DOCSLIB.ORG

Polysubstituted Cyclopentadienes and Their Ferrocenes

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Polysubstituted Cyclopentadienes and Their Ferrocenes Research Collection Doctoral Thesis Polysubstituted Cyclopentadienes and Their Ferrocenes Author(s): Lauber, Alex Publication Date: 2018-12 Permanent Link: https://doi.org/10.3929/ethz-b-000307868 Rights / License: In Copyright - Non-Commercial Use Permitted This page was generated automatically upon download from the ETH Zurich Research Collection. For more information please consult the Terms of use. ETH Library Diss. ETH NO. 25126 Polysubstituted Cyclopentadienes and Their Ferrocenes A thesis submitted to attain the degree of DOCTOR OF SCIENCES of ETH ZURICH (Dr. sc. ETH Zurich) presented by ALEX SANDRO LAUBER MSc in Chemistry, ETHZ born on 14.12.1988 citizen of T¨asch VS accepted on the recommendation of Prof. Dr. Antonio Togni, examiner Prof. Dr. Erick M. Carreira, co-examiner 2018 I could put my thumb up to a window and completely hide the Earth. I thought, ’everything I’ve ever known is behind my thumb’. James Arthur Lovell Jr. Danksagung Ich hatte das Gluck¨ viele Leute w¨ahrend meiner Zeit an der ETH kennenzulernen, die mich in jeglichen Belangen unterstutzt¨ haben. Es ist mir daher eine Freude, hier meine Dankbarkeit ausdrucken¨ zu durfen.¨ Der grosste¨ Dank geht an meinen Doktorvater Antonio Togni, der mich uber¨ die Jahre geleitet und begleitet hat. Danke dir, Antonio, fur¨ deine Menschlichkeit und Freundlichkeit, dein Vertrauen und deine Unterstutzung,¨ sowie fur¨ deine Leidenschaft in der Lehre und Forschung. Durch dich habe ich das Gluck¨ eine ausserordentliche Ausbildung genossen zu haben. Prof. Erick M. Carreira mochte¨ ich ganz herzlich fur¨ die Ubernahme¨ der Rolle des Koreferenten danken, sowie fur¨ die zahlreichen packenden und lehrreichenden Seminare w¨ahrend der Ausbildung. Meine allerliebste Andrea Sachs: ein Danke ist keineswegs genug fur¨ die vielen Unterhal- tungen, die einem den Tag immer wieder erfrischt haben und die st¨andige Hilfe in allen moglichen¨ Angelegenheiten. Fur¨ seine grosszugige¨ Hilfsbereitschaft mochte¨ ich mich bei Antonio Mezzetti bedanken denn, komme was wolle, ich konnte immer auf seine Unterstutzung¨ z¨ahlen. Ein grosser Teil meiner Zeit durfte ich fern(er) vom Tageslicht im Keller verbringen. Dennoch freute ich mich (fast) jedes Mal wenn es hiess ”s’NMR goht nume”,¨ und ich alles Wissen, welches mir Ren´e Verel mit viel Geduld und Passion beigebracht hatte, zur Geltung bringen durfte. Danke dir, Ren´e fur¨ die zus¨atzliche Ausbildung welche ich in einer Umgebung geniessen durfte welche ich bereits vermisse. Doch war es jemand anders der mir in letztere Welt den Eingang ermoglicht¨ hatte. Meine liebe Barbara Czarniecki: deine ansteckende Leidenschaft machten einem das Privileg der Aufgabe des NMR Assistenten noch klarer. Den Bewohnern des H222, welche mir bei der Verfassung dieser Arbeit geholfen haben, mochte¨ ich ebenfalls meine Dankbarkeit hier zeigen: Fabian Bruning,¨ danke dir fur¨ deine lockere und gleichzeitig gewissenhafte Art, sowie fur¨ die Ubernahme¨ der Rolle des “Sicherheits-Salamanders”. Meiner lieben Mona Wagner muss ich vor allem fur¨ Ihre Fursorglichkeit¨ danken. Mit ihren lieben Gesten vermochte sie mich w¨ahrend dem Schreiben immer wieder aufzumuntern. Dem jungsten¨ Mitglied, Phil Liebig mochte¨ ich herzlich fur¨ seine - wie es der Name ankundigt¨ - liebe Art und fur¨ die hilfreichen Diskussionen danken. Ich hatte w¨ahrend den letzten Jahren das Privileg in der Lehre t¨atig sein zu durfen,¨ und das zum ersten Mal auch hinter der Kulisse. Ich hatte dabei das Gluck,¨ dass ich diese spannende und intensive Aufgabe mit einer sehr f¨ahigen Person teilen durfte. Carl Philipp Rosenau: die unz¨ahligen Stunden welche wir zusammen gekrampft haben gehoren¨ zu den besten Erinnerungen die ich mitnehme. Unseren Kristallographen Lukas Sigrist und Mona Wagner bin ich unendlich dankbar fur¨ ihre Zeit und Arbeit welche mir noch so einige schone¨ Strukturen hingezaubert haben. Bei meinen Studenten Christian Rueger,¨ Jonas Bosken,¨ Salome Heilig und Raphael Lengacher mochte¨ ich mich ganz herzlich fur¨ ihre Motivation bedanken, welche diese Arbeit weitreichend unterstutzt¨ und geformt hat. Ich h¨atte mir keine besseren Schuler¨ wunschen¨ konnen¨ und es war mir ein Freude, mit euch zu arbeiten und dabei zu lernen. Ich hatte das Vergnugen¨ und die Ehre gleich zwei wurdige¨ NMR-Assistenten ausbilden zu durfen.¨ Ein grosses Danke an Matthew Baker und Pascal Tripet fur¨ Ihre Bereitschaft dieses Amt zu ubernehmen.¨ Jelier Benson mochte¨ ich fur¨ die vielen netten Worte und interessanten Diskussionen danken. Sein Engagement in der Gruppe und die vielen Aufgaben die er ubernommen¨ hat sorgen dafur,¨ dass doch so einiges rund l¨auft. Einige faszinierende wissenschaftliche Werke w¨aren mir verneint geblieben wenn diese nicht durch Dmitry Katayev aus dem Russischen ubersetzt¨ worden w¨aren. Allgemein, muss ich allen Mitgliedern der Togni und Mezzetti Gruppen danken fur¨ die Hilfe w¨ahrend den Jahren und den vielen Freizeitaktivit¨aten die wir unternommen haben. Allen Angestellten des HCI-Shops und des MS-Services (vor allem Louis Bertschi) danke ich fur¨ ihre ausgezeichnete Arbeit ohne welche nicht viel von dieser Dissertation moglich¨ gewesen w¨are. Ein grosses Danke geht an einige, teils ehemalige, Veteranen der Gruppe: Rima Drissi, Lukas Sigrist, Remo Senn, Simon Foser, Peter Ludwig, Jan Welch, Barbara Czarniecki, Rino Schwenk und Harutake Kajita. Danke euch, fur¨ die vielen schonen¨ Zeiten die ich mit euch erleben durfte. Einfach gesagt, mein Leben w¨are niemals das Gleiche ohne euch. Ein besonderer Dank geht an meine Eltern Anna und Clemente, sowie meinen Brudern¨ Anthony und Joel. Ohne eure Unterstutzung¨ w¨are ich nie so weit gekommen und es gibt keine Worte um meine Dankbarkeit euch gegenuber¨ entsprechend auszudrucken.¨ Contents Abstract iv Zusammenfassung vi Introductory Remarks ix 1 General Introduction1 1.1 Cyclopentadiene: A Historical Note....................1 1.2 Cyclopentadiene in Organometallic Chemistry...............1 1.3 Syntheses of Pentamethylcyclopentadiene.................2 1.4 Syntheses of Chiral Cyclopentadienes: The Advantage of Modularity...4 1.5 Aim of this Thesis.............................7 2 First Generation Approach for the Synthesis of Polysubstituted Cyclopen- tadienes9 2.1 Introduction................................9 2.1.1 General Retrosynthetic Analysis..................9 2.1.2 Model Ligand........................... 11 2.2 Results and Discussion........................... 12 2.2.1 Preparation of 1,2,3-Trimethylcyclopentadiene.......... 12 2.2.1.1 Preparation of a Disubstituted Cyclopentadiene Model Compound........................ 14 2.2.2 Cross Coupling Reactions..................... 15 2.3 Summary and Conclusion......................... 17 2.4 Outlook.................................. 18 3 Second Generation Approach for the Synthesis of Polysubstituted Cy- clopentadienes 19 3.1 Introduction................................ 19 3.1.1 General Retrosynthetic Analysis.................. 19 3.1.2 Conversion of Cyclopentenones to Cyclopentadienes: A Closer Look 21 3.1.2.1 Model Ligand and Retrosynthetic Analysis....... 21 3.2 Results and Discussion........................... 23 3.2.1 Preparation of Cyclopentenones.................. 23 3.2.2 Preparation of Cyclopentadienes.................. 26 3.2.3 Attempted Reduction of the Cyano Group............ 28 3.2.4 Preparation of Methoxy-Substituted Cyanocyclopentadienes... 28 3.3 Summary and Conclusion......................... 32 3.4 Outlook.................................. 33 i Table of Contents 4 Polysubstituted Ferrocenes 35 4.1 Introduction................................ 35 4.1.1 Goals and Synthetic Planning................... 36 4.1.2 O-Substituted Ferrocenes..................... 38 4.1.2.1 Preparation of Ferrocenol and Derivatives Thereof... 39 4.1.2.2 Alternative Preparations of Ferrocenols and Derivatives Thereof......................... 40 4.1.2.3 Applications of Ferrocenols and Derivatives Thereof.. 41 4.1.3 Cyanoferrocenes.......................... 42 4.1.3.1 Single Step Preparations of Cyanoferrocenes from Fer- rocene.......................... 42 4.1.3.2 Multistep Transformations Yielding Cyanoferrocenes.. 42 4.1.3.3 Cyanoferrocenes from Cyanocyclopentadienes..... 43 4.1.3.4 Applications of Cyanoferrocenes............. 44 4.1.4 The Only Example of a 1-Alkoxy-2-Cyanoferrocene........ 44 4.1.5 Cyclopentadienyl Iron(II) Transfer Reagents for the Preparation of Heteroleptic Ferrocenes..................... 45 4.1.5.1 Heteroleptic Ferrocenes from Cyclopentadienyl Arene Iron(II) Compounds................... 47 4.2 Results and Discussion........................... 49 4.2.1 Synthesis of Homoleptic Ferrocenes................ 49 4.2.2 Heteroleptic Ferrocenes...................... 50 4.2.2.1 Preparation of Cyclopentadienyl Arene Iron(II) Compounds 50 4.2.2.2 Synthesis of Heteroleptic Ferrocenes: Photolysis Protocol 51 4.2.2.3 Synthesis of Heteroleptic Ferrocenes: Thermal Protocol 52 4.2.2.4 Optimizations of Reaction Conditions for the Synthesis of Heteroleptic Ferrocenes................ 53 4.2.2.5 Structural Considerations of Heteroleptic Cyanoferrocenes 61 4.2.3 Investigations on the Reactivity of Heteroleptic Ferrocenes.... 66 4.3 Summary and Conclusion......................... 68 4.4 Outlook.................................. 69 5 General Conclusion and Outlook 71 5.1 Summary.................................. 71 5.1.1 First Generation Synthesis..................... 72 5.1.2 Second Generation Synthesis................... 73 5.1.3 Synthesis of Ferrocenes...................... 74 5.2 Outlook and Concluding
Load more

Recommended publications
  • Edinburgh Research Explorer
    Edinburgh Research Explorer Organometallic Neptunium Chemistry Citation for published version: Arnold, P, Dutkiewicz, MS & Walter, O 2017, 'Organometallic Neptunium Chemistry', Chemical Reviews. https://doi.org/10.1021/acs.chemrev.7b00192 Digital Object Identifier (DOI): 10.1021/acs.chemrev.7b00192 Link: Link to publication record in Edinburgh Research Explorer Document Version: Peer reviewed version Published In: Chemical Reviews General rights Copyright for the publications made accessible via the Edinburgh Research Explorer is retained by the author(s) and / or other copyright owners and it is a condition of accessing these publications that users recognise and abide by the legal requirements associated with these rights. Take down policy The University of Edinburgh has made every reasonable effort to ensure that Edinburgh Research Explorer content complies with UK legislation. If you believe that the public display of this file breaches copyright please contact [email protected] providing details, and we will remove access to the work immediately and investigate your claim. Download date: 29. Sep. 2021 Organometallic Neptunium Chemistry Polly L. Arnold,*a Michał S. Dutkiewicz,a,b Olaf Walter,b [a] EaStCHEM School of Chemistry, University of Edinburgh, The King’s Buildings, Edinburgh, EH9 3FJ, UK. E-mail: [email protected]. [b] European Commission, DG Joint Research Centre, Directorate G - Nuclear Safety and Security, Advanced Nuclear Knowledge – G.I.5, Postfach 2340, D-76125, Karlsruhe, Germany. ABSTRACT Fifty years have passed since the foundation of organometallic neptunium chemistry, and yet only a handful of complexes have been reported, and even fewer fully characterised. Yet increasingly, combined synthetic/spectroscopic/computational studies are demonstrating how covalently binding, soft, carbocyclic organometallic ligands provide an excellent platform for advancing the fundamental understanding of the differences in orbital contributions and covalency in f-block metal – ligand bonding.
    [Show full text]
  • Synthesis and Reactivity of Cyclopentadienyl Based Organometallic Compounds and Their Electrochemical and Biological Properties
    Synthesis and reactivity of cyclopentadienyl based organometallic compounds and their electrochemical and biological properties Sasmita Mishra Department of Chemistry National Institute of Technology Rourkela Synthesis and reactivity of cyclopentadienyl based organometallic compounds and their electrochemical and biological properties Dissertation submitted to the National Institute of Technology Rourkela In partial fulfillment of the requirements of the degree of Doctor of Philosophy in Chemistry by Sasmita Mishra (Roll Number: 511CY604) Under the supervision of Prof. Saurav Chatterjee February, 2017 Department of Chemistry National Institute of Technology Rourkela Department of Chemistry National Institute of Technology Rourkela Certificate of Examination Roll Number: 511CY604 Name: Sasmita Mishra Title of Dissertation: ''Synthesis and reactivity of cyclopentadienyl based organometallic compounds and their electrochemical and biological properties We the below signed, after checking the dissertation mentioned above and the official record book(s) of the student, hereby state our approval of the dissertation submitted in partial fulfillment of the requirements of the degree of Doctor of Philosophy in Chemistry at National Institute of Technology Rourkela. We are satisfied with the volume, quality, correctness, and originality of the work. --------------------------- Prof. Saurav Chatterjee Principal Supervisor --------------------------- --------------------------- Prof. A. Sahoo. Prof. G. Hota Member (DSC) Member (DSC) ---------------------------
    [Show full text]
  • 1 Signature Page Biphenyl Substituted Cyclopentadienyl Ligand
    Signature page Biphenyl substituted Cyclopentadienyl Ligand Complexes By Ketnavi Ramgoolam A Thesis Submitted to Saint Mary’s University, Halifax, Nova Scotia in Partial Fulfillment of the Requirements for the Degree of Bachelor of Science Degree with Honours in Chemistry April 2019, Halifax, Nova Scotia Copyright Ketnavi Ramgoolam, 2019. Approved: Dr. Jason Masuda Supervisor Department of Chemistry Date: April 24, 2019 1 Biphenyl substituted Cyclopentadienyl Ligand Complexes By Ketnavi Ramgoolam A Thesis Submitted to Saint Mary’s University, Halifax, Nova Scotia in Partial Fulfillment of the Requirements for the Degree of Bachelor of Science Degree with Honours in Chemistry April 2019, Halifax, Nova Scotia Copyright Ketnavi Ramgoolam, 2019. Approved: Dr. Jason Masuda Supervisor Department of Chemistry Date: April 24, 2019 2 Biphenyl substituted Cyclopentadienyl Ligand Complexes by Ketnavi Ramgoolam Abstract The synthesis of biphenyl substituted cyclopentadienyl ligands are described. The synthetic route is accomplished through the reaction of aryl lithium reagents with cobaltocenium salts, followed by oxidation of the intermediate cobalt(I) species to give the corresponding cyclopentadiene. Detailed information on their preparation, structural, and spectroscopic properties are described. A preliminary reaction towards the biphenyl substituted cyclopentadienyl ligand complexes yielding the corresponding alkali metal salt (K) is also described. Its structural and spectroscopic properties are described briefly. March 20, 2019 3 Acknowledgements First of all, I would like to express my most sincere gratitude to my supervisor, Dr. Jason Masuda, for all of his time, efforts, teachings and guidance. Thank you for being a most wonderful and understanding human being. This project helped me in discovering my potential as a chemist and I had plenty of wonderful experiences and opportunities that I personally believe will forever shape and influence my professional life as well as my personal growth.
    [Show full text]
  • Differentiation Between Spin State, Electrostatic and Covalent Bonding
    Inorganica Chimica Acta 360 (2007) 179–189 www.elsevier.com/locate/ica Metal–ligand bonding in metallocenes: Differentiation between spin state, electrostatic and covalent bonding Marcel Swart Institucio´ Catalana de Recerca i Estudis Avanc¸ats (ICREA), 08010 Barcelona, Spain Institut de Quı´mica Computacional, Universitat de Girona, Campus Montilivi, 17071 Girona, Spain Received 16 June 2006; received in revised form 26 July 2006; accepted 26 July 2006 Available online 5 August 2006 Inorganic Chemistry – The Next Generation. Abstract We have analyzed metal–ligand bonding in metallocenes using density functional theory (DFT) at the OPBE/TZP level. This level of theory was recently shown to be the only DFT method able to correctly predict the spin ground state of iron complexes, and similar accuracy for spin ground states is found here. We considered metallocenes along the first-row transition metals (Sc–Zn) extended with alkaline-earth metals (Mg, Ca) and several second-row transition metals (Ru, Pd, Ag, Cd). Using an energy decomposition analysis, we have studied trends in metal–ligand bonding in these complexes. The OPBE/TZP enthalpy of heterolytic association for ferrocene (À658 kcal/mol) as obtained from the decomposition analysis is in excellent agreement with benchmark CCSD(T) and CASPT2 results. Covalent bonding is shown to vary largely for the different metallocenes and is found in the range from À155 to À635 kcal/mol. Much smaller variation is observed for Pauli repulsion (55–345 kcal/mol) or electrostatic interactions, which are however strong (À480 to À620 kcal/mol). The covalent bonding, and thus the metal–ligand bonding, is larger for low spin states than for higher spin states, due to better suitability of acceptor d-orbitals of the metal in the low spin state.
    [Show full text]
  • N-Metal Compounds
    31 N-METAL COMPOUNDS n the 85 years following Kekulk's brilliant proposal for the structure of ben- zene, organic chemistry underwent a tremendous expansion, and in the process a wide variety of paradigms or working hypotheses were developed about what kinds of compounds could "exist" and what kinds of reactions could occur. In many cases, acceptance of these hypotheses appeared to stifle many possible lines of investigation and caused contrary evidence to be pigeonholed as "interesting but not conclusive." As one example, the paradigm of angle strain was believed to wholly preclude substances that we know now are either stable or important reaction intermediates, such as cubane (Section 12- 1O), cyclo- propanone (Section 17-1 I), and benzyne (Sections 14-6C and 23-8). No paradigm did more to retard the development of organic chemistry than the notion that, with a "few" exceptions, compounds with bonds between carbon and transition metals (Fe, Co, Ni, Ti, and so on) are inherently un- stable. This idea was swept away in 1951 with the discovery of ferrocene, (C,H,),Fe, by P. L. Pauson. Ferrocene has unheard of properties for an organoiron compound, stable to more than 500" and able to be dissolved in, and recovered from, concentrated sulfuric acid! Pauson's work started an avalanche of research on transition metals in the general area between organic and inorganic chemistry, which has flourished ever since and has led to an improved understanding of important biochemical processes. 31-1 Metallocenes 31-1 METALLOCENES The discovery of ferrocene was one of those fortuitous accidents that was wholly unforeseeable- the kind of discovery which, over and over again, has changed the course of science.
    [Show full text]
  • "Mixed-Ligand" Homocyclopentadienyl Ruthenocenes
    Western Michigan University ScholarWorks at WMU Master's Theses Graduate College 12-1992 Synthesis of Symmetric and "Mixed-Ligand" Homocyclopentadienyl Ruthenocenes John Adjeiku Amanfu Follow this and additional works at: https://scholarworks.wmich.edu/masters_theses Part of the Organic Chemistry Commons Recommended Citation Amanfu, John Adjeiku, "Synthesis of Symmetric and "Mixed-Ligand" Homocyclopentadienyl Ruthenocenes" (1992). Master's Theses. 902. https://scholarworks.wmich.edu/masters_theses/902 This Masters Thesis-Open Access is brought to you for free and open access by the Graduate College at ScholarWorks at WMU. It has been accepted for inclusion in Master's Theses by an authorized administrator of ScholarWorks at WMU. For more information, please contact [email protected]. SYNTHESIS OF SYMMETRIC AND "MDCED-LIGAND" HOMOCYCLOPENTADEENYL RUTHENOCENES John Adjeiku Amanfu A Thesis Submitted to the Faculty of The Graduate College in partial fulfillment of the requirements for the Degree of Master of Arts Department of Chemistry Western Michigan University Kalamazoo, Michigan December 1992 Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. SYNTHESIS OF SYMMETRIC AND "MIXED-LIGAND HOMOCYCLOPENTADIENYL RUTHENOCENES John Adjeiku Amanfu, M.A. Western Michigan University, 1992 Muller and co-workers were the first to report the synthesis of a symmetric bicyclic analogue of ferroene, by treating the anion of bicy- cio[3.2.2]nona-2,6,8-triene (BCNT) with ferrous chloride. This compound was found to be thermally less stable than ferrocene decomposing above 50°C. We report the synthesis and characterization of two homocy- clopentadienyl ruthenocenes; namely (pentamethylcyclopentadienyl)- (bicyclo[3.2.1]octa-2,6-dienyl) ruthenium(II), {ri^-(C5Me5)Ru(BCOD)} and (cyclopentadienyl)(bicyclo[3.2.1]octa-2,6-dienyl)ruthenium(II) {^-(CsHs)- Ru(BCOD)} by treating bicyclo[3.2.1]octa-2,6-dienyl anion with the ruthenium complexes, [Cp*RuCl2]2 and [(NBD)RuCl 2 ]2 respectively.
    [Show full text]
  • A Qualitative Molecular Orbital Diagram for Ferrocene
    Ferrocene Ferrocene was first accidently discovered sandwich compound in 1951 at Duquesne University in Pittsburgh, Pennsylvania by T.J. Kealy and P.L.Paulson. Cyclopentadienyl magnesium bromide (CpMgBr) was reacted with iron (II) chloride in attempt to create a fulvalene. When an orange complex formed instead, the chemists hypothesized that the iron was bound to one carbon in each ring. After one year, in 1952, G. Wilkinson and R. B. Woodward correctly deduced the sandwich structure: two anionic cyclopentadienyl (Cp) rings each donating 6π electrons to the Fe2+ cation between them. Fulvalene H MgBr + FeCl2 Fe H H Kealy & Paulson's Hypothesized Structure Fe Fe Actual Ferrocene structure Fig1. First synthesis of ferrocene Wilkinson shared the Nobel Prize for his work in this area in 1973. Ferrocene’s cyclopentadienyl rings are aromatic – each containing 6 delocalized π electrons like benzene. If a strong base is used to deprotonate cyclopentadiene (Cp), the H+ is removed from the only sp3 (tetrahedral) carbon in the structure. A lone pair of electrons is then formally assigned to a nonbonding p orbital of that carbon (which is now sp2 hybridized). How many resonance structures can be created for a cyclopentadienyl anion (Cp−)? That lone pair of electrons joins the 4 electrons from the two π bonds to create an aromaticity in the ring. :B H H H : Fig 2. Aromaticity of cyclopentadienyl ring Properties of Ferrocene: [1] Ferrocene is the first sandwitch compound discovered accidently in 1951. [2] Ferrocene is a diamagnetic yellow crystalline solid in which Fe is exist as zero oxidation state. [3] The melting point of ferrocene is 174 0C and boiling point is 249 0C.
    [Show full text]
  • Fusing Nickelocene and Cyclopentadiene by Two Silyl Bridges
    Fusing Nickelocene and Cyclopentadiene by Two Silyl Bridges. Synthesis and *H, 13C, and 29Si NMR Investigation of a Paramagnetic Building Block for High-Nuclear Metallocenes Monika Fritz, Johann Hiermeier, Frank H. Köhler* Anorganisch-chemisches Institut, Technische Universität München, Lichtenbergstraße 4, D-85747 Garching Z. Naturforsch. 49b, 763-769 (1994); received March 16, 1994 Nickelocenes, Disilylcyclopentadiene. Lithium Cyclopentadienide, Paramagnetic NMR Spectra Two isomers of tetrahydro-4,4,8,8-tetramethyl-4,8-disila-s-indacene (LH2) were monode- protonated and treated with cyclopentadienyl anion and NiBr2(THF)i 5 to give a 72% yield of the mixed nickelocene CpNi(LH) where a cyclopentadiene is fused to a nickelocene. The analysis of the paramagnetic 'H, 13C, and 29Si NMR spectra demonstrated that the syn and anti isomer of CpNi(LH) formed in a ratio of 5/1. Both isomers could be deprotonated to yield the anion CpNi(L~). According to its 13C NMR spectrum the bridging ligand L is not planar. Introduction tadienyl (Cp) ligands it was realized recently by Stacking of organometallic fragments or mol­ formal condensation of two Cps to conjugated six- ecules is a general strategy to obtain coordination membered rings [4], In previous studies we have polymers. The repeat unit within these polymers addressed stepwise stacking by using a building block concept where a metallocene is linked with or oligomers usually contains one or two jz ligands leading to different types of stacking. For instance, Cp_ through two silyl groups as represented by A with boron-containing ring systems linear stacks or [5]. The reaction of A with metal halides should fragments of linear stacks were obtained [1] which lead to trimetallic model compounds which allow are also known as oligodecker complexes.
    [Show full text]
  • Fusing Nickelocene and Cyclopentadiene by Two Silyl Bridges
    Fusing Nickelocene and Cyclopentadiene by Two Silyl Bridges. Synthesis and *H, 13C, and 29Si NMR Investigation of a Paramagnetic Building Block for High-Nuclear Metallocenes Monika Fritz, Johann Hiermeier, Frank H. Köhler* Anorganisch-chemisches Institut, Technische Universität München, Lichtenbergstraße 4, D-85747 Garching Z. Naturforsch. 49b, 763-769 (1994); received March 16, 1994 Nickelocenes, Disilylcyclopentadiene. Lithium Cyclopentadienide, Paramagnetic NMR Spectra Two isomers of tetrahydro-4,4,8,8-tetramethyl-4,8-disila-s-indacene (LH2) were monode- protonated and treated with cyclopentadienyl anion and NiBr2(THF)i 5 to give a 72% yield of the mixed nickelocene CpNi(LH) where a cyclopentadiene is fused to a nickelocene. The analysis of the paramagnetic 'H, 13C, and 29Si NMR spectra demonstrated that the syn and anti isomer of CpNi(LH) formed in a ratio of 5/1. Both isomers could be deprotonated to yield the anion CpNi(L~). According to its 13C NMR spectrum the bridging ligand L is not planar. Introduction tadienyl (Cp) ligands it was realized recently by Stacking of organometallic fragments or mol­ formal condensation of two Cps to conjugated six- ecules is a general strategy to obtain coordination membered rings [4], In previous studies we have polymers. The repeat unit within these polymers addressed stepwise stacking by using a building block concept where a metallocene is linked with or oligomers usually contains one or two jz ligands leading to different types of stacking. For instance, Cp_ through two silyl groups as represented by A with boron-containing ring systems linear stacks or [5]. The reaction of A with metal halides should fragments of linear stacks were obtained [1] which lead to trimetallic model compounds which allow are also known as oligodecker complexes.
    [Show full text]
  • Improved Methods for Preparation of Cyclopentadienyliron \II\ Arenes
    Office europeen des brevets (fi) Publication number : 0 476 805 A1 @ EUROPEAN PATENT APPLICATION @ Application number: 91305401.1 @ Int. CI.5: C07F 15/02 (22) Date of filing : 14.06.91 (30) Priority : 20.09.90 US 585865 (72) Inventor : Keipert, Steven J., c/o Minnesota Mining and Manufact. Co., 2501 Hudson Road, P.O. Box (43) Date of publication of application : 33427 25.03.92 Bulletin 92/13 St. Paul, Minnesota 55133-3427 (US) @ Designated Contracting States : @ Representative : Baillie, lain Cameron et al BE CH DE FR GB IT LI NL c/o Ladas & Parry, Altheimer Eck 2 W-8000 Miinchen 2 (DE) © Applicant : MINNESOTA MINING AND MANUFACTURING COMPANY 3M Center, P.O. Box 33427 St. Paul, Minnesota 55133-3427 (US) (54) Improved methods for preparation of cyclopentadienyliron (II) arenes. (57) Two improved methods for preparation of compounds with the structure shown in equation X [(cp)-Fe-(Ar)]+b (X) where cp is an eta5 complexed, substituted or unsubstituted, cyclopentadienyl or indenyl anion, Ar is an eta6 complexed substituted or unsubstituted, pi-arene ligand and x is a b-valent anion where b is an integer between 1 and 3. The two methods, which differ in the source of the cyclopentadienyl anion - Lewis acid complex, utilize a Lewis acid assisted ligand transfer reaction. The cyclopentadienyl anion ligand, assisted by a Lewis acid is transferred to ferrous ion in the presence of an arene. In the first method, the cyclopentadienyl anion is derived from ferrocene and ferrous chloride. In this reaction, the cyclopentadienyliron (II) arene product is derived partially from ferrocene and partially from the ferrous salt.
    [Show full text]
  • Synthesis of Cyclopentadienyl Derivatives: Stereoelectronic Effects in the Diels-Alder Cyclocondensation Reaction
    Louisiana State University LSU Digital Commons LSU Historical Dissertations and Theses Graduate School 1990 Synthesis of Cyclopentadienyl Derivatives: Stereoelectronic Effects in the Diels-Alder Cyclocondensation Reaction. Jose Gabriel Garcia Louisiana State University and Agricultural & Mechanical College Follow this and additional works at: https://digitalcommons.lsu.edu/gradschool_disstheses Recommended Citation Garcia, Jose Gabriel, "Synthesis of Cyclopentadienyl Derivatives: Stereoelectronic Effects in the Diels-Alder Cyclocondensation Reaction." (1990). LSU Historical Dissertations and Theses. 5047. https://digitalcommons.lsu.edu/gradschool_disstheses/5047 This Dissertation is brought to you for free and open access by the Graduate School at LSU Digital Commons. It has been accepted for inclusion in LSU Historical Dissertations and Theses by an authorized administrator of LSU Digital Commons. For more information, please contact [email protected]. INFORMATION TO USERS This manuscript has been reproduced from the microfilm master. UMI films the text directly from the original or copy submitted. Thus, some thesis and dissertation copies are in typewriter face, while others may be from any type of computer printer. The quality of this reproduction is dependent upon the quality of the copy submitted. Broken or indistinct print, colored or poor quality illustrations and photographs, print bleedthrough, substandard margins, and improper alignment can adversely affect reproduction. In the unlikely event that the author did not send UMI a complete manuscript and there are missing pages,, these will be noted. Also, if unauthorized copyright material had to be removed, a note will indicate the deletion. Oversize materials (e.g., maps, drawings, charts) are reproduced by sectioning the original, beginning at the upper left-hand corner and continuing from left to right in equal sections with small overlaps.
    [Show full text]
  • Synthetic Applications of Polar Transition Metal Metallocenes
    Synthetic Applications of Polar Transition Metal Metallocenes Francesca A. Stokes Jesus College University of Cambridge This dissertation is submitted for the degree of Doctor of Philosophy September 2013 \Pour yourself a drink, put on some lipstick, and pull yourself together." - Elizabeth Taylor i Declaration This Dissertation is submitted to the Academic Division Student Registry in partial fulfilment of the requirements for the qualification of Doctor of Philosophy at the University of Cambridge. Research presented herein was carried out by the author at the University Chemical Laboratories between October 2009 and March 3013. Except where specific reference is made to the contrary, it is original work and contains nothing that is the outcome of collaboration. Neither the whole, nor any part of this work has been submitted before for a degree in any other institution. This thesis does not exceed 60,000 words. ii Acknowledgements I wish to thank those Who made this work possible In haiku format. My supervisors Dom Wright and Andy Wheatley For time and guidance Also to Rob Less For all his help and advice Friendship is magic! I am grateful to All technical services - For their expertise. Thanks to the teams at NMR spectroscopy And elemental. For assistance with X-ray crystallography Doctors John Davies And Aggi Steiner. DFT calculations Were performed by both Professor Kloo and Dr Vincent. Thanks to both. SQUID measurements were Undertaken by Dr Eichh¨ofer. I am Extremely grateful. iii Thanks are due to the EPSRC as they funded my research. To everyone in Lab 301for making My time here so fun In particular Hayley, Phil and Spud, for cake, Shuffling and Guess Who? To all my great friends Above all Dave, HJ and JessthebestBerry My BFF Rose For always making me laugh Your face is so great Thanks to my parents And my sister Erica Always there for me Christopher Elsmore For patience, support and love Thank you most of all.
    [Show full text]