The Activation Of Small Molecules By Ditungsten And Dirhenium Complexes

Author : Sonja Marie Peterson
Publisher :
ISBN 13 : 9781267570864
Total Pages : 147 pages
Book Rating : 4.5/5 (78 download)

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Download or read book Ligand Design Considerations for the Activation of Small Molecules written by Sonja Marie Peterson and published by . This book was released on 2012 with total page 147 pages. Available in PDF, EPUB and Kindle. Book excerpt: In Nature, the effective control of both the primary and secondary coordination spheres by metal-containing proteins has led to highly efficient and selective catalysts. Much effort has been put forth by the synthetic chemistry community to design complexes that explore the effects of modifying the primary coordination sphere. However, understanding the implications of both coordination spheres together is necessary to ultimately lead to the development of effective synthetic complexes for small molecule activation. For the research described herein, inspiration from biology has led to the design and preparation of ligands, paying special attention to both environments to meet the specific requirements of the small molecules targeted. Chapter 2 discusses the design and synthesis efforts of two new tripodal and tridentate ligands and complexes that feature both a redox-active primary coordination sphere and contain intramolecular H-bond donors in the secondary coordination sphere. This project was in collaboration with the laboratory of Alan Heyduk. Chapter 3 describes the synthesis and characterization of [Co II[superscript] H2bupa]− and [Ni II[superscript] H2bupa]− complexes. The reactivity of both of these complexes with dioxygen was explored in order to detect intermediates during activation yielding proposed Co III[superscript] -superoxo and Ni III[superscript] -hydroxo species. [Co II[superscript] H2bupa]− was also found to reduce dioxygen to water. Water measurements were carried out for [Co II[superscript] H2bupa]− and [Mn II[superscript] H2bupa]− in the presence of an internal standard. The turnover number for these complexes was determined and will also be discussed. Chapter 4 features the synthesis of a new tripodal ligand, H3btspa. It contains the carboxyamidopyridine group reminiscent of H5bupa, but contains two sufonamido groups capable of acting as H-bond acceptors. Upon deprotonation it ready forms complexes with Mn II[superscript], Fe II[superscript], Co II[superscript], and Zn II[superscript] salts. The stability of these complexes will also be described. Chapter 5 discusses nitrogen-containing complexes made from [Fe II[superscript] MST]-. Both the Fe II[superscript] and Fe III[superscript]-ammine complexes were synthesized along with the Fe II[superscript] -hydrazine complex. Attempts to deprotonate the Fe III[superscript]-ammine complex resulted in the reformation of the Fe II[superscript] ammine complex, leading to the proposal of a transient Fe III[superscript]-amido intermediate. Attempts to perform amination chemistry from the Fe II[superscript] and Fe III[superscript]-ammine complexes will also be highlighted.