Encyclopediaof INORG ANIC CHEMISTRY

Total Page:16

File Type:pdf, Size:1020Kb

Encyclopediaof INORG ANIC CHEMISTRY Encyclopedia of INORG ANIC CHEMISTRY Second Edition Editor-in-Chief R. Bruce King University of Georgia, Athens, GA, USA Volume IX T-Z WILEY Contents VOLUME I Ammonolysis 236 Ammoxidation 236 Amphoterism 236 Ab Initio Calculations Analytical Chemistry of the Transition Elements 236 Acceptor Level Ancillary Ligand 248 Acetogen Anderson Localization 248 Acid Catalyzed Reaction Angular Overlap Model 248 7r-Acid Ligand Anion 249 Acidity Constants Antiaromatic Compound 249 Acidity: Pauling's Rules 2 Antibonding 250 Acids & Acidity 2 Antiferromagnetism 250 Actinides: Inorganic & Coordination Chemistry 2 Antigen 250 Actinides: Organometallic Chemistry 33 Antimony: Inorganic Chemistry 250 Activated Complex 59 Antimony: Organometallic Chemistry 258 Activation 59 Antioxidant 266 Activation Parameters 59 Antiport 266 Activation Volume 60 Antistructure 266 Active Site 60 Antitumor Activity 266 Adamson's Rules 60 Apoprotein 266 Addition Compound 60 Aqua 267 Agostic Bonding 60 Arachno Cluster 267 Alkali Metals: Inorganic Chemistry 61 Arbuzov Rearrangement 267 Alkali Metals: Organometallic Chemistry 84 Archaea 267 Alkalides 94 Arene Complexes 267 Alkaline Earth Metals: Inorganic Chemistry 94 Arsenic: Inorganic Chemistry 268 Alkaline Earth Metals: Organometallic Chemistry 116 Arsenic: Organoarsenic Chemistry 288 Alkane Carbon-Hydrogen Bond Activation 147 Arsine & As-donor Ligands 308 Alkene Complexes 153 Associative Substitution 309 Alkene Metathesis 154 Asymmetrie Synthesis 309 Alkene Polymerization 154 Asymmetrie Synthesis by Homogeneous Catalysis 309 Alkoxycarbonylation 154 Asymmetrie Unit 332 Alkyl Complexes 154 Ate Complexes 332 Alkyl Migration 154 Atom Transfer 332 Alkylidene 155 Atomic Mass 332 Alkylidyne 155 Atomic Number 332 Alkyne Complexes 155 Atomization Enthalpy of Metals 332 Alkyne Metathesis 155 Atoms & Ions 333 Allosterism 155 Aufbau Principle 333 Allotrope 156 Auger Spectroscopy 333 Alloys 156 Autoprotolysis 334 AUyl Complexes 169 Autoxidation 334 Alpha Helix 170 Alumina - 170 Back Bonding 335 Aluminum: Inorganic Chemistry 170 Bacteria 335 Aluminuni: Organometallic Chemistry 185 Bailar Twist 335 Ambidentate Ligand 210 Band Gap 336 Amide (Amido) Complexes 210 Band Theory 336 Ammonia & N-donor Ligands 210 :r-Base 336 XXII CONTENTS BCS Theory 336 VOLUME II Becquerel 337 Bent Metallocenes 337 C-Terminus 603 Berry Pseudorotation 337 Cadmium: Inorganic & Coordination Chemistry 603 Beryllium: Inorganic Chemistry 337 Cadmium: Organometallic Chemistry 620 Beryllium & Magnesium: Organometallic Cage Effect 630 Chemistry 342 Calcium-binding Proteins 630 Beta Sheet 369 Calixarenes 666 Beta Turn 369 Carbanion 666 Bidentate Ligand 370 Carbene Complexes 666 Binary Compounds 370 Carbides: Transition Metal Solid-state Chemistry 674 Binding Energy of Nuclei 370 Carbocation 690 Bioavailability 370 Carbometalation 690 Bioconjugate Chemistry 370 Carbon-Carbon & Carbon-Heteroatom Activation 690 Bioinformatics 370 Carbon: Fullerenes 696 Bioinorganic Chemistry 370 Carbon: Inorganic Chemistry 718 Biomimesis 371 Carbon: Nanotubes 730 Biomimetic Synthesis of Nanoparticles 371 Carbonyl Complexes of the Transition Metals 764 Biomineralization 391 Carbonyl Compound 781 Biosynthesis 404 Carbonylation 781 Biphasic Process 404 Carbonylation Processes by Homogeneous Catalysis 781 Bismuth: Inorganic Chemistry 404 Carborane 814 Carbyne Complexes 814 Bismuth: Organometallic Chemistry 425 Catalase 814 Bite Angle 440 Catalysis 815 Bleomycin 440 Catenation 815 5-Bond 440 Cation 815 7T-Bond 441 Cation-activated Enzymes 815 er-Bond 441 Ceramic Material 824 er-Bond Complexes 441 Ceramics 824 Bond Dissociation Energy 441 Chalcogenides: Solid-state Chemistry 825 Bond Energies 442 Chalcogens 863 Bond Length 445 Chalcophiles 863 Bond Lengths in Inorganic Solids & Liquids 446 Charge Carrier 864 a-Bond Metathesis 452 Charge Controlled Reactions 864 Bond Multiplicity 452 Charge Density Wave 864 Bond Order 452 Charge Transfer 864 Bond Valence Method 453 Chauvin Mechanism 864 Bonding Energetics of Organometallic Compounds 453 Chelate Effect 865 Borates: Solid-state Chemistry 472 Chelating Ligands 865 Borazine 481 Chelation Therapy 865 Borides: Solid-state Chemistry 481 Chemical Bonding 865 Chemical Vapor Deposition 865 Born-Haber Cycle 494 Chevrel Phases 865 Boron Hydrides 494 Chimie Douce 866 Boron: Inorganic Chemistry 499 Chiral 866 Boron: Metallacarbaboranes 524 Chiral Auxiliary 866 Boron: Metalloboranes 544 Chlorine, Bromine, Iodine, & Astatine: Inorganic Boron-Nitrogen Compounds 544 Chemistry 866 Boron: Organoboranes 560 Chlorophyll 887 Boron: Polyhedral Carboranes 598 Chloroplast 887 Borosilicate Glass 601 Chromium: Biological Relevance 888 Bridging Ligand 601 Chromium: Inorganic & Coordination Chemistry 893 Brillouin Zone 602 Chromium: Organometallic Chemistry 907 Buckminsterfullerene 602 Chromocene 925 CONTENTS XXIII Class A & Class B Behavior 925 Counter Ions 1226 Clathrate 925 Counting Electrons 1226 Clay Minerals 925 Coupling 1226 Close Packing 925 Covalent Bonds 1226 Closo Cluster 925 Covalent Radii 1227 Cluster 926 Crabtree's Catalyst 1227 Cluster Compounds: Inorganometallic Compounds Creutz-Taube Complex 1227 Containing.
Recommended publications
  • CHEM 250 (4 Credits): Reactions of Nucleophiles and Electrophiles (Reactivity 1)
    CHEM 250 (4 credits): Reactions of Nucleophiles and Electrophiles (Reactivity 1): Description: This course investigates fundamental carbonyl reactivity (addition and substitution) in understanding organic, inorganic and biochemical processes. Some emphasis is placed on enthalpy, entropy and free energy as a basis of understanding reactivity. An understanding of chemical reactivity is based on principles of Lewis acidity and basicity. The formation, stability and reactivity of coordination complexes are included. Together, these topics lead to an understanding of biochemical pathways such as glycolysis. Enzyme regulation and inhibition is discussed in the context of thermodynamics and mechanisms. Various applications of modern multi-disciplinary research will be explored. Prerequisite: CHEM 125. Course Goals and Objectives: 1. Students will gain a qualitative understanding of thermodynamics. A. Students will develop a qualitative understanding of enthalpy and entropy. B. Students will predict the sign of an entropy change for chemical or physical processes. C. Students will understand entropy effects such as the chelate effect on chemical reactions. D. Students will use bond enthalpies or pKas to determine the enthalpy change for a reaction. E. Students will draw or interpret a reaction progress diagram. F. Students will apply the Principle of Microscopic Reversibility to understand reaction mechanisms. G. Students will use Gibbs free energy to relate enthalpy and entropy changes. H. Students will develop a qualitative understanding of progress toward equilibrium under physiological conditions (the difference between G and Go.) I. Students will understand coupled reactions and how this can be used to drive a non- spontaneous reaction toward products. J. Students will apply LeChatelier’s Principle to affect the position of anequilibrium by adding or removing reactants or products.
    [Show full text]
  • An Earlier Collection of These Notes in One PDF File
    UNIVERSITY OF THE WEST INDIES MONA, JAMAICA Chemistry of the First Row Transition Metal Complexes C21J Inorganic Chemistry http://wwwchem.uwimona.edu.jm/courses/index.html Prof. R. J. Lancashire September 2005 Chemistry of the First Row Transition Metal Complexes. C21J Inorganic Chemistry 24 Lectures 2005/2006 1. Review of Crystal Field Theory. Crystal Field Stabilisation Energies: origin and effects on structures and thermodynamic properties. Introduction to Absorption Spectroscopy and Magnetism. The d1 case. Ligand Field Theory and evidence for the interaction of ligand orbitals with metal orbitals. 2. Spectroscopic properties of first row transition metal complexes. a) Electronic states of partly filled quantum levels. l, ml and s quantum numbers. Selection rules for electronic transitions. b) Splitting of the free ion energy levels in Octahedral and Tetrahedral complexes. Orgel and Tanabe-Sugano diagrams. c) Spectra of aquated metal ions. Factors affecting positions, intensities and shapes of absorption bands. 3. Magnetic Susceptibilities of first row transition metal complexes. a) Effect of orbital contributions arising from ground and excited states. b) Deviation from the spin-only approximation. c) Experimental determination of magnetic moments. Interpretation of data. 4. General properties (physical and chemical) of the 3d transition metals as a consequence of their electronic configuration. Periodic trends in stabilities of common oxidation states. Contrast between first-row elements and their heavier congeners. 5. A survey of the chemistry of some of the elements Ti....Cu, which will include the following topics: a) Occurrence, extraction, biological significance, reactions and uses b) Redox reactions, effects of pH on the simple aqua ions c) Simple oxides, halides and other simple binary compounds.
    [Show full text]
  • Clusters – Contemporary Insight in Structure and Bonding 174 Structure and Bonding
    Structure and Bonding 174 Series Editor: D.M.P. Mingos Stefanie Dehnen Editor Clusters – Contemporary Insight in Structure and Bonding 174 Structure and Bonding Series Editor: D.M.P. Mingos, Oxford, United Kingdom Editorial Board: X. Duan, Beijing, China L.H. Gade, Heidelberg, Germany Y. Lu, Urbana, IL, USA F. Neese, Mulheim€ an der Ruhr, Germany J.P. Pariente, Madrid, Spain S. Schneider, Gottingen,€ Germany D. Stalke, Go¨ttingen, Germany Aims and Scope Structure and Bonding is a publication which uniquely bridges the journal and book format. Organized into topical volumes, the series publishes in depth and critical reviews on all topics concerning structure and bonding. With over 50 years of history, the series has developed from covering theoretical methods for simple molecules to more complex systems. Topics addressed in the series now include the design and engineering of molecular solids such as molecular machines, surfaces, two dimensional materials, metal clusters and supramolecular species based either on complementary hydrogen bonding networks or metal coordination centers in metal-organic framework mate- rials (MOFs). Also of interest is the study of reaction coordinates of organometallic transformations and catalytic processes, and the electronic properties of metal ions involved in important biochemical enzymatic reactions. Volumes on physical and spectroscopic techniques used to provide insights into structural and bonding problems, as well as experimental studies associated with the development of bonding models, reactivity pathways and rates of chemical processes are also relevant for the series. Structure and Bonding is able to contribute to the challenges of communicating the enormous amount of data now produced in contemporary research by producing volumes which summarize important developments in selected areas of current interest and provide the conceptual framework necessary to use and interpret mega- databases.
    [Show full text]
  • Structure and Dynamics of Iron Pentacarbonyl † § ‡ § ∥ ⊥ # Peter Portius,*, , Michael Bühl, Michael W
    This is an open access article published under an ACS AuthorChoice License, which permits copying and redistribution of the article or any adaptations for non-commercial purposes. Article Cite This: Organometallics 2019, 38, 4288−4297 pubs.acs.org/Organometallics Structure and Dynamics of Iron Pentacarbonyl † § ‡ § ∥ ⊥ # Peter Portius,*, , Michael Bühl, Michael W. George, , Friedrich-Wilhelm Grevels, , § and James J. Turner*, † Department of Chemistry, The University of Sheffield, Western Bank, Sheffield S3 7HF, United Kingdom ‡ School of Chemistry, University of St. Andrews, St. Andrews, Fife KY16 9ST, United Kingdom § School of Chemistry, University of Nottingham, University Park, Nottingham NG7 2RD, United Kingdom ∥ Department of Chemical and Environmental Engineering, University of Nottingham Ningbo China, 199 Taikang East Road, Ningbo 315100, China ⊥ Max-Planck-Institut für Bioanorganische Chemie, Stiftstraße 34-36, D-45470 Mülheim an der Ruhr, Germany *S Supporting Information ABSTRACT: The dynamics of CO ligand scrambling in Fe(CO)5 has been investigated by linear infrared spectroscopy in super- critical xenon solution. The activation barrier for the Berry pseudorotation in Fe(CO)5 was determined experimentally to be ± −1 Ea = 2.5 0.4 kcal mol by quantitative analysis of the temperature-dependent spectral line shape. This compares well −1 with the range of Ea/(kcal mol ) = 2.0 to 2.3 calculated by various DFT methods and the value of 1.6 ± 0.3 previously obtained from 2D IR measurements by Harris et al. (Science 2008, 319, 1820). ··· The involvement of Fe(CO)5 Xe interactions in the ligand scrambling process was tested computationally at the BP86-D3/ AE2 level and found to be negligible.
    [Show full text]
  • Topological Analysis of the Metal-Metal Bond: a Tutorial Review Christine Lepetit, Pierre Fau, Katia Fajerwerg, Myrtil L
    Topological analysis of the metal-metal bond: A tutorial review Christine Lepetit, Pierre Fau, Katia Fajerwerg, Myrtil L. Kahn, Bernard Silvi To cite this version: Christine Lepetit, Pierre Fau, Katia Fajerwerg, Myrtil L. Kahn, Bernard Silvi. Topological analysis of the metal-metal bond: A tutorial review. Coordination Chemistry Reviews, Elsevier, 2017, 345, pp.150-181. 10.1016/j.ccr.2017.04.009. hal-01540328 HAL Id: hal-01540328 https://hal.sorbonne-universite.fr/hal-01540328 Submitted on 16 Jun 2017 HAL is a multi-disciplinary open access L’archive ouverte pluridisciplinaire HAL, est archive for the deposit and dissemination of sci- destinée au dépôt et à la diffusion de documents entific research documents, whether they are pub- scientifiques de niveau recherche, publiés ou non, lished or not. The documents may come from émanant des établissements d’enseignement et de teaching and research institutions in France or recherche français ou étrangers, des laboratoires abroad, or from public or private research centers. publics ou privés. Topological analysis of the metal-metal bond: a tutorial review Christine Lepetita,b, Pierre Faua,b, Katia Fajerwerga,b, MyrtilL. Kahn a,b, Bernard Silvic,∗ aCNRS, LCC (Laboratoire de Chimie de Coordination), 205, route de Narbonne, BP 44099, F-31077 Toulouse Cedex 4, France. bUniversité de Toulouse, UPS, INPT, F-31077 Toulouse Cedex 4, i France cSorbonne Universités, UPMC, Univ Paris 06, UMR 7616, Laboratoire de Chimie Théorique, case courrier 137, 4 place Jussieu, F-75005 Paris, France Abstract This contribution explains how the topological methods of analysis of the electron density and related functions such as the electron localization function (ELF) and the electron localizability indicator (ELI-D) enable the theoretical characterization of various metal-metal (M-M) bonds (multiple M-M bonds, dative M-M bonds).
    [Show full text]
  • This Thesis Has Been Submitted in Fulfilment of the Requirements for a Postgraduate Degree (E.G
    This thesis has been submitted in fulfilment of the requirements for a postgraduate degree (e.g. PhD, MPhil, DClinPsychol) at the University of Edinburgh. Please note the following terms and conditions of use: • This work is protected by copyright and other intellectual property rights, which are retained by the thesis author, unless otherwise stated. • A copy can be downloaded for personal non-commercial research or study, without prior permission or charge. • This thesis cannot be reproduced or quoted extensively from without first obtaining permission in writing from the author. • The content must not be changed in any way or sold commercially in any format or medium without the formal permission of the author. • When referring to this work, full bibliographic details including the author, title, awarding institution and date of the thesis must be given. Development of Novel Metal-Catalysed Methods for the Transformation of Ynamides Thesis Submitted in Accordance with the Requirements of The University of Edinburgh for the Degree of Doctor of Philosophy By Donna L. Smith Supervised by Dr. Hon Wai Lam School of Chemistry College of Science and Engineering 2013 Declaration I hereby declare that, except where specific reference is made to other sources, the work contained within this thesis is the original work of my own research since the registration of the PhD degree in September 2009, and any collaboration is clearly indicated. This thesis has been composed by myself and has not been submitted, in whole or part, for any other degree, diploma or other qualification. Donna L. Smith 2 Abstract I. Rhodium-Catalysed Carbometalation of Ynamides using Organoboron Reagents As an expansion of existing procedures for the carbometalation of ynamides, it was discovered that [Rh(cod)(MeCN)2]BF4 successfully promotes the carbometalation of ynamides with organoboron reagents.
    [Show full text]
  • (T = C/Si/Ge): the Uniqueness of Carbon Bonds in Tetrel Bonds
    Preprints (www.preprints.org) | NOT PEER-REVIEWED | Posted: 13 September 2018 doi:10.20944/preprints201809.0228.v1 Inter/intramolecular Bonds in TH5+ (T = C/Si/Ge): The Uniqueness of Carbon bonds in Tetrel Bonds Sharon Priya Gnanasekar and Elangannan Arunan* Department of Inorganic and Physical Chemistry Indian Institute of Science, Bangalore. 560012 INDIA * Email: [email protected] Abstract Atoms in Molecules (AIM), Natural Bond Orbital (NBO), and normal coordinate analysis have been carried out at the global minimum structures of TH5+ (T = C/Si/Ge). All these analyses lead to a consistent structure for these three protonated TH4 molecules. The CH5+ has a structure with three short and two long C-H covalent bonds and no H-H bond. Hence, the popular characterization of protonated methane as a weakly bound CH3+ and H2 is inconsistent with these results. However, SiH5+ and GeH5+ are both indeed a complex formed between TH3+ and H2 stabilized by a tetrel bond, with the H2 being the tetrel bond acceptor. The three-center-two-electron bond (3c-2e) in CH5+ has an open structure, which can be characterized as a V-type 3c-2e bond and that found in SiH5+ and GeH5+ is a T-type 3c-2e bond. This difference could be understood based on the typical C-H, Si-H, Ge-H and H-H bond energies. Moreover, this structural difference observed in TH5+ can explain the trend in proton affinity of TH4. Carbon is selective in forming a ‘tetrel bond’ and when it does, it might be worthwhile to highlight it as a ‘carbon bond’.
    [Show full text]
  • A Focus on Vinyl Selenones
    molecules Review ReviewModern Synthetic Strategies with Organoselenium Reagents: Modern Synthetic Strategies with Organoselenium Reagents: AA FocusFocus onon VinylVinyl SelenonesSelenones Martina Palomba, Italo Franco Coelho Dias, Ornelio Rosati and Francesca Marini * Martina Palomba, Italo Franco Coelho Dias, Ornelio Rosati and Francesca Marini * Department of Pharmaceutical Sciences (Group of Catalysis, Synthesis and Organic Green Chemistry), UniversityGroup of Catalysis, of Perugia, Synthesis Via del andLiceo, Organic 06123 GreenPerugia, Chemistry, Italy; [email protected] Department of Pharmaceutical (M.P.); Sciences, italo.francocoelhodias@studeUniversity of Perugia, Via delnti.unipg.it Liceo, 06123 (I.F.C.D.); Perugia, [email protected] Italy; [email protected] (O.R.) (M.P.); *[email protected] Correspondence: [email protected] (I.F.C.D.); [email protected] (O.R.) * Correspondence: [email protected] Abstract: In recent years, vinyl selenones were rediscovered as useful building blocks for new syn- Abstract: In recent years, vinyl selenones were rediscovered as useful building blocks for new thetic transformations. This review will highlight these advances in the field of multiple-bond-form- synthetic transformations. This review will highlight these advances in the field of multiple-bond- ing reactions, one-pot synthesis of carbo- and heterocycles, enantioselective construction of densely forming reactions, one-pot synthesis of carbo- and heterocycles, enantioselective construction of functionalized molecules, and total synthesis of natural products. densely functionalized molecules, and total synthesis of natural products. Keywords: selenium; domino reactions; heterocycles; natural products; spiro compounds; annula- Keywords: selenium; domino reactions; heterocycles; natural products; spiro compounds; annula- tions; enantioselective synthesis; organocatalysis tions; enantioselective synthesis; organocatalysis Citation: Palomba, M.; Dias, I.F.C.; Rosati, O.; Marini, F.
    [Show full text]
  • Crystal Field Theory (CFT)
    Crystal Field Theory (CFT) The bonding of transition metal complexes can be explained by two approaches: crystal field theory and molecular orbital theory. Molecular orbital theory takes a covalent approach, and considers the overlap of d-orbitals with orbitals on the ligands to form molecular orbitals; this is not covered on this site. Crystal field theory takes the ionic approach and considers the ligands as point charges around a central metal positive ion, ignoring any covalent interactions. The negative charge on the ligands is repelled by electrons in the d-orbitals of the metal. The orientation of the d orbitals with respect to the ligands around the central metal ion is important, and can be used to explain why the five d-orbitals are not degenerate (= at the same energy). Whether the d orbitals point along or in between the cartesian axes determines how the orbitals are split into groups of different energies. Why is it required? The valence bond approach could not explain the Electronic spectra, Magnetic moments, Reaction mechanisms of the complexes. Assumptions of CFT: 1. The central Metal cation is surrounded by ligand which contain one or more lone pair of electrons. 2. The ionic ligand (F-, Cl- etc.) are regarded as point charges and neutral molecules (H2O, NH3 etc.) as point dipoles. 3. The electrons of ligand does not enter metal orbital. Thus there is no orbital overlap takes place. 4. The bonding between metal and ligand is purely electrostatic i.e. only ionic interaction. The approach taken uses classical potential energy equations that take into account the attractive and repulsive interactions between charged particles (that is, Coulomb's Law interactions).
    [Show full text]
  • Nobel Lecture, 8 December 1981 by ROALD HOFFMANN Department of Chemistry, Cornell University, Ithaca, N.Y
    BUILDING BRIDGES BETWEEN INORGANIC AND ORGANIC CHEMISTRY Nobel lecture, 8 December 1981 by ROALD HOFFMANN Department of Chemistry, Cornell University, Ithaca, N.Y. 14853 R. B. Woodward, a supreme patterner of chaos, was one of my teachers. I dedicate this lecture to him, for it is our collaboration on orbital symmetry conservation, the electronic factors which govern the course of chemical reac- tions, which is recognized by half of the 1981 Nobel Prize in Chemistry. From Woodward I learned much: the significance of the experimental stimulus to theory, the craft of constructing explanations, the importance of aesthetics in science. I will try to show you how these characteristics of chemical theory may be applied to the construction of conceptual bridges between inorganic and organic chemistry. FRAGMENTS Chains, rings, substituents - those are the building blocks of the marvelous edifice of modern organic chemistry. Any hydrocarbon may be constructed on paper from methyl groups, CH 3, methylenes, CH 2, methynes, CH, and carbon atoms, C. By substitution and the introduction of heteroatoms all of the skeletons and functional groupings imaginable, from ethane to tetrodotoxin, may be obtained. The last thirty years have witnessed a remarkable renaissance of inorganic chemistry, and the particular flowering of the field of transition metal organo- metallic chemistry. Scheme 1 shows a selection of some of the simpler creations of the laboratory in this rich and ever-growing field. Structures l-3 illustrate at a glance one remarkable feature of transition metal fragments. Here are three iron tricarbonyl complexes of organic moie- ties - cyclobutadiene, trimethylenemethane, an enol, hydroxybutadiene - which on their own would have little kinetic or thermodynamic stability.
    [Show full text]
  • EI-ICHI NEGISHI Herbert C
    MAGICAL POWER OF TRANSITION METALS: PAST, PRESENT, AND FUTURE Nobel Lecture, December 8, 2010 by EI-ICHI NEGISHI Herbert C. Brown Laboratories of Chemistry, Purdue University, 560 Oval Drive, West Lafayette, IN 47907-2084, U.S.A. Not long ago, the primary goal of the synthesis of complex natural products and related compounds of biological and medicinal interest was to be able to synthesize them, preferably before anyone else. While this still remains a very important goal, a number of today’s top-notch synthetic chemists must feel and even think that, given ample resources and time, they are capable of synthesizing virtually all natural products and many analogues thereof. Accepting this notion, what would then be the major goals of organic synthesis in the twenty-first century? One thing appears to be unmistakably certain. Namely, we will always need, perhaps increasingly so with time, the uniquely creative field of synthetic organic and organometallic chemistry to prepare both new and existing organic compounds for the benefit and well-being of mankind. It then seems reasonably clear that, in addition to the question of what compounds to synthesize, that of how best to synthesize them will become increasingly important. As some may have said, the primary goal would then shift from aiming to be the first to synthesize a given compound to seeking its ultimately satisfactory or “last synthesis”. If one carefully goes over various aspects of organic synthetic methodology, one would soon note how primitive and limited it had been until rather recently, or perhaps even today. For the sake of argument, we may propose here that the ultimate goal of organic synthesis is “to be able to synthesize any desired and fundamentally synthesizable organic compounds (a) in high yields, (b) efficiently (in as few steps as possible, for example), (c) selectively, preferably all in t98–99% selectivity, (d) economically, and (e) safely, abbreviated hereafter as the y(es)2 manner.” with or without catalyst R1M + R2X R1R2 + MX R1, R2: carbon groups.
    [Show full text]
  • Werner-Type Complexes of Uranium(III) and (IV) Judith Riedhammer, J
    pubs.acs.org/IC Article Werner-Type Complexes of Uranium(III) and (IV) Judith Riedhammer, J. Rolando Aguilar-Calderon,́ Matthias Miehlich, Dominik P. Halter, Dominik Munz, Frank W. Heinemann, Skye Fortier, Karsten Meyer,* and Daniel J. Mindiola* Cite This: Inorg. Chem. 2020, 59, 2443−2449 Read Online ACCESS Metrics & More Article Recommendations *sı Supporting Information ABSTRACT: Transmetalation of the β-diketiminate salt [M]- Me Ph + Me Ph− − [ nacnac ](M =NaorK; nacnac = {PhNC(CH3)}2CH ) with UI3(THF)4 resulted in the formation of the homoleptic, Me Ph octahedral complex [U( nacnac )3](1). Green colored 1 was fully characterized by a solid-state X-ray diffraction analysis and a combination of UV/vis/NIR, NMR, and EPR spectroscopic studies as well as solid-state SQUID magnetization studies and density functional theory calculations. Electrochemical studies of 1 revealed this species to possess two anodic waves for the U(III/IV) and U(IV/V) redox couples, with the former being chemically accessible. Using mild oxidants, such as [CoCp2][PF6]or [FeCp ][Al{OC(CF ) } ], yields the discrete salts [1][A] (A = − 2 3 −3 4 PF6 , Al{OC(CF3)3}4 ), whereas the anion exchange of [1][PF6] with NaBPh4 yields [1][BPh4]. Me Dipp μ 12 ■ INTRODUCTION UCl3(THF)] and [{( nacnac )UCl}2( 2-Cl)3]Cl. In Me Dipp− ’ some cases, disubstitution of nacnac generates the Alfred Werner s disapproval of the complex ion-chain theory Me Dipp η3 Me Dipp 13 proposed by Jørgensen and Blomstrand,1 via the introduction rearranged species [( nacnac )( - nacnac )UI], of coordination complexes and the concept of Nebenvalenz,1,2 where one ligand has changed hapticity, most likely due to fi steric constraints.
    [Show full text]