Download or read book Complexes of Group 4 Transition Metals with Novel ONSO and ONNO Type Ligands Coordination Chemistry and Catalytic Activity in Polymerization of Lactides written by Ayellet Maayani Stopper and published by . This book was released on 2014 with total page 131 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Group IV Metal Complexes of Asymmetric Diamine Diphenolate Type Ligands and Dithio Diphenolate Type Ligands written by Ad Cohen and published by . This book was released on 2012 with total page 164 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Macromolecules Containing Metal and Metal Like Elements Volume 6 written by Alaa S. Abd-El-Aziz and published by John Wiley & Sons. This book was released on 2005-10-27 with total page 235 pages. Available in PDF, EPUB and Kindle. Book excerpt: This series provides a useful, applications-oriented forum for the next generation of macromolecules and materials. The sixth volume in this series provides useful descriptions of the transition metals and their applications, edited by high-quality team of macromolecular experts from around the world.

Download or read book Transition Metals and Organometallics as Catalysts for Olefin Polymerization written by Walter Kaminsky and published by Springer. This book was released on 1988 with total page 472 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Macromolecules Containing Metal and Metal Like Elements Volume 5 written by Alaa S. Abd-El-Aziz and published by John Wiley & Sons. This book was released on 2005-07-22 with total page 434 pages. Available in PDF, EPUB and Kindle. Book excerpt: This series provides a useful, applications-oriented forum for the next generation of macromolecules and materials. The fifth volume in this series provides useful descriptions of the transition metals and their applications. Transition Metals are covered in 2 volumes, the second part is covered in Volume 6.

Download or read book Novel N Ligand Stabilized Transition Metal Complexes of the Group IV Triad as Efficient Catalysts for Polymerization and Oligomerization written by Isabelle Haas and published by . This book was released on 2013 with total page 170 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Group 4 Complexes Bearing Tridentate Aryloxide Based Ancillary Ligands written by Ka-Ho Tam and published by Open Dissertation Press. This book was released on 2017-01-27 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This dissertation, "Group 4 Complexes Bearing Tridentate Aryloxide-based Ancillary Ligands: Synthesis, Characterization and Application as Olefin Polymerization Catalysts" by Ka-ho, Tam, 譚家豪, was obtained from The University of Hong Kong (Pokfulam, Hong Kong) and is being sold pursuant to Creative Commons: Attribution 3.0 Hong Kong License. The content of this dissertation has not been altered in any way. We have altered the formatting in order to facilitate the ease of printing and reading of the dissertation. All rights not granted by the above license are retained by the author. Abstract: Abstract of thesis entitled GROUP 4 COMPLEXES BEARING TRIDENTATE ARYLOXIDE- BASED ANCILLARY LIGANDS: SYNTHESIS, CHARACTERIZATION AND APPLICATION AS OLEFIN POLYMERIZATION CATALYSTS Submitted by Tam Ka Ho for the degree of Doctor of Philosophy at The University of Hong Kong in 2006 The preparation, characterization, crystal structures and olefin polymerization behavior of a class of Group 4 complexes, and in particular the Zr(IV) derivatives 1 1 [Zr(L )Cl (D)] [H L = 2,6-di(3-tert-butyl-5-methylphen-2-ol)pyridine; D = ethers, 2 2 ketones and Cl(HPR )], have been undertaken. These [O, N, O] catalysts exhibit excellent activities with MAO for ethylene polymerization. Studies to assess the impact of the donor group during catalysis suggest that the same active species is generated and the donor does not play an active role. Superior activities were observed with the Bu Al/Ph CB(C F ) cocatalyst in ethylene polymerization and - 3 3 6 5 4 -1 -1 propylene copolymerization (36,590 and 15,700 g mmol h respectively). Insight into the behavior of the catalytic system with MAO has been derived from gel permeation chromatography and NMR analyses of the polymers prepared under 1 13 different reaction conditions. H and C NMR end-group analyses reveal resonances for saturated methyl chain-end groups only, and undetectable levels of unsaturated vinyl chain ends. This indicates that for the polymerization chain-transfer mechanism, the conventional β-H transfer reactions are insignificant and the unusual chain transfer to Al pathway is vastly dominant. Group 4 complexes supported by unsymmetric tridentate [O, N, O] ligands bearing different substituents on the two aryloxide rings have been prepared, in order to develop new catalytic systems capable of stereospecific α-olefin polymerization. Their activities for ethylene polymerization with MAO are significantly lower than the symmetric [O, N, O] analogues. A number of group 4 bis(benzyl) complexes supported by tridentate pyridine-2- phenolate-6-aryl [O, N, C] ligands, with alkyl and halogen substituents at the R position ortho to the metal, have been prepared. This enabled direct comparison with the CF -substituted [O, N, C] analogues, which were recently reported to exhibit novel C-H---F-C contacts in solution with potential applications for attractive ligand---polymer interactions. The molecular structure of the Zr derivative bearing an ortho-Cl group was determined, revealing the benzyl moieties in an unusual 'anti, anti' configuration. Saliently, this polyethylene catalyst in conjunction with Bu Al/Ph CB(C F ) displayed the best activity thus far observed for [O, N, C] 3 3 6 5 4 -1 -1 catalysts (8630 g mmol h ). A series of group 4 bis(benzyl) complexes supported by newly designed [O, C, N] ligands bearing R substituents ortho to the metal has been prepared, such that the σ- aryl moiety resides trans to the alkyl/polymer chain, and catalyst decomposition pathways such as olefin insertion into the M-C(sp ) bond are impeded. The crystal structure of the CF -substituted hafnium(IV) complex features weak intramolecular 31 C-H---F-C (CF ---methylene) interactions. The H NMR spectra of [M(O, C, N- CF )(CH Ph) ] analogues revealed coupling (assigned to J [via M---F] for Hf and

Download or read book Designing of Novel Tetradentate Ligands of the ONNO and OSSO Types for Early Transition Metals written by Ekaterina Sergeeva and published by . This book was released on 2011 with total page 126 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Metal Ligand Multiple Bonds written by William A. Nugent and published by Wiley-Interscience. This book was released on 1988-11-14 with total page 360 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.

Download or read book Transition Metal Complexes of Neutral Eta1 Carbon Ligands written by Remi Chauvin and published by Springer Science & Business Media. This book was released on 2010-01-12 with total page 260 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book is part of a series that gives the broad scientific readership a comprehensive summary and critical overview of specific topics in the field of organometallic chemistry. This text focuses on transition metal complexes of neutral eta1-carbon ligands.

Download or read book Development of Constrained Geometry Complexes of Group 4 and 5 Metals written by Ryan Thomas Rondo and published by . This book was released on 2010 with total page 218 pages. Available in PDF, EPUB and Kindle. Book excerpt: Constrained geometry catalysts (CGC) are known to be active in the polymerization and copolymerization of alkenes with a distinct control over polymer tacticity. The tethering of one eta-5-cyclopentadienyl moiety and one pendant donor gives these compounds an accessible metal center as well as ability to maintain their structure throughout the catalytic process. Complexes of this type typically feature one pendant amido donor. Replacement of the pendant amido donor with a nitrogen heterocycle such as an indolyl- or pyrrolyl-group should result in electrophilic metal centers due to reduced N to M pi donation, a consequence of electron delocalization of the nitrogen lone pair in the aromatic system. This dissertation reports the development of a new series of constrained geometry ligands that feature indolyl- and pyrrolyl- donor moieties. In chapter 2, the synthesis and characterization of a series of acetal precursors and their corresponding di(3-methylindolyl)ethane and dipyrrolylethane constrained geometry ligands is reported. Within this report are two new acetal precursors, fluorenyl acetaldehyde diethylacetal, and indenyl acetaldehyde diethylacetal. Also described are the new constrained geometry ligands fluorenyl di(3-methylindolyl)ethane (H3FDI), fluorenyl dipyrrolylethane (H3FDP), indenyl di(3-methylindolyl)ethane (H3IDI), and indenyl dipyrrolylethane (H3IDP). These compounds have been characterized by 1H and 13C NMR spectroscopy as well as mass spectrometry and elemental analysis. The molecular structure of H3FDI THF has been confirmed by X-ray crystallography. This new set of ligands serves as a framework for constrained geometry complexes of group 4 and 5 transition metals. Chapter 3 reports the synthesis and characterization of group 4 and 5 constrained geometry complexes of fluorenyl di(3-methylindolyl)ethane (H3FDI) and indenyl di(3-methylindolyl)ethane (H3IDI). Within this report are the first examples of 3-methylindolyl-based CGC's of group 4 and 5 metals, specifically in the complexes (HFDI)Zr(NEt2)2(THF), (HFDI)Ti(NEt2)2, (IDI)Zr(NEt2), which were prepared using amine elimination methods, and (IDI)Nb(NtBu)(py), (IDI)Nb(NPh), (FDI)Zr(CH3), and (FDI)Ti(CH3), which were prepared via salt metathesis. These complexes have been characterized by 1H and 13C NMR spectroscopy. X-ray crystallography confirmed the bidentate nature of the HFDI ligand in (HFDI)Zr(NEt2)2(THF) as well as the eta-5-coordination of the indene moiety in (IDI)Zr(NEt2). The structures of analogous complexes (HFDI)Ti(NEt2)2 and (IDI)Nb(NtBu)(py) were determined by 1H and 13C NMR spectroscopy. Another eta-5-coordinated complex, (FDI)Zr(CH3) was characterized by NMR spectroscopy. This complex exhibits a methyl resonance indicative of transition metal-methyl complexes. These constrained geometry complexes serve as a representative sample for the preparation of various CGC's with this ligand framework. Chapter 3 also reports the initial preparation of titanium metal-imido complexes that feature di(3-methylindolyl)methane ligands with one neutral pendant donor. Three complexes, (tBuN)Ti{(2-py)di(3-methylindolyl)methane}, (tBuN)Ti{(N-methylimidazolyl)di(3-methylindolyl)methane}, and (tBuN)Ti{(2-MeOC6H4)di(3-methylindolyl)methane} were characterized by 1H and 13C NMR spectroscopy. X-ray crystallographic analysis of (tBuN)Ti{(2-py)di(3-methylindolyl)methane}, while incomplete, confirmed the connectivity of this complex. In chapter 4, the in situ generation of copper(I)-pyridine derivative complexes and their olefin binding properties are reported. The new complexes [(Me-nic)3Cu(NCCH3)]PF6 (Me-nic = methylnicotinate), [(3-MeOpy)3Cu(NCCH3)]PF6, and [(3-HOpy)3Cu(NCCH3)]PF6 have been generated in situ and characterized by 1H and 13C NMR spectroscopy. These complexes were examined for their affinity to bind ethylene, propylene, 1-hexene, and cis- and trans-3-hexene. Variable-temperature NMR spectra of these alkene complexes revealed a dynamic system with fast exchange between free and coordinated alkene at temperatures as low as -80 deg C. Using an extrapolation method, room temperature binding constants were determined for these alkene complexes. These copper(I) compounds exhibit binding constants for ethylene and propylene that are significantly lower than those of complexes featuring multidentate amine-based donor ligands. Furthermore, these complexes do not appear to bind 1-hexene, cis-3-hexene, or trans-3-hexene. Appendix 1 reports the synthesis and characterization of metallophosphinate complexes of aluminum and gallium. These complexes are believed to consist of a M2P2O4 (M = Al, Ga) ring structure, which was confirmed by X-ray crystallographic analysis of [Ph2AlO2PPh2]2. Specifically, the complexes [Ph2AlO2PPh2]2, [Ph2GaO2PPh2]2, [Ph2AlO2P(OPh)2]2, and [Ph2GaO2P(OPh)2]2 have been synthesized. Also reported in this appendix are reactions of triphenylaluminum and triphenylgallium with phosphonic acids. Products isolated in reactions with phosphonic acids were difficult to characterize due to their insoluble nature and amorphous morphology.

Download or read book Synthesis Characterization and Reactivity of Transition Metal Complexes Supported by Heteropolydentate Ligation written by Adam Ruddy and published by . This book was released on 2014 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Early Transition Metal Complexes of Amine phenolate Ligands written by Edit Y. Tshuva and published by . This book was released on 2001 with total page 150 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Metallocenes in Regio and Stereoselective Synthesis written by Marko Hapke and published by Springer. This book was released on 2024-06-20 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book presents the latest synthetic protocols for the assembly of functionalized Cp ligands and their transition metal complexes. Cyclopentadienyl (Cp) complexes of transition metals belong to the most important classes of transition metal complexes with tightly bound ligands in the coordination sphere since their discovery in the middle of the last century. Even though they have been known for a long time, this field constantly evolves to deliver novel modified Cp ligands and complexes and to blossom into new fields of application. Beside the synthesis of ligands and metal complexes this book concentrates on novel and prospering fields of their application in organic synthesis. In this respect the Cp complexes have been applied to induce and catalyze various significant chemical transformations such as new C-C bond formation involving unsaturated substrates (e.g. cyclotrimerizations, cycloadditions, carbometallations, etc.), C-H bond and C-C bond activations followed by subsequent reactions (e.g. arylation, alkenylations, annulations, etc.), as well as many other processes. This volume also covers the recent development and application of chiral Cp complexes in enantioselective synthesis.

Download or read book Conducting Metallopolymers with Tridentate Ligands and Coordination Chemistry with Corresponding Model Compounds written by Şeyma Keskin and published by . This book was released on 2013 with total page 380 pages. Available in PDF, EPUB and Kindle. Book excerpt: Conducting polymers that contain metals are remarkable materials, because they have the properties of both organic backbones and metals. Depending on the position of the metal relative to the conjugated backbone, i.e. attached to or directly in the backbone, these two can couple resulting in advancement of the functionality and therefore potential applications of these types of materials. Complexes of tridentate ligands with donor atoms such as phosphorus, nitrogen, and sulfur also have a wide variety of applications. In addition, complexes of tridentate ligands have advantages of stability and control of electron density by variation of donor atoms. Therefore, conjugated polymers with tridentate ligand units will have promise for various applications and advantages in their designs. Complexes of PNP ligand with molybdenum and carbonyl ancillary ligands were synthesized and characterized. Isomerization and conversion reactions between them were investigated as well as the coordination modes. Many types of PNP ligands have been studied in the literature because the hemilabile property of the nitrogen atom promotes some catalytic reactions and gives different coordination geometries. Conducting polymers can be used as redox-active ligands and they can be used to control electron density on the metal attached to them. Synthesis and characterization of a novel polymerizable ligand 3,5-bis-EDOT-N,N-bis[2-diphenylphosphinoethyl]aniline was achieved. Related molybdenum complexes with ancillary ligands as carbonyls were also synthesized and characterized. Monomer complexes and the free ligand were electropolymerized and studied. Tris(bipyridine)ruthenium(II) chloride and analogous complexes have been studied extensively in the literature due to their luminescent and photochemical properties, and excited state lifetimes. Conducting polymers with similar ruthenium groups have been investigated for various applications. Synthesis of four ruthenium complexes with the polymerizable ligand 2,6-Bis[4-[2-(3,4-diethylenedioxy)thiophene]pyrazol-1-yl]pyridine and four different bidentate ligands were reproduced; electropolymerizations of the complexes were achieved; electrochemical, UV-Vis and luminescence studies were performed and discussed. Various complexes of copper, silver, platinum, and palladium with nitrogen and phosphorus donors have been reported for their luminescence behavior as well as their interesting structures. Model complexes of these metals with N,N-bis[2-(diphenylphosphino)ethyl]phenyl-amine (a PNP ligand) have been synthesized and characterized. Absorption and luminescence behaviors as well as the coordination modes were investigated.

Download or read book Transition Metals and Organometallics as Catalysts for Olefin Polymerization written by Walter Kaminsky and published by . This book was released on 1988-04-29 with total page 470 pages. Available in PDF, EPUB and Kindle. Book excerpt: The "International Symposium on Transition Metals and Organometallics as Catalysts for Olefin Polymerization" held in Hamburg from September 21 - 24, 1987 gives an overview of today's research for olefin polymerization with metalorganic compounds. The goal of the symposium was to show direction for further development of catalysts, to find proper methods in the determination of the number of active centres, to investigate the kinetics and the overall mechanism of the catalysis with heterogeneous and homogeneous catalysts, to provide with synthetic pathways for new polyolefins and copolymers with different properties, and finally to develop tools and techniques for a comprehensive characterization of the polymers. More than 30 years after the discovery of transition metals and organometallics as catalysts for olefin polymerization these catalysts have not lost their fascination. New impulses for olefinpolymerizations have been brought about by the discovery of the very high cocatalytic activity of alumoxanes instead of aluminumalkyls together with the soluble transition metal compounds of titanocene, zirconocene and hafnocene. The 41 contributions printed in this volume are arranged in four sections: Studies of the Active Sites, and Kinetics and Mechanism in Heterogeneous Catalysts - New Aspects in the Heterogeneous Catalysts Polymerization of Olefins - Homogeneous Catalysts for Olefin Polymerization - The Influence of the Reactor Design, Polyolefin Characterization.

Download or read book Transition Metal Complexes with P N Ligands and Silylenes Synthesis and Catalytic Studies written by Eva Neumann and published by Cuvillier Verlag. This book was released on 2006-02-15 with total page 244 pages. Available in PDF, EPUB and Kindle. Book excerpt: The term ligand [latin, ligare = bind] has its origin in coordination chemistry. It denotes a molecule that is able to bind to a metal center in most cases via one or several free electron pairs.[1] Ligands can be described by the number of electron-pair donor atoms as monodentate, bidentate, tridentate etc. ligands. The latter are also called chelating ligands [greek, chele = (crab’s) claw]. A typical classification of ligands is according to their electronic properties. They serve either as a σ-donating, σ-donating/π-accepting, or σ,π-donating/π-accepting ligands.[2] A more practical, often encountered approach is the classification of ligands according to their donor atoms, especially when larger molecules and molecules containing heteroatoms are regarded (compare 1.2). Coordination chemistry was already established in the 19th century. In 1893 Alfred Werner suggested an octahedral arrangement of ligands coordinated to a central metal ion for many compounds. This explained, for example, the appearance and reactivity of four different cobalt(III) complexes (Figure 1.1), when CoCl2 is dissolved in aqueous ammonia and then oxidized by air to the +3 oxidation state. The formulas of these complexes can be written as depicted in Figure 1.1. Werner’s work was rewarded with the Nobel prize in 1913.[3]