Advances in the Fluorine Chemistry of Transition Metals and N-Heterocyclic Carbenes

Advances in the Fluorine Chemistry of Transition Metals and N-Heterocyclic Carbenes
Author: Matthew Leclerc
Publisher:
Total Pages:
Release: 2017
Genre: Heterocyclic compounds
ISBN:

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The importance of fluorine in a wide array of different areas within chemistry and biochemistry has been demonstrated time and time again. Fluorine-containing products range from essential substituents in pharmaceuticals and relatively long-lived tracers for PET imagining, to fluoropolymers with outstanding properties, to essential components in most of the strongest acids available to chemists today. Fluorine's extreme electronegativity makes it a truly unique element, but its acute toxicity in its elemental F2 form makes it difficult to handle, prompting researchers to explore different options for incorporating this important element into a variety of different molecular scaffolds. Due to the remarkable thermodynamic and kinetic stabilities of C-F bonds, methods for forming and breaking these cleanly, and under relatively mild conditions, are in high demand. Fortunately, transition metals have greatly aided in this process. However, fluoroorganometallic chemistry is much less developed than transition metal chemistry involving hydrocarbons, and certainly less understood. One of the primary reasons for this relative dearth of fluoroorganometallic complexes is the difficulty associated with their synthesis. In this work, important steps towards perfluoroalkyl chain-growth within the coordination sphere of a transition metal will be presented, stemming in part from the synthesis and characterization of novel cobalt fluoride and bis(perfluoroalkyl) complexes. As important electrophiles, fluoroalkenes have primarily been used as monomers for the formation of important fluoropolymers. However, their direct reactivity with organics remains rare and is usually difficult to control, with limited substrate scopes. Herein, the formation of stable N-heterocyclic fluoroalkene adducts as versatile synthons for the incorporation of fluoroalkene fragments into various chemical environments will be introduced. By forming these adducts, the inconvenience of manipulating fluorinated gases in further reactions can be avoided, and the N-heterocyclic fragment is shown to aid in directing substitutions involving polyfluoroalkenyl imidazolium salts and organic nucleophiles to form a variety of C-E (E = C, N, O, S) and C-M bonds (M = Mn, Mo). The ease with which C-F bonds are manipulated in these systems is quite remarkable, as the substitution reactions occur cleanly and efficiently at room temperature, to form a variety of new bonds without the need for a transition metal. By expanding on the fundamental reactivity between N-heterocyclic carbenes and fluoroalkenes, attempts were made to correlate the observed reactivity with certain electronic and steric parameters unique to the utilized carbenes. Although a correlation has not yet been established, the effects of atypical steric constraints in a cyclic (alkyl)(amino)carbene were demonstrated, wherein the initial point of attack by the carbene on the fluoroalkene was modified. It is hoped that this work will eventually lead to new roles for organocatalysts in fluoroalkene transformations.

Journal

Journal
Author: American Chemical Society
Publisher:
Total Pages: 1308
Release: 2001
Genre: Chemistry
ISBN:

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Late Transition Metal Polymerization Catalysis

Late Transition Metal Polymerization Catalysis
Author: Bernhard Rieger
Publisher: John Wiley & Sons
Total Pages: 345
Release: 2006-03-06
Genre: Technology & Engineering
ISBN: 3527605266

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At the start of the 1950s, Ziegler and Natta discovered that simple metallorganic catalysts are capable of transforming olefins into linear polymers with highly ordered structures. This pioneering discovery was recognized with a Nobel Prize in 1963. In the 80s and 90s, the development of molecular defined metallocenes led to a renaissance for non-polar polyolefin materials. Designer catalysts allowed a greater precision in defining properties of the material. The past 10 years have seen the discovery of new catalysts based on late transition metals, which allow the combination of polar monomers with non-polar olefins and thus lead to innovative materials. Here, the world's leading authors from industry and academia describe the latest developments in this fascinating field for the first time in such comprehensive detail. In so doing, they introduce readers systematically to the basic principles and show how these new catalysts can effectively be used for polymerization reactions. This makes the book an ideal and indispensable reference for specialists, advanced students, and scientists of various disciplines dealing with research into catalysts and materials science.

Organometallic Syntheses

Organometallic Syntheses
Author: R. Bruce King
Publisher: Elsevier
Total Pages: 686
Release: 2013-10-22
Genre: Science
ISBN: 1483289931

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Organometallic Syntheses, Volume 3 focuses on the synthesis of compounds containing carbon-metal bonds, including ligands, compounds, chlorides, and derivatives. The selection first elaborates on bis(cyclopentadienyl) organolanthanide and organoyttrium chloride, methyl, and hydride complexes and base stabilized alkali metal halide adducts of bis (pentamethylcyclopentadienyl) lanthanide chlorides. The text then examines cyclopentadienyl metal carbonyl and nitrosyl derivatives, ferrocenylamine, cobalticinium and rhodicinium salts, and alkyl transition metal derivatives. The publication takes a look at transition metal complexes containing organophosphorus ligands, transition metal derivatives containing chalcogen ligands, and coinage metal derivatives. The text also reviews transition metal organometallic compounds, including compounds of group IA, IIA, IIB, and IVA. The selection is a vital reference for researchers interested in the synthesis of compounds containing carbon-metal bonds.

Inorganometallic Chemistry

Inorganometallic Chemistry
Author: Thomas P. Fehlner
Publisher: Springer Science & Business Media
Total Pages: 409
Release: 2013-11-22
Genre: Science
ISBN: 1489924590

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There is a certain fascination associated with words. The manipulation of strings of symbols according to mutually accepted rules allows a language to express history as well as to formulate challenges for the future. But language changes as old words are used in a new context and new words are created to describe changing situations. How many words has the computer revolution alone added to languages? "Inorganometallic" is a word you probably have never encountered before. It is one created from old words to express a new presence. A strange sounding word, it is also a term fraught with internal contradiction caused by the accepted meanings of its constituent parts. "In organic" is the name of a discipline of chemistry while "metallic" refers to a set of elements constituting a subsection of that discipline. Why then this Carrollian approach to entitling a set of serious academic papers? Organic, the acknowledged doyenne of chemistry, is distinguished from her brother, inorganic, by the prefix "in," i. e. , he gets everything not organic. Organometallic refers to compounds with carbon-metal bonds. It is simple! Inorganometallic is everything else, i. e. , compounds with noncarbon-metal element bonds. But why a new term? Is not inorganic sufficient? By virtue of training, limited time, resources, co-workers, and so on, chemists tend to work on a specific element class, on a particular compound type, or in a particular phase. Thus, one finds element-oriented chemists (e. g.

Zinc Catalysis

Zinc Catalysis
Author: Stephan Enthaler
Publisher: John Wiley & Sons
Total Pages: 326
Release: 2015-04-27
Genre: Technology & Engineering
ISBN: 3527335986

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Filling the gap in the market for comprehensive coverage of this hot topic, this timely book covers a wide range of organic transformations, e. g. reductions of unsaturated compounds, oxidation reactions, Friedel-Crafts reactions, hydroamination reactions, depolymerizations, transformations of carbon dioxide, oxidative coupling reactions, as well as C-C, C-N, and C-O bond formation reactions. A chapter on the application of zinc catalysts in total synthesis is also included. With its aim of stimulating further research and discussion in the field, this is a valuable reference for professionals in academia and industry wishing to learn about the latest developments.