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101.
Manju K. Saroj Ritu Payal Sapan K. Jain Neera Sharma Ramesh C. Rastogi 《Journal of inclusion phenomena and macrocyclic chemistry》2018,90(3-4):305-320
The study focuses on the formation of inclusion complexes of indole chalcone (IC) derivatives with β-cyclodextrin (β-CD), which involves absorption and steady state fluorescence spectroscopies. The formation of inclusion complexes is validated by increase in their absorbance and fluorescence intensity as well as the blue shift with increase in the concentration of β-CD in the aqueous solution. The stoichiometries and binding constants (Kin) of these complexes have been investigated by monitoring their absorbance and fluorescence spectral profiles. The data are analyzed by Benesi–Hildebrand plots as well as Job’s method, which indicate 1:1 stoichiometry of IC:β-CD complexes. Fluorescence measurements are also used to investigate the effect of temperature on the stability of inclusion complexes. Stability of IC:β-CD complexes is significantly affected with variation in substituents on the phenyl ring and temperature. It is observed that the stability of the inclusion complex decreases with increase in temperature; Kin(293 K)?>?Kin(298 K)?>?Kin(308 K)?>?Kin(318 K). All the experimental results and the geometrical data obtained using PM3 semiempirical method illustrate the partial inclusion of IC derivatives from the phenyl ring side in β-CD cavity. The binding process of IC derivatives with β-CD is found to be exothermic in nature and seems to be controlled by electrostatic and hydrophobic forces. The binding free energies calculated using semiemprical PM3 method for IC:β-CD complexes are found to be in the order: I?<?OH–I?<?Me–I?<?OMe–I?<?NH2–I, which largely supports the findings based on the experimental binding constants. 相似文献
102.
Feng Jun Chernova Natasha A. Omenya Fredrick Tong Lingyue Rastogi Alok C. Stanley Whittingham M. 《Journal of Solid State Electrochemistry》2018,22(4):1063-1078
Journal of Solid State Electrochemistry - Hybrid supercapacitors using asymmetric, LiFePO4 (LFP) lithium intercalation and electric double layer activated carbon (AC) electrodes combining the high... 相似文献
103.
Bhavana Gupta Lin Zhang Ambrose Ashwin Melvin Bertrand Goudeau Laurent Bouffier Alexander Kuhn 《Chemical science》2021,12(6):2071
Rational design and shaping of soft smart materials offer potential applications that cannot be addressed with rigid systems. In particular, electroresponsive elastic materials are well-suited for developing original active devices, such as pumps and actuators. However, applying the electric stimulus requires usually a physical connection between the active part and a power supply. Here we report about the design of an electromechanical system based on conducting polymers, enabling the actuation of a wireless microfluidic pump. Using the electric field-induced asymmetric polarization of miniaturized polypyrrole tubes, it is possible to trigger simultaneously site-specific chemical reactions, leading to shrinking and swelling in aqueous solution without any physical connection to a power source. The complementary electrochemical reactions occurring at the opposite extremities of the tube result in a differential change of its diameter. In turn, this electromechanical deformation allows inducing highly controlled fluid dynamics. The performance of such a remotely triggered electrochemically active soft pump can be fine-tuned by optimizing the wall thickness, length and inner diameter of the material. The efficient and fast actuation of the polymer pump opens up new opportunities for actuators in the field of fluidic or microfluidic devices, such as controlled drug release, artificial organs and bioinspired actuators.Tubular conducting polymer actuators are used for developing a wireless electropumping device. Bipolar electrochemistry, allowing symmetry breaking in terms of polarization and electrochemical reactions, is the key ingredient for efficient pumping. 相似文献
104.
105.
V.K Rastogi C.B Arora S.K Singhal D.N Singh R.A Yadav 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》1997,53(14):2505-2510
Raman spectrum of 2,6-difluorobenzonitrile in the powder form has been recorded in the region 50–4000 cm−1 on a Jasco K-500 spectrophotometer using the 488.0 nm radiation from an argon laser. IR spectra in the region 200–4000 cm−1 have been recorded in KBr pellet and nujol mull on a Nicolet DX spectrometer and in liquid and vapour phases on a Jasco FTIR/7000 spectrometer. Using these observed frequencies force field calculations for the planar and non-planar modes have been carried out assuming a general valence force field. 相似文献
106.
The stability constants of the fluoride complexes of cerium(IV) in 1 M (HClO(4), NaClO(4)) medium have been measured potentiometrically using a fluoride ion-selective electrode. Quantitative oxidation of cerium to its tetravalent state and its stabilisation in the perchlorate medium were accomplished by oxidation with AgO followed by quick addition of a known amount of fluoride ion. This procedure ensures stability of the oxidation state and prevents hydrolysis and polymerisation of Ce(IV). Logarithms of the average values of beta(1), beta(2), beta(3) and beta(4) were estimated to be 7.57+/-0.04, 14.50+/-0.03, 20.13+/-0.37 and 24.14+/-0.10 respectively. 相似文献
107.
The FSGO model has been used to make ab initio calculations of the geometry of B2H ion. The results indicate that the acetylenic structure has the lowest energy (?43.881 a.u.) and the planar structure has the highest energy (?43.838 a.u.). The energy of the non-symmetric structure is only slightly higher (?43.879 a.u.) than that of the acetylenic one. Results of CNDO /2 calculations reported here also predict the acetylenic structure to be the most stable one. 相似文献
108.
Determination of fluoride by spectrophotometry of Arsenazo(III) complex of the back-extracted Th(IV)
R. K. Rastogi M. A. Mahajan N. K. Chaudhuri 《Journal of Radioanalytical and Nuclear Chemistry》1994,188(4):291-298
A method based on the back-extraction of Th(IV) from its TTA complex in benzene by aqueous F– followed by spectrophotometric measurement of Th(IV), for the determination of fluoride has been developed. The coefficients of variation obtained are 2.4% and 1.4% in 11 determinations at F– concentration levels of 1.0 g ml–1, respectively. 相似文献
109.
Rastogi SC Zachariae C Johansen JD Devantier C Menné T 《Journal of chromatography. A》2004,1031(1-2):315-317
An increased frequency of contact allergy to methyldibromoglutaronitrile (MDBGN), a commonly used preservative in cosmetics and other consumer products, has been reported in recent years. A high-performance liquid chromatography (HPLC) method for the determination of MDBGN in cosmetic products has been validated in the present study. The identification is performed by reductive electrochemical detection of the bromine present in the molecule. The method is suitable for compliance testing of cosmetic products as well as for the research to support clinical and epidemiological studies. 相似文献
110.
Rheological material functions are used to form our conceptual understanding of a material response. For a nonlinear rheological response, the possible deformation protocols and material measures span a high-dimensional space. Here, we use asymptotic expansions to outline low-dimensional measures for describing leading-order nonlinear responses in large amplitude oscillatory shear (LAOS). This amplitude-intrinsic regime is sometimes called medium amplitude oscillatory shear (MAOS). These intrinsic nonlinear material functions are only a function of oscillatory frequency, and not amplitude. Such measures have been suggested in the past, but here, we clarify what measures exist and give physically meaningful interpretations. Both shear strain control (LAOStrain) and shear stress control (LAOStress) protocols are considered, and nomenclature is introduced to encode the physical interpretations. We report the first experimental measurement of all four intrinsic shear nonlinearities of LAOStrain. For the polymeric hydrogel (polyvinyl alcohol - Borax) we observe typical integer power function asymptotics. The magnitudes and signs of the intrinsic nonlinear fingerprints are used to conceptually model the mechanical response and to infer molecular and microscale features of the material. 相似文献