The Amide Linkage

The Amide Linkage
Author: Arthur Greenberg
Publisher: John Wiley & Sons
Total Pages: 672
Release: 2002-11-11
Genre: Science
ISBN: 9780471420255

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An authoritative reference to an important and ubiquitous chemical linkage The amide linkage is one of the most fundamental and widespread chemical bonds in nature, underlying the properties of a vast array of organic molecules, polymers, and materials, including peptides and proteins. Arthur Greenberg, Curt Breneman, and Joel Liebman's peerless text provides comprehensive coverage of the experimental, structural, and computational findings that shed light on the chemical and physical properties of the amide linkage, as well as its emerging applications in materials and biotechnology. Chapters in The Amide Linkage highlight how this chemical bond factors in the design of enzyme inhibitors, cyclic peptides, antibacterial agents, and emerging nanotechnology applications. This one-of-a-kind study also: * Discusses selected aspects of chemical reactions, structure, bonding, and energetics of the amide bond, including amide rotational barriers, stereochemistry, complexation, spectroscopy, and thermochemistry * Presents specific applications to supramolecular and stereospecific synthesis * Discusses key aspects of peptide and protein chemistry-such as molecular recognition, conformation, and folding-in terms of the amide linkage * Includes chapters contributed by numerous eminent chemists and biochemists Organic, medicinal, polymer, and physical chemists, as well as biochemists and materials scientists, will find The Amide Linkage to be an invaluable addition to their professional libraries.

Coordination Chemistry of Multidentate Ligands from a Multi-component Reaction

Coordination Chemistry of Multidentate Ligands from a Multi-component Reaction
Author: Ann Almesaker
Publisher:
Total Pages: 250
Release: 2009
Genre:
ISBN:

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The application of a multi-component reaction approach has been explored in the synthesis of intricate ligands incorporating the commonly employed ligand motifs bis(2-pyridylmethyl)amine (bPMA) and tris(2-aminoethyl)amine (tren). The synthesis of these ligands demonstrates that multi-component reactions can be an area with high exploratory power in ligand syntheses as they have the potential to afford ligands with a diverse variety of structures by a simple methodology.The coordination chemistry of one bPMA based ligand has been examined with a range of transition metal ions (i.e. MnII, CoII and CuII). The structures of several of these products have been determined by X-ray crystallography and their properties examined by various spectroscopic methods. The complexes are discussed in terms of similarities and differences in the solid state between the different metal ions in combination with different counter ions. Mononuclear and dinuclear complexes, and one case of a 1D coordination polymer were isolated.The spectroscopic properties of copper(II) complexes formed by two analogous tren based ligands were studied. From these studies, it could be concluded that the two ligands formed analogous complexes in both solution and in the solid state. Data on three of the copper(II) tren complexes were collected using synchrotron radiation due to the small size of the isolated crystals. These complexes were found to have trigonal bipyramidal coordination geometry around the mononuclear copper(II) centre. Two isomeric copper(II) nitrate complexes with minor differences in the copper(II) geometries were isolated. In addition, a copper(II) fluoride complex [CuLF]BF4·THF (L = tren based ligand) was studied which interestingly exhibited a very short Cu-F bond, in fact theshortest reported to present time.The copper(II) complexes were further investigated in catalytic oxidation reactions and small ion stabilisation studies. The complexes had poor catalytic activity in catechol oxidation and in oxidative coupling of 2,6-di-tert-butylphenol. However, the bPMA based copper(II) complex showed an initially relatively high catalytic activity in the oxidative coupling reaction, but underwent deactivation. The complexes were not worthy of further investigation in these reactions due to the low catalytic activity. Preliminary results pointed to the fact that the tren based ligands were able to stabilise Cu-OOH species in the solution at low temperatures (-60 and -80 °C). Such complexes are of interest in the elucidation of enzymatic mechanisms of monooxygenases such as peptidylglycine [alpha]-hydroxylating monooxygenases and dopamine [beta]-monooxygenases. These Cu-OOH complexes also demonstrated evidence of partial ligand oxidation upon warming the solutions containing the complexes.Overall a range of ligands structures with intricate structures have been synthesised by a multi-component approach and used to prepare transition metal complexes (CuII, CoII and MnII) which display interesting properties due to the unusual ligand frameworks with large pendant substituents.

Reactions of Coordinated Ligands

Reactions of Coordinated Ligands
Author: P.S. Braterman
Publisher: Springer Science & Business Media
Total Pages: 419
Release: 2012-12-06
Genre: Science
ISBN: 1461307554

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This, the second and final volume of Reactions of Coordinated Ligands, describes the chemistry of ligands bound through non-carbon atoms, and of coordinated carbon dioxide. As before, emphasis is on the underlying mechanisms, which provide a unity of understanding for superficially disparate processes. The wide range of topics covered illustrates well both the versatility and the usefulness of coordination chemistry in the controlled activation of ligands. Looking to the future, carbon dioxide is the feedstock of last resort. The homogeneous reduction of dinitrogen to ammonia now seems unlikely to replace the Haber process, but solution reactions also lead to more complex, varied, and valuable products. Nitrogen monoxide, a "non innocent" ligand, impinges as pollutant and reagent. Its rich chemistry stems from its linked roles as three-electron donor, and as extremely powerful -acceptor. In the hydrolysis and condensation of complexed amides, esters etc. , metals act both as templates and as tunable and poly functional Lewis acids. Here the control of hydrophobic and steric interactions begins to model the subtle mechanisms of biological specificity. Finally, phosphorus and sulfur are imporant both as ligand atoms in themselves, and as anchors for other functionalities. I would like to thank all those who have been involved in the writing and production of this work, and also my colleagues old and new, at Glasgow and the University of North Texas, for their support. Paul S. Braterman v CONTENTS 1. Reactions of Coordinated Carbon Dioxide 1 J. D. Miller 1.

Synthetic Coordination and Organometallic Chemistry

Synthetic Coordination and Organometallic Chemistry
Author: Alexander D. Garnovskii
Publisher: CRC Press
Total Pages: 559
Release: 2003-04-25
Genre: Science
ISBN: 0203911520

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This reference describes standard and nonstandard coordination modes of ligands in complexes, the intricacies of polyhedron-programmed and regioselective synthesis, and the controlled creation of coordination compounds such as molecular and hn-p-complexes, chelates, and homo- and hetero-nuclear compounds. It offers a clear and concise review of modern synthetic techniques of metal complexes as well as lesser known gas- and solid-phase synthesis, electrosynthesis, and microwave and ultrasonic treatment of the reaction system. The authors pay special attention to o-hydroxyazomethines and their S-, Se-containing analogues, b-diketones, and quinines, among others, and examine the immediate interaction of ligands and metal salts or carbonyls.

Variety in Coordination Modes of Ligands in Metal Complexes

Variety in Coordination Modes of Ligands in Metal Complexes
Author: Shinichi Kawaguchi
Publisher: Springer Science & Business Media
Total Pages: 129
Release: 2012-12-06
Genre: Science
ISBN: 3642501486

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Metal complexes play important roles as catalysts or other participants in synthetic and biological reactions. Substrates and sometimes attacking reagents also are activated through coordination with metal atoms or ions. In these events the natures not only of the central metals but also of ancillary ligands exert important influences on the stability and reactivity of the coordinated substrates. A ligand in general can adopt various coordination modes depending on its chemical environment, thus functioning as a probe. The number of coordination modes increases with increasing complexity of the ligand. In this book it is shown that even the simplest mono- and diatomic ligands such as H, CO, and N2 exhibit a variety of coordination modes, which are related to their reactions. The thiocyanate anion is taken up as a representative of the triatomic ambidentate ligands, and factors influencing the preferences for N- und S-bonding are summarized. Coordination chemistry of ß-dicarbonyl compounds is a highlight of this book. Acetylacetone, one of the most familiar Werner ligands, is shown to favor -carbon and n-allylic bonding in many instances. Its versatile behaviour in changing coordination modes is revealed.

Synthesis and Coordination Chemistry of Polypyridyl Amide Ligands

Synthesis and Coordination Chemistry of Polypyridyl Amide Ligands
Author: Maisara Abdul Kadir
Publisher:
Total Pages: 331
Release: 2012
Genre: Coordination compounds
ISBN:

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This thesis provides an account of the synthesis and study of fifteen amide-containing polypyridyl ligands, eleven of which are new compounds. These ligands all possess at least one amide moiety, potentially capable of anion binding and one or more pendant pyridyl donor groups as the metal coordinating sites. A further evolution over previously reported compounds is that a majority of the amide compounds incorporate a pre-organised amide component that will constitute the anion binding region. The alkyl and phenyl spacers were utilised to confer flexibility to these compounds and to extend the spacing between the anion binding moiety and the pendant metal complexing groups. The compounds investigated in this work are divided into three categories; (i) unsymmetrical monoamide ligands that possess one amide functional group, one ester protected carboxylate and one external donor pyridyl moiety; (ii) symmetrical flexible amide ligands that possess two or more internal amide groups and two external pyridyl metal coordinating sites, and; (iii) symmetrical amide bridging ligands that incorporate two di-2-pyridylmethylamine chelating motifs. The coordination chemistry and metallo-supramolecular chemistry of these ligands was investigated with a range of late transition metals including cadmium(II), copper(II), cobalt(II), silver(I), zinc(II) and palladium(II). Palladium(II) precursors, with a selection of monodentate or bidentate chelating ancillary blocking ligands, were utilised to form discrete mono- and dinuclear assemblies with a view to investigating anion complexation in solution. Other transition metal precursors were studied with a focus on the synthesis of coordination polymers that display anion coordinating pockets.