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21.
22.
Dr. Ramasamy Jayarajan Jayabrata Das Sukdev Bag Rajdip Chowdhury Prof. Dr. Debabrata Maiti 《Angewandte Chemie (International ed. in English)》2018,57(26):7659-7663
Arenes containing conformationally flexible long alkyl chains have been successfully functionalized at the meta‐position. Good to excellent meta selectivity is achieved for systems with up to 20 atoms between the target C?H bond and the coordinating heteroatom of the directing group. The palladium‐catalyzed functionalization reactions include alkylation, cyanation, olefination, and acetoxylation. The meta selectivity is exclusively governed by the design of flexible pyrimidine‐based scaffolds. 相似文献
23.
B. Sachin Kumar C. Dhanasekhar A. Venimadhav Sreeram K. Kalpathy S. Anandhan 《Journal of Sol-Gel Science and Technology》2018,85(3):664-676
Poly(chloropropyl-methyl)silsesquioxanes (PCMSQ) were prepared using the base catalyzed sol–gel processing on methyltrimethoxysilane (MTMS) and 3-chloropropyltriethoxysilane (CPTES) with 5:5, 6:4, and 7:3 molar ratios in methanol and water. The PCMSQ with 6:4 molar ratio of MTMS:CPTES, which has the maximum yield, according to the elemental analysis, was chosen and some chlorine atoms of the chloropropyl groups were changed to different amines by refluxing it with ethylenediamine (en), diethylenetriamine (dien), ortho-phenylenediamine (opda), and 2-imidazolidinethion (imt). The amine grafted PCMSQ were then used to support MoO2(acac)2 complex and dien grafted PCMSQ with higher metal content was applied to the epoxidation of cis-cyclooctene with TBHP. The product yields were studied by gas liquid chromatography and the catalytic procedure was optimized for the parameters involved such as the solvent and oxidant. The catalytic activity of this catalyst also was investigated toward epoxidation of some other alkenes. It was also applied to check its reuse ability. 相似文献
24.
The influence of concentration, ageing and pH of the gel medium on the periodic precipitation of cobalt oxinate in agar gel
is reported. The results are explained on the basis of Shinohara’s revised flocculation theory. The flocculation value (F) increases with increase in the gel concentration whereas it decreases with increase in ageing and pH of the gel. The raise
in temperature of the gel increases the solubility of the sparingly soluble substance and hence theF value. The effect of additives on the periodic precipitation of cobalt (II) oxinate is reported. 相似文献
25.
The oxidation of aniline in glacial acetic acid with percarbonate, a dry carrier of hydrogen peroxide, is a second-order reaction conforming to the isokinetic relationship. The hitherto followed method of correlation of the reaction rates in terms of the structure-reactivity relationships is unsatisfactory and erroneous. But the reaction rates of molecular anilines, obtained for the first time, conform to the structure-reactivity relationships. 相似文献
26.
27.
Mayilmurugan R Harum BN Volpe M Sax AF Palaniandavar M Mösch-Zanetti NC 《Chemistry (Weinheim an der Bergstrasse, Germany)》2011,17(2):704-713
The asymmetric molybdenum(VI) dioxo complexes of the bis(phenolate) ligands 1,4‐bis(2‐hydroxybenzyl)‐1,4‐diazepane, 1,4‐bis(2‐hydroxy‐4‐methylbenzyl)‐1,4‐diazepane, 1,4‐bis(2‐hydroxy‐3,5‐dimethylbenzyl)‐1,4‐diazepane, 1,4‐bis(2‐hydroxy‐3,5‐di‐tert‐butylbenzyl)‐1,4‐diazepane, 1,4‐bis(2‐hydroxy‐4‐flurobenzyl)‐1,4‐diazepane, and 1,4‐bis(2‐hydroxy‐4‐chlorobenzyl)‐1,4‐diazepane (H2(L1)–H2(L6), respectively) have been isolated and studied as functional models for molybdenum oxotransferase enzymes. These complexes have been characterized as asymmetric complexes of type [MoO2(L)] 1–6 by using NMR spectroscopy, mass spectrometry, elemental analysis, and electrochemical methods. The molecular structures of [MoO2(L)] 1–4 have been successfully determined by single‐crystal X‐ray diffraction analyses, which show them to exhibit a distorted octahedral coordination geometry around molybdenum(VI) in an asymmetrical cis‐β configuration. The Mo? Ooxo bond lengths differ only by ≈0.01 Å. Complexes 1 , 2 , 5 , and 6 exhibit two successive MoVI/MoV (E1/2, ?1.141 to ?1.848 V) and MoV/MoIV (E1/2, ?1.531 to ?2.114 V) redox processes. However, only the MoVI/MoV redox couple was observed for 3 and 4 , suggesting that the subsequent reduction of the molybdenum(V) species is difficult. Complexes 1 , 2 , 5 , and 6 elicit efficient catalytic oxygen‐atom transfer (OAT) from dimethylsulfoxide (DMSO) to PMe3 at 65 °C at a significantly faster rate than the symmetric molybdenum(VI) complexes of the analogous linear bis(phenolate) ligands known so far to exhibit OAT reactions at a higher temperature (130 °C). However, complexes 3 and 4 fail to perform the OAT reaction from DMSO to PMe3 at 65 °C. DFT/B3LYP calculations on the OAT mechanism reveal a strong trans effect. 相似文献
28.
Ramasamy K Mazumdar D Zhou Z Wang YH Gupta A 《Journal of the American Chemical Society》2011,133(51):20716-20719
Nanocrystals and nanoclusters of the room-temperature magnetic spinel CuCr(2)S(4) have been synthesized using a facile solution-based method. The synthesis involves hot injection of an excess of 1-dodecanethiol (1-DDT) into a boiling coordinating solvent containing CuCl(2) and CrCl(3)·6H(2)O. Using octadecylamine (ODA) as a solvent yields cube-shaped nanocrystals with an average size of 20 ± 2 nm, while with oleylamine (OLA), nanoclusters with an average size of 31 ± 2.5 nm are obtained. In both cases, powder X-ray diffraction patterns confirmed the formation of the pure spinel phase without any impurities. While the synthesized powders are superparamagnetic near room temperature, they exhibit ferromagnetic behavior at lower temperatures, with magnetization (M(S)) values of 30 emu/g (1.63 μ(B)/f.u.) and 33 emu/g (1.79 μ(B)/f.u.) for the ODA- and OLA-capped nanocrystals and nanoclusters, respectively, at 5 K. 相似文献
29.
A simple and efficient method for the -deprotection of tetrahydropyranyl and 4,4′-dimethoxytrityl ethers using iodine in methanol is described. 相似文献
30.
Jang JS Ham DJ Ramasamy E Lee J Lee JS 《Chemical communications (Cambridge, England)》2010,46(45):8600-8602
Mesoporous tungsten carbides displayed an excellent solar conversion efficiency (7.01%) as a counter electrode for dye sensitized solar cells under 100 mW cm(-2), AM 1.5G illumination, which corresponded to ca. 85% of the efficiency of the conventional platinum electrode. 相似文献