The interplay of inverted redox potentials and aromaticity in the oxidized states of new pi-electron donors: 9-(1,3-dithiol-2-ylidene)fluorene and 9-(1,3-dithiol-2-ylidene)thioxanthene derivatives

Derivatives of 9-(1,3-dithiol-2-ylidene)fluorene (9) and 9-(1,3-dithiol-2-ylidene)thioxanthene (10) have been synthesised using Horner-Wadsworth-Emmons reactions of (1,3-dithiol-2-yl)phosphonate reagents with fluorenone and thioxanthen-9-one. X-ray crystallography, solution electrochemistry, optical spectroscopy, spectroelectrochemistry and simultaneous electrochemistry and electron paramagnetic resonance (SEEPR), combined with theoretical calculations performed at the B3P86/6-31G** level, elucidate the interplay of the electronic and structural properties in these molecules. These compounds are strong two-electron donors, and the oxidation potentials depend on the electronic structure of the oxidised state. Two, single-electron oxidations (E(1)ox < E(1)ox) were observed for 9-(1,3-dithiol-2-ylidene)fluorene systems (9). In contrast, derivatives of 9-(1,3-dithiol-2-ylidene)thioxanthene (10) display the unusual phenomenon of inverted potentials (E(1)ox > E(1)ox) resulting in a single, two-electron oxidation process. The latter is due to the aromatic structure of the thioxanthenium cation (formed on the loss of a second electron), which stabilises the dication state (10(2+)) compared with the radical cation. This contrasts with the nonaromatic structure of the fluorenium cation of system 9. The two-electron oxidation wave in the thioxanthene derivatives is split into two separate one-electron waves in the corresponding sulfoxide and sulfone derivatives 27-29 owing to destabilisation of the dication state.     

Efficient photodegradation of methylthioninium chloride dye in aqueous using barium tungstate nanoparticles

BaWO₄ nanoparticles were successfully used as the photocatalysts in the degradation of methylthioninium chloride (MTC) dye at different pH levels of aqueous solution. Pure phase of barium tungstate (BaWO₄) nanoparticles was synthesized by modified molten salt process at 500 °C for 6 h. Structural and morphological characterizations of BaWO₄ nanoparticles (average particle size of ~40 nm) were studied in details using powder x-ray diffraction (XRD), FTIR, Raman, energy-dispersive, electron microscopic, and x-ray photoelectron spectroscopy (XPS) techniques. Direct band gap energy of BaWO₄ nanoparticles was found to be ~3.06 eV from the UV–visible absorption spectroscopy followed by Tauc’s model. Photocatalytic properties of the nanoparticles were also investigated systematically for the degradation of MTC dye solution in various mediums. BaWO₄ nanoparticles claim the significant enhancement of the photocatalytic degradation of aqueous MTC dye to non-hazardous inorganic constitutes under alkaline, neutral, and acidic mediums.

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Graphical abstract BaWO₄ nanoparticles enhance the rate of photocatalytic degradation of organic dyes in various mediums.

     

Lyciumaside and Lyciumate: A New Diacylglycoside and Sesquiterpene Lactone from Lycium shawii

One new diacylglycoside named lyciumaside ( 1 ) and a new sesquiterpene lactone named lyciumate ( 2 ) were isolated from Lycium shawii Roem . & Schult . The structures of the two new compounds were elucidated based on 1D‐ (¹H‐ and ¹³C‐NMR and NOE) and 2D‐NMR (COSY, HSQC, and HMBC) spectroscopic techniques, and mass spectrometry (ESI‐MS). Preliminary evaluations demonstrated lyciumaside ( 1 ) possesses strong antioxidant activity with an IC₅₀ = 30 μg/ml (80% inhibition) while it was inactive in α‐glucosidase and urease enzymes assays.     

Simple,rapid, and clean condensation of sulfonamide and maleic anhydride derivatives: Synthesis of novel 1H- Pyrrole-2,5-diones under heterogeneous conditions

H₆P₂W₁₈O₆₂ is used as an efficient catalyst for the synthesis of novel N-substituted sulfonyl maleimides (1H-Pyrrole-2,5-diones) via the condensation of sulfonamide and maleic anhydride derivatives. The Dawson heteropolyacid was used with a catalytic amount of 2 mmol% in acetonitrile at reflux. The reuse of H₆P₂W₁₈O₆₂ as heterogeneous catalyst several times without decrease in their activity, short reaction times, easy isolation of desired products with good to excellent yields shows the advantages of this novel methodology.     

Synthesis and Characterization of New Light Emitter Symmetrical Phenoxazinium Salt and Its Potential Application as Sensor for Assessment of Hg2+

The sensitization of the excited triplet state of a novel symmetrical Bis(dialkylamino)phenoxazinium salt was developed in the presence of Hg²⁺. This effect was used to determine the concentration of Hg²⁺ in different water samples. The phenoxazinium salt sensor was characterized by different spectroscopic tools such as: UV, FTIR, NMR and fluorescence spectra. The sensor has an emission band at 347 nm in DMSO. Hg²⁺ in DMSO at pH 5.6 can remarkably quench the fluorescence intensity of the sensor at 347 nm and a new band was appeared at 436 nm due to the strong complex formation between Hg²⁺ and sensor. The quenching of the band intensity at 347 and the enhancement of the intensity of the new band at 436 were used to determine the Hg²⁺ in different waste water samples. The dynamic range found for the determination of Hg²⁺ concentration is 8.7?×?10^-10 – 1.4?×?10^-6 mol L^?1 with a detection limit of 5.8?×?10^?10 mol L^?1 and quantification detection limit of 1.8?×?10^-9 mol L^-1.     

Synthesis and Biological Evaluation of a Novel Series of Chalcones Incorporated Pyrazole Moiety as Anticancer and Antimicrobial Agents

A newly synthesized series of chalcone derivatives containing pyrazole rings were synthesized and evaluated for their cytotoxic activities in vitro against several human cancer cell lines. Most of the prepared compounds showed potential cytotoxicity against human breast cancer cell lines MCF-7, HEPG-2, and HCT-116. Also the compounds were evaluated as antimicrobial agents. The three compounds 3, 4, and 5 were proved to be better anticancer agents than the positive standard doxorubicin with IC50 values (4.7, 4.4, and 3.9???g/ml) against the same human cancer cell lines, whereas compounds 5 and 6 showed the most active antimicrobial compounds in comparison to the other chalcones.     

Phase unwrapping algorithm based on singularity compensation for three-dimensional shape measurement

Three-dimensional (3D) imaging continues to attract much research interest for its wide applications. In 3D shape measurement, the phase carries information about the object. However, phase mapping is ambiguous as the extracted phase is returned in a form that suffers from 2π phase jumps. In this case, the phase data must be unwrapped to be fit for use. Furthermore, sometimes the presence of noise in the measured data, in which many singular points (SPs) are found, makes general phase unwrapping algorithms fail to produce accurate unwrapped results. For this reason, we propose a new phase unwrapping method for dynamic 3D shape measurement. The new algorithm is based on compensating the singularity of discontinuity sources. It uses direct compensators for adjoining SP pairs and uses rotational compensators for other SP pairs. The proposed algorithm has been evaluated and compared with past phase unwrapping methods. Results show that the proposed method gives satisfactory unwrapped results with a low computation time.     

The Bertlmann–Martin Inequality and Spin Degrees of Freedom

The Bertlmann–Martin inequality based on the dipole sum rule is revisited taking into account the spin degrees of freedom. We consider 1 and 2 particles of spin 1/2 in a mean field, adding a spin dependent interaction. The derivation of the inequality relies on the closure relation. We discuss the effect of the Pauli principle, and the restrictions it imposes on the use of the closure relation. The problem is exemplified by a simple model based on harmonic forces. Moreover, in the 2 particle case, the model we use is separable in the relative and centre of mass coordinates. In this case, we show that for operators connecting only singlet states, their sum rule can be calculated in the usual way, i.e. via the double commutator of this operator with the Hamiltonian. An upper bound can also be obtained by using the Bertlmann–Martin technique. This is not possible for operators involving a transition between singlet and triplet states.     

Variation in fat soluble vitamins (A,D, E,K) in in vitro and ex vitro germinated chickpea (Cicer arietinum L.) seedlings,as revealed by high performance liquid chromatography

In present communication, effect of in vitro and ex vitro culture conditions was investigated on the yield of fat soluble vitamins in chickpea (Cicer arietinum L.) seedlings analyzed by high performance liquid chromatography (HPLC). Amongst the tested culture conditions (in vitro and ex vitro); in vitro condition proved to be highly effective compared to ex vitro. We noticed a significant difference in vitamins D (ergocalciferol), E (α-tocopherol) and K (phylloquinone) yields in chickpea seedlings grown in two different conditions. Maximum yield with a linear increase in vitamins D and E was noticed upto 9 days old in vitro grown seedlings. Vitamin K yield was also high in in vitro grown seedlings with a linear increase upto 11 days. Although, vitamin A was not detected, the vitamin production in germinating seeds was, therefore, age and culture condition dependent. The study revealed that, in in vitro condition, the level of fat soluble vitamins enhanced in seedlings, which could be used for human consumption with value addition in the diet of vegetarians.     

Site-specific immobilisation of gold nanoparticles on a porous monolith surface by using a thiol-yne click photopatterning approach

A monolith surface with alkyne functionality was reacted with cysteamine through radical-mediated thiol-yne addition reaction providing a hydrophilic and chelating interface. Photochemical initiation affords spatial control over the reaction site and further site-specific immobilisation of gold nanoparticles.