Download or read book Syntheses and Structural Studies of Cobalt III alkylperoxo Complexes and Their Role in Oxidation of Hydrocarbons written by Ferman Albert Chavez and published by . This book was released on 1999 with total page 438 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Synthesis and Reactivities of Cobalt iii Alkylperoxo Complexes Bearing Quaterpyridine Ligand written by Yunzhou Chen and published by . This book was released on 2022 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Direct use of dioxygen (O2) in functionalizing organic molecules is highly desirable. In nature, enzymes perform alkane oxidation efficiently at ambient conditions. The transition metals involved in the active sites of enzymes play vital roles in binding with O2 and transferring electrons and protons during metabolism. Many metal-oxygen species, such as hydro(alkyl) peroxo complexes, are invoked as reactive intermediates in these biological processes. Given the complexity of enzymes, studying the reactivity of these enzymes with simple synthetic coordination compounds is one of the strategies. This thesis is mainly concerned with the oxidation of alkanes and alkenes catalyzed by tailor-made cobalt(III) alkylperoxo complexes at ambient conditions. In the first part, we report the design and synthesis of the highly electrophilic cobalt(III) alkylperoxo complex, [CoIII(qpy)(OOtBu)(NCCH3)]2+ (2), supported by a planar tetradentate quaterpyridine ligand (qpy = 2,2′:6′,2′′:6′′,2′′′-quaterpyridine). This complex activates C(sp3)–H bonds of a variety of organic molecules at ambient conditions and yields a series of alkylperoxo complexes with the general formula [CoIII(qpy)(OOR)(NCCH3)]2+ [RH = Et2O (3), THF (4), tBuOMe (5), ethylbenzene (6), toluene (7), cyclopentene (8), and 3-hexyne (9)], which have been well characterized by various spectroscopic techniques including NMR, ESI-MS, UV-vis, FT-IR, and CHN elemental analysis. The structures of these complexes have also been characterized by X-ray crystallography. In the second part, the mechanism for the alkane oxidation catalyzed by [CoIII(qpy)(OOR)(NCCH3)]2+ was extensively studied at room temperature and one atmospheric pressure. NMR study reveals the reaction stoichiometry. ESI-MS study indicates exogeneous O2 is crucial with the support of 18O-labeled experiments. Kinetics study by UV-vis and a significant kinetic isotopic effect resulted for the oxidation of ethylbenzene by 2 suggest a rate-limiting hydrogen-atom abstraction from organic substrates (R′H) by [CoIII(qpy)OOR]2+ via the proximal oxygen atom of the peroxo group (i.e., [CoIII(qpy)OOR]2+ + R′H → [CoII(qpy)]2+ + R′• + ROOH). The resulting alkyl radical R′• bound with O2 to form alkyl peroxyl radical R′OO•, which was rapidly scavenged by the [CoII(qpy)]2+ to give another alkylperoxo complex [CoIII(qpy)OOR′]2+. The proposed mechanism in the peroxidation of organic molecules b y alkyl(hydro)peroxo complexes is unprecedented. In the third part, we examine the catalytic properties of [CoIII(qpy)(OOR)(NCCH3)]2+ in aerobic oxidation of various substrates. Using ethylbenzene, cumene, cyclopentene, and cyclohexene as the substrates, [CoIII(qpy)(OOR)(NCCH3)]2+ are found to be active and robust catalysts to produce the corresponding hydroperoxides, alcohols, and ketones catalytically. A turnover of >3000 is achieved in the oxidation of cyclohexene for 7 d. In the fourth part, the reactivities of [CoIII(qpy)OOR]2+ with alkenes were explored. Alkenes with weak C–H bonds (e.g., 1,4-cyclohexadiene and cycloalkenes) resulted in C–H functionalization. In case there are no weak C–Hs in the alkenes (e.g., styrene), [CoIII(qpy)OOR]2+ catalyzes the polymerization of styrenes in O2 to produce polyalkylperoxo species. The [CoIII(qpy)(OOCH(OOtBu)CH2Ph)(NCCH3)]2+ ( bisalkylperoxo 11), has complex, been isolated and characterized by ESI-MS, NMR, and X-ray crystallography. In summary, this work demonstrates the highly electrophilic character of Co(III) alkylperoxo complexes supported by the qpy ligand. Under ambient conditions, these complexes are suitable catalysts to perform aerobic peroxidation of a variety of alkanes and alkenes
Download or read book Hydrocarbon Oxidation by Alkylperoxo Complexes of Tervalent Iron and Cobalt written by Cattien Van Nguyen and published by . This book was released on 1996 with total page 366 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book American Doctoral Dissertations written by and published by . This book was released on 1998 with total page 784 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Dissertation Abstracts International written by and published by . This book was released on 1999 with total page 700 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Modern Syntheses of Cobalt III Complexes written by M. Shibata and published by Springer. This book was released on 1983-07-01 with total page 118 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Modern Syntheses of Cobalt III Complexes written by M. Shibata and published by Springer. This book was released on 2013-10-03 with total page 118 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Modern Syntheses of Cobalt III Complexes written by M. Yamatera H. Shibata and published by . This book was released on 2014-01-15 with total page 136 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Cumulated Index Medicus written by and published by . This book was released on 2000 with total page 1828 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Modern Syntheses of Cobalt III Complexes written by Muraji Shibata and published by Springer Verlag. This book was released on 1983-01-01 with total page 118 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Pincer Compounds written by David Morales-Morales and published by Elsevier. This book was released on 2018-04-11 with total page 756 pages. Available in PDF, EPUB and Kindle. Book excerpt: Pincer Compounds: Chemistry and Applications offers valuable state-of-the-art coverage highlighting highly active areas of research—from mechanistic work to synthesis and characterization. The book focuses on small molecule activation chemistry (particularly H2 and hydrogenation), earth abundant metals (such as Fe), actinides, carbene-pincers, chiral catalysis, and alternative solvent usage. The book covers the current state of the field, featuring chapters from renowned contributors, covering four continents and ranging from still-active pioneers to new names emerging as creative strong contributors to this fascinating and promising area. Over a decade since the publication of Morales-Morales and Jensen’s The Chemistry of Pincer Compounds (Elsevier 2007), research in this unique area has flourished, finding a plethora of applications in almost every single branch of chemistry—from their traditional application as very robust and active catalysts all the way to potential biological and pharmaceutical applications. Describes the chemistry and applications of this important class of organometallic and coordination compounds Includes contributions from global leaders in the field, featuring pioneers in the area as well as emerging experts conducting exciting research on pincer complexes Highlights areas of promising and active research, including small molecule activation, earth abundant metals, and actinide chemistry
Download or read book Cobalt III Complexes Containing Analogues of Bioactive Anticancer Compounds written by Meet Mistry and published by . This book was released on 2016 with total page 269 pages. Available in PDF, EPUB and Kindle. Book excerpt: Since the discovery of cisplatin as a potent anticancer agent, transition metal complexes have played a significant role in the development of new anticancer compounds. The anticancer potential of cobalt complexes has been extensively studied over the last three decades, and much time has been devoted to understanding their mechanisms of action. After understanding the Co(III)/Co(II) reduction activation mechanism, several Co(III) complexes of bioactive anticancer agents have been investigated as potential hypoxia activated prodrugs. Furthermore, after the initial use of nitrogen mustard, several bioactive compounds and their analogues have been investigated as ligands to develop hypoxia activated Co(III) complexes. This thesis describes syntheses and characterisation of Co(III) complexes that have been designed using structural analogues of bioactive anticancer compounds. Chapter 1 gives an overview of the prodrug strategy in cancer therapy, prodrug design using a trigger and an effector unit, and different mechanisms for prodrug activation. Several examples of Co(III) complexes are given, which have been investigated as potential prodrugs to target tumour hypoxia. There are three different parts to this research. Chapters 2, 3 and 4 describe the syntheses and characterisation of Co(III) complexes designed using ligands, which are structural analogues of bioactive anticancer compounds. Chapter 2 describes syntheses of dipeptide analogues of bortezomib, a proteasome inhibitor that is currently being used for the treatment for multiple myeloma. The Co(III)-dipeptide complexes were also analysed for their possible use as hypoxia activated prodrugs in Chapter 2. Chapter 3 includes the continuation to the previous investigation by Ware et al. on Co(III)-cyclen complex using 8-hydroxyquinoline (8HQ) as a model cytotoxin. Efforts were made to establish a synthetic route to introduce a porphyrin derivative into prodrug design, with the aim of improving tumour cell targeting properties of the prodrug complex. Chapter 4 describes syntheses of two polypyridyl carboxamide ligands, PDPA and MID(AMP)2, and syntheses of their Co(III) complexes. PDPA and MID(AMP)2, are structural analogues of PMAH, Py3PH2, which are carboxamide ligands containing a similar metal-binding domain as bleomycins. The experimental procedures are detailed in Chapter 5.
Download or read book Structural and Mechanistic Studies of Cobalt III Complexes Containing a Macrocyclic Quadridentate Schiff Baseamine written by 溫雲基 and published by Open Dissertation Press. This book was released on 2017-01-27 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This dissertation, "Structural and Mechanistic Studies of Cobalt (III) Complexes Containing a Macrocyclic Quadridentate Schiff Baseamine" by 溫雲基, Wan-kei, Wan, was obtained from The University of Hong Kong (Pokfulam, Hong Kong) and is being sold pursuant to Creative Commons: Attribution 3.0 Hong Kong License. The content of this dissertation has not been altered in any way. We have altered the formatting in order to facilitate the ease of printing and reading of the dissertation. All rights not granted by the above license are retained by the author. DOI: 10.5353/th_b3120346 Subjects: Chemical kinetics Cobalt
Download or read book Variations on Cobalt Hexaamine CoN6 written by Chang Jin Qin and published by . This book was released on 1997 with total page 346 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Modern Syntheses of Cobalt III complexes written by Muraji Shibata and published by . This book was released on 1983 with total page 116 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Directory of Graduate Research written by and published by . This book was released on 2001 with total page 1846 pages. Available in PDF, EPUB and Kindle. Book excerpt: Faculties, publications and doctoral theses in departments or divisions of chemistry, chemical engineering, biochemistry and pharmaceutical and/or medicinal chemistry at universities in the United States and Canada.
Download or read book Structural Studies of Binuclear Cobalt III Cyano Complexes written by Franklin Robert Fronczek and published by . This book was released on 1975 with total page 374 pages. Available in PDF, EPUB and Kindle. Book excerpt:
