Dissertations / Theses on the topic 'Group IV metals'
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Janeway, Felix David. "Aluminium and group IV metals for polymerisation of lactide." Thesis, University of Leeds, 2015. http://etheses.whiterose.ac.uk/12492/.
Full textJaggar, Andrew James. "The synthesis and reactions of cationic alkyl complexes of group(IV) transition metals." Thesis, University of East Anglia, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.332355.
Full textGribkov, Denis. "Novel catalysts for stereoselective hydroamination of olefins based on rare earth and group IV metals." [S.l.] : [s.n.], 2005. http://deposit.ddb.de/cgi-bin/dokserv?idn=976595567.
Full textLapenta, Rosita. "New metal catalysts for the synthesis of polyolefins and bioderived polymers." Doctoral thesis, Universita degli studi di Salerno, 2018. http://hdl.handle.net/10556/2980.
Full textThe aim of PhD project is the synthesis of new metal catalysts active in the polymerization of polar monomer and α-olefins. In the last decade, transition metal complexes bearing tetradentate bis(phenolato) ligands are widely studied for their high polymerization control and activity.1 The bis(phenolato) ligand is composed of two phenoxide groups linked by a bridge comprising two donor heteroatoms; when the donors are two sulfur atoms, the ligand is called of OSSO-type... [edited by Author]
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Patel, Bhavesh. "Hard/soft interactions : Group IV metal halide complexes with soft donor ligands of Groups 15 and 16." Thesis, University of Southampton, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.395952.
Full textLundberg, Helena. "Group (IV) Metal-Catalyzed Direct Amidation : Synthesis and Mechanistic Considerations." Doctoral thesis, Stockholms universitet, Institutionen för organisk kemi, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-116955.
Full textAmidbindningen är en kemisk enhet som utgör ryggraden i proteiner, och som även återfinns i en stor mängd läkemedelsmolekyler, polymera material som nylon och Kevlar, samt i tillsatser i livsmedelsindustrin, exempelvis aspartam. Amider produceras i enorma mängder varje år, och det är av stor vikt att utveckla miljövänliga och selektiva metoder för deras framställning. Denna avhandling behandlar direkt amidering av icke-aktiverade karboxylsyror och aminer med hjälp av katalytiska mängder metallkomplex, baserade på titan, zirkonium och hafnium. Den enda biprodukten från denna amideringsreaktion är vatten. Jämfört med de metoder som generellt används idag för amidsyntes, så är de presenterade metoderna avsevärt mer miljövänliga med avseende på toxicitet hos reagensen såväl som på mängden avfall som genereras. Dessutom redovisas här en katalytisk metod för syntes av primära och tertiära amider genom att använda olika karbamat som källa till gasformiga aminer, vilka annars kan vara praktiskt svåra att arbeta med. Preliminära resultat från en pågående mekanistisk studie av de zirkonium- och hafnium-katalyserade processerna är också inkluderade.
At the time of the doctoral defense, the following paper was unpublished and had a status as follows: Paper 2: Accepted.
Theurkauff, Gabriel. "Investigations on the stereoselective polymerization of α-olefins by single-site group IV metal catalysts." Thesis, Rennes 1, 2014. http://www.theses.fr/2014REN1S158/document.
Full textThe work presented in the manuscript focus on α-olefin polymerization catalysis, and is divided into four distinct parts. The first part is dedicated to the study of catalytic systems for the production of elastomeric polypropylene. The analysis of the produced polymers and the characterization of the catalysts showed the presence of two homopolymers as a blend in the elastomeric polypropylene. The second part focuses on the copolymerization of bifunctionnal vinyl-vinylidene monomers with propylene. The characterization of the polymers revealed the reactivity of the vinylidène bonds and showed different polymerization mechanisms for the different catalysts. The third part reports a study on the activation and deactivation pathways of the active species in polymerization. The characterization of model cationic species and the study of their behavior in solution and in polymerization showed the relationship between the electrophilicity of the species and its productivity in propylene polymerization. The last part is dedicated to the polymerization of hindered α-olefins. The quest for a productive catalyst led to test various single site catalysts with different structures. Deactivating interactions between the monomers and the catalyst are supposed to explain the low productivity of the tested catalysts
Wintersgill, S. "Reactions of group IV metal compounds with isocyanates, and their catalytic applications." Thesis, University of Newcastle Upon Tyne, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.311171.
Full textThompson, Joseph. "Development of single-source CVD precursors for group IV, V and VI metal disulfides." Thesis, University of Bath, 2017. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.715262.
Full textLoukova, G. V., V. V. Vasiliev, V. L. Ivanov, M. Ya Melnikov, V. A. Smirnov, and E. E. Melnichuk. "Two−photon Processes in Organometallic Molecules and Clusters: T−T Absorption of Group IV Metal Complexes." Thesis, Sumy State University, 2013. http://essuir.sumdu.edu.ua/handle/123456789/35395.
Full textZeng, Li. "Disordered electronic and magnetic systems - transition metal (Mn) and rare earth (Gd) doped amorphous group IV semiconductors (C, Si, Ge)." Connect to a 24 p. preview or request complete full text in PDF format. Access restricted to UC campuses, 2007. http://wwwlib.umi.com/cr/ucsd/fullcit?p3284117.
Full textTitle from first page of PDF file (viewed January 9, 2008). Available via ProQuest Digital Dissertations. Vita. Includes bibliographical references (p. 123-132).
David, Jérémy. "Étude des mécanismes de réduction carbothermique d'oxydes métalliques du groupe IV par MET : Apport de précurseurs de type polymères de coordination." Limoges, 2013. https://aurore.unilim.fr/theses/nxfile/default/f239d478-5a37-46db-8ffc-dda194277ff8/blobholder:0/2013LIMO4013.pdf.
Full textThis thesis is dedicated to the study of the reactional mechanisms involved in the formation of oxycarbides by different synthesis routes. It reconsiders the literature that used to deal with thermochemical and kinetical approaches. This original work deals with a structural and chemical study mainly led by transmission electron microscopy (TEM) and X-ray diffraction (XRD) on samples obtained at different advancement rates. The first part of this study is about the classical carbothermal reduction transformations of dioxides (TiO2, ZrO2, HfO2) reducted by carbon black into oxycarbide. We highlight that the reactional mechanisms involved into the parent phases destabilization are intrinsically linked to the dioxides structure and that the initial size of oxide particles has no influence on the ones of the oxycarbides. The nucleation site of the oxycarbide and the growth mechanisms have also been highlighted and discussed. A second part of the manuscript is dedicated to an original study aiming to synthesize carbide from Metal-Organic Frameworks (MOF). The progressive transformation of the precursors into oxycarbides is very likely to the ones highlighted in the field of classical carbothermal reactions
Haas, Isabelle [Verfasser], and Rhett [Akademischer Betreuer] Kempe. "Novel N-Ligand Stabilized Transition Metal Complexes of the Group IV Triad as Efficient Catalysts for Polymerization and Oligomerization / Isabelle Haas. Betreuer: Rhett Kempe." Bayreuth : Universität Bayreuth, 2013. http://d-nb.info/106000948X/34.
Full textGribkov, Denis [Verfasser]. "Novel catalysts for stereoselective hydroamination of olefins based on rare earth and group IV metals / vorgelegt von Denis Gribkov." 2005. http://d-nb.info/976595567/34.
Full textTzer, An Hung, and 洪澤安. "Group IV Element Metal-Oxide-Semiconductor Light Emitting Devices." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/62421984380314050293.
Full text國立臺灣大學
電子工程學研究所
96
In this thesis, various metal-oxide-semiconductor light-emitting-devices (MOS LED) were fabricated and investigated of their luminescence characteristics. The MOS LED structures include the Ge MOS LED with silicon dioxide (SiO2), Ge MOS LED with aluminum oxide (Al2O3) and the 6H-SiC MOS LED. Infrared emission is observed from the Ge MOS LED. A spectral line fit is performed on the luminescence spectrum with the electron-hole-plasma (EHP) recombination model with 5 phonon assisted replica, including TO, LA, TA emission, and TA, LA absorption. Intensity of the TA phonon absorption is seen to increase at elevated temperatures. Reduced thermal quenching in electroluminescence compared to photoluminescence measurements is due to the large difference in concentration between the majority and minority carriers in EL, which limits the cause of the decrease of radiative recombination probability to only the lowering of the minority concentration. The Ge MOS LED with Al2O3 insulator shows improvements in performance that include smaller operating voltage, smaller leakage current, stronger light emission, reduced nonradiative radiation and an increase in light emission intensity at elevated operation temperatures. Blue luminescence at reverse bias is observed in the 6H-SiC MOS LED.
Lan, Huang-Siang, and 藍偟翔. "Electric Conduction of Group IV Alloy and Group III-V as Metal Gate Device." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/37951531957492049608.
Full text國立臺灣大學
電子工程學研究所
96
Abstract In this thesis, three topics are included. One is the direct band gap Ge1-xSnx alloys simulated by valence band anti-crossing method and nonlocal empirical pseudopotential method and the other is the Si-like (x<0.85) strained Si1-xGex N-MOSFETs mobility calculations which include alloy scattering, phonon scattering and roughness scattering. Lastly, Poly-III-V compound semiconductor was proposed to be used as gate electrode first time. Part I : For a long time, group IV semiconductors applied on photoelectric devices have been limited in efficiency by nature indirect band gap. Tensile strained Ge can also be a direct band gap material in theoretical simulations, but not easy to fabricate in practice. However, Ge1-xSnx alloys can form the narrow direct band gap and have been fabricated in the reported experiments successfully. Ge1-xSnx alloys can be applied on infrared optoelectronic applications and may be fabricated new high speed transistors further. In this thesis, chapter 2, energy band structures of Ge1-xSnx alloys are simulated to find the possible direct band gap in group IV semiconductors. Part II : Strained silicon is the main stream to produce higher mobility in transistors. However, the reasons of increase mobility in N-MOSFETs are not only split the lower delta 2 subband and higher delta 4 subband but also change some important elements under strain. In this topic, chapter 3, we simulate the mobility of Si on Si1-xGex substrates and Si1-xGex on Si1-xGex substrates N-MOSFETs and include difference kinds of scattering effects. Part III : As High-k dielectrics were used to replace conventional SiO2 as insulators of MOSFETs, poly-silicon gate must also been replaced by different kinds of metals. In this topic, chapter 4, ploy-III-V semiconductor was fabricated as gate electrode of metal-oxide semiconductors (MOS) first time. Utilizing band gap of III-V semiconductor can adjust the work function and the results of experiments were discussed.
Lan, Huang-Siang. "Electric Conduction of Group IV Alloy and Group III-V as Metal Gate Device." 2008. http://www.cetd.com.tw/ec/thesisdetail.aspx?etdun=U0001-1307200813282900.
Full textKumar, Akshai A. S. "Reductive And Metathetic Coupling Reactions Mediated By Group (IV) Metal Alkoxides." Thesis, 2009. http://hdl.handle.net/2005/919.
Full textLUCONI, LAPO. "“Group-IV Organometallics for the Catalytic Polymerization and Hydroamination of Unactivated Olefins”." Doctoral thesis, 2014. http://hdl.handle.net/2158/835116.
Full textBrusich, Mark John. "Theoretical Insights into the Bonding in Thorium Organometallic Complexes: A Comparison with Group IV Transition Metal Chemistry." Thesis, 1988. https://thesis.library.caltech.edu/5307/4/Brusich_MJ_1988.pdf.
Full textIn this thesis a detailed ab initio theoretical study of organothorium chemistry is presented. The first part is devoted to examining both the bonding in and the reaction chemistry of various substituted thorium complexes. Using the chlorine ligand as a model for the usual cyclopentadienyl groups found in these systems, we examine the bonding of hydrogen and methyl ligands to thorium. Frequent comparisons with the experimental results on similar species are made. In addition, by contrasting the bonding in the thorium complexes with the bonding in the analogous Group IVB systems, a qualitative and quantitative picture of bonding, as the atomic number of the metal becomes larger, can be obtained. The reaction chemistry is studied via two different sets of processes. In the first, the deuterium (D2) exchange reaction with a thorium-hydrogen bond is examined. Several studies have been done previously, both experimentally and theoretically, on the Group IVB exchange reactions. Hence, there is enough information to see trends and to make predictions about relative reaction rates. Also, from our investigation the effect that different types of ligands have on the activation barrier to reaction can be ascertained.
In the second part of the thesis, the factors that go into stabilizing bond formation are discussed concerning both main group elements and transition metals, including actinides. In particular, the process of bond formation between hydrogen atom and the alkali metals is compared with the same process in the Group IVB-hydrogen and thorium-hydrogen saturated complexes. The main difference between the alkali metal and the transition metal bonds with hydrogen is the bond strength trends with increasing atomic number. For the alkali metals the bond energies decrease down the column, yet for the transition metals and thorium it is the reverse. The conclusion is that the shape of the mostly d in character transition metal bonding orbitals is such that better overlap can be achieved with hydrogen as the orbitals become more diffuse. In the alkali metals the bonds can be described as s—s bonds whose overlap decreases with increasing diffuseness.
Tsai, Jie-Ying, and 蔡杰穎. "Aluminum, Zinc and Group IV Metal Complexes Containing Ketiminate Ligands. Synthesis, Characterization, and Ring-Opening Polymerization of ε-Caprolactone." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/3a6zan.
Full text國立彰化師範大學
化學系
104
A series of main and transition metal complexes containing ketiminate ligand, [OCMeCHCMeNHC6H4-2-tBu] (L1), [OCMeCHCMeNHCH2C6H4-4-Me] (L2), [OCPhCHCMeNHCH2(C4H7O)] (L3), [OCPhCHCMeNHCH2Ph] (L4), [OCMeCHCMeNHCH2(C4H7O)] (L5), [OCMeCHCMeNHCH2Ph] (L6) and [OCMeCHCMeNHMes] (L7) were synthesized and characterized. Treatment of 1 equiv of AlMe3 with L1-L4 generates aluminum complexes [AlMe2(OCMeCHCMeNC6H4-2-tBu)]（1）, [AlMe2(OCMeCHCMeNCH2C6H4-4-Me)]（2）, {AlMe2[OCPhCHCMeNCH2(C4H7O)]}（3）, [AlMe2(OCPhCHCMeNCH2Ph] （4）. Treatment of 2 equiv of L1-L7 with ZnMe2 generates Zinc complexes [Zn(OCMeCHCMeNC6H4-2-tBu) 2] （5）, [Zn(OCMeCHCMeNCH2C6H4-4-Me) 2]（6）, {Zn[OCPhCHCMeNCH2(C4H7O)]2} （7）, [Zn(OCPhCHCMeNCH2Ph)2] （8）, {Zn[OCMeCHCMeNCH2(C4H7O)]2}（9）, [Zn(OCMeCHCMeNCH2Ph)2] （10）, [Zn(OCMeCHCMeNMes)2] （11）. Treatment of 2 equiv of L6 or L7 with MR4 generates group IV complexes ML2R2 (12, M=Ti, R1=CH2Ph, R=NMe2; 13, M=Zr, R1=CH2Ph, R=NMe2; 14, M=Zr, R1=CH2Ph, R=NEt2; 15, M=Hf, R1=CH2Ph, R=NEt2; 16, M=Ti, R1=Mes, R=OiPr; 17, M=Ti, R1=Mes, R=NMe2; 18, M=Zr, R1=Mes, R=NMe2; 19, M=Zr, R1=Mes, R=NEt2; 20, M=Hf, R1=Mes, R=NEt2). All the aforementioned complexes have been characterized by 1H and 13C NMR spectroscopy and have been determined by single X-ray diffractometry in solid state (except 2, 3, 4, 7, 8, 9, 11, 12, 13, 14, 15, 19 and 20). Complexes 16, 17, 18, 19 and 20 were tested as initiators for the ring-opening polymerization of ε-caprolactone.
Chen, Yun-Fan, and 陳韻帆. "Synthesis, Characterization and Ring Opening Polymerization of Main Group and Group IV Metal Complexes Containing Bi- or Tri-dentate Keto-amine, Furanyl-amine or Pyridyl-amine Ligands." Thesis, 2019. http://ndltd.ncl.edu.tw/handle/g9yw9m.
Full text國立彰化師範大學
化學系
107
應文摘要 A series of group 4 metal and main group complexes containing bi- or tri-dentate keto-amine, furanyl-amine or pyridyl-amine ligands are synthesized and characterized. Reacting furfural with 2-(aminomethyl)pyridine and (+/-)-tetrahydrofurfurylamine in the presents of NaBH4 result new tridentate amine ligands NC5H4CH2NHCH2C4H3O (L1H) and OC4H3CH2NHCH2C4H7O (L4H), respectively. Similarly, reacting Pyridine-2-carboxaldedehyde with 2-(aminomethyl)pyridine and (+/-)-tetrahydrofurfurylamine in the presents of NaBH4 result NC5H4CH2NHCH2C5H4N (L2H) and NC5H4CH2NHCH2C4H7O (L3H), respectively. In addition, adding 2,4-pentandione with one equivalent of 2-(1-cyclohexenyl)ethylamine in methanol gives a new keto-amine ligand MeC(OH)CHCMe(CH2CH2C6H9) (L6H). Similarly, adding 2,4-pentandione with one equivalent of 2-(aminomethyl)pyridine in methanol gives a new keto-amine ligand MeC(OH)CHCMe(NCH2NC5H4) (L5H). Ligands L1H-L6H have been characterized by 1H and 13C NMR spectroscopy. Reacting ligands L1H-L6H with main group and group 4 metal amide (M(NR2)4, M = Ti, Zr, Hf; R = Me, Et) yield corresponding ligand-metal amide complexes. Characterization of these metal complexes have been performed and related catalytic reactions will be performed.