Folding of a Donor‐Containing Ionene by Intercalation with an Acceptor

Cationic ionenes that bear electron‐rich 1,5‐dialkoxynaphthalene (DAN) units within the alkylene segment were allowed to interact with different types of electron‐deficient, acceptor‐containing molecules in an effort to realize intercalation‐induced folding of the ionenes; the collapse of the chains was expected to occur in such a way that the donor and acceptor units become arranged in an alternating fashion. Several acceptor‐bearing molecules were prepared by the derivatization of pyromellitic dianhydride and naphthalene tetracarboxylic dianhydride with two different oligoethylene glycol monomethyl ether monoamines. This yielded acceptor molecules with different water solubility and allowed the examination of solvophobic effects in the folding process. UV/Vis spectroscopic studies were carried out by using a 1:1 mixture of the DAN–ionenes and different acceptor molecules in water/DMSO solvent mixtures. The intensity of the charge‐transfer (CT) band was seen to increase with the water content in the solvent mixture, thereby suggesting that the intercalation is indeed aided by solvophobic effects. The naphthalene diimide (NDI) bearing acceptor molecules consistently formed significantly stronger CT complexes when compared to the pyromellitic diimide (PDI) bearing acceptor molecules, which is a reflection of the stronger π‐stacking tendency of the former. AFM studies of drop‐cast films of different ionene–acceptor combinations revealed that compact folded structures are formed most effectively under conditions in which the strongest CT complex is formed.     

Pharmacological evaluation of isochromen-1-ones and their thioanalogues derived from anti-inflammatory drug ketoprofen

The 3-[1-(3-benzoylphenyl)ethyl]-1H-isochromen-1-one, 2 and their thio-analogues 3-[1-(3-benzoylphenyl)ethyl]-1H-isochromen-1-thione, 3 and 3-{1-[3-(benzothioyl) phenyl]ethyl}-1H-isochromen-1-one, 5 were successfully obtained in good yield and purity from anti-inflammatory drug ketoprofen, 1 and its thio analogue, 4. The compounds were successfully characterized by FT-IR, MASS, ¹HNMR and ¹³CNMR spectral techniques. The in vitro anti-inflammatory and anti-oxidant screening revealed that 3-[1-(3-benzoylphenyl) ethyl]-1H-isochromen-1-one, 2 possesses better anti-oxidant and anti-inflammatory activity whereas 3-(1-(3-benzoylphenyl)ethyl)-1H-isochromene-1-thione, 3 and 3-(1-(3-benzothioyl) phenyl] ethyl}-1H-isochromen-1-one, 5 showed moderate anti-oxidant activity in comparison to ketoprofen.     

Mechanistic Studies on the Roles of the Oxidant and Hydrogen Bonding in Determining the Selectivity in Alkene Oxidation in the Presence of Molybdenum Catalysts

When the molybdenum oxo(peroxo) acetylide complex [CpMo(O? O)(O)C?CPh] is used as a catalyst for the oxidation of olefins, completely different product selectivity is obtained depending on the oxidant employed. When tert‐butyl hydroperoxide (TBHP, 5.5 M ) in dodecane is used as the oxidant for the oxidation of cyclohexene, cyclohexene oxide is formed with high selectivity. However, when H₂O₂ is used as the oxidant, the corresponding cis‐1,2‐diol is formed as the major product. Calculations performed by using density functional theory revealed the nature of the different competing mechanisms operating during the catalysis process and also provided an insight into the influence of the oxidant and hydrogen bonding on the catalysis process. The mechanistic investigations can therefore serve as a guide in the design of molybdenum‐based catalysts for the oxidation of olefins.     

Determination of disulfiram by micellar liquid chromatography in illicit preparations

Presently, disulfiram is used in aversion therapy for recovering alcoholics. It acts by inhibiting aldehyde dehydrogenase, leading to high blood levels of acetaldehyde. A simple direct injection micellar liquid chromatographic procedure was developed to determine disulfiram in illicit preparations (ayurvedic, herbal, divine ash, and traditional medicine), as well as in pharmaceuticals and biological samples (urine). After application of a predictive optimization strategy, the proposed method was developed using a 0.1 M sodium dodecyl sulfate-butanol 4% (v/v) buffered to pH 7 as the mobile phase at a flow rate of 1 mL/min, an octyl silyl (C8) 150 mm column, and diode array detection at 248 nm. Under the above conditions, the analysis time was below 8 min. Validation studies were based on U.S. Food and Drug Administration guidelines. The LOD (3 x SD criterion) was 15 ng/mL and LOQ (10 x SD criterion) was 70 ng/mL for disulfiram. The intraday and interday precisions were below 3.5%, recoveries were in the range of 97-102%, and robustness was below 3%. The optimized and validated micellar liquid chromatographic method was successfully applied to the determination of disulfiram in ayurvedic, herbal, divine ash, and other samples. The procedure developed could also be used in the fields of QC, routine analysis, and pharmacokinetic studies.     

Modeling and design of 2D photonic crystal based Y type dual band wavelength demultiplexer

In this paper, photonic bandgap (PBG) induced wave guiding application of photonic crystals is exploited to design Dual Band Wavelength Demultiplexer (DBWD) for separating two telecommunication wavelengths, 1.31 and 1.55 μm. Two designs that use silicon rods in air and embedded air holes in silicon are realized for this purpose. Plane wave expansion (PWE) method and two dimension Finite Difference Time Domain (FDTD) methods are used to design and analyze the DBWD in Y type photonic crystal structure. Numerical analysis indicates that these designs enable the separation of two wavelengths with very high optical power extinction ratios. Other filter parameters like transmittance and quality factor are also calculated to confirm superior performance of the proposed design of photonic crystal based DBWD.     

Laser-Patterned Carbon-Supported Graphitic Carbon Nitride Quantum Dots for Flexible Nanozyme-Based Fluoride Sensor

Graphitic carbon nitride quantum dots (g-CNQDs)-based colorimetric sensors are typically solution-based and hence incompatible with wearable electronics. Today's competitive technology demands safe and reliable, high-performance sensors suitable for integration with sophisticated electronics—all at a low cost. Herein, a flexible and reusable solid-state fluoride ion sensor manufactured by combining the intriguing surface properties of laser-patterned carbon (LP-C) with the sensitivity of g-CNQDs is reported. LP-C is obtained by direct IR-laser writing onto polyimide films, and g-CNQDs are synthesized via a solvent-free and zero-waste green process. The hybrid of LP-C and g-CNQDs (g-CNQDs/LP-C), mimics the natural enzyme horseradish peroxidase and oxidizes the chromogenic substrate 3,3’,5,5’-tetramethylbenzidine in the presence of H₂O₂ in acidic media. The highly selective and user-friendly nanozyme sensors feature a lower limit of detection of 0.568 ± 0.006  × 10⁻⁶ m (23.8 ± 1.5 µg L⁻¹) with linearity in the range of 0.5 × 10⁻⁶ to 100  × 10⁻⁶ m . A sensing mechanism based on the electronic transitions of g-CNQDs and LP-C, the two variants of nitrogen-containing carbon used in this work, is established. Finally, the device is tested for fluoride ion sensing in natural water samples collected from the Uhl river in Mandi, India.     

Suitable Stress Waveforms for the Deformation-Induced Electronic Excitation in Crystals

A quantum mechanical approach is made to the deformation-induced electronic excitation in crystals. The ML intensity is assumed to be related to the transition probability P(m, n) from n^th to m^th state, and it may be expressed as I_ML = βP(m, n) where P(m, n) = 4π²/hα² |σ_mn (ω_mn)|² ·( n · μ )_mn·². It is shown that the ML excitation can take place only by the time-dependent applied stress. The ML excitation probability is analysed for different waveforms of the applied stress such as constant stress, δ-function, rectangular stress, single sided and double sided exponential stress, unit step function, external sinusoidal signals cos ω₀t and sin ω₀t, external exponential function, a periodic function and the stress of sequence of equidistant impulses of unit strength separated by a particular time. It is found that when the stress is a δ-function, a rectangular waveform, sinusoidal singals cos ω₀t and sin ω₀t or a sequence of equidistant impulses of unit strength and separated by a particular time, then there is a considerable probability of electronic excitation by the resonance transfer mechanism between the Fourier transform of the stress waveform and the frequency of the emitting electronic system i.e. (E₂ – E₁)/h.