Download or read book Design and Synthesis of Organometallic Lanthanide Complexes Based on Poly pyrazolyl borohydride Ligand for Olefin Polymerization written by Li Qiang and published by . This book was released on 2000 with total page 142 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Lanthanide Alkyl and Hydride Complexes Containing the Tris pyrazolyl borohydride Ligand and Their Activity as Homogeneous Polymerization Catalysts written by David P. Long and published by . This book was released on 1998 with total page 468 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Lanthanides Chemistry and Use in Organic Synthesis written by Shu Kobayashi and published by Springer. This book was released on 2003-07-01 with total page 311 pages. Available in PDF, EPUB and Kindle. Book excerpt: With contributions by numerous experts
Download or read book Organometallic Reactions and Polymerization written by Kohtaro Osakada and published by Springer. This book was released on 2014-07-15 with total page 307 pages. Available in PDF, EPUB and Kindle. Book excerpt: This compilation provides advanced graduate students and researchers with a structured overview of olefin polymerization. Divided into eight chapters written by international experts, this book covers polymerization using various organotransition-metal catalysts, including early and late transition metal complexes, new trends in olefin oligomerization and related reactions. All authors address the historic and scientific backgrounds of the field as well as current research progress and potential for further research. The complete book is designed to present eight independent lectures and, because all authors are well versed in organometallic chemistry, each is based on a profound understanding of the reactions and structures of organotransition metal complexes. This book is an ideal accompaniment for researchers taking courses in olefin polymerization and also serves as a valuable resource for teachers and lecturers of chemistry when planning and researching material for advanced lecture courses.
Download or read book Olefin Metathesis and Polymerization Catalysts written by Yavuz Imamogammalu and published by Springer Science & Business Media. This book was released on 1990-11-30 with total page 602 pages. Available in PDF, EPUB and Kindle. Book excerpt: Proceedings of the NATO Advanced Study Institute, Akçay, Turkey, September 10-22, 1989
Download or read book New Lanthanide Complexes as Polymerisation Catalysts written by Hellen Elizabeth Dyer and published by . This book was released on 2009 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This Thesis describes the synthesis and characterisation of a series ofbisphenolate supported samarium borohydride, amide and zwitterionic rare earth complexes and their ability to effect the ring opening polymerisation (ROP) of cyclic esters and methylmethacrylate (MMA). Chapter 1 introduces ROP from both an industrial and an academic perspective and describes in detail the research in this area, with emphasis on rare earth initiators. The lanthanide elements and the bisphenolate ligand are also introduced. Chapter 2 describes the synthesis and characterisation ofbisphenolate supported samarium borohydride and silylamide complexes. Chapter 3 describes the ability of a selection of samarium borohydride and amide complexes to effect the ROP of the cyclic esters s-caprolactone (f-CL) and rac- lactide (rac-LA). Emphasis is placed on the effect that the nature of the bisphenolate pendant arm and the initiating moiety has on the polymerisation process. Chapter 4 describes the synthesis and characterisation of rare earth zwitterionic complexes and the ability ofa range of these complexes to effect the ROP of s-Cl. and rac-lactide. Mechanistic aspects ofthe ROP process will be discussed, as will the ability of these complexes to yield amide functionalised poly(rac-LA). Chapter 5 describes the ability ofbisphenolate samarium borohydride complexes to initiate the polymerisation of MMA. The experimental work conducted as part of this study is further supported computationally by calculations at the DFT level, both aspects will be described. Aspects concerning the synthesis and characterisation of the related borohydride derivative [Sm(N2siMe3NNPY)(BH4)2Li]oo will also be emphasised. Chapter 6 contains full experimental and characterising data for all 0 f the new compounds reported in this Thesis. Appendices A- T contain tables of selected crystallographic data for all new crystallographically characterised complexes described in this Thesis (partially on CD).
Download or read book Beyond Metallocenes written by Abhimanyu O. Patil and published by . This book was released on 2003 with total page 272 pages. Available in PDF, EPUB and Kindle. Book excerpt: The past 15 years have witnessed tremendous advances in the design and use of organometallic complexes as precatalysts for olefin polymerization. Most recently, an intense search has been started in next-generation single-site catalysts. New approaches have been taken to ligand design. This research has yielded extraordinary results such as catalysts with activities as high or higher than those of conventional metallocenes, stereospecific and living polymerizations, and amazing new polymer structures such as highly-branched ethylene homopolymers. This volume presents some of the recent disclosures in this exciting and rapidly expanding field, featuring papers by some of the leading investigators.
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 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 Pyrazole borate Lanthanide Organometallic Catalyst for Olefin Copolymers written by Birgit Schwenzer and published by . This book was released on 1998 with total page 132 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Organometallic Catalysis for Controlled Olefin Polymerization and Oligomerization written by Kyung-Sun Son and published by . This book was released on 2010 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: My Ph. D. work primarily involves the synthesis of ethylene-based oligomers and ethylene-styrene copolymers using organometallic catalysis. Chapter 1 reviews selective ethylene oligomerization that produces 1-hexene and 1-octene, with particular emphasis on the chromium-based catalytic systems and the mechanism by which they operate. Its application to the preparation of value-added chemicals is also covered. Chapter 2 and Chapter 3 present investigations on selective ethylene oligomerization with a Cr(PNP)Cl3/MAO catalyst system (PNP = Ph2PN(iPr)PPh2) in the presence of dialkyl zinc as an effective strategy for the co-generation of 1-octene and functionalized ethylene oligomers. Transmetallation with ZnMe2 during Cr-catalyzed ethylene tetramerization generated end-labeled 1-alkenes in Cn> 10 along with 1-octene, while that with ZnEt2 or ZnBu2 produced a mixture of end-labeled linear alkanes and 1-alkenes in Cn> 10 as well as 1-octene. Labeling studies with D2O provided a mechanistic test for metallacycle intermediates. Mechanistic proposals are presented to explain the formation of end-labeled products in the presence of various types of zinc alkyls. Chapter 4 and Chapter 5 examine a series of titanocenes [CpTiCl3, CpTiCl2TEMPO, CpNTiCl3, CpNTiCl2TEMPO, where Cp = C5H5, CpN = C5H4CH2CH2N(CH3)2, and TEMPO = 2,2,6,6-tetramethylpiperidine-N-oxyl] for styrene homopolymerization and ethylene-styrene (ES) copolymerization at 70 °C and 120 °C to determine the influence of the pendant amine group and the hydroxylaminato ligand on comonomer incorporation and distribution. Titanocenes bearing the pendant amine ligand were active for ES copolymerization, whereas complexes lacking the pendant group afforded only mixtures of homopolymers, revealing the critical role of the pendant amine donor on the copolymerization behavior. At 120 °C, the titanocene complexes with the amine group generated high molecular weight ES copolymers along with an atactic polystyrene (aPS) byproduct. The molecular weight of the ES copolymers produced by a coordination mechanism was found to coincide with that of the aPS produced by a radical polymerization mechanism. A method to separate these two components was developed by the addition of a catalytic chain-transfer agent, cobalt tetraphenylporphyrin, successfully decreasing the molecular weight of the radically-produced aPS and offering expedient separation of the ES copolymer from the aPS. Chapter 6 describes a series of new mono-, bi-, and trimetallic complexes based on the dinucleating ligand, N, N'-bis[2-(diphenylphosphino)phenyl] formamidine (PNNP), which provides two binding sites suitable for accommodating Pd, Ni, Co, Fe, and Cu. Definitive evidence for the structures of all complexes were given by X-ray crystal structures. The synthesis, characterization and crystal structure of each complex are discussed.
Download or read book American Doctoral Dissertations written by and published by . This book was released on 1998 with total page 784 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Synthesis and Characterization of Lanthanide Complexes with Phenalenide and Aromatic fused Cyclopentadienyls as Ligands written by and published by . This book was released on 2002 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The synthesis of yttrium phenalenide complexes 129-132 was achieved by salt metathesis reactions between ligand anions and YCI3. Ytterbium phenalenide complexes 133-137 were synthesized by protonolysis reactions between neutral ligands and Yb[N(SiMe3)2]2(THF)2. The solid state structure of (Pni1Bu)2Yb(THF) 136 reveals a unique n3 bonding pattern, however the electrons of the phenalenide ligand remain delocalized even when bonded to the metal center. Mono-alkyl complexes (PCpR)2Y(CH2SiMe3)(THFSiMe3)(THF) 147-149 (R = Me. Ph. H) and bis-alkyl complexes (PCp*)Y(CH2SiMe3)2(THF) 150 and (sCp)Y(CH2SiMe3)2(THF) 152 were synthesized by direct protonolysis reactions between Y(CH2SiMe3)3(THF)2 and neutral ligands. When treated with phenylsilane, complex 148 generated the crowded hydride dimer [(PCpPh)2Y(u-H)]2 161. Complexes 150 and 152 undergo acid-base. metallation. insertion reactions and polymerization of small substrates. A variable temperature `H NMR study of 150 and 152 at low temperature reveals an equilibrium between 150/152-THF and 1501152. The THF-free complexes. 150/152-THF. appear to undergo inversion of a pyramidal ground state structure to generate a C2 symmetric intermediate. The X-ray structures of 136, 147, 150. 152, (sCp)Y(CH2SiMe3)2(bipy) 154, 161. [PCp*Y(CCSiMe3)(THF)]2(u2-CCSiMe3)2] 167, acetylide cluster 169 and bis-(Me3Si)2Cp yttrium chloride dimer 176 were determined and structural features discussed.
Download or read book The Synthesis and Characterization of Lanthanide Complexes with Phenalenide and Aromatic fused Cyclopentadienyls as Ligands written by Jianlong Sun and published by . This book was released on 2007 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The synthesis of yttrium phenalenide complexes 129-132 was achieved by salt metathesis reactions between ligand anions and YCI3. Ytterbium phenalenide complexes 133-137 were synthesized by protonolysis reactions between neutral ligands and Yb[N(SiMe3)2]2(THF)2. The solid state structure of (Pni1Bu)2Yb(THF) 136 reveals a unique n3 bonding pattern, however the electrons of the phenalenide ligand remain delocalized even when bonded to the metal center.Mono-alkyl complexes (PCpR)2Y(CH2SiMe3)(THFSiMe3)(THF) 147-149 (R = Me. Ph. H) and bis-alkyl complexes (PCp*)Y(CH2SiMe3)2(THF) 150 and (sCp)Y(CH2SiMe3)2(THF) 152 were synthesized by direct protonolysis reactions between Y(CH2SiMe3)3(THF)2 and neutral ligands. When treated with phenylsilane, complex 148 generated the crowded hydride dimer [(PCpPh)2Y(u-H)]2 161. Complexes 150 and 152 undergo acid-base. metallation. insertion reactions and polymerization of small substrates. A variable temperature `H NMR study of 150 and 152 at low temperature reveals an equilibrium between 150/152-THF and 1501152. The THF-free complexes. 150/152-THF. appear to undergo inversion of a pyramidal ground state structure to generate a C2 symmetric intermediate. The X-ray structures of 136, 147, 150. 152, (sCp)Y(CH2SiMe3)2(bipy) 154, 161. [PCp*Y(CCSiMe3)(THF)]2(u2-CCSiMe3)2] 167, acetylide cluster 169 and bis-(Me3Si)2Cp yttrium chloride dimer 176 were determined and structural features discussed.
Download or read book Synthesis and Chemistry of Lanthanide Complexes with Phosphorus Ylides Amides Or Porphyrinate Ligands and of Transition Metal Complexes with Polydentate Ligands written by Lilu Zhang and published by . This book was released on 1999 with total page 492 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Synthesis and Characterization of Lanthanide Complexes with Phenalenide and Aromatic fused Cyclopentadienyls as Ligands written by Jianlong Sun and published by . This book was released on 2007 with total page 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 . This book was released on 2006 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
