structure was confirmed by infrared spectroscopy. The crystal structure consists of ribbons of chloranilate anions and 1-(2-methoxyphenyl)piperazinium cations linked together by NH…O hydrogen bonds. Two protons are transferred from a chloranilic acid molecule to the nitrogen of the piperazine in this structure. Measurements of AC conductivity as a function of frequency at different temperatures indicated the hopping conduction mechanism; in addition, the variation of dielectric constant as a function ofTconfirmed the transition phase indicated by the differential scanning calorimetry (DSC). The physico-chemical properties, UV-Vis, DSC and dielectric properties are described. Hirshfeld surface analyzes all the intermolecular interactions involved within the structure, which are important to stabilize the structure. [ABSTRACT FROM AUTHOR]

8, 9, 11-Trichloro-5 H -benzofuro[3,2- c ]carbazol-10-ol analogues have been synthesized by treating 2,3-dihydro-1 H -carbazol-4(9 H )-one with chloranil/fluoranil without any catalyst and is found to be applicable across a range of carbazolone substrates. A possible mechanism has been proposed. [ABSTRACT FROM AUTHOR]

Our previous studies illustrated tetrachlorobenzoquinone (TCBQ)-caused toxicities in neuron-like cells which imply its association with neurodegenerative disorders. Although it is known that TCBQ induces oxidative damage that in turn results in endoplasmic reticulum (ER) stress and apoptosis, it is unclear how TCBQ triggers the signaling switch from pro-survival (to restore cellular homeostasis) to pro-death (trigger apoptosis). Protein disulfide isomerase family proteins (PDIs) regulate the progress of various neurodegenerative disorders, including Parkinson's disease and Alzheimer's disease. We tested the hypothesis that subcellular translocation of PDIs implicates the survival/death signaling switch by inducing mitochondrial outer membrane permeabilization (MOMP). The rat pheochromocytoma PC12 cells were exposed to TCBQ, and the concentration-dependent ER stress was observed upon TCBQ treatment, as indicated by the increase in inositol-requiring kinase/endonuclease 1a (IRE1a) phosphorylation, C/EBP homologous protein (CHOP) expression, X-box-binding protein 1 (XBP1) splicing, and caspase 12 activation. Interestingly, pharmacological (or siRNA) abrogation of PDIA1/PDIA3 aggravated the loss of cell viability induced by the relatively low concentration (10 µM) of TCBQ. However, inhibition of PDIA1/PDIA3 rescued the high concentration (20 µM) of TCBQ-induced cell death. Further mechanistic study illustrated that PDIs initially acted to restore cellular homeostasis to pro-survival but that the constant ER stress promoted the signaling switch to pro-apoptotis by the release of PDIA1/PDIA3 from the ER lumen to induce Bak-dependent MOMP. Our findings suggested that subcellular translocation of PDIs determined the "life or death" fate of PC12 cells to TCBQ-induced oxidative insult. [ABSTRACT FROM AUTHOR]

The transformation and detoxification of halobenzoquinones (HBQs), a class of emerging disinfection byproducts (DBPs), was studied in the presence of amino acids (AAs). The reaction activity of three HBQs with AAs generally ranked as 2-chlorobenzoquinone (CBQ) < 2,6-dichlorobezoquinone (DCBQ) < tetrachloroquinone (TCBQ), consistent with their halogenation degree and the calculated electron affinity (EA) results. According to mass spectrometry and density functional theory (DFT) calculations, AAs can easily covalently incorporate into HBQs via nucleophilic addition (CBQ and DCBQ) or substitution (TCBQ) through C N C or C S C linkages. Hydroxylation, nucleophilic reaction and decarboxylation were proposed to be the three major reaction pathways for HBQs transformation with AAs. HBQs firstly underwent the spontaneous hydrolysis, resulting in OH-HBQs formation. Then, nucleophilic addition/substitution of AAs occurred on HBQs and OH-HBQs to produce AA-HBQs/AA-HBQs-OH adducts. These adducts were subsequently oxidized into their corresponding decarboxylated forms. Based on the results of Luminous bacterium Q67 acute toxicity test, the toxicity of HBQs solution greatly decreased with AAs presented. The toxicity change was well explained by the lowest unoccupied molecular orbital energy ( E LUMO ) of formed products. Notably, the step that AAs nucleophilic bonded with HBQs led to the highest rise of E LUMO , which should be the most effective pathway for HBQs detoxification. This study shows that binding with amino nitrogen compounds should be an important process for HBQs transformation and detoxification, which helps to better understand the fate of this typical DBP in surface water. [ABSTRACT FROM AUTHOR]