Download or read book Synthesis Reactivity and Olefin Polymerization Characteristics of Palladium Complexes Bearing an Ortho phosphino sulfonate Ancillary Ligand written by Jacqueline J. DeFoe and published by . This book was released on 2011 with total page 170 pages. Available in PDF, EPUB and Kindle. Book excerpt: The objective of this thesis is to develop a [PO]Pd catalyst ([PO] = generic phosphinearenesulfonate ligand) that exhibits high activity and stability, produces polymers with high molecular weight, and incorporates high levels of vinyl ethers in ethylene/alkyl-vinyl-ether copolymerizations, and to probe the factors that govern these properties.
Download or read book Olefin Polymerization Behavior and Reactivity of Palladium II Alkyl and Fluoride Complexes Bearing Phosphine Sulfonate Ligands written by Rebecca E. Black and published by . This book was released on 2018 with total page 258 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis describes the synthesis of Pd(II) complexes that contain phosphine-sulfonate ligands (PO-) and their performances as catalysts for ethylene (E) homopolymerization and ethylene/vinyl-fluoride (VF) and ethylene/methyl-acrylate (MA) copolymerization. The objectives of this thesis were to identify new ways of modifying the (PO)Pd scaffold (i.e. incorporating a cyclopentane linker), to elucidate the effects of these modifications on polymerization performance, and to study the olefin polymerization and insertion behavior by new (PO)Pd alkyl and fluoride complexes.
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 Synthesis Characterization and Reactivity of Mononuclear Palladium Complexes Bearing Nitrogen and Carbon donor Ligands written by Nicholas Ruhs and published by . This book was released on 2017 with total page 226 pages. Available in PDF, EPUB and Kindle. Book excerpt: The importance of Pd-catalyzed C--H functionalization reactions for chemical transformations has been widely studied over the last several decades. Much of the research to date has focused on conventional Pd0/II catalytic cycles. However, more recent studies have shown that many transformations can also follow a PdII/IV catalytic cycle. High-valent PdIII and PdIV species are often proposed to be important intermediates in such transformations. C--H coupling reactions involving high-valent intermediates often involve the oxidation of a PdII species to a PdIII or PdIV complex, which can then undergo subsequent C--heteroatom bond formation. However, the need for harsh oxidants and reaction conditions in many of these reactions hinders their practical applicability. The focus of this work is to study the properties and reactivity of PdII, PdIII, and PdIV complexes through modifications of the supporting macrocyclic ligands. Another goal of this work is to probe the ability of these complexes to facilitate C--H activation and C--heteroatom bond formation reactions using environmentally benign oxidants.Our lab reported the synthesis and characterization of the first organometallic mononuclear PdIII complexes stabilized by the tetradentate ligand N,N'-di-tert-butyl-2,11-diaza[3,3](2,6)pyridinophane (tBuN4). In order to further probe the Pd chemistry with this class of ligands, we prepared ligands with modifications to the steric bulk on the amine groups. In the first study detailed in chapter 2, the synthesis and characterization of PdII and PdIII complexes supported by N,N'-di-neo-pentyl-2,11-diaza[3,3](2,6)-pyridinophane(NpN4) and N,N'-di-benzyl-2,11-diaza[3,3](2,6)-pyridinophane(BzN4) is reported. Interestingly, the spectroscopic and crystallographic property of the newly synthesized complexes falls between the tBuN4 and MeN4 complexes. The C--C and C--heteroatom bond formation reactivity of the NpN4 and BzN4 supported complexes is also similar to our group's previously reported complexes.We also prepared and studied a series of Pd complexes bearing a modified tetradentate pyridinophane ligand, tBuN3CH. Essentially, we have replaced one of the nitrogen donor atoms from the N4 ligand with a carbon atom and have also introduced a new C--H bond. Due to its expected positioning near the metal center, this bond has the potential to undergo intramolecular C--H bond activation. In order to study the reactivity of this ligand, electronic modifications were made by substituting various electron-donating and withdrawing groups in the para position to this new C--H bond. In chapter 3, the synthesis and characterization of a series of PdII, PdIII, and PdIV complexes stabilized by the N3CH ligand is reported. Interestingly, a spectroscopic and crystallographic study of the pRN3CHPdII(OAc)2 complexes reveals that the Cipso--H bond remains unactivated at the PdII stage. However, upon oxidation to PdIII, the Cipso--H bond is activated.Interestingly, we discovered that the aerobic oxidation of the PdII complex [pRN3CHPdII(MeCN)](BF4) leads to the formation of the PdIII complex [pRN3CHPdIII(MeCN)](ClO4)2 at room temperature. Surprisingly, the C--H activation reaction proceeds in the presence of oxygen without the need for external base. Furthermore, the moderate rate of the reaction allowed us to investigate the mechanism of the reaction by utilizing kinetics and UV-Vis spectroscopy. Detailed mechanistic studies revealed that C--H activation of the Cipso--H bond is the rate determining step of the reaction.
Download or read book Olefin Polymerization written by Walter Kaminsky and published by Wiley-VCH. This book was released on 2006-08-18 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: With an enormous velocity, olefin polymerization has expanded to one of the most significant fields in polymers since the first industrial use about 50 years ago. In 2005, 100 million tons of polyolefins were produced - the biggest part was catalyzed by metallorganic compounds. The Hamburg Macromolecular Symposium 2005 with the title "Olefin Polymerization" involved topics such as new catalysts and cocatalysts, kinetics, mechanism and polymer reaction engineering, synthesis of special polymers, and characterization of polyolefins. The conference combined scientists from different disciplines to discuss latest research results of polymers and to offer each other the possibility of cooperation. This is reflected in this volume, which contains invited lectures and selected posters presented at the symposium.
Download or read book Well defined Nickel and Palladium Initiators for Olefin Polymerization written by Jason David Azoulay and published by . This book was released on 2010 with total page 362 pages. Available in PDF, EPUB and Kindle. Book excerpt: Furthermore, the synthesis of discrete cationic alpha-keto-beta-diimine complexes of nickel, amenable to spectroscopic characterization have allowed for insight into the features characteristic of the propagating species. Utilizing design features relevant to nickel alpha-keto-beta-diimine complexes, the synthesis, characterization and activation of a palladium alpha- keto-beta-diimine complex was also carried out. Polymer products and reactivity profiles for this complex compare well with some of the best performing neutral nickel and palladium systems.
Download or read book Synthesis and Reactivity of Unusual Palladium II Complexes Supported by a Diarylamido BIS Phosphine PNP Pincer Ligand written by Rafael Huacuja and published by . This book was released on 2015 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This dissertation discusses the synthesis and reactivity of divalent palladium complexes supported by diarylamido bis-phosphine pincer ligands (PNP). The PNP is a tridentate pincer type ligand which typically adopts meridional type coordination. The rigidity and tight coordination of the PNP ligand provides the unique opportunity to study the coordination of ligands such as O2 and C2H4 to a single coordination site on palladium, or the reactivity of a single empty coordination site trans to a weak trans-influencing ligand such as diarylamido. Irradiation of [(^(F)PNP^(iPr))Pd-]2 under an atmosphere of dioxygen irreversibly produces a mixture of a monohapto palladium(II) superoxide ((^(F)PNP^(iPr))PdO2) and a palladium micro-peroxide ([(^(F)PNP^(iPr))PdO-]2). Under photolytic conditions these two complexes are in equilibrium with each other. (^(F)PNP^(iPr))PdO2, an open-shell paramagnetic species, was characterized by a combination of single-crystal X-ray crystallography, EPR, and 19F NMR spectroscopies. In addition, irradiation of [(PNP)Pd-]2 under an atmosphere of C2H4 produces a mixture of [(PNP)Pd-]2 and a ethylene-bridged dinuclear palladium complex ([(PNP)Pd-CH2-]2). If the ethylene headspace is removed, and [(PNP)Pd-CH2-]2 is irradiated it is completely converted to [(PNP)Pd-]2. This suggests that in the presence of ethylene these two complexes are in photolytic equilibrium with each other. In addition, this dissertation will also discuss the synthesis and reactivity of [(PNPR)Pd]+ (R = ^(i)Pr, ^(t)Bu) cations. [(^(F)PNP^(iPr))Pd]+ cations are highly electrophilic complexes that are able to coordinate Lewis bases such as THF, H2O, and even extremely poor Lewis bases such as toluene and benzene. In addition, irradiation of [(^(F)PNP^(iPr))Pd]+ cations in bromobenzene induces the abstraction of a bromine atom from bromobenzene, consistent with a metalloradical species. Addition of dioxygen to [(^(F)PNP^(iPr))Pd]+ cations generates a paramagnetic, cationic [eta]1 superoxide. In non-halogenated arene solvents [(^(F)PNP^(iPr))Pd]+ cations undergo a highly unusual photo-induced isomerization of the isopropyl groups on the supporting phosphines to n-propyl. This unprecedented isomerization is believed to occur via C-P bond cleavage and is driven by the decrease in sterics around the metal, which allows for the facilitated coordination of the arene solvent. The electronic version of this dissertation is accessible from http://hdl.handle.net/1969.1/152457
Download or read book Palladium Reagents and Catalysts written by Jiro Tsuji and published by . This book was released on 1995 with total page 596 pages. Available in PDF, EPUB and Kindle. Book excerpt: Basic chemistry of organopalladium compounds; Classification of the reactions involving Pd(II) compounds and Pd(O) complexes.
Download or read book Square planar Dichloro Palladium Complexes with i trans i configurated Phosphine Ligands Avoiding i ortho i metallation Ligand Design Complex Synthesis Molecular Structure and Catalytic Potential for Suzuki Cross coupling Reactions written by and published by . This book was released on with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Palladium Reagents in Organic Syntheses written by Richard F. Heck and published by . This book was released on 1985 with total page 496 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Part 1 eta 3 norcamphene Allyl Palladium 2 Phosphine Species written by Kurt Blaine Gundlach and published by . This book was released on 1986 with total page 446 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Synthesis of the Cyclometallated Palladium Complexes and Their Applications in Olefin Oligomerization and in Phenylacetylene Oligemerization polymerization written by Nothando Wandile Mungwe and published by . This book was released on 2007 with total page 278 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis reports the synthesis of the imine ligands from Schiff base condensation reaction of aldehyde derivatives and equimolar quantities of aniline derivatives. The imine ligands L1-L5 were characterized by NMR, FTIR spectroscopy and GC-MS spectrometry.
Download or read book Palladium in Organic Synthesis written by Jiro Tsuji and published by Springer. This book was released on 2010-11-23 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Palladium is a remarkable metal. In particular, organopalladium chemistry has made remarkable progress over the last 30 years. That progress is still continuing, without any end in sight. This book presents a number of accounts and reviews on the novel Pd-catalyzed reactions discovered mainly in the last five years. The book covers Pd-catalyzed reactions that are new – entirely different from the more standard ones. Topics such as new reactions involving ß-carbon elimination and formation of palladacycles as key reactions, cross-coupling of unactivated alkyl electrophiles with organometallic compounds, arylation via C-H bond cleavage, Pd/norbornene-catalyzed aromatic functionalizations, three-component cyclizations of allenes, use of N-heterocyclic carbenes as ligands, asymmetric reactions catalyzed by Pd(II) compounds such as Lewis acids, cycloadditions of arynes and alkynes, and nucleophilic attack by Pd species are surveyed in detail by researchers who have made important contributions to these fields. The book addresses graduate students majoring in organic synthesis and researchers in academic and industrial institutes.
Download or read book Synthesis and Reactivity of Palladium Complexes that Contain Redox active Verdazyl Ligands written by Corey A. Sanz and published by . This book was released on 2017 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis presents the synthesis, characterization and reactivity of a series of palladium complexes that contain redox-active verdazyl ligands. This work was motivated by the possibility of discovering new and interesting reactivity that may eventually lead to the development of new chemical reactions. A bidentate verdazyl radical ligand that contains an aryl phosphine was synthesized. Reaction of this ligand with (PhCN)2PdCl2 yielded a square planar (verdazyl)PdCl2 complex. Structural and spectroscopic data suggest that this compound consists of a ligand-centered radical coordinated to a Pd(II) center. The radical complex was chemically reduced by one-electron to generate a binuclear chloride-bridged [(verdazyl)PdCl]2 complex. In this reduced complex, both metals were still Pd(II) and the verdazyl ligand was determined to be in its singly reduced, monoanionic charge state. The original radical PdCl2 complex could be regenerated via one-electron oxidation of the reduced complex using PhICl2. The verdazyl ligands in the reduced complex could also be reversibly protonated to generate "leuco" verdazyl complex (verdazyl-H)PdCl2. Reaction of the radical (verdazyl)PdCl2 complex with water triggers a ligand-centered redox disproportionation reaction. A series of bis(verdazyl) palladium complexes were synthesized using a bidentate pyridine-substituted verdazyl ligand. Reaction of two equivalents of radical ligand with (CH3CN)4Pd2+ yielded a (verdazyl)2Pd(solvent)2+ complex (solvent = CH3CN or DMSO). In this complex, one verdazyl radical ligand chelates to palladium and the other binds as a monodentate ligand. Two-electron reduction of this complex generated a (verdazyl)2Pd complex in which two monoanionic verdazyl ligands are bound to a central Pd(II) ion. This reduced complex could also be made via reaction of 0.5 equivalents of Pd(0)2(dba)3 with two equivalents of radical ligand. In this reaction, the metal is oxidized by two electrons and each ligand is reduced by a single electron. Two-electron oxidation of the reduced complex in the presence of DMSO yielded the original bis(radical)complex, (verdazyl)2Pd(DMSO)2+. Chlorination of the reduced complex using one equivalent of PhICl2 (two-electron oxidation) resulted in dissociation of one verdazyl ligand to afford a 1:1 mixture of free verdazyl : (verdazyl)PdCl2, in which both of the verdazyls are neutral radicals. Reaction of the reduced complex with 0.5 equivalents of PhICl2 (one-electron oxidation) yielded a (verdazyl)2PdCl complex that contained a bidentate reduced verdazyl ligand and a monodentate radical ligand. All three of the oxidation reactions described above adhere to ligand-centered redox chemistry. Reaction of the reduced (verdazyl)2Pd complex with excess HCl resulted in protonation of both the anionic verdazyl ring and the pyridyl group to generate a leuco/pyridinium tetrachloropalladate salt, (verdazyl-H2)2(PdCl4). The protonated salt could be converted back to the original (verdazyl)2Pd complex by deprotonation with water. Palladium complexes of a tridentate NNN-chelating verdazyl ligand were prepared and their redox chemistry was explored. Reaction of the radical ligand with (CH3CN)4Pd2+ yielded radical complex (verdazyl)Pd(NCCH3)2+. The tridentate ligand was also prepared in its reduced, leuco form (verdazyl-H). Reaction of the leuco verdazyl with (CH3CN)2PdCl2 generated HCl and a (verdazyl)PdCl complex in which the ligand is in its monoanionic charge state. The reduced (verdazyl)PdCl complex was reacted with AgBF4 to afford (verdazyl)Pd(NCCH3)+ via chloride abstraction; the verdazyl remained in its reduced charge state following the reaction. Both reduced complexes (chloro and acetonitrile) were oxidized by a single electron to afford the corresponding radical complexes. These radical complexes could be reduced by a single electron to regenerate the original reduced complexes. Like the previous two projects, all of the redox chemistry was ligand-centered. The reactivity of these complexes with primary amines was also explored. Reaction of radical complex (verdazyl)Pd(NCCH3)2+ with n-butylamine resulted in one-electron reduction of the verdazyl ligand. We were unable to determine the mechanism of the reaction, but the reactivity that was observed demonstrates the potential for verdazyl-palladium complexes to be used in the design of new radical reactions.
Download or read book Olefin Polymerization and Oligomerization by Cationic Ni II and Pd II Complexes Bearing P O Chelating Ligands written by Jon M. Malinoski and published by . This book was released on 2003 with total page 272 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Isomerization and Reactivity of Pd II Olefin Polymerization Catalysts written by Matthew P. Conley and published by . This book was released on 2008 with total page 332 pages. Available in PDF, EPUB and Kindle. Book excerpt:
