Multidentate Phosphino-alkene Ligands and Their Late Transition Metal Complexes

Multidentate Phosphino-alkene Ligands and Their Late Transition Metal Complexes
Author: Amanda G. Jarvis
Publisher:
Total Pages:
Release: 2011
Genre:
ISBN:

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The synthesis and characterisation of a new class of multidentate conformationally flexible phosphino-alkene ligands, called dbaPHOS (127) and monodbaPHOS (128), are described is this PhD thesis. The related phosphine sulphide ligands, namely dbaTHIOPHOS (137) and monodbaTHIOPHOS (149), have also been prepared. The coordination chemistry of the novel ligands was investigated with a variety of late-transition metals, including Cu, Rh, Pd and Pt. X-ray crystal structure determination of the complexes containing these ligands highlights the multiple coordination modes and versatility of each ligand system. The ability of the 1,4-dien-3-one backbone to adopt different conformational geometries around metal centers is of particular note. DbaPHOS (127) was found to act as a cis- and trans-chelating bisphosphine in both square planar PdII and PtII complexes. The 1,4-dien-3-one motif is hemilabile; exchange between coordinated and non-coordinated alkenes is observed in both the Pd0 complex, 167, and the related cationic CuI complex, 193. An investigation into the CuI complexes' activity in the cyclopropanation of styrene, as catalysts, showed that they are commensurate with other recently reported systems. In addition to the coordination chemistry of the novel ligand systems, some interesting findings emerged in the ligand synthesis and characterisation studies. For example, monodbaTHIOPHOS (149) undergoes an interesting solid-state [2+2] intramolecular cycloaddition transformation, giving cycloadduct, 206. Furthermore, 2-hydroperoxytetrahydrofuran was found to be an impurity in the microwave-assisted Horner-Wadsworth-Emmons reaction of 2-(diphenylthiophosphine)benzaldehyde (136) with 1,3-bis-(ethoxyphosphonato)-acetone (130) to give of dbaTHIOPHOS (137) and an unexpected THF insertion product, 138. The latter is explained by a side reaction involving the reduced compound, tetrahydrofuran-2-ol, derived from 2-hydroperoxytetrahydrofuran.

Hybrid Multidentate Phosphine-alkene Ligands for Transition Metal Coordination Chemistry and Catalysis

Hybrid Multidentate Phosphine-alkene Ligands for Transition Metal Coordination Chemistry and Catalysis
Author: Somia Ehsan Bajwa
Publisher:
Total Pages:
Release: 2012
Genre:
ISBN:

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The development of a new class of phosphine-alkene and thio-phosphine-alkene ligands based on a chalcone ferrocene framework, represents the primary focus of this study. The synthesis and characterisation of novel ligands, ferrochalcone 32 and thio-ferrochalcone 33, are described. The related alkene-phosphine ligands, the Lei ligand 17 and novel thio-Lei ligand 46, are further detailed. The coordination chemistry of four ligands (17, 32, 33 and 46) with various transition metals (Pt, Pd, Cu, Rh and Au) has been investigated in a comprehensive spectroscopis study. Single crystal X-ray analysis has been conducted at suitable junctures within the project. A surprising finding was that some solution-state structures were found to be different when studied in the solid state. The AuI complexes-containing the ligands have been successfully used in 1,5-enyne cycloisomerisation reactions. In addition to the coordination chemistry of the novel ligand systems, some interesting findings emerged For example, AuI complex of Lei ligand 17 and monodbaPHOS 74 undergoes an interesting solid-state [2+2] intramolecular cycloaddition transformation, giving cycloadduct, 72 and 77. An interesting finding includes the presence of impurity in commercially available Pd(OAc)2. Cyclopalladation of papaverine was carried out using pure and impure Pd(OAc)2, which resulted in the identification of novel Pd-dimer complex, 86. The result suggest that nitrite contaminants derive from impurities in Pd(OAc)2, and not from the oxidation of acetonitrile mediated by metallic Pd0, explain the formation of PdII-nitrito cyclopalladated products. Photocrystallographic metastable linkage isomerisation and complete conversion to an oxygen-bound nitrito complex 90 was also observed.

The Organometallic Chemistry of the Transition Metals

The Organometallic Chemistry of the Transition Metals
Author: Robert H. Crabtree
Publisher: John Wiley & Sons
Total Pages: 600
Release: 2005-06-14
Genre: Science
ISBN: 0471718750

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Fully updated and expanded to reflect recent advances, this Fourth Edition of the classic text provides students and professional chemists with an excellent introduction to the principles and general properties of organometallic compounds, as well as including practical information on reaction mechanisms and detailed descriptions of contemporary applications.

Phosphorus(III)Ligands in Homogeneous Catalysis

Phosphorus(III)Ligands in Homogeneous Catalysis
Author: Paul C. J. Kamer
Publisher: John Wiley & Sons
Total Pages: 673
Release: 2012-05-09
Genre: Technology & Engineering
ISBN: 1118299701

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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.

Transition Metal Complexes of Neutral eta1-Carbon Ligands

Transition Metal Complexes of Neutral eta1-Carbon Ligands
Author: Remi Chauvin
Publisher: Springer
Total Pages: 260
Release: 2009-12-18
Genre: Science
ISBN: 364204722X

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Contents: Yves Canac and Remi Chauvin: Neutral eta1-carbon ligands: beyond carbon monoxide; Esteban P. Urriolabeitia: Ylide Ligands; Wolfgang Petz and Gernot Frenking: Carbodiphosphoranes and related ligands; Mareike C. Jahnke and F. Ekkehardt Hahn: Chemistry of N-Heterocyclic Carbene Ligands; Tsuyoshi Kato, Eddy Maerten, Antoine Baceiredo: Non-NHCs stable singlet carbene ligands; Victorio Cadierno, Sergio E. García-Garrido: All-Carbon-Substituted Allenylidene and Related Cumulenylidene Ligands; Victorio Cadierno, Sergio E. García-Garrido: Heteroatom-Conjugated Allenylidene and Related Cumulenylidene Ligands.

Metal-Ligand Multiple Bonds

Metal-Ligand Multiple Bonds
Author: William A. Nugent
Publisher: Wiley-Interscience
Total Pages: 360
Release: 1988-11-14
Genre: Science
ISBN:

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The only comprehensive one-volume text/reference on metal-ligand multiple bonds. Stresses the unified nature of the field and includes handy new tabulations of data. The flow within each subtopic is oxygen to nitrogen to carbon. Coverage is up-to-date--virtually every subtopic leads to interesting questions for future research. Presents information otherwise scattered through hundreds of publications.