The Use of Iron Carbonyl Complexes in Organic
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New Applications of Cyclobutadiene Cycloadditions: Diversity and Target Oriented Synthesis
New Applications of Cyclobutadiene Cycloadditions: Diversity and Target Oriented Synthesis Author: Jason Joseph Marineau Persistent link: http://hdl.handle.net/2345/1741 This work is posted on eScholarship@BC, Boston College University Libraries. Boston College Electronic Thesis or Dissertation, 2010 Copyright is held by the author, with all rights reserved, unless otherwise noted. Boston College The Graduate School of Arts and Sciences Department of Chemistry NEW APPLICATIONS OF CYCLOBUTADIENE CYCLOADDITIONS: DIVERSITY AND TARGET ORIENTED SYNTHESIS a dissertation by JASON JOSEPH MARINEAU submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy December 2010 © Copyright by JASON JOSEPH MARINEAU 2010 New Applications of Cyclobutadiene Cycloadditions: Diversity and Target Oriented Synthesis Jason J. Marineau Thesis Advisor: Professor Marc. L. Snapper Abstract Cyclobutadiene cycloadditions provide rapid access to rigid polycyclic systems with high strain energy and unusual molecular geometries. Further functionalization of these systems allows entry into unexplored chemical space. A tricarbonylcyclobutadiene iron complex on solid support enables exploration of these cycloadditions in a parallel format amenable to diversity oriented synthesis. Modeling of the cycloaddition transition states with density functional calculations provides a theoretical basis for analysis of the regioselectivity observed in generation of these substituted bicyclo[2.2.0]hexene derivatives. The high strain energy accessible in cyclobutadiene cycloadducts and their derivatives renders them useful synthons for access to medium-ring natural products through ring expansion. Torilin, a guaiane sesquiterpene isolated from extracts of the fruits of Torilis japonica, exhibits a range of biological activities including testosterone 5 -reductase inhibition, hKv1.5 channel blocking, hepatoprotective, anti-inflammatory and anti-cancer effects. -
CHEMISTRY 412/512 MIDTERM # 1 – Answer Key February 14, 2007 1
CHEMISTRY 412/512 MIDTERM # 1 – answer key February 14, 2007 1. (8 pts) Acyl cations ( RCO ) are key intermediates in Friedel – Crafts acylation reactions. They are stabilized by the presence of oxygen and this can be demonstrated through either resonance or MO analysis. a. Consider the formyl cation, shown below. Show how it is stabilized, using appropriate resonance structures. HCO formyl cation HCO HCO Acyl cations are stabilized by conjugation of one of the lone pairs at the oxygen center. b. Construct the orbital mixing diagram for the formyl cation, starting with group orbitals for CH and O-atom. Consider only first order mixing. Place the appropriate number of valence electrons and demonstrate how QMOT explains the stabilization of the cation. O HC The mixing diagram clearly shows the formation of TWO equivalent π-bonds, which is analogous to the resonance structure on the right, i.e. there is significant contribution by the O-atom. 2. (6 pts) Antiaromatic molecules avoid antiaromaticity by structural distortion. For example, cyclobutadiene is not square (and antiaromatic) but rectangular. Show, using π-group orbital analysis, that such distortion would indeed be stabilizing. square rectangular Solution: Instability of square cyclobutadiene is due to the presence of two degenerate, half-filled π-molecular orbitals (π2 and π3). In the rectangular form, qualitatively, the MOs remain the same, but the strength of some bonding/antibonding interactions is affected and it causes the degeneracy to be lifted. Focus on π2 and π3. Upon stretching, the antibonding interaction in π2 is reduced, while the same geometric distortion leads to reduction of the bonding interaction in π3. -
Richardmooremscthesis1970 O
University of St Andrews Full metadata for this thesis is available in St Andrews Research Repository at: http://research-repository.st-andrews.ac.uk/ This thesis is protected by original copyright sOMd MBTAL 3ARB0NYL JOMPL^XBS OF THIOJARBUNYL JQKPUUNud BEING AM a.SC. THESIS PRESENTED TO THE UNIVERSITY OF ST. ANDREWS The thesis deals with three main subjects. Firstly, the preparation of a new class of organosulphur-metal carbonyl compounds is described. Secondly, an attempted preparation of sulphines is describee, and finally, a new method of preparing methylthioketones is described. The metal carbonyl complexes were prepared from three types of thiocarbonyl compound. Pyrao- and thiopyran-A—thiones were found to readily form complexes provided that the 3 and 5 positions on the nucleus were unsubstituted, or at the most, mono-substituted. Indolizine thioaldebydes were also found to form stable complexes with molybdenum hexacarbonyl, although in lower yields than with pyran- and thiopyranthiones. Also forming stable complexes, the pyrrolothiazole thioaldehydes. Some difficulty was experienced in assigning a molecular formula to these compondds as two possibilities remained after elementary analysis, namely the-rr-complex M(G0)3L and the er-complex M(G0)5L where M is the metal, and L is the ligand. The obvious solution to the problem, X-Ray crystallography, was ruled out by not being able to obtain large enough crystals of the complex. Similarly mass spectra was unhelpful in assigning a correct formula, as no recognised molecular ion peaks were discernible. However one peak to be recognised was MoCOS indicating that bonding is througn the thiocarbonyl sulphur, or in other words a <r—complex had been formed. -
An Indicator of Triplet State Baird-Aromaticity
inorganics Article The Silacyclobutene Ring: An Indicator of Triplet State Baird-Aromaticity Rabia Ayub 1,2, Kjell Jorner 1,2 ID and Henrik Ottosson 1,2,* 1 Department of Chemistry—BMC, Uppsala University, Box 576, SE-751 23 Uppsala, Sweden; [email protected] (R.A.); [email protected] (K.J.) 2 Department of Chemistry-Ångström Laboratory Uppsala University, Box 523, SE-751 20 Uppsala, Sweden * Correspondence: [email protected]; Tel.: +46-18-4717476 Received: 23 October 2017; Accepted: 11 December 2017; Published: 15 December 2017 Abstract: Baird’s rule tells that the electron counts for aromaticity and antiaromaticity in the first ππ* triplet and singlet excited states (T1 and S1) are opposite to those in the ground state (S0). Our hypothesis is that a silacyclobutene (SCB) ring fused with a [4n]annulene will remain closed in the T1 state so as to retain T1 aromaticity of the annulene while it will ring-open when fused to a [4n + 2]annulene in order to alleviate T1 antiaromaticity. This feature should allow the SCB ring to function as an indicator for triplet state aromaticity. Quantum chemical calculations of energy and (anti)aromaticity changes along the reaction paths in the T1 state support our hypothesis. The SCB ring should indicate T1 aromaticity of [4n]annulenes by being photoinert except when fused to cyclobutadiene, where it ring-opens due to ring-strain relief. Keywords: Baird’s rule; computational chemistry; excited state aromaticity; Photostability 1. Introduction Baird showed in 1972 that the rules for aromaticity and antiaromaticity of annulenes are reversed in the lowest ππ* triplet state (T1) when compared to Hückel’s rule for the electronic ground state (S0)[1–3]. -
Chemical Intercalation of Zerovalent Metals Into 2D Layered Bi2se3 Nanoribbons † † ‡ † † † § Kristie J
Article pubs.acs.org/JACS Chemical Intercalation of Zerovalent Metals into 2D Layered Bi2Se3 Nanoribbons † † ‡ † † † § Kristie J. Koski, Colin D. Wessells, Bryan W. Reed, Judy J. Cha, Desheng Kong, and Yi Cui*, , † Department of Materials Science and Engineering, Stanford University, Stanford, California 94305, United States ‡ Physical and Life Sciences Directorate, Lawrence Livermore National Laboratory, 7000 East Avenue, Livermore, California 94550, United States § SLAC National Accelerator Laboratory, Stanford Institute for Materials and Energy Sciences, 2575 Sand Hill Road, Menlo Park, California 94025, United States *S Supporting Information ABSTRACT: We have developed a chemical method to intercalate a variety of zerovalent metal atoms into two-dimen- sional (2D) layered Bi2Se3 chalcogenide nanoribbons. We use a chemical reaction, such as a disproportionation redox reaction, to generate dilute zerovalent metal atoms in a refluxing solution, which intercalate into the layered Bi2Se3 structure. The zerovalent nature of the intercalant allows superstoichiometric intercalation of metal atoms such as Ag, Au, Co, Cu, Fe, In, Ni, and Sn. We foresee the impact of this methodology in establishing novel fundamental physical behaviors and in possible energy applications. 1. INTRODUCTION Ni, and Sn. Some interesting effects that could arise with − 7−10 intercalation are superconductivity, such as in Cu Bi2Se3, Intercalation is the insertion of a guest species into a host 6 lattice. Intercalation into layered materials is essential to battery enhanced conductivity, or possibly opening a surface state gap electrodes, electrochromics, detergents, and solid lubricants and in topological insulator Bi2Se3. This method of zerovalent metal is important in exotic fundamental two-dimensional (2D) intercalation may also be extended to other layered materials. -
Synthesis, Characterization and Reactivity of Functionalized Iron-Sulfur Clusters As Bioinspired Hydrogenase Models
Technisch-Naturwissenschaftliche Fakultät Synthesis, Characterization and Reactivity of Functionalized Iron-Sulfur Clusters as Bioinspired Hydrogenase Models DISSERTATION zur Erlangung des akademischen Grades Doktor der Technischen Wissenschaften im Doktoratsstudium der Technischen Wissenschaften Eingereicht von: DI Manuel Kaiser Angefertigt am: Institut für Anorganische Chemie Beurteilung: Prof. Dr. Günther Knör Assoc.-Prof. Mario Waser Mitwirkung: Linz, November 2015 Eidesstattliche Erklärung Ich erkläre an Eides statt, dass ich die vorliegende Dissertation selbstständig und ohne fremde Hilfe verfasst, andere als die angegebenen Quellen und Hilfsmittel nicht benutzt bzw. die wörtlich oder sinngemäß entnommenen Stellen als solche kenntlich gemacht habe. Die vorliegende Dissertation ist mit dem elektronisch übermittelten Textdokument identisch. Linz, November 2015 ________________________________ Manuel Kaiser I Dipl.‐Ing. Manuel Kaiser Persönliche Daten Geburtsdatum 15.11.1985 Staatsangehörigkeit Österreich Familienstand ledig Telefon 0699/12123124 Mail [email protected] Adresse Johann‐Wilhelm‐Klein‐Straße 2‐4, 4040 Linz Ausbildung 10/2012 – 12/2015 Doktoratsstudium Technische Wissenschaften, JKU Linz Dissertation am Institut für Anorganische Chemie betreut von Prof. Dr. Günther Knör: „Synthesis, Characterization and Reactivity of Functionalized Iron‐Sulfur Clusters as Bioinspired Hydrogenase Models“ 10/2005 – 09/2012 Diplomstudium Technische Chemie, JKU Linz (Abschluss: Dipl.‐Ing.) Diplomarbeit am Institut für Anorganische Chemie -
Bond Distances and Bond Orders in Binuclear Metal Complexes of the First Row Transition Metals Titanium Through Zinc
Metal-Metal (MM) Bond Distances and Bond Orders in Binuclear Metal Complexes of the First Row Transition Metals Titanium Through Zinc Richard H. Duncan Lyngdoh*,a, Henry F. Schaefer III*,b and R. Bruce King*,b a Department of Chemistry, North-Eastern Hill University, Shillong 793022, India B Centre for Computational Quantum Chemistry, University of Georgia, Athens GA 30602 ABSTRACT: This survey of metal-metal (MM) bond distances in binuclear complexes of the first row 3d-block elements reviews experimental and computational research on a wide range of such systems. The metals surveyed are titanium, vanadium, chromium, manganese, iron, cobalt, nickel, copper, and zinc, representing the only comprehensive presentation of such results to date. Factors impacting MM bond lengths that are discussed here include (a) n+ the formal MM bond order, (b) size of the metal ion present in the bimetallic core (M2) , (c) the metal oxidation state, (d) effects of ligand basicity, coordination mode and number, and (e) steric effects of bulky ligands. Correlations between experimental and computational findings are examined wherever possible, often yielding good agreement for MM bond lengths. The formal bond order provides a key basis for assessing experimental and computationally derived MM bond lengths. The effects of change in the metal upon MM bond length ranges in binuclear complexes suggest trends for single, double, triple, and quadruple MM bonds which are related to the available information on metal atomic radii. It emerges that while specific factors for a limited range of complexes are found to have their expected impact in many cases, the assessment of the net effect of these factors is challenging. -
Using SMILES Strings for the Description of Chemical Connectivity in the Crystallography Open Database
Quirós et al. J Cheminform (2018) 10:23 https://doi.org/10.1186/s13321-018-0279-6 RESEARCH ARTICLE Open Access Using SMILES strings for the description of chemical connectivity in the Crystallography Open Database Miguel Quirós1* , Saulius Gražulis2,3 , Saulė Girdzijauskaitė3, Andrius Merkys2 and Antanas Vaitkus2 Abstract Computer descriptions of chemical molecular connectivity are necessary for searching chemical databases and for predicting chemical properties from molecular structure. In this article, the ongoing work to describe the chemical connectivity of entries contained in the Crystallography Open Database (COD) in SMILES format is reported. This col- lection of SMILES is publicly available for chemical (substructure) search or for any other purpose on an open-access basis, as is the COD itself. The conventions that have been followed for the representation of compounds that do not ft into the valence bond theory are outlined for the most frequently found cases. The procedure for getting the SMILES out of the CIF fles starts with checking whether the atoms in the asymmetric unit are a chemically accept- able image of the compound. When they are not (molecule in a symmetry element, disorder, polymeric species,etc.), the previously published cif_molecule program is used to get such image in many cases. The program package Open Babel is then applied to get SMILES strings from the CIF fles (either those directly taken from the COD or those produced by cif_molecule when applicable). The results are then checked and/or fxed by a human editor, in a computer-aided task that at present still consumes a great deal of human time. -
Iron Pentacarbonyl
Poison Facts: Low Chemicals: Iron Pentacarbonyl Properties of the Chemical Iron carbonyl (pentacarbonyl iron), C5FeO5, is a yellow, oily liquid. It is pyrophoric in air and burns to Fe2O3 (Iron[III] oxide) and decomposes by light to Fe2(CO)9 and CO. It is practically insoluble in water, readily soluble in most organic solvents (ether, acetone, ethyl acetate) and slightly soluble in alcohol. The vapor is heavier than air and may travel along the ground. Distant ignition is possible, and it may explode on heating. It may also spontaneously ignite in contact with air. Iron pentacarbonyl is a strong reducing agent and reacts violently with oxidants. Uses of the Chemical Iron pentacarbonyl is prepared from iron (and iron compounds) and CO. It is used in the manufacture of powdered iron cores for high-frequency coils used in the radio and television industries. It is also used as an anti-knock agent in motor fuels and as a catalyst in organic reactions. Absorption, Distribution, Metabolism and Excretion (ADME) Iron pentacarbonyl can be absorbed into the body by inhalation of the vapor, through the skin or by ingestion. No other pharmacokinetic data is available. Clinical Effects of Acute Exposure • Ocular exposures: Iron pentacarbonyl is a local irritant and may cause irritation and injury to eyes. • Dermal exposures: The chemical may irritate the skin and mucous membranes. It may be absorbed through the skin. • Inhalation exposures: If inhaled, iron pentacarbonyl is a local irritant to the lungs and gastrointestinal tract. Symptoms of acute exposure to high concentrations resemble those of exposures to nickel carbonyl. -
Alkyl and Fluoroalkyl Manganese Pentacarbonyl Complexes As
En vue de l'obtention du DOCTORAT DE L'UNIVERSITÉ DE TOULOUSE Délivré par : Institut National Polytechnique de Toulouse (Toulouse INP) Discipline ou spécialité : Chimie Organométallique et de Coordination Présentée et soutenue par : M. ROBERTO MORALES CERRADA le jeudi 15 novembre 2018 Titre : Complexes de manganèse pentacarbonyle alkyle et fluoroalkyle comme modèles d'espèces dormantes de l'OMRP Ecole doctorale : Sciences de la Matière (SDM) Unité de recherche : Laboratoire de Chimie de Coordination (L.C.C.) Directeur(s) de Thèse : MME FLORENCE GAYET M. BRUNO AMEDURI Rapporteurs : M. GERARD JAOUEN, UNIVERSITE PARIS 6 Mme SOPHIE GUILLAUME, CNRS Membre(s) du jury : M. MATHIAS DESTARAC, UNIVERSITE TOULOUSE 3, Président M. BRUNO AMEDURI, CNRS, Membre M. HENRI CRAMAIL, INP BORDEAUX, Membre Mme FLORENCE GAYET, INP TOULOUSE, Membre A mi abuelo Antonio ‐ i ‐ ‐ ii ‐ Remerciements Ce travail a été réalisé dans deux unités de recherche du CNRS : le laboratoire de Chimie de Coordination (LCC) à Toulouse, au sein de l’équipe LAC2, et l’Institut Charles Gerhardt de Montpellier (ICGM), au sein de l’équipe IAM. Il a été codirigé par Dr. Florence Gayet et Dr. Bruno Améduri. Je tiens tout d’abord à remercier Dr. Azzedine Bousseksou, directeur du LCC, et Dr. Patrick Lacroix‐Desmazes, directeur de l’équipe IAM à l’ICGM, pour avoir accepté de m’accueillir au sein de ses laboratoires. Je remercie tout particulièrement mes directeurs de thèse, Dr. Florence Gayet et Dr. Bruno Améduri, pour m’avoir encadré durant ces trois années de doctorat. Un immense merci à tous les deux pour tous leurs conseils, leur patience et leurs connaissances qui m’ont apporté et qui m’ont permis de mener à bien ce travail. -
Organometallic and Catalysis
ORGANOMETALLIC AND CATALYSIS Dr. Malay Dolai, Assistant Professor, Department of Chemistry, Prabhat Kumar College, Contai, Purba Medinipur-721404, WB, India. 1.Introduction Organometallic chemistry is the study of organometallic compounds, chemical compounds containing at least one chemical bond between a carbon atom of an organic molecule and a metal, including alkaline, alkaline earth, and transition metals, and sometimes broadened to include metalloids like boron, silicon, and tin, as well. Aside from bonds to organyl fragments or molecules, bonds to 'inorganic' carbon, like carbon monoxide (metal carbonyls), cyanide, or carbide, are generally considered to be organometallic as well. Some related compounds such as transition metal hydrides and metal phosphine complexes are often included in discussions of organometallic compounds, though strictly speaking, they are not necessarily organometallic. The related but distinct term "metalorganic compound" refers to metal-containing compounds lacking direct metal-carbon bonds but which contain organic ligands. In 1827, Zeise's salt is the first platinum- olefin complex: K[PtCl3(C2H4)].H2O, the first invented organometallic compound. Organometallic compounds find wide use in commercial reactions, both as homogeneous catalysis and as stoichiometric reagents For instance, organolithium, organomagnesium, and organoaluminium compounds, examples of which are highly basic and highly reducing, are useful stoichiometrically, but also catalyze many polymerization reactions. Almost all processes involving carbon monoxide rely on catalysts, notable examples being described as carbonylations. The production of acetic acid from methanol and carbon monoxide is catalyzed via metal carbonyl complexes in the Monsanto process and Cativa process. Most synthetic aldehydes are produced via hydroformylation. The bulk of the synthetic alcohols, at least those larger than ethanol, are produced by hydrogenation of hydroformylation- derived aldehydes. -
Cyclobutadiene
View metadata, citation and similar papers at core.ac.uk brought to you by CORE Published in "Angewandte Chemie International Edition 45(40): 6616 - 6619, 20 provided by RERO DOC Digital Library which should be cited to refer to this work. Cyclobutadiene: The Antiaromatic Paradigm? Thomas Bally* Keywords: In memory of Satoru Masamune antiaromaticity · cyclobutadiene · thermochemistry (1928–2003) There is probably no other single widely accepted (and hardly disputed) London proposed in 1937 a very appeal- molecule that has fascinated experimen- that benzene, with its six cyclically ing model that accounts for these effects tal and theoretical chemists so consis- delocalized p electrons, represents the in terms of ring currents that are in- tently over the past 40 years as has paradigm of aromaticity. In view of the duced by the external magnetic field in cyclobutadiene (CBD). On average, famous Hckel 4n/4n + 2 electron rule, the system of cyclically delocalized 16 publications which deal, in one form one is tempted to rush to the conclusion p electrons.[5] or another, with the parent compound that CBD, with its four cyclically delo- There has been a vigorous debate in p C4H4 and 40 which deal with cyclo- calized electrons, is therefore the recent years about whether and to what butdienes in general have appeared in paradigm of antiaromaticity. extent these ring currents contribute to every year of this time span, and there However, this conclusion is not as the deshielding or shielding of protons are probably many more on derivatives straightforward as it might seem, be- attached to aromatic or antiaromatic and metal complexes.