Download or read book Eta6 arene Tethered Ruthenium ii Complexes and Half metallocene Dithiocarbamate Ruthenium iv Complex for Olefin Polymerization written by Miguel Angel Camacho Fernandez and published by . This book was released on 2014 with total page 300 pages. Available in PDF, EPUB and Kindle. Book excerpt: There are very few reports of ruthenium complexes for olefin polymerization and the active species are unknown. In this dissertation we explore a series of new ruthenium II and IV complexes for olefin polymerization catalysis. We synthesized an arene-tethered ruthenium complex (eta6-C6H5(CH2)3SCH3RuCl2) capable of catalyzing ethylene polymerization using AlMe2Cl as cocatalyst. Homologous dimethylated eta6-C6H5(CH2)3SCH3Ru(CH3)2 complex in the presence of ethylene also yielded polyethylene when activated with HBArF ([H(Et2O)2]+[BAr'4]- (where Ar'=3,5-(CF3)2C6H3)). Mechanistic studies by 1H-NMR and mass spectrometry support a ruthenium cationic [eta6-C6H5(CH2)3SCH3Ru(oligomer)]+ complex as the polymerization active species. This has unambiguously demonstrated for the first time a ruthenium complex as the active species for catalyzing olefin insertion polymerization. We also studied heteroatom effect eta6-Arene tethered ruthenium (II) complexes on polymerization activity. Complexes (eta6-C6H5(CH2)3SCH3RuCl2), (eta6-C6H5(CH2)3N(CH3)2RuCl2), and [(eta6-C6H5(CH2)3OCH3RuCl2)]2 with coordinating oxygen, sulfur, and nitrogen heteroatoms in the tethered arms have been compared for olefin polymerization. Nitrogen and sulfur-containing complexes are active for olefin polymerization while oxygen-containing complex is inactive. The nitrogen-containing complex is 1.5-fold more active than the sulfur-containing complex. The polymers obtained are composed of two different fractions, a high molecular weight fraction (55-161 kg*mol-1) and a low molecular weight fraction (276-761 g*mol-1). The polydispersities of both fractions are narrow, indicating a single-site catalyst. DFT calculations were carried out on to determine the migratory insertion barriers. Nitrogen-containing complex was found to have a migratory insertion barrier of the chain propagation of 19.4 kcal*mol-1 while sulfur-containing was found to be 21.8 kcal*mol-1. Theoretical calculations are in agreement with the experimental polymerization activity results. We hypothesize that a more electron deficient ruthenium complex will be more active. We synthesized Ru(IV) dimethyl complex [Cp*(k2-S2CNMe2)RuIVMe2] that polymerizes ethylene with higher activity. The polymers obtained were linear with high molecular weights (up to 322 kg*mol-1) and narrow monomodal molecular weight distributions (Mw/Mn=1.69-2.50). Pronounced counterion effects were observed: the methylaluminoxane activator gave the highest productivities, whereas HBArF resulted in no activity. These results are further supported by DFT calculations, which indicate a low migratory insertion barrier for chain propagation (9.8 kcal*mol-1) but high ethylene uptake energies (15.6 kcal*mol-1).
Download or read book Chiral Ansa ligated Ruthenium II 6 arene Complexes ruthenium II eta 6 arene written by Immo Weber and published by . This book was released on 2006 with total page 317 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Chiral Ansa ligated Ruthenium II j63 1hn6 arene Complexes ruthenium II eta 6 arene written by Immo Weber and published by . This book was released on 2006 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Chiral Ansa ligated Ruthenium II j6 arene Complexes ruthenium II eta 6 arene written by Immo Weber and published by . This book was released on 2006 with total page 317 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Synthesis and Characterisation of Half sandwich N6 arene B diketiminato Ruthenium II and Osmium II Complexes and Application in Homogeneous Catalysis written by and published by . This book was released on 2012 with total page 240 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book N6 Arene Ruthenium II Complexes Containing Hybrid and Conformationally Rigid Chiral Diphosphine Ligands written by Kesete Y. Ghebreyessus and published by . This book was released on 2003 with total page 856 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Chiral Ansa ligated Ruthenium II j63 1hn6 arene Complexes ruthenium II eta 6 arene written by Immo Weber and published by . This book was released on 2006 with total page 317 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Half sandwich Complexes of Ruthenium Synthesis and Application to Catalysis written by Sun Hwa Lee 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 Ruthenium II Arene Complexes for Asymmetric Catalysis written by Zhenyu Zhu and published by . This book was released on 2019 with total page 36 pages. Available in PDF, EPUB and Kindle. Book excerpt: Within the last few years, a significant contribution to the discovery of sp2C−H activation processes and useful applications for cross-coupling C−C bond formation has been achieved by the use of ruthenium(II) arene catalysts. The aim of this thesis is to describe a modular approach for the synthesis of several ruthenium(II) arene complexes with the potential for C−H activation. Another cutting-edge field, catalytic enantioselective functionalization of C−H bonds by transitional metal catalysts, has also been realized within the last few years. It represents a highly atom- and step-economic approach toward the generation of structural complexity. However, the majority of current methodologies rely on the usage of late third- row transition metals such as pallidum, iridium and rhodium. There is a need that motivates the search for cheaper, relative earth abundant metals that could have similar catalytic ability. Herein is also represented a preliminary study of a ruthenium(II)-catalyzed enantioselective access to chromane moiety enabled by chiral transient directing group.
Download or read book Chemical Physics and Quantum Chemistry written by and published by Academic Press. This book was released on 2020-09-18 with total page 350 pages. Available in PDF, EPUB and Kindle. Book excerpt: Advances in Quantum Chemistry presents surveys of current topics in this rapidly developing field one that has emerged at the cross section of the historically established areas of mathematics, physics, chemistry, and biology. It features detailed reviews written by leading international researchers. In this volume the readers are presented with an exciting combination of themes. Presents surveys of current topics in this rapidly-developing field that has emerged at the cross section of the historically established areas of mathematics, physics, chemistry and biology Features detailed reviews written by leading international researchers Topics include: New advances in Quantum Chemical Physics; Original theory and a contemporary overview of the field of Theoretical Chemical Physics; State-of-the-Art calculations in Theoretical Chemistry
Download or read book Metastable Microstructures written by Dipankar Banerjee and published by . This book was released on 1993 with total page 360 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Metallic Alloys Experimental and Theoretical Perspectives written by J.S. Faulkner and published by Springer Science & Business Media. This book was released on 1994-02-28 with total page 486 pages. Available in PDF, EPUB and Kindle. Book excerpt: The development of new materials is recognized as one of the major elements in the overall technological evolution that must go on in order to sustain and even improve the quality of life for citizens of all nations. There are many components to this development, but one is to achieve a better understanding of the properties of materials using the most sophisticated scientific tools that are available. As condensed matter physicists and materials scientists work toward this goal, they find that it is useful to divide their efforts and focus on specific areas, because certain analytical and theoretical techniques will be more useful for the study of one class of materials than another. One such area is the study of metals and metallic alloys, which are used in the manufacture of products as diverse as automobiles and space stations. Progress in this area has been very rapid in recent years, and the new developments come from many different countries. For these reasons the Advanced Research Workshop Programme in the NATO Scientific Affairs Division has seen fit to sponsor several meetings to bring together the researchers and students working in this field from the NATO countries and elsewhere. There have been a series of NATO-ASI's that have dealt with the results of research on the electronic structure of materials and the properties of metals, alloys, and interfaces. They are: "Electrons in finite and infinite structures" P. Phariseau and L.
Download or read book Modern Quantum Chemistry written by Declan Hicks and published by . This book was released on 2020-09-15 with total page 217 pages. Available in PDF, EPUB and Kindle. Book excerpt: The branch of chemistry which focuses on the application of quantum mechanics in physical models is referred to as quantum chemistry. It deals with the study of ground state of individual molecules and atoms as well as the transition and excited states that occur during chemical reactions. The two major branches of quantum chemistry are experimental quantum chemistry and theoretical quantum chemistry. Experimental quantum chemistry seeks to obtain information regarding the quantization of energy on a molecular scale. It relies extensively on spectroscopy. Nuclear magnetic resonance spectroscopy, infrared spectroscopy and scanning probe microscopy are a few of the common methods used in this area. The predictions of quantum theory are calculated within the field of theoretical quantum chemistry. This book aims to shed light on some of the unexplored aspects of quantum chemistry. While understanding the long-term perspectives of the topics, it makes an effort in highlighting their impact as a modern tool for the growth of the discipline. Those in search of information to further their knowledge will be greatly assisted by this book.
