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21.
Turdybekov K. M. Nurkenov O. A. Seilkhanov T. M. Fazylov S. D. Turdybekova Ya. G. Kudusov A. S. 《Journal of Structural Chemistry》2022,63(6):944-950
Journal of Structural Chemistry - N-cyanomethylanabasine is prepared with an yield of 70% by the interaction of the alkaloid anabasine with glyconitrile. It is shown that the highest yield of the... 相似文献
22.
Ab initio calculations have been performed to investigate some of the spectroscopic properties, like geometry, frequency, electron affinity, ionization potential and finally adiabatic bond dissociation energies (BDEs) of lead monohalides, lead dihalides and their ions viz. PbX, PbX±, PbX2, (X ?= ?F, Cl, Br, I) in their ground state at the QCISD(T)//MP2 level of theory using correlation consistent basis sets. For the validation of MP2 optimized geometry and frequency, we further obtained geometry and frequency of all the neutral and ionic systems using QCISD(T) method with the same basis sets. The BDEs of PbX2 molecules are calculated using the BDEs of ions and taking ionization potential and electron affinity of various systems. The calculated values are found in good agreement with the available data. Most of the data for ionic systems are reported first time in literature. 相似文献
23.
S. Venkatesan S. Suresh P. Ramu M. Kandasamy J. Arumugam S. Thambidurai K.M. Prabu N. Pugazhenthiran 《印度化学会志》2022,99(5):100436
A facile biosynthesis route was followed to prepare zinc oxide nanoparticles (ZnO NPs) using Euphorbia milii (E. milii) leaf constituents. The SEM images exhibited presence of spherical ZnO NPs and the corresponding TEM images disclosed monodisperse nature of the ZnO NPs with diameter ranges between 12 and 20 nm. The Brunauer–Emmett–Teller (BET) analysis revealed that the ZnO NPs have specific surface area of 20.46 m2/g with pore diameter of 2 nm–10 nm and pore volume of 0.908 cm3/g. The EDAX spectrum exemplified the existence of Zn and O elements and non-appearance of impurities that confirmed pristine nature of the ZnO NPs. The XRD pattern indicated crystalline peaks corresponding to hexagonal wurtzite structured ZnO with an average crystallite size of 16.11 nm. The FTIR spectrum displayed strong absorption bands at 512 and 534 cm?1 related to ZnO. The photocatalytic action of ZnO NPs exhibited noteworthy degradation of methylene blue dye under natural sunlight illumination. The maximum degradation efficiency achieved was 98.17% at an illumination period of 50 min. The reusability study proved considerable photostability of the ZnO NPs during photocatalytic experiments. These findings suggest that the E. milii leaf constituents can be utilized as suitable biological source to synthesis ZnO NPs for photocatalytic applications. 相似文献
24.
Bodnarchuk V. I. Boulkin A. P. Kravtsov E. A. Pleshanov N. K. Syromyatnikov V. G. Ul’yanov V. A. 《Crystallography Reports》2022,67(1):50-63
Crystallography Reports - The review is devoted to the current state of affairs and prospects for development in the field of neutron reflectometry on the existing and future neutron sources in the... 相似文献
25.
Ye Jingyao Al-Jobory Alaa Zhang Qian-Chong Cao Wenqiang Alshehab Abdullah Qu Kai Alotaibi Turki Chen Hang Liu Junyang Ismael Ali K. Chen Zhong-Ning Lambert Colin J. Hong Wenjing 《中国科学:化学(英文版)》2022,65(9):1822-1828
Science China Chemistry - Destructive quantum interference (DQI) provides a unique approach to controlling the leakage current in the OFF state of molecular devices. However, the DQI in... 相似文献
26.
Roopa K. P. Keshavamurthy K. Mahesh B. Veena K. P. Shankara B. S. Basavaiah K. 《Journal of Applied Spectroscopy》2022,89(4):809-818
Journal of Applied Spectroscopy - Three simple, sensitive, precise, and rapid spectrophotometric methods are developed and optimized for the assay of vardenafil in pharmaceutical formulations. The... 相似文献
27.
Rastsvetaeva R. K. Chukanov N. V. Pekov I. V. Varlamov D. A. Kazheva O. N. 《Crystallography Reports》2022,67(2):166-171
Crystallography Reports - The crystal structure and crystallochemical features of a Fe-deficient zirconium-rich analog of eudialyte from the Lovozero alkaline massif (Kola peninsula) have been... 相似文献
28.
Reshma Jose Dr. Srinivasu Kancharlapalli Dr. Tapan K. Ghanty Prof. Sourav Pal Prof. Gopalan Rajaraman 《Chemistry (Weinheim an der Bergstrasse, Germany)》2022,28(18):e202104526
The coordinatively unsaturated chromium(II)-based Cr3[(Cr4Cl)3(BTT)8]2 (Cr−BTT; BTT3−=1,3,5-benzenetristetrazolate) metal–organic framework (MOF) has been shown to exhibit exceptional selectivity towards adsorption of O2 over N2/H2. Using periodic density functional theory (DFT) calculations, we attempted to decipher the origin of this puzzling selectivity. By computing and analyzing the magnetic exchange coupling, binding energies, the partial density of states (pDOS), and adsorption isotherms for the pristine and gas-bound MOFs [(Cr4(X)4Cl)3(BTT)8]3− (X=O2, N2, and H2), we unequivocally established the role of spin states and spin coupling in controlling the gas selectivity. The computed geometries and gas adsorption isotherms are consistent with the earlier experiments. The binding of O2 to the MOF follows an electron-transfer mechanism resulting in a CrIII superoxo species (O2.−) with a very strong antiferromagnetic coupling between the two centers, whereas N2/H2 are found to weakly interact with the metal center and hence only slightly perturb the associated coupling constants. Although the gas-bound and unbound MOFs have an S=0 ground state (GS), the nature of spin the configurations and the associated magnetic exchanges are dramatically different. The binding energy and the number of oxygen molecules that can favorably bind to the Cr center were found to vary with respect to the spin state, with a significant energy margin (47.6 kJ mol−1). This study offers a hitherto unknown strategy of using spin state/spin couplings to control gas adsorption selectivity in MOFs. 相似文献
29.
Dong Gun Oh Prof. Hristiyan A. Aleksandrov Haneul Kim Dr. Iskra Z. Koleva Dr. Konstantin Khivantsev Prof. Georgi N. Vayssilov Prof. Ja Hun Kwak 《Chemistry (Weinheim an der Bergstrasse, Germany)》2022,28(49):e202200684
Pd-based catalysts are the most widely used for CO oxidation because of their outstanding catalytic activity and thermal stability. However, fundamental understanding of the detailed catalytic processes occurring on Pd-based catalysts under realistic conditions is still lacking. In this study, we investigated CO oxidation on metallic Pd clusters supported on Al2O3 and SiO2. High-angle annular dark-field scanning transmission electron microscopy revealed the formation of similar-sized Pd clusters on Al2O3 and SiO2. In contrast, CO chemisorption analysis indicated a gradual change in the dispersion of Pd (from 0.79 to 0.2) on Pd/Al2O3 and a marginal change in the dispersion (from 0.4 to 0.24) on Pd/SiO2 as the Pd loading increased from 0.27 to 5.5 wt %; these changes were attributed to differences in the metal-support interactions. Diffuse reflectance infrared Fourier-transform spectroscopy revealed that fewer a-top CO species were present in Pd supported on Al2O3 than those in Pd supported on SiO2, which is related to the morphological differences in the metallic Pd clusters on these two supports. Despite the different dispersion profiles and surface characteristics of Pd, O2 titration demonstrated that linearly bound CO (with an infrared signal at 2090 cm−1) reacted first with oxygen in the case of CO-saturated Pd on Al2O3 and SiO2, which suggests that a-top CO on the terrace site plays an important role in CO oxidation. The experimental observations were corroborated by periodic density functional calculations, which confirmed that CO oxidation on the (111) terrace sites is most plausible, both kinetically and thermodynamically, compared to that on the edge or corner sites. This study will deepen the fundamental understanding of the effect of Pd clusters on CO oxidation under reaction conditions. 相似文献
30.
Mohammad A. Khalilzadeh Soo Young Kim Ho Won Jang Rafael Luque Rajender S. Varma Richard A. Venditti Mohammadreza Shokouhimehr 《Materials Today Chemistry》2022
The requirement of green and sustainable materials to prepare heterogeneous catalysts has intensified for practical reasons over the past few decades. Carbohydrates are possibly the most plentiful and renewable organic materials in nature with inimitable physiochemical properties, plausible low-cost and large-scale production, and sustainability features could be exploited in the generation of nanostructured heterogeneous catalysts. This review article outlines the organic transformations catalyzed by diverse carbohydrate-based nanostructured catalysts in greener and environmentally friendly processes. Selected examples are highlighted for a variety of organic reactions exploiting the proposed catalysts’ reactivity and reusability, and interactions with the intrinsic nature of the applied carbohydrate supports; advantages and speculated challenges of the introduced catalysts are deliberated as well. 相似文献