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Author : Benjamin Keith Leipzig
Publisher :
ISBN 13 :
Total Pages : 159 pages
Book Rating : 4.:/5 (1 download)
Download or read book Electronic Activation and Tuning of Redox-active Ligand Orbitals written by Benjamin Keith Leipzig and published by . This book was released on 2017 with total page 159 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Author : Marine Desage-El Murr
Publisher : John Wiley & Sons
ISBN 13 : 3527348506
Total Pages : 373 pages
Book Rating : 4.5/5 (273 download)
Download or read book Redox-Active Ligands written by Marine Desage-El Murr and published by John Wiley & Sons. This book was released on 2024-02-05 with total page 373 pages. Available in PDF, EPUB and Kindle. Book excerpt: Redox-Active Ligands Authoritative resource showcasing a new family of ligands that can lead to better catalysts and promising applications in organic synthesis Redox-Active Ligands gives a comprehensive overview of the unique features of redox-active ligands, describing their structure and synthesis, the characterization of their coordination complexes, and important applications in homogeneous catalysis. The work reflects the diversity of the subject by including ongoing research spanning coordination chemistry, organometallic chemistry, bioinspired catalysis, proton and electron transfer, and the ability of such ligands to interact with early and late transition metals, lanthanides, and actinides. The book is divided into three parts, devoted to introduction and concepts, applications, and case studies. After the introduction on key concepts related to the field, and the different types of ligands and complexes in which ligand-centered redox activity is commonly observed, mechanistic and computational studies are described. The second part focuses on catalytic applications of redox-active complexes, including examples from radical transformations, coordination chemistry and organic synthesis. Finally, case studies of redox-active guanidine ligands, and of lanthanides and actinides are presented. Other specific sample topics covered include: An overview of the electronic features of redox-active ligands, covering their historical perspective and biological background The versatility and mode of action of redox-active ligands, which sets them apart from more classic and tunable ligands such as phosphines or N-heterocyclic carbenes Preparation and catalytic applications of complexes of stable N-aryl radicals Metal complexes with redox-active ligands in H+/e- transfer transformations By providing up-to-date information on important concepts and applications, Redox-Active Ligands is an essential reading for researchers working in organometallic and coordination chemistry, catalysis, organic synthesis, and (bio)inorganic chemistry, as well as newcomers to the field.
Author : Linus Kai Ho Chiang
Publisher :
ISBN 13 :
Total Pages : 187 pages
Book Rating : 4.:/5 (112 download)
Download or read book Elucidating the Electronic Structure of Transition Metal Complexes Featuring Redox Active Ligands written by Linus Kai Ho Chiang and published by . This book was released on 2014 with total page 187 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this thesis a number of projects involving the design and characterization of complexes bearing redox active ligands are described. Focusing on the phenolate containing ligands, the properties and electronic structure of their corresponding metal complexes were studied by a series of experimental (i.e. electrochemistry, UV-Vis-NIR, EPR, rR etc.) and theoretical (DFT) methods. Specifically, the redox processes of these metal complexes were tuned by varying the para-ring substituents. In one study, nickel-salen (salen is a common abbreviation for N2O2 bis-Schiff-base bis-phenolate ligands) complexes were investigated, where the oxidation potentials of the ligand were predictably decreased as the electron donating ability of the para-ring substituents was increased (NMe2 > OMe > tBu > CF3). Interestingly, the oxidation of these geometrically-symmetric complexes afforded an asymmetric electronic structure in a number of cases, in which the ligand radical was localized on one phenolate rather than delocalized across the ligand framework. This difference in electronic structure was found to be dependent on the electron donating ability of the substituents; a delocalized ligand radical was observed for electron-withdrawing substituents and a localized ligand radical for strongly donating substituents. These studies highlight that para-ring substituents can be used to tune the electronic structure (metal vs. ligand based, localized vs. delocalized radical character) of metallosalen complexes. To evaluate if this electronic tuning can be applied to the metal center, a series of cobalt complexes of these salen ligands were prepared. Indeed, the electronic properties of the metal center were also significantly affected by para-ring substitution. These cobalt-salen complexes were tested as catalysts in organometallic radical-mediated polymerizations, where the most electron rich complexes displayed the best conversion rates. With a firm understanding of the role that the para-ring substituent can play in influencing the electronic structure and reactivity of metallosalen complexes in catalysis, two novel iron complexes, which contain a number of redox active phenolate fragments, were prepared. In addition, these iron-complexes feature a chiral bipyrrolidine backbone. Ligands with this chiral diamine backbone bind metals ions diastereoselectively owing to its increased rigidity, which is critical to stereoselectivity in catalysis. A symmetric (with two phenolates) ligand was prepared by reported methods, and a novel route to synthesize an asymmetric ligand (one phenolate and one pyridine) from symmetric starting materials was established. The neutral iron-complexes were found to be high spin (S = 5/2), and can undergo ligand based oxidation to form an antiferromagnetically-coupled (Stotal = 2) species. The results presented will serve as the basis for catalyst development using complexes of similar ligands.
Author : Mark R. Ringenberg
Publisher :
ISBN 13 :
Total Pages : pages
Book Rating : 4.:/5 (774 download)
Download or read book Reactions at Coordinated Ligands: Redox-active Ligands and Coordination of Lewis Acids written by Mark R. Ringenberg and published by . This book was released on 2011 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The theme of this study is reactivity at the ligand and how remote, relative to the metal, activation affects the metal center. The three approaches were the use of redox-active ligands, ligand protonation and Lewis acid coordination to ligands. The focus is on ligand design rather than substrate or metal optimization with a primary interest in reactivity with dihydrogen. The main thrust of the work has been the investigation of redox-active ligands in which redox occurs at the ligand. Redox-active ligands have been generally a curiosity in organometallic chemistry and have only recently been realized in catalysis. Presented here is one of the first examples of a system that incorporates redox-active ligands as a critical component to the catalysts. The complexes utilizing redox-active ligands became Lewis acidic upon oxidation, similar in behavior to the Noyori type catalyst that became Lewis acidic upon protonation. The catalysts containing redox-active ligand were used for the oxidation of H2. The interest in H2 oxidation is the hope that it will fulfill the need for a new fuel source. This interest has lead to the development of soluble catalyst that can oxidize H2 to protons and electrons, in order to further study the mechanism. Redox-active ligands have lower reorganizational barriers because redox at organic substituents are typically lower than for inorganic centers. Furthermore, redox-active ligands can supplement the electrons/holes transferred from the metal, which can facilitate reactions that require multi-electron transfers. The next theme was the use of borane Lewis acids bound to a coordinated ligand, which dramatically changed the ligands from a donor to an acceptor. This type of reaction at the ligand fundamentally changes the reactivity at the metal, however, the affects are not as dramatic as say substituting the ligand. A largh enough change in ligand polarity can affect oxidation-state at the metal. The oxidation state of a metal becomes very difficult to assign when multiple electronic structures exist between the metal and the ligand. In fact in many ways the concept of metal oxidation state becomes meaningless as the electronic structure of the ligand becomes more complicated. These subtler changes in ligand oxidation state and the affects they have on reactivity at metal have not been as widely explored in catalysis. Remote activation of a metal center through reacts at coordinated ligands will be explored here in. The coordination of boranes to cyanide ligands is well know, however, this theme has not been applied to hydrogenase models. Cyanide is an essential component of the [FeFe]- and [NiFe]-hydrogenase active sites, both enzymes feature two cyanide ligands, however, models using cyanides ligands are plagued by undesirable side reactions such as metal-cyanide bridged polymers and decomposition. The bound boranes are used to simulate the hydrogen bonding found in the enzymes. The complexation of Lewis acids to cyanides offers an advantage over alkylation, in that the inductive affect of the borane can be tuned to better approximate the correct level of hydrogen bonding found in the enzyme.
Author : Ryan A. Zarkesh
Publisher :
ISBN 13 : 9781267171108
Total Pages : 150 pages
Book Rating : 4.1/5 (711 download)
Download or read book Synthesis, Reactivity, and Multi-electron Redox Behavior of a Bis(phenoxy)amide Ligand Coordinated to a Tantalum Metal Center written by Ryan A. Zarkesh and published by . This book was released on 2012 with total page 150 pages. Available in PDF, EPUB and Kindle. Book excerpt: This dissertation describes the synthesis and reactivity of tantalum metal complexes containing a tridentate redox-active ligand. Fundamental studies have focused on utilizing the redox-active ligand to store multiple electron equivalents for oxidative addition and reductive elimination reactions. Chapter 1 provides an introduction to the characteristics of redox-active ligands and provides an overview of group transfer reactions involving redox-active ligands. The previous published results of bidentate redox-active ligands coordinated to Group IV d0 metals are discussed in terms of their decomposition side reactions. Chapter 2 describes the coordination of a known tridentate redox-active bis(phenoxy)amide ligand, (ONO), to a d0 tantalum(V) metal center and the examination of the redox properties of the resulting chloro oxidation products by electrochemical and spectroscopic methods. Chapter 3 examines the reactivity of the (ONO)TaR2 complexes in the general context of organometallic chemistry with a focus on protonolysis and reactivity with aryl azides, a known source of nitrene fragments upon oxidation. Chapter 4 examines the reactivity of the (ONO)TaX2 (X = Me, Cl) compounds with bulky diazoalkanes, a known carbene transfer reagent. The (ONO)TaCl2 complex proved to be a competent catalyst to generate cyclopropanes from styrene and the corresponding diazoalkane. Chapter 5 explores the utilization of the (ONO) ligand to store electron equivalents for the catalytic nitrene-nitrene coupling reactions with organoazides to afford organodiazenes. Finally, Chapter 6 addresses the electronic considerations of a related redox-active triamido ligand in an effort to tune the ligand's redox potentials.
Author : Daniël Laurens Johannes Broere
Publisher :
ISBN 13 : 9789402801767
Total Pages : 0 pages
Book Rating : 4.8/5 (17 download)
Download or read book New Avenues for Redox-active Ligands written by Daniël Laurens Johannes Broere and published by . This book was released on 2016 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: "Many homogeneous and heterogeneous catalyst systems contain one or more transition metals. The widespread employment of these metals as catalysts is ascribed to their accessible d-orbitals to activate chemical bonds, and the ability to undergo metal-based oxidation state changes to facilitate desirable chemical transformations. The fine-tuning of homogeneous catalyst systems is commonly achieved by the coordination of (spectator) ligands, which can vary greatly in steric bulk or electron-donating ability. For such ligands the energy required for oxidation or reduction of the ligand is much bigger than that needed to change the oxidation state of the metal. Accordingly, the redox changes required for bond making and breaking processes typically occur at the metal center. Redox-active ligands have more energetically accessible levels for reduction and/or oxidation upon coordination to a metal. As a result, either solely ligand-centered redox processes can occur, with the metal center remaining in the same oxidation state, or more diffuse scenarios, wherein both the ligand and metal change oxidation states in a synergistic fashion. Although initially thought of as a spectroscopic curiosity, redox-active ligands are nowadays recognized for their ability to induce new reactivity at metal centers. Within this thesis we have shown that o-aminophenol derived architectures can give fascinating spectroscopic properties upon coordination to late transition metals. Moreover, these ligands can expand upon a metal's "common" reactivity by actively taking part in intramolecular redox processes. We have demonstrated that intramolecular single-electron transfer processes can facilitate homolytic bond cleaving reactions and the generation of reactive nitrogen-centered radicals."--Samenvatting auteur.
Author : Edwin Wing Yip Wong
Publisher :
ISBN 13 :
Total Pages : 610 pages
Book Rating : 4.:/5 (91 download)
Download or read book An Investigation of Redox-active Isoindoline-based Ligands and Their Coordination Complexes written by Edwin Wing Yip Wong and published by . This book was released on 2012 with total page 610 pages. Available in PDF, EPUB and Kindle. Book excerpt: The structural and electronic properties of metal complexes with isoindoline-based redox-active ligands and the ability of these ligands to stabilize unusual oxidation states was investigated. Two types of redox-active ligands were examined: phthalocyanines (Pc) and bis(2-pyridylimino)isoindolines also known as lobsterates (Lb). In contrast to the ancillary or spectator ligands more commonly used in coordination chemistry, redox-active ligands can exist in a range of oxidation states. Additionally, the chemical inertness of the Pc ligand could be used to develop new catalysts where the Pc ligand can stabilize a highly reactive metal centre and also act as an electron reservoir in a catalytic cycle. With this in mind, the reduction of trichloro(phthalocyanato)niobium(V) was performed with various reducing agents in order to study the bond activating ability of the reduced species and to determine the crystal structure of the reduced products. C-O bond activation of ether-type solvents suggests that the Pc ligand is able to withstand bond activation from a highly reduced niobium centre while, at the same time, allowing the niobium centre to activate the C-O bonds of the solvent. NbPc complexes containing Pc(4-) ligands were structurally characterized. A reduced MgPc complex containing a Pc(3-) ligand was also structurally characterized. A report of gold(II) Pc and the ability of Pc to stabilize gold in an unusual, paramagnetic +2 oxidation state was re-investigated. Attempts to synthesize soluble versions of AuPc as well as the original AuPc did not produce the desired gold(II) products and only diamagnetic gold(III) Pcs were obtained. An unprecedented, ring- contracted gold(III) Pc analogue was discovered and structurally characterized in the process of these studies. A series of three new 5,6-substituted Lb ligands were synthesized and the redox properties of these ligands in copper(II) acetate complexes were evaluated using cyclic voltammetry. The reductions of the copper acetate Lb complexes were not chemically reversible. The 2,6-diisopropylphenoxy-substituted Lb copper acetate complexes formed acetate-bridged 1-D chains. Superconducting quantum interference device magnetometry suggests that the Cu centres are very weakly antiferromagnetically coupled.
Author : Marcel Swart
Publisher : John Wiley & Sons
ISBN 13 : 1118898303
Total Pages : 472 pages
Book Rating : 4.1/5 (188 download)
Download or read book Spin States in Biochemistry and Inorganic Chemistry written by Marcel Swart and published by John Wiley & Sons. This book was released on 2015-09-17 with total page 472 pages. Available in PDF, EPUB and Kindle. Book excerpt: It has long been recognized that metal spin states play a central role in the reactivity of important biomolecules, in industrial catalysis and in spin crossover compounds. As the fields of inorganic chemistry and catalysis move towards the use of cheap, non-toxic first row transition metals, it is essential to understand the important role of spin states in influencing molecular structure, bonding and reactivity. Spin States in Biochemistry and Inorganic Chemistry provides a complete picture on the importance of spin states for reactivity in biochemistry and inorganic chemistry, presenting both theoretical and experimental perspectives. The successes and pitfalls of theoretical methods such as DFT, ligand-field theory and coupled cluster theory are discussed, and these methods are applied in studies throughout the book. Important spectroscopic techniques to determine spin states in transition metal complexes and proteins are explained, and the use of NMR for the analysis of spin densities is described. Topics covered include: DFT and ab initio wavefunction approaches to spin states Experimental techniques for determining spin states Molecular discovery in spin crossover Multiple spin state scenarios in organometallic reactivity and gas phase reactions Transition-metal complexes involving redox non-innocent ligands Polynuclear iron sulfur clusters Molecular magnetism NMR analysis of spin densities This book is a valuable reference for researchers working in bioinorganic and inorganic chemistry, computational chemistry, organometallic chemistry, catalysis, spin-crossover materials, materials science, biophysics and pharmaceutical chemistry.
![Download Synthesis, Structural and Electronic Properties, and Reactivity of Group 5 Metal Complexes Incorporating the Redox-active [ONO] Ligand Platform PDF Online Free](https://books.google.com/books/content/images/frontcover/-nL-oAEACAAJ?fife=w200-h370)
Author : Steven Paul Hananouchi
Publisher :
ISBN 13 : 9781303814730
Total Pages : 67 pages
Book Rating : 4.8/5 (147 download)
Download or read book Synthesis, Structural and Electronic Properties, and Reactivity of Group 5 Metal Complexes Incorporating the Redox-active [ONO] Ligand Platform written by Steven Paul Hananouchi and published by . This book was released on 2014 with total page 67 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis describes the synthesis, electronic and structural properties, and reactivity of Group 5 metal complexes incorporating the [ONO] ligand platform. A study of the electronic and structural properties of the Group 5 metal complexes incorporating the [ONO] ligand is performed. Once the electronic properties of the complexes are known, the reactivity of the complexes is compared. Chapter 1 describes a brief history of redox-active ligands. The previously published results of redox-active ligands acting as an electron source are discussed. In Chapter 2, the synthesis and electronic and structural properties of metal dichlorides and trichlorides of Group 5 metal complexes incorporating the [ONO] ligand and comparing the metal-ligand cooperativity are performed. In Chapter 3, the synthesis and reactivity of [ONO]NbMe2 and the reactivity of reduced species of [ONO]V(L)n are discussed.
Author : Seth N. Brown
Publisher : Wiley
ISBN 13 : 9781118646854
Total Pages : 368 pages
Book Rating : 4.6/5 (468 download)
Download or read book The Age of Noninnocence written by Seth N. Brown and published by Wiley. This book was released on 2017-01-24 with total page 368 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book presents a comprehensive introduction to the unique and fundamental features of redox-active ligands, the preparation and characterization of their coordination complexes, and finally the importance of this class of molecules to biology, catalysis and materials. The book aims to provide a broadly accessible introduction to the particular features and opportunities unique to redox-active ligands. It begins with an introduction to the intellectual challenges posed by redox-active ligands and descriptions of the types of ligands and complexes in which ligand-centered redox activity are commonly observed. Following this, the book is divided into two sections as follows: The first section focuses on electronic structure and bonding, which has historically dominated this field and continues to be actively researched. The spectroscopic and other physical measurements that have been used to elucidate the electronic structure of these compounds are described. The interplay between synthesis, bonding models, and physical measurements has often been critical in shaping our understanding of these compounds. This interplay is illustrated by a number of case studies. The second section focuses on the use of redox-active complexes in stoichiometric and catalytic reactions. The scope of known reactions is presented, including examples from bioinorganic chemistry (both enzymes and model compounds). Where possible, the significance of the redox-active ligand is discussed, with an eye both to summarizing existing knowledge and pointing out possibilities for future research. This book explains the underpinnings of physical and theoretical techniques of redox-active ligands, providing up to date information on definitions, scope and applications for research scientists and graduate students working in organic and inorganic chemistry, organometallics and coordination chemistry.
Author : Peter Henry Dinolfo
Publisher :
ISBN 13 :
Total Pages : pages
Book Rating : 4.:/5 (584 download)
Download or read book Investigation of Ligand-centered Mixed Valency and Optical Electron Transfer in Rhenium Based Supramolecular Coordination Compounds written by Peter Henry Dinolfo and published by . This book was released on 2004 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The primary focus of this thesis is the examination of intramolecular electron transfer processes in mixed valence compounds. Rhenium based supramolecular coordination chemistry has been used create a number of highly symmetrical structures that contain cofacially arranged, redox active ligands. When reduced by an odd number of electrons, the molecules belong to an unusual class of mixed valence compounds where the ligands are the degenerate redox centers, i.e. Ligand-Centered Mixed Valency. Inter-ligand electronic communication in these systems is controlled by direct donor/acceptor orbital overlap rather than by superexchange through the molecular framework. As shown by X-ray crystallography and semiempirical modeling, the spectroscopically determined electronic coupling strengths are consistent with geometrical configurational differences between the cofacial ligand pairs. In a number of cases, electroabsorbance (Stark) spectroscopy has been employed to directly evaluate the adiabatic charge transfer distances. Depending the geometrical arrangement of the redox active ligand pairs, the degree of electronic communication can be tuned from non-interacting (Robin-Day Class I), to fully delocalized (Class III).
Author : Romain Kunert
Publisher :
ISBN 13 :
Total Pages : 0 pages
Book Rating : 4.:/5 (139 download)
Download or read book Synthesis, Characterization and Applications of Complexes Involving Redox-active Ligands written by Romain Kunert and published by . This book was released on 2022 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: We developed a new type of redox-active ligand, involving two N-heterocyclic carbenes and two phenolate units. The strong electron donating properties of the NHC moieties were utilized to stabilize complexes in high oxidation states while the phenolate groups were used as redox-active units. Group 10 metal complexes were developed. Their oxidation chemistry showed the formation of phenoxyl radicals, reaching up to two-electron oxidized, bis(phenoxyl) complexes. We also report the first Ni(III) complex with NHC donors. The ligand was also used to develop metal complexes with nitride ligands. The nitridomanganese complex proved to be unstable and degraded in successive intramolecular nitride-NHC reductive couplings. The degradation afforded a peculiar organic salt with three fused rings forming a central triazone pattern. Conversely, the chromium nitride complex could be isolated and thoroughly characterized. The one-electron oxidized product was generated reversibly at low temperature but readily evolved at room temperature. In a parallel work, we also developed new types of sterically hindered salen ligands to form distorted copper salen complexes as molecular models of galactose oxidase. The copper salen catalysts showed to be effective for the aerobic oxidation of non-activated alcohol substrates.
Author : Aaron M. Hollas
Publisher :
ISBN 13 : 9781369227055
Total Pages : 188 pages
Book Rating : 4.2/5 (27 download)
Download or read book Synthesis and Ligand-Enabled Reactivity of Transition Metal Complexes Bearing a Redox-Active Bis(phenoxy)amide Ligand written by Aaron M. Hollas and published by . This book was released on 2016 with total page 188 pages. Available in PDF, EPUB and Kindle. Book excerpt: The work described herein focuses on the ability of redox-active ligands to enable multi-electron reactivity at transition metal centers. A parallel theme is the effect of ancillary ligands on controlling and modulating the electronic structure of the redox-active ligand and metal center in addition to ancillary ligand effects as they relate to controlling the primary coordination sphere of the metal. (Abstract shortened by ProQuest.).
Author : Gerard van Koten
Publisher : Springer
ISBN 13 : 3642310818
Total Pages : 363 pages
Book Rating : 4.6/5 (423 download)
Download or read book Organometallic Pincer Chemistry written by Gerard van Koten and published by Springer. This book was released on 2012-09-17 with total page 363 pages. Available in PDF, EPUB and Kindle. Book excerpt: Gerard van Koten: The Mono-anionic ECE-Pincer Ligand - a Versatile Privileged Ligand Platform: General Considerations.- Elena Poverenov, David Milstein: Non-Innocent Behavior of PCP and PCN Pincer Ligands of Late Metal Complexes.- Dean M. Roddick: Tuning of PCP Pincer Ligand Electronic and Steric Properties.- Gemma R. Freeman, J. A. Gareth Williams: Metal Complexes of Pincer Ligands: Excited States, Photochemistry, and Luminescence.- Davit Zargarian, Annie Castonguay, Denis M. Spasyuk: ECE-Type Pincer Complexes of Nickel.- Roman Jambor and Libor Dostál: The Chemistry of Pincer Complexes of 13 - 15 Main Group Elements.- Kálmán J. Szabo: Pincer Complexes as Catalysts in Organic Chemistry.- Jun-ichi Ito and Hisao Nishiyama: Optically Active Bis(oxazolinyl)phenyl Metal Complexes as Multi-potent Catalysts.- Anthony St. John, Karen I. Goldberg, and D. Michael Heinekey: Pincer Complexes as Catalysts for Amine Borane Dehydrogenation.- Dmitri Gelman and Ronit Romm: PC(sp3)P Transition Metal Pincer Complexes: Properties and Catalytic Applications.- Jennifer Hawk and Steve Craig: Physical Applications of Pincer Complexes.
Author : Warren VandeVen
Publisher :
ISBN 13 :
Total Pages : 0 pages
Book Rating : 4.:/5 (141 download)
Download or read book Tuning the Electronic Structure and Reactivity of Oxidized Chromium Salen Nitride Complexes written by Warren VandeVen and published by . This book was released on 2023 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Transition metal nitride (N3-) complexes exhibit useful reactivity towards heteroatom transfer, as well as providing valuable insight into the mechanisms of dinitrogen reduction and ammonia oxidation. Salen ligands are capable of forming complexes with a large number of metal ions in different oxidation states and are thus a versatile platform in coordination chemistry research. By incorporating salen ligands with a variety of R-group substituents at the para position of the phenolate moieties, the electronic structure and thus the reactivity of the nitride ligand can be modified. This thesis will focus on the synthesis, characterization and reactivity of Cr nitride complexes bearing modified salen ligands (R = NO2, CF3, tBu, OMe, OiPr, NMe2, and NEt2). Salen ligands are well-known for their ability to form ligand radicals upon oxidation, as opposed to metal-based oxidation. Oxidation of CrNSalNMe2 and CrNSalNEt2 yields CrV ligand radical species, whereas the other less donating R-groups yield high-valent CrVI nitride complexes. Oxidized complexes were characterized by both experimental and theoretical techniques including UV-vis-NIR spectroscopy, electron paramagnetic resonance spectroscopy, electrochemistry, and density functional theory calculations. Depending on the locus of oxidation, desirable reactivity may be observed such as C-H bond activation. The addition of exogenous ligands may further activate the nitride ligand and facilitate homocoupling or C-H bond activation pathways.
Author : D. D. Perrin
Publisher : Elsevier
ISBN 13 : 1483284611
Total Pages : 195 pages
Book Rating : 4.4/5 (832 download)
Download or read book Ionisation Constants of Inorganic Acids and Bases in Aqueous Solution written by D. D. Perrin and published by Elsevier. This book was released on 2016-09-14 with total page 195 pages. Available in PDF, EPUB and Kindle. Book excerpt: Ionisation Constants of Inorganic Acids and Bases in Aqueous Solution, Second Edition provides a compilation of tables that summarize relevant data recorded in the literature up to the end of 1980 for the ionization constants of inorganic acids and bases in aqueous solution. This book includes references to acidity functions for strong acids and bases, as well as details about the formation of polynuclear species. This text then explains the details of each column of the tables, wherein column 1 gives the name of the substance and the negative logarithm of the ionization constant and column 2 gives the temperature of measurements in degree Celsius. This book presents as well the method of measurement and the literature references that are listed alphabetically at the end of the tables. Chemists will find this book useful.
Author : Khrystyna Herasymchuk
Publisher :
ISBN 13 :
Total Pages : 207 pages
Book Rating : 4.:/5 (124 download)
Download or read book Controlling Redox Processes in Metal Complexes and Multifunctional Materials written by Khrystyna Herasymchuk and published by . This book was released on 2020 with total page 207 pages. Available in PDF, EPUB and Kindle. Book excerpt: Transition metal complexes incorporating redox-active ligands have the potential to facilitate controlled multielectron chemistry, enabling their use in catalysis and energy storage applications. Moreover, the use of transition metal complexes containing redox-active ligands has been extended to two- (2D) and three-dimensional (3D) materials, such as supramolecular assemblies (i.e., metallacycles, molecular cages, or macrocycles) and metal-organic frameworks (MOFs) for catalytic, magnetic, electronic, and sensing applications. Salens (N2O2 bis(Schiff-base)-bis(phenolate) are an important class of redox-active ligands, and have been investigated in detail as they are able to stabilize both low and high metal oxidation states for the above-mentioned applications. The work in this thesis focuses on the synthesis and electronic structure elucidation of metal salen complexes in monomeric form, as discrete supramolecular assemblies and 3D MOFs. Structural and spectroscopic characterization of the neutral and oxidized species was completed using mass spectrometry, cyclic voltammetry, X-ray diffraction, NMR, UV-Vis-NIR, and EPR spectroscopies, as well as theoretical (DFT) calculations. Chapter 2 discusses the synthesis and electronic structure evaluation of a series of oxidized uranyl complexes, containing redox-active salen ligands with varying para-ring substituents (tBu, OMe, NMe2). Chapters 3 and 4 discuss the incorporation of a redox-active nickel salen complex equipped with pyridyl groups on the peripheral positions of the ligand framework into supramolecular structures via coordination-driven self-assembly. The self-assembly results in formation of a number of distinct metallacycles, affording di-, tetra-, and octa-ligand radical species. Finally, the design, synthesis, and incorporation of metal salen units into MOFs is discussed in Chapter 5. Preliminary assembly and oxidation experiments are presented as an opportunity to explore the redox-properties of salen complexes incorporated into a solid-state 3D framework. Overall, the work described in this thesis provides a pathway for salen ligand radical systems to be used in redox-controlled host-guest chemistry, catalysis, and sensing.
