Author: Adam Scharf
Publisher:
ISBN:
Category :
Languages : en
Pages : 196

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Author: Nicholas Ruhs
Publisher:
ISBN:
Category : Electronic dissertations
Languages : en
Pages : 226

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The importance of Pd-catalyzed C--H functionalization reactions for chemical transformations has been widely studied over the last several decades. Much of the research to date has focused on conventional Pd0/II catalytic cycles. However, more recent studies have shown that many transformations can also follow a PdII/IV catalytic cycle. High-valent PdIII and PdIV species are often proposed to be important intermediates in such transformations. C--H coupling reactions involving high-valent intermediates often involve the oxidation of a PdII species to a PdIII or PdIV complex, which can then undergo subsequent C--heteroatom bond formation. However, the need for harsh oxidants and reaction conditions in many of these reactions hinders their practical applicability. The focus of this work is to study the properties and reactivity of PdII, PdIII, and PdIV complexes through modifications of the supporting macrocyclic ligands. Another goal of this work is to probe the ability of these complexes to facilitate C--H activation and C--heteroatom bond formation reactions using environmentally benign oxidants.Our lab reported the synthesis and characterization of the first organometallic mononuclear PdIII complexes stabilized by the tetradentate ligand N,N'-di-tert-butyl-2,11-diaza[3,3](2,6)pyridinophane (tBuN4). In order to further probe the Pd chemistry with this class of ligands, we prepared ligands with modifications to the steric bulk on the amine groups. In the first study detailed in chapter 2, the synthesis and characterization of PdII and PdIII complexes supported by N,N'-di-neo-pentyl-2,11-diaza[3,3](2,6)-pyridinophane(NpN4) and N,N'-di-benzyl-2,11-diaza[3,3](2,6)-pyridinophane(BzN4) is reported. Interestingly, the spectroscopic and crystallographic property of the newly synthesized complexes falls between the tBuN4 and MeN4 complexes. The C--C and C--heteroatom bond formation reactivity of the NpN4 and BzN4 supported complexes is also similar to our group's previously reported complexes.We also prepared and studied a series of Pd complexes bearing a modified tetradentate pyridinophane ligand, tBuN3CH. Essentially, we have replaced one of the nitrogen donor atoms from the N4 ligand with a carbon atom and have also introduced a new C--H bond. Due to its expected positioning near the metal center, this bond has the potential to undergo intramolecular C--H bond activation. In order to study the reactivity of this ligand, electronic modifications were made by substituting various electron-donating and withdrawing groups in the para position to this new C--H bond. In chapter 3, the synthesis and characterization of a series of PdII, PdIII, and PdIV complexes stabilized by the N3CH ligand is reported. Interestingly, a spectroscopic and crystallographic study of the pRN3CHPdII(OAc)2 complexes reveals that the Cipso--H bond remains unactivated at the PdII stage. However, upon oxidation to PdIII, the Cipso--H bond is activated.Interestingly, we discovered that the aerobic oxidation of the PdII complex [pRN3CHPdII(MeCN)](BF4) leads to the formation of the PdIII complex [pRN3CHPdIII(MeCN)](ClO4)2 at room temperature. Surprisingly, the C--H activation reaction proceeds in the presence of oxygen without the need for external base. Furthermore, the moderate rate of the reaction allowed us to investigate the mechanism of the reaction by utilizing kinetics and UV-Vis spectroscopy. Detailed mechanistic studies revealed that C--H activation of the Cipso--H bond is the rate determining step of the reaction.

Author: Peter Maitlis
Publisher: Elsevier
ISBN: 0323155324
Category : Science
Languages : en
Pages : 336

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The Organic Chemistry of Palladium, Volume 1: Metal Complexes deals with the number of organic reactions that can be catalyzed by palladium, particularly as regards the structures bonding, and reactions of the metal complexes. The book discusses monodentate ligands which are either neutral (carbonyls, isonitriles, carbenes) or anionic (methyl, phenyl, ethynyl, hydride). The text also examines the complexes formed by 1,3-. 1,4-, and 1,5-diolefins where four carbon atoms are bound to the metal. Palladium (II) can undergo a reaction with the 1,3-dienes and results in a ?-allylic complexes where only three carbon atoms are coordinated to the metal. (The bonding situation in complexes 1,4- and 1,5-dienes, where no great interaction between the olefins are similar to that in monoolefin complexes, is straightforward), Olefins can also react with palladium chloride in protic solvents to produce ketones (or aldehydes) or organic coupling products. Some experiments conducted by Huttel et al shows that some palladium was precipitated from the reactions giving lower yields, resulting in various aldehydes and ketones as by products. The book also discusses cyclopentadienyl and benzene complexes. The text can prove beneficial for researchers, investigators and scientists whose works involve organic chemistry, analytical chemistry, physical chemistry and inorganic chemistry.

Author: F. R. Hartley
Publisher:
ISBN:
Category : Science
Languages : en
Pages : 570

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Author: Stefan Warsink
Publisher:
ISBN:
Category :
Languages : en
Pages : 172

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Author: Kenneth Kam-Wing Lo
Publisher: Academic Press
ISBN: 012803887X
Category : Science
Languages : en
Pages : 408

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Inorganic and Organometallic Transition Metal Complexes with Biological Molecules and Living Cells provides a complete overview of this important research area that is perfect for both newcomers and expert researchers in the field. Through concise chapters written and edited by esteemed experts, this book brings together a comprehensive treatment of the area previously only available through scattered, lengthy review articles in the literature. Advanced topics of research are covered, with particular focus on recent advances in the biological applications of transition metal complexes, including inorganic medicine, enzyme inhibitors, antiparasital agents, and biological imaging reagents. - Geared toward researchers and students who seek an introductory overview of the field, as well as researchers working in advanced areas - Focuses on the interactions of inorganic and organometallic transition metal complexes with biological molecules and live cells - Foscuses on the fundamentals and their potential therapeutic and diagnostic applications - Covers recent biological applications of transition metal complexes, such as anticancer drugs, enzyme inhibitors, bioconjugation agents, chemical biology tools, and bioimaging reagents

Author: Robert Alan Kolodny
Publisher:
ISBN:
Category : Cations
Languages : en
Pages : 198

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Author: David Morales-Morales
Publisher: Elsevier
ISBN: 0128129328
Category : Science
Languages : en
Pages : 756

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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

Author: David Morales-Morales
Publisher: Elsevier
ISBN: 0080545157
Category : Science
Languages : en
Pages : 467

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Pincer complexes are formed by the binding of a chemical structure to a metal atom with at least one carbon-metal bond. Usually the metal atom has three bonds to a chemical backbone, enclosing the atom like a pincer. The resulting structure protects the metal atom and gives it unique properties.The last decade has witnessed the continuous growth in the development of pincer complexes. These species have passed from being curiosity compounds to chemical chameleons able to perform a wide variety of applications. Their unique metal bound structures provide some of the most active catalysts yet known for organic transformations involving the activation of bonds. The Chemistry of Pincer Compounds details use of pincer compounds including homogeneous catalysis, enantioselective organic transformations, the activation of strong bonds, the biological importance of pincer compounds as potential therapeutic or pharmaceutical agents, dendrimeric and supported materials.* Describes the chemistry and applications of this important class of organometallic and coordination compounds* Covers the areas in which pincer complexes have had an impact* Includes information on more recent and interesting pincer compounds not just those that are well-known

Author: Naseer Ahmad
Publisher:
ISBN:
Category : Chemistry
Languages : en
Pages : 6

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