Preparation and Stoichiometric and Catalytic Chemistry of Low-valent Iron Complexes of Phosphine and Phosphite Ligands

Preparation and Stoichiometric and Catalytic Chemistry of Low-valent Iron Complexes of Phosphine and Phosphite Ligands PDF Author: Thomas Van Harris
Publisher:
ISBN:
Category : Complex compounds
Languages : en
Pages : 250

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Preparation and Stoichiometric and Catalytic Chemistry of Low-valent Iron Complexes of Phosphine and Phosphite Ligands

Preparation and Stoichiometric and Catalytic Chemistry of Low-valent Iron Complexes of Phosphine and Phosphite Ligands PDF Author: Thomas Van Harris
Publisher:
ISBN:
Category : Complex compounds
Languages : en
Pages : 250

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Synthesis and Chemistry of Low-valent Iron Complexes Incorporating Chelating Perfluoroalkyl Phosphine Ligands

Synthesis and Chemistry of Low-valent Iron Complexes Incorporating Chelating Perfluoroalkyl Phosphine Ligands PDF Author: Wayne Allen Chandler
Publisher:
ISBN:
Category : Alkanes
Languages : en
Pages : 300

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Phosphorus(III)Ligands in Homogeneous Catalysis

Phosphorus(III)Ligands in Homogeneous Catalysis PDF Author: Paul C. J. Kamer
Publisher: John Wiley & Sons
ISBN: 1118299701
Category : Technology & Engineering
Languages : en
Pages : 673

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Book Description
Over the last 60 years the increasing knowledge of transition metal chemistry has resulted in an enormous advance of homogeneous catalysis as an essential tool in both academic and industrial fields. Remarkably, phosphorus(III) donor ligands have played an important role in several of the acknowledged catalytic reactions. The positive effects of phosphine ligands in transition metal homogeneous catalysis have contributed largely to the evolution of the field into an indispensable tool in organic synthesis and the industrial production of chemicals. This book aims to address the design and synthesis of a comprehensive compilation of P(III) ligands for homogeneous catalysis. It not only focuses on the well-known traditional ligands that have been explored by catalysis researchers, but also includes promising ligand types that have traditionally been ignored mainly because of their challenging synthesis. Topics covered include ligand effects in homogeneous catalysis and rational catalyst design, P-stereogenic ligands, calixarenes, supramolecular approaches, solid phase synthesis, biological approaches, and solubility and separation. Ligand families covered in this book include phosphine, diphosphine, phosphite, diphosphite, phosphoramidite, phosphonite, phosphinite, phosphole, phosphinine, phosphinidenene, phosphaalkenes, phosphaalkynes, P-chiral ligands, and cage ligands. Each ligand class is accompanied by detailed and reliable synthetic procedures. Often the rate limiting step in the application of ligands in catalysis is the synthesis of the ligands themselves, which can often be very challenging and time consuming. This book will provide helpful advice as to the accessibility of ligands as well as their synthesis, thereby allowing researchers to make a more informed choice. Phosphorus(III) Ligands in Homogeneous Catalysis: Design and Synthesis is an essential overview of this important class of catalysts for academic and industrial researchers working in catalyst development, organometallic and synthetic chemistry.

Phosphorus(iii) Ligands in Homogeneous Catalysis

Phosphorus(iii) Ligands in Homogeneous Catalysis PDF Author: Paul Kamer
Publisher: John Wiley & Sons
ISBN: 9781119943990
Category : Catalysis
Languages : en
Pages :

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Book Description
Over the last 60 years the increasing knowledge of transition metal chemistry has resulted in an enormous advance of homogeneous catalysis as an essential tool in both academic and industrial fields. Remarkably, phosphorus(III) donor ligands have played an important role in several of the acknowledged catalytic reactions. The positive effects of phosphine ligands in transition metal homogeneous catalysis have contributed largely to the evolution of the field into an indispensable tool in organic synthesis and the industrial production of chemicals. This book aims to address the design and synthesis of a comprehensive compilation of P(III) ligands for homogeneous catalysis. It not only focuses on the well-known traditional ligands that have been explored by catalysis researchers, but also includes promising ligand types that have traditionally been ignored mainly because of their challenging synthesis. Topics covered include ligand effects in homogeneous catalysis and rational catalyst design, P-stereogenic ligands, calixarenes, supramolecular approaches, solid phase synthesis, biological approaches, and solubility and separation. Ligand families covered in this book include phosphine, diphosphine, phosphite, diphosphite, phosphoramidite, phosphonite, phosphinite, phosphole, phosphinine, phosphinidenene, phosphaalkenes, phosphaalkynes, P-chiral ligands, and cage ligands. Each ligand class is accompanied by detailed and reliable synthetic procedures. Often the rate limiting step in the application of ligands in catalysis is the synthesis of the ligands themselves, which can often be very challenging and time consuming. This book will provide helpful advice as to the accessibility of ligands as well as their synthesis, thereby allowing researchers to make a more informed choice. "Phosphorus(III) Ligands in Homogeneous Catalysis: Design and Synthesis" is an essential overview of this important class of catalysts for academic and industrial researchers working in catalyst development, organometallic and synthetic chemistry.

Iron Chemistry of Hemilabile SNS Ligands

Iron Chemistry of Hemilabile SNS Ligands PDF Author: Uttam Das
Publisher:
ISBN:
Category :
Languages : en
Pages :

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Book Description
The development of abundant and economical first-row transition metal-based catalysts is an appealing area of research for efficient and selective chemical transformations. In this context, iron complexes are highly desirable as they feature a range of accessible oxidation states allowing for transfer of one or two electrons to or from a substrate. Therefore, over the past two decades, many iron-based catalysts have been developed, extensively studied, and exploited for catalysis ranging from oxidation and reduction to C-C bond forming reactions. In homogeneous transition metal catalysis, the ligand plays a vital role in determining activity and selectivity of the above stated catalytic reactions. Some key features of ligands that support both stoichiometric and catalytic reactions of metal complexes include: 1) strong chelation ability to metals, 2) tunability of donor atoms, 3) strong field ligands such as phosphine, phosphite, CO, and hydride favoring low-spin complexes, 4) hemilability allowing substrate activation via reversible dissociation of one donor atom, and 5) redox-activity enabling donation or accepting of electrons, thus avoiding a change of metal oxidation state. To this end, bifunctional ligands containing the above described properties have emerged as important elements in chemical synthesis and in catalysis. Iron and other transition metal complexes containing multidentate bifunctional ligands have recently been shown to activate small molecules and catalyze a number of chemical transformations with activity and selectivity typical of more well-studied precious metals. The objective of this thesis is to further advance the field of bifunctional ligands by preparing new sterically svelte tridentate ligands with a mixture of hard nitrogen and soft sulfur donors and to investigate their iron chemistry. The overall goal is to then explore the utility of these iron complexes as potential bifunctional catalysts. Chapter 2 describes a one-step synthesis of a new SMeNHS ligand in excellent yield that undergoes ring-opening on treatment with Fe(OTf)2 affording a thiolate-bridged, trinuclear iron complex, [Fe3(μ2-SMeNS−)4](OTf)2. The structure, spectroscopic, magnetic, and computational studies of this iron complex are provided along with its solvent-dependent reactivity towards monodentate donor ligands that yields both dinuclear and mononuclear derivatives. Chapter 3 describes the formation of an electron-rich Fe(II) thiolate complex, [Fe(SMeNS)(PMe3)3](OTf) and its substitution reactivity with both mono- and bidentate donor ligands. On heating this complex, an oxidative thioether Caryl-S bond cleavage is observed, leading to a cationic Fe(III)-CNS thiolate analog. Reduction of this Fe(III) species with cobaltocene yielded a neutral Fe(II)-CNS thiolate complex. To investigate the bifunctional activity of these Fe(II) complexes, both Fe(II)-SNS and -CNS species were assessed as precatalysts for amine-borane dehydrogenation. Chapter 4 employs the SMeNHS ligand in formation of a neutral, imine-coupled Fe-N2S2 complex that serves as an efficient and selective aldehyde hydroboration catalyst using pinacolborane. A reaction profile kinetic analysis implicates the hemilability and redox-active properties of this complex. Chapter 5 introduces the new unsymmetrical amine ligand, SMeNHSMe, and details its iron chemistry with formation of a pseudooctahedral Fe(II) bis(amido) complex. The Mössbauer spectra, MCD study, and DFT calculations support formation of a minor five-coordinate isomer in solution due to the hemilability of the six-membered ring thioether group. Reactivity studies of this Fe(II) species with a variety of donor ligands confirmed this lability and protonation at nitrogen yielded a cationic Fe(II) amine-amido complex. Reaction of the latter with the tridentate phosphine, triphos, gave a 16e-, low-spin, square-pyramidal Fe(II) complex that proved to be a robust precatalyst that is more active for dehydrogenation of dimethylamine-borane vs. ammonia-borane. Formation of a monohydride catalyst resting state under these reaction conditions is suggestive of a bifunctional activation pathway. Finally, Chapter 6 concludes the outcomes of the iron chemistry of hemilabile SNS ligands and discusses future directions and opportunities to extend these ligand systems to other transition metals. The knowledge gained by the stoichiometric and catalytic reactivity of iron-SNS complexes presented herein contributes to our understanding of bifunctional catalysis. With the increasing demand for base metal catalysts in chemical industry for efficient and selective synthesis of value-added chemicals, iron SNS complexes could offer economical, active, and selective catalyst precursors.

Directory of Graduate Research

Directory of Graduate Research PDF Author: American Chemical Society. Committee on Professional Training
Publisher:
ISBN:
Category : Chemical engineering
Languages : en
Pages : 1030

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Dissertation Abstracts International

Dissertation Abstracts International PDF Author:
Publisher:
ISBN:
Category : Dissertations, Academic
Languages : en
Pages : 630

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National Union Catalog

National Union Catalog PDF Author:
Publisher:
ISBN:
Category : Union catalogs
Languages : en
Pages : 1032

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Copper(I) Chemistry of Phosphines, Functionalized Phosphines and Phosphorus Heterocycles

Copper(I) Chemistry of Phosphines, Functionalized Phosphines and Phosphorus Heterocycles PDF Author: Maravanji S. Balakrishna
Publisher: Elsevier
ISBN: 0128156945
Category : Science
Languages : en
Pages : 445

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Book Description
Copper(I) Complexes of Phosphines, Functionalized Phosphines and Phosphorus Heterocycles is a comprehensive guide to one of the most widely used and extensively studied metals: copper. The numerous practical applications of copper compounds are discussed, including homogeneous and heterogeneous catalysis and their use as fungicides, pesticides, pigments for paints, resins and glasses, and in high-temperature superconductors. The remarkable structural flexibility of simple copper(I) complexes, such as cuprous halides is covered, including numerous structural motifs that, when combined with different ligand systems, exhibit linear, trigonal planar or tetrahedral geometries. This work is an essential reference for inorganic and coordination chemists, as well as researchers working on catalysis, anticancer reagents, luminescence, fluorescence and photophysical aspects. Discusses the properties of copper and similarities to noble metals, such as their corrosion resistance, high thermal and electrical conductivity and rich coordination chemistry Includes the copper(I) coordination chemistry of tertiary phosphines, bisphosphines and phosphines containing other donor atoms and their potential application in catalysis, biosystems and photochemical areas Features a discussion of the rich photochemistry exhibited by some mixed-ligand copper(I) complexes (phosphines with heteroaromatic ligands) which can exhibit coprophilic interactions, photoluminescence and thermochromic properties

Synthesis, Characterization, and Reactivity of Low Valent Technetium Phosphine Complexes

Synthesis, Characterization, and Reactivity of Low Valent Technetium Phosphine Complexes PDF Author: Evan Freiberg
Publisher:
ISBN:
Category :
Languages : en
Pages : 446

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Book Description
Chapter 1. The chemistry of the metal-metal multiply bonded Tc2(II, II) core has been investigated with bis(diphenylphosphino)methane (dppm). The parent complex, Tc2Cl4(dppm)2, has been prepared from the reaction of Tc2C14(PEt3)4 with dppm. The reactivity of Tc2Cl4(dppm)2 with tert-butyl isocyanide has been studied and a neutral 1:1 adduct, Tc2Cl4(dppm)2CNBut, a cationic 1:2 adduct, [Tc2Cl3(dppm)4(CNBut)2](PF6), and a [mu]-iminyl complex, [Tc2Cl3(dppm)2(CNBut)2CNHBul(PF6), have been prepared. The parent compound and its reaction products have been characterized via a combination of spectroscopic techniques and single crystal X-ray crystallography. The metal-metal bonded ditechnetium bis(dppm) motif is retained in the reaction products. Chapter 2. The reduction of ammonium pertechnetate with bis(diphenylphosphino)methane (dppm), and with diphenyl-2-pyridyl phosphine (Ph2Ppy), has been investigated. The neutral Tc(II) complex, TcCl2(dppm)2, has been isolated from the reaction of (NH4)[TcO4] with excess dppm in refluxing EtOH/HCl. Chemical oxidation with ferricinium hexafluorophosphate results in formation of the cationic Tc(III) analogue, [TcCl2(dppm)2](PF6). The dppm ligands adopt the chelating bonding mode in both complexes, resulting in strained four member metallocycles. With excess PhPpy, the reduction of (NH4)[TcO4] in refluxing EtOH/HCl yields a complex with one chelating Ph2Ppy ligand and one unidentate Ph2Ppy ligand, TcCl3(Ph2Ppy-P, N)(Ph2Ppy-P).