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11.
A series of novel monoazo disperse dyes derived from the coupling of diazotized 2-aminobenzo[b]thiophene derivatives with N-arylmaleimides is described. The monoazo disperse dyes applied to nylon fabric and their dyeing performance has been assessed. These dyes have been found to give light yellow to reddish pink color shades with very good depth and levelness on nylon fabric. The dyed fabric shows moderate light fastness and excellent washing, rubbing, perspiration, and sublimation fastness. The percentage dyebath exhaustion on nylon fabric has been found to be good and acceptable. 相似文献
12.
The properties of precipitate-based copper sulphide electrodes are investigated. Solid-phase studies wre done by x-ray photoelectron spectroscopy and solution-phase studies by combined potentiometric and atomic absorptioni spectrometric techniques. The predominant valence state of copper in the copper sulphide samples is shown to be Cu(I), but Cu(II) can also be identified at the surfaces. The oxidation of the membrane surface results in dissolution of copper ion and a decrease in the Cu/S ratio in the solid phase; reduction of the surface causes sulphide dissolution and an increase in the Cu/S ratio. Application of anodic or cathodic curents was used to study the redox behaviour of the copper suphide memebrane. 相似文献
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14.
Zinc ion (Zn2+) is an important and a most useful biological trace nutrient responsible for the activity of several enzymes. Zn2+ concentrations in the environment as well as in the human body increase beyond permissible limits as a consequence of its mining and widespread industrial applications. Such excess Zn2+ concentrations are toxic to humans and many aquatic organisms. The magnetic inertness and spin paired electronic configuration of Zn2+ makes it hard to detect by common analytical techniques. Therefore, fluorometric detection using chemosensor is the most effective tool for the environmental and biological detection of Zn2+. We have developed a novel pyridine-constrained bis(triazole-linked hydroxyquinoline) ligand as a reversible fluorescent chemosensor for Zn2+. The symmetrical ligand is highly selective for Zn2+ and fluoresces brightly upon complexation compared with other metal ions based on chelation-enhanced fluorescence mechanism. Interestingly, free ligand can be regenerated by treating the ligand–Zn2+ complex with aqueous ammonia. 相似文献
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An efficient, straightforward and environmentally benign process has been developed for the synthesis of fluorenone and 1-tetralone derivatives using cyclic 1,3-dione, malononitrile and dialkylacetylenedicarboxylate as starting materials in aqueous medium. The reaction is favoured in presence of resorcin[4]arene which is effective as a reusable organocatalyst. The catalyst has been easily synthesized and characterized by 1H, 13C NMR, IR, XRD and HRMS analyses. Resorcin[4]arene afforded the resulted products in a shorter time and in good yields. The recyclability of the catalyst was established up to 6th cycle by FT-IR and SEM images. 相似文献
17.
Debanjan Chakraborty Shyamapada Nandi Rahul Maity Dr. Radha Kishan Motkuri Dr. Kee Sung Han Sean Collins Dr. Paul Humble Dr. James C. Hayes Prof. Tom K. Woo Dr. Ramanathan Vaidhyanathan Dr. Praveen K. Thallapally 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(55):12544-12548
Molecular confinement plays a significant effect on trapped gas and solvent molecules. A fundamental understanding of gas adsorption within the porous confinement provides information necessary to design a material with improved selectivity. In this regard, metal–organic framework (MOF) adsorbents are ideal candidate materials to study confinement effects for weakly interacting gas molecules, such as noble gases. Among the noble gases, xenon (Xe) has practical applications in the medical, automotive and aerospace industries. In this Communication, we report an ultra-microporous nickel-isonicotinate MOF with exceptional Xe uptake and selectivity compared to all benchmark MOF and porous organic cage materials. The selectivity arises because of the near perfect fit of the atomic Xe inside the porous confinement. Notably, at low partial pressure, the Ni–MOF interacts very strongly with Xe compared to the closely related Krypton gas (Kr) and more polarizable CO2. Further 129Xe NMR suggests a broad isotropic chemical shift due to the reduced motion as a result of confinement. 相似文献
18.
Chinmoy Biswas Prof. Venugopal Rao Soma Dr. Prabhakar Chetti Dr. Sai Santosh Kumar Raavi 《Chemphyschem》2021,22(24):2562-2572
An all-inclusive investigation of the ultrafast excited state relaxation dynamics of a triphenylmethane derivative molecule, New Fuchsine (NF), using a combined approach of density functional theory (DFT), femtosecond transient absorption spectroscopy (fs-TAS), and photoluminescence spectroscopy is presented in this work. The DFT calculations confirmed the formation of twisted molecular structure in the excited state of NF in ethanol solution with bond rotation of ≈86°. TAS measurements of NF solution exhibited ultrafast ground state-recovery pathway via a conical intersection confirming an ultrafast structural reorientation. On the contrary, TAS measurements of NF thin-film exhibited a longer excited-state lifetime suggesting a hindered molecular twisted state formed as an intermediate step. Photophysical kinetic models are proposed to globally fit the fs-TAS data establishing the twisted intramolecular charge transfer (TICT) state mediated ground state recovery for NF in solution and thin film, respectively. Temperature-dependent photoluminescence study of NF film provided a clear insight into the effect of rotational motion of phenyl rings in NF molecules over the TICT mediated emission. 相似文献
19.
An analytical study on nonlinear evolution of Langmuir waves in warm electron-positron-dusty plasmas is presented. The massive dust grains of either positively or negatively charged are assumed to form a fixed charge neutralizing background. A perturbative analysis of the fluid-Maxwell's equations confirms that the excited Langmuir waves phase-mix and eventually break, even at arbitrarily low amplitudes. It is shown that the nature of the dust-charge as well as the amount of dust grains can significantly influence the Langmuir wave phase-mixing process. The phase-mixing time is also found to increase with the temperature. 相似文献
20.
Shyamaprosad Goswami Abhishek Manna Sima Paul Avijit K. Das Prasanta K. Nandi Anup Kumar Maity Partha Saha 《Tetrahedron letters》2014
5(Benzothiazol-2-yl)-4-hydroxyisophthalaldehyde (BHI), an intense ESIPT containing molecule in mixed media loses its properties due to resonance-assisted H-bond (RAHB) in absolute water. Due to resonance-assisted H-bond the o-aldehyde is more reactive than the other one. With addition of cysteine/homocysteine into this solution the o-aldehyde group gets transformed into thiazolidine/thiazine ring, respectively, and the phenolic proton becomes free enough for transfer to nitrogen of the benzothiazole ring in excited state, that is, the ESIPT of BHI is turned on. Thus we can detect cysteine/homocysteine in water as well as in live cells. 相似文献