171 |
Asymmetric synthesis via iron acyl complexesWalker, Jonathan Charles January 1986 (has links)
No description available.
|
172 |
The investigation of indium halides and graphite intercalation compounds using time-differential perturbed angular correlation gamma-ray spectrosocopyDong, Sunny Ronald January 1988 (has links)
This thesis discusses in general terms the theory and application of time-differential perturbed angular correlation gamma-ray spectroscopy (TDPAC) to the study of solid state physics. The technique yields valuable information on the electric field gradients experienced by radionuclides which have been substituted for nonradioactive isotopes or inserted as impurities into various inorganic compounds. The indium halides are examined in a series of experiments. The first applications of this technique to the study of graphite intercalation compounds are discussed. / Science, Faculty of / Physics and Astronomy, Department of / Graduate
|
173 |
SYNTHESIS OF NOVEL METAL HALIDES AND THEIR STRUCTURE-PROPERTY RELATIONS / 新規金属ハライドの合成とその構造物性相関Koedtruad, Anucha 23 March 2021 (has links)
京都大学 / 新制・課程博士 / 博士(理学) / 甲第23023号 / 理博第4700号 / 新制||理||1674(附属図書館) / 京都大学大学院理学研究科化学専攻 / (主査)教授 島川 祐一, 教授 寺西 利治, 教授 長谷川 健 / 学位規則第4条第1項該当 / Doctor of Science / Kyoto University / DGAM
|
174 |
Use of Suzuki Coupling Reaction for Synthesis of Functionalized MaterialsKuvayskaya, Anastasia, Vasiliev, Aleksey 12 April 2019 (has links)
Hybrid materials synthesized by grafting of organic molecules onto silica surface have found numerous applications in chemistry, biochemistry, and chemical engineering. In particular, the functionalization of silica gel can be accomplished by various surface reactions of immobilized boronic acids. Suzuki coupling has been chosen due to several advantages, such as mild reaction conditions, tolerance to the aqueous environment, and high yields of the products. The objective of this work was to determine the most effective reaction conditions for modifying porous hybrid materials with large specific surface areas and high density of surface organoboron reactive sites by various functional groups. Prior to modification by Suzuki coupling, the surface of silica gel was functionalized by phenylboronic acid. Two methods were tested for immobilization of phenylboronic acid: hydrosilylation and thiol-ene coupling. The later radical reaction between surface alkylthiol groups and 4-vinylphenylboronic acid was found more effective. Obtained boronated silica gel was used for further functionalization by various aryl halides. Surface Suzuki coupling reaction was catalyzed by palladium acetate in the presence of cesium carbonate as a base, while dimethylformamide was chosen as a solvent. The coupling reactions proceeded at mild heating under constant sonication. Such ultrasonic irradiation was reported earlier to have an activating effect on Suzuki coupling. The analysis of the obtained products indicated formation of surface biaryl compounds, the highest yields have been obtained in reactions with iodobenzene and bromobenzene. Thus, novel functionalized organic/inorganic hybrid materials were successfully synthesized by surface modification of mesoporous silica gel.
|
175 |
Functionalization of Silica Gel by Ultrasound-Assisted Surface Suzuki CouplingKuvayskaya, Anastasia, Vasiliev, Aleksey 12 September 2019 (has links)
Mesoporous silica gel was functionalized by various organic functional groups using thiol-ene coupling of surface thiol groups with 4-vinylphenylboronic acid followed by Suzuki coupling with aromatic halides. For better performance, the synthesis was conducted under sonication. The presence of surface functional groups was confirmed by thermoanalysis, FT-IR spectroscopy and characteristic reactions of these groups. Solid-phase conditions of the synthesis eliminate the risk of side reactions of boronic acids.
|
176 |
Base- and Visible Light-Promoted Activation of Aryl Halides under Transition-Metal-Free Conditions: Applications and Mechanistic StudiesPan, Lei 12 1900 (has links)
Indiana University-Purdue University Indianapolis (IUPUI) / Aromatic rings are universal motifs in natural products, pharmaceuticals, agrochemicals,
and wide variety of organic materials. Aromatic halides are widely used as synthetic precursors
in all these applications. Therefore, tremendous effort has been devoted to activate aryl halides in
the past decades. The common methods to activate aryl halides require the use of transition-
metals either in the form of Grignard reagents or through the use of transition-metal catalysis.
Over the past decade, photoredox catalysis has attracted significant attention as a cogent tool to
develop greener synthetic processes and enable new molecular activation pathways under mild
conditions. The most common of these approaches uses a photoredox/nickel dual catalytic cycle.
While this technology has greatly expanded the toolbox of organic chemists, this method still
requires expensive rare-metal-based catalyts. Herein, we present a series of visible light-induced
methods that are transition-metal-free. These new base-promoted transformations and their
mechanistic work will be discussed in the following order:
We will first present our discovery that the dimsyl anion enables visible-light-promoted
charge transfer in cross-coupling reactions of aryl halides. This work was applied to the synthesis
of unsymmetrical diaryl chalcogenides. This method has a broad scope and functional group
tolerance. An electron-donor-acceptor (EDA) complex between a dimsyl anion and the aryl
halide is formed during the reaction and explains the observed aryl radical reactivity observed.
Then, a visible-light-induced borylation and phosphorylation of aryl halides under mild
conditions was developed. Inspired by the mechanistic breakthroughs observed in the previous
work. The mechanism of this reaction also involves an aryl radical that is presumed to be formed
also via an EDA complex. In other work, a photo-induced phosphonation of ArI using N,N-
diisopropylethylamine (DIPEA) and trialkyl phosphites was developed. This method uses very
mild conditions, which allowed the preparation a wide variety of functionalized aromatic
phosphonates derivatives, including natural products and medicinal compounds. Finally, a
photochemical amination of amides was developed via a C(sp 3 )–H bond functionalization
process under visible light irradiation. This reaction showed good functional group compatibility
without the use of external radical initiators, strong oxidants, or heat source. An EDA complex
between N-bromophthalimide and LiOtBu is formed during the reaction.
|
177 |
Voltammetric and electrochemical kinetic studies of the halides and halogens at a platinum rotating ring-disk electrode in anhydrous acetic acidCranney, Donald Harrison 01 December 1976 (has links)
The electrochemical behavior of the iodine-iodide couple was investigated in both basic and neutral acetic acid solutions at a platinum rotating ring-disk electrode. Voltammetric curves were obtained and discussed. Various kinetic parameters were determined and by comparing to theoretical kinetic parameters a probable reaction mechanism was deduced. The mechanism that best fit experimental results is the following I- + S = I(S) + e- I(S) + I- = I2 + S + e (slow). The electrochemical behavior of bromine, bromide, and chloride was also investigated in the same media. Voltammetric curves were recorded and discussed with emphasis on the hysteresis that occurs between anodic and cathodic scans. Surface phenomenon that cause this hysteresis were, in some cases, determined. The involvement of surface oxides and adsorption phenomena in causing the hysteresis were evident. Some kinetic parameters were obtained.
|
178 |
Study of the Structure Property Relationships of Metal HalidesGray, Matthew January 2021 (has links)
No description available.
|
179 |
Reactions in non-aqueous mediaMattox, Vernon Ro January 1939 (has links)
M.S.
|
180 |
The sodium borohydride reduction of organic halides and related derivatives in aprotic solventsVanderslice, Charles Warren January 1968 (has links)
Sodium borohydride reduces alkyl halides and their related tosylate derivatives in the order primary > secondary > tertiary, while the relative order of leaving-group ability is Ts⁻ ≥ I⁻ > Br⁻ > > Cl⁻. The yields obtained ranged from 90-100% for most simple, primary and secondary iodides, bromides, and tosylates, to 1-2% for the tertiary compounds. As in the case of the more reactive lithium aluminum hydride, the. reduction is believed to occur by an S<sub>N</sub>2 displacement on carbon.
The reduction of a series of para-substituted benzyl chlorides revealed that the electronic effects of groups ranging from p-methoxy to p-nitro had a rather small effect on the rate of reduction.
Aryl halides arc reduced by sodium borohydride in yields dependent upon the particular halogen involved, the presence of other ortho and para electron-withdrawing substituents, and the reaction temperature, among other factors. The same relative order of dehalogenation displayed by the alkyl halides was found.
Polyhalomethanes such as carbon tetrachloride react with sodium borohydride to give the monohydro and dihydro compounds as the major products, the former predominating. The exact mechanism of the reduction is as yet undetermined, as water apparently catalyzes the reaction in some unknown manner. / Master of Science
|
Page generated in 0.0266 seconds