DOCSLIB.ORG

High-Level Ab Initio Quantum Chemical Studies of the Competition

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text

Load more

HIGH-LEVEL AB INITIO QUANTUM CHEMICAL STUDIES OF THE COMPETITION BETWEEN CUMULENES, CARBENES, AND CARBONES by SHIBLEE RATAN BARUA (Under the Direction of WESLEY D. ALLEN) ABSTRACT High-accuracy computations involving coupled-cluster methods in concert with series of correlation-consistent basis sets are utilized to explore the geometric structures, relative energetics, and vibrational spectra of some molecular systems with unusual properties, namely C(BH) 2, C(AlH) 2 and HCNO. Reliable focal point analyses (FPA) targeting the CCSDT(Q)/CBS limit for the ground electronic state of C(BH) 2 reveals a relative energy difference of only 0.02 kcal mol −1 between a linear and a bent (∠BCB ≈ 90°) structure, thus identifying an unusual case of an “angle-deformation” isomer. Highly accurate CCSD(T)/cc-pVTZ and composite c~CCSDT(Q)/cc-pCVQZ anahrmonic vibrational frequency computations precisely reproduced the experimental IR spectra for linear C(BH) 2, and made excellent predictions for the hitherto unobserved bent isomer. With the aid of elaborate bonding analyses, linear C(BH) 2 is described as a cumulene, while bent C(BH) 2 can be best characterized as a carbene with a little carbone character. A similar FPA treatment yields bent C(AlH) 2 (∠AlCAl ≈ 98°) as the ground electronic structure, comfortably placing it 9.60 kcal mol −1 below its linear counterpart, thus confirming the dominance of a carbene/carbone model for the Al analogue of C(BH)2. Confident predictions for the heretofore undetected bent C(AlH) 2 are made through anharmonic frequency computations at the CCSD(T)/cc-pV(T+d)Z level. Next, a highly accurate and computationally demanding AE-CCSDT(Q)/CBS treatment predicts a bent ground electronic structure for the classic quasilinear HCNO molecule (∠HCN ≈ 174°), lying a miniscule 0.22 cm −1 below the corresponding linear geometry, thus indicating an intermediate between a cumulene and a carbene model. Exhaustive investigation is carried out on the geometric structures and for the harmonic vibrational frequencies for both linear and bent HCNO, and a similarly elaborate benchmarking is pursued for the HCN molecule. Finally, a rigorous theoretical analysis of the topology of polytwistane is performed to reveal a non-repeating, helical, carbon nanotube. Utilizing homodesmotic equations and including explicit computations as high as CCSD(T)/cc- pVQZ, the FPA treatment of the enthalpy of formation ultimately yields (polytwistane) = ° ∆ +1.28 kcal (mol CH) −1 , thus demonstrating the thermodynamic and synthetic viability of this polymer when compared to acetylene. INDEX WORDS: Cumulene; Carbene; Carbone; Coupled-cluster theory; Correlation- consistent basis sets; Basis-set extrapolation; Focal point analysis; Angle- deformation isomer; Vibrational perturbation theory; Isotopic shifts; Intrinsic reaction path; Quantum tunneling; Quasilinear; Homodesmotic equations; Carbon nanotube; Saturated polymer; Double helix; Irrational periodicity. HIGH-LEVEL AB INITIO QUANTUM CHEMICAL STUDIES OF THE COMPETITION BETWEEN CUMULENES, CARBENES, AND CARBONES by SHIBLEE RATAN BARUA B.A., Berea College, Berea, KY, 2008 A Dissertation Submitted to the Graduate Faculty of The University of Georgia in Partial Fulfillment of the Requirements for the Degree DOCTOR OF PHILOSOPHY ATHENS, GEORGIA 2014 © 2014 Shiblee Ratan Barua All Rights Reserved HIGH-LEVEL AB INITIO QUANTUM CHEMICAL STUDIES OF THE COMPETITION BETWEEN CUMULENES, CARBENES, AND CARBONES by SHIBLEE RATAN BARUA Major Professor: Wesley D. Allen Committee: Henry F. Schaefer III Gary E. Douberly Electronic Version Approved: Maureen Grasso Dean of the Graduate School The University of Georgia May 2014 DEDICATION To my Dad, Mr. Mukul Ratan Barua , whose constant encouragement and support have brought me this far. iv ACKNOWLEDGEMENTS A lot of people have influenced me in positive ways, but the one person who stood a mile ahead of everyone else was my Dad. His constant encouragement, his support, and his compassion for the growth and success of his two children were unparalleled in my opinion. He was not only my father, but a great friend as well. Despite his limited income as a government official, he provided the best education available out there in Bangladesh for his two children, and I am ever so grateful to him for that. From thousands of miles away during our phone conversations, however brief they might be, he always mentioned how happy he would be to see me get my Doctorate. I could not fulfill his wish during his lifetime, nor could I be there when he breathed his last on May 3 rd 2013. As I inch closer to my degree, I realize that he would be the happiest person in the world right now; happier than me would probably not be an exaggeration. I would like to take this opportunity to show my utmost gratefulness to the best Dad in the world for always being there for me and believing in me. Thank You. Thank You from the depth of my heart. My family members have always played a huge supporting role in my life. My elder brother Parag and my mom have backed me up and urged me forward. It’s sad how the three of us are so far apart from each other right now; my mom in Bangladesh, my brother in Sydney, and me being here in the States. Hopefully some day we could all live close together as a family once again. Special thanks to all my cousins (Muna, Nina, Turna, Upama, Pallab, Kallol, Hillol), who still remain the closest people in my life no matter how much time passes between our phone conversations. I have a lot of friends here in the States and back in Bangladesh that I need to v mention right now, but would soon run out of pages if I do so. However, I would especially like to thank my friend Kelsey Turner for providing me the support that I needed during my father’s death, and for always being there for me when I needed somebody to rely on. I often jokingly call my group-mate Jowa as my “semi-mentor”, and rightly so. He has helped me enormously throughout my research work. Being completely unaware of how computational quantum chemistry actually works, I had to learn everything from scratch. Jowa was patient with me and taught me well. I was very lucky to have someone like him to guide me through. He is an excellent co-worker and a very good friend, and I am still trying to find a way to beat him in badminton. I would also like to thank my friend Kedan for keeping me entertained with her lively smile in the office; I’ll definitely miss our fun and random conversations. Last, but not least, I would like to show my sincere gratefulness to the faculty members at the CCQC, Dr. Schaefer and Dr. Allen. Dr. Schaefer has provided us with a wonderful facility conducive for state-of-the-art research work. I admire his friendly personality and great stories during his lectures. My mentor, Dr. Allen, has been very supportive, caring, and accommodating towards all his students. Our group has a good number of international students, and he has never said no to any of our requests for visiting our respective homelands. The only thing he would ask for is whether we have internet access back home so that we could continue our research work away from the office. His Advanced Quantum course gifted me many sleepless nights and hundreds of pages of homework assignments. In hindsight, the struggle was totally worth it since I learned an outrageous amount in that class. It has surely been a pleasure working under Dr. Allen for the last six years or so. Now, off to some quantum chemistry... vi TABLE OF CONTENTS Page ACKNOWLEDGEMENTS .............................................................................................................v CHAPTER 1 HIGH-LEVEL AB INITIO QUANTUM CHEMICAL THEORY AND ITS APPLICATION IN CARBON CHEMISTRY 1 1.1 INTRODUCTION .............................................................................................1 1.2 THEORETICAL METHODS ............................................................................3 1.3 BASIS-SET EXTRAPOLATION ...................................................................10 1.4 FOCAL POINT ANALYSIS ...........................................................................11 1.5 AUXILIARY CORRECTIONS.......................................................................15 1.6 ANHARMONIC VIBRATIONAL FREQUENCIES .....................................16 1.7 RESEARCH OVERVIEW ..............................................................................19 REFERENCES ......................................................................................................20 2 NEARLY DEGENERATE ISOMERS OF C(BH) 2: CUMULENE, CARBENE, OR CARBONE? 24 2.1 ABSTRACT .....................................................................................................25 2.2 INTRODUCTION ...........................................................................................26 2.3 COMPUTATIONAL METHODS ...................................................................28 2.4 RESULTS AND DISCUSSION ......................................................................31 2.5 THE ALUMINUM ANALOGUE, C(AlH) 2....................................................59 vii 2.6 CONCLUSIONS..............................................................................................71 2.7 ACKNOWLEDGEMENTS .............................................................................73 REFERENCES ......................................................................................................74 3 QUASILINEARITY IN FULMINIC ACID (HCNO) MOLECULE 84 3.1 ABSTRACT .....................................................................................................84
Recommended publications
  • An Empirical Formula Expressing the Mutual Dependence of C-C Bond Distances* Arpad Furka Department of Organic Chemistry Eotvos Lorcind University, Muzeum Krt

    An Empirical Formula Expressing the Mutual Dependence of C-C Bond Distances* Arpad Furka Department of Organic Chemistry Eotvos Lorcind University, Muzeum Krt

    CROATICA CHEMICA ACTA CCACAA 56 (2) 191-197 (1983) YU ISSN 0011-1643 CCA-1368 UDC 547 :541.6 Originai Scientific Paper An Empirical Formula Expressing the Mutual Dependence of C-C Bond Distances* Arpad Furka Department of Organic Chemistry Eotvos Lorcind University, Muzeum krt. 4/B Budapest, 1088, Hungary Received August 30, 1982 An empirical formula is suggested to describe the mutuaJ dependence of the length of the bonds formed by a central atom in systems built up from equivalent carbon atoms, e.g. diamond, graphite, the cumulene and polyyne chains and intermediate struc­ tures between them. A geometrical representation of the relation­ ship is a regular tetrahedron. A point of this tetrahedron charac­ terizes the arrangement of the atoms around the central one. From the position of the point the bond distances - and possibly the bond angles - can be deduced. Experimental bond length determinations have made clear in the last few decades that the C-C bond distances vary over a relatively long range, from about 1.2 A to about 1.6 A. There were several attempts to correlate these bond distances on empirical way to different factors like double-bond 1 2 4 character, • n:-bond order,3 state of hybridization, •5 the number of adjacent bonds,6 or the overlap integrals.7 Recently ·a new empirical formula has been suggested to describe the mutual dependence of the C-C bond distances.8 The subject of this paper is the interpretation of this empirical equation. Carbon has three allotropic modifications: diamond, graphite and the not completely characterized chain form9•10 (carbynes).
  • Conversion of Methoxy and Hydroxyl Functionalities of Phenolic Monomers Over Zeolites Rajeeva Thilakaratne Iowa State University

    Conversion of Methoxy and Hydroxyl Functionalities of Phenolic Monomers Over Zeolites Rajeeva Thilakaratne Iowa State University

    Chemical and Biological Engineering Publications Chemical and Biological Engineering 2016 Conversion of methoxy and hydroxyl functionalities of phenolic monomers over zeolites Rajeeva Thilakaratne Iowa State University Jean-Philippe Tessonnier Iowa State University, [email protected] Robert C. Brown Iowa State University, [email protected] Follow this and additional works at: https://lib.dr.iastate.edu/cbe_pubs Part of the Biomechanical Engineering Commons, and the Catalysis and Reaction Engineering Commons The ompc lete bibliographic information for this item can be found at https://lib.dr.iastate.edu/ cbe_pubs/328. For information on how to cite this item, please visit http://lib.dr.iastate.edu/ howtocite.html. This Article is brought to you for free and open access by the Chemical and Biological Engineering at Iowa State University Digital Repository. It has been accepted for inclusion in Chemical and Biological Engineering Publications by an authorized administrator of Iowa State University Digital Repository. For more information, please contact [email protected]. Conversion of methoxy and hydroxyl functionalities of phenolic monomers over zeolites Abstract This study investigates the mechanisms of gas phase anisole and phenol conversion over zeolite catalyst. These monomers contain methoxy and hydroxyl groups, the predominant functionalities of the phenolic products of lignin pyrolysis. The proposed reaction mechanisms for anisole and phenol are distinct, with significant differences in product distributions. The nia sole mechanism involves methenium ions in the conversion of phenol and alkylating aromatics inside zeolite pores. Phenol converts primarily to benzene and naphthalene via a ring opening reaction promoted by hydroxyl radicals. The hep nol mechanism sheds insights on how reactive bi-radicals generated from fragmented phenol aromatic rings (identified as dominant coke precursors) cyclize rapidly to produce polyaromatic hydrocarbons (PAHs).
  • Chemistry 0310 - Organic Chemistry 1 Chapter 3

    Chemistry 0310 - Organic Chemistry 1 Chapter 3

    Dr. Peter Wipf Chemistry 0310 - Organic Chemistry 1 Chapter 3. Reactions of Alkanes The heterolysis of covalent bonds yields anions and cations, whereas the homolysis creates radicals. Radicals are species with unpaired electrons that react mostly as electrophiles, seeking a single electron to complete their octet. Free radicals are important reaction intermediates and are formed in initiation reactions under conditions that cause the homolytic cleavage of bonds. In propagation steps, radicals abstract hydrogen or halogen atoms to create new radicals. Combinations of radicals are rare due to the low concentration of these reactive intermediates and result in termination of the radical chain. !CHAIN REACTION SUMMARY reactant product initiation PhCH3 HCl Cl 2 h DH = -16 kcal/mol chain-carrying intermediates n o r D (low concentrations) PhCH2 . Cl . propagation PhCH2 . or Cl . PhCH . 2 DH = -15 kcal/mol or Cl . PhCH2Cl or PhCH CH Ph PhCH2Cl Cl2 2 2 PhCH2Cl or Cl2 termination product reactant termination Alkanes are converted to alkyl halides by free radical halogenation reactions. The relative stability of radicals is increased by conjugation and hyperconjugation: R H H H . CH2 > R C . > R C . > H C . > H C . R R R H Oxygen is a diradical. In the presence of free-radical initiators such as metal salts, organic compounds and oxygen react to give hydroperoxides. These autoxidation reactions are responsible for the degradation reactions of oils, fatty acids, and other biological substances when exposed to air. Antioxidants such as hindered phenols are important food additives. Vitamins E and C are biological antioxidants. Radical chain reactions of chlorinated fluorocarbons in the stratosphere are responsible for the "ozone hole".
  • Stabilization of Anti-Aromatic and Strained Five-Membered Rings with A

    Stabilization of Anti-Aromatic and Strained Five-Membered Rings with A

    ARTICLES PUBLISHED ONLINE: 23 JUNE 2013 | DOI: 10.1038/NCHEM.1690 Stabilization of anti-aromatic and strained five-membered rings with a transition metal Congqing Zhu1, Shunhua Li1,MingLuo1, Xiaoxi Zhou1, Yufen Niu1, Minglian Lin2, Jun Zhu1,2*, Zexing Cao1,2,XinLu1,2, Tingbin Wen1, Zhaoxiong Xie1,Paulv.R.Schleyer3 and Haiping Xia1* Anti-aromatic compounds, as well as small cyclic alkynes or carbynes, are particularly challenging synthetic goals. The combination of their destabilizing features hinders attempts to prepare molecules such as pentalyne, an 8p-electron anti- aromatic bicycle with extremely high ring strain. Here we describe the facile synthesis of osmapentalyne derivatives that are thermally viable, despite containing the smallest angles observed so far at a carbyne carbon. The compounds are characterized using X-ray crystallography, and their computed energies and magnetic properties reveal aromatic character. Hence, the incorporation of the osmium centre not only reduces the ring strain of the parent pentalyne, but also converts its Hu¨ckel anti-aromaticity into Craig-type Mo¨bius aromaticity in the metallapentalynes. The concept of aromaticity is thus extended to five-membered rings containing a metal–carbon triple bond. Moreover, these metal–aromatic compounds exhibit unusual optical effects such as near-infrared photoluminescence with particularly large Stokes shifts, long lifetimes and aggregation enhancement. romaticity is a fascinating topic that has long interested Results and discussion both experimentalists and theoreticians because of its ever- Synthesis, characterization and reactivity of osmapentalynes. Aincreasing diversity1–5. The Hu¨ckel aromaticity rule6 applies Treatment of complex 1 (ref. 32) with methyl propiolate to cyclic circuits of 4n þ 2 mobile electrons, but Mo¨bius topologies (HC;CCOOCH3) at room temperature produced osmapentalyne favour 4n delocalized electron counts7–10.
  • Supporting Information

    Supporting Information

    Supplementary Material (ESI) for Chemical Communications This journal is © The Royal Society of Chemistry 2008 Supporting information Thermal cyclotrimerization of tetraphenyl[5]cumulene (tetraphenylhexapentaene) to tricyclodecadiene derivative † Nazrul Islam, Takashi Ooi , Tetsuo Iwasawa, Masaki Nishiuchi and Yasuhiko * Kawamura Institute of Technology and Science, The University of Tokushima, 2-1 Minamijosanjima-cho, Tokushima 770-8506, Japan †Institute of Health Biosciences, The University of Tokushima, 1-78 Shomachi, Tokushima 770-8505, Japan *Corresponding author. E-mail: [email protected] Experimental section 1. General Methods: Chemicals were obtained from Tokyo Kasei (Tokyo Chemical Industry), Wako (Wako Pure Chemical Industries), Aldrich, and Merck and used as received if not specified 1 13 otherwise. H NMR and C NMR spectra were recorded in CDCl3 on a JEOL EX-400 spectrometer with TMS as an internal standard. HPLC analysis was performed on a JASCO high-performance liquid chromatography system equipped with a 4.6 x 250 mm silica gel column (JASCO Finepak® SIL) and a HITACHI diode array detector (HITACHI L-2450; detector wavelength = 254 nm; mobile phase, CH3CN : H2O = 8:2 v/v). UV-VIS spectra were measured with a Hitachi UV-2000 spectrophotometer. Mass spectra were determined by a Shimadzu GC-MS QP-1000 with a direct inlet attachment using an ionizing voltage of 20 and 70 eV. Elemental analyses were performed by using Yanoco MT-5 instrument at the microanalytical laboratory of this university. X-ray crystallographic analysis was performed with a Rigaku RAXIS-RAPID instrument 1 Supplementary Material (ESI) for Chemical Communications This journal is © The Royal Society of Chemistry 2008 (Rigaku Corporation).
  • Introduction to Alkenes and Alkynes in an Alkane, All Covalent Bonds

    Introduction to Alkenes and Alkynes in an Alkane, All Covalent Bonds

    Introduction to Alkenes and Alkynes In an alkane, all covalent bonds between carbon were σ (σ bonds are defined as bonds where the electron density is symmetric about the internuclear axis) In an alkene, however, only three σ bonds are formed from the alkene carbon -the carbon thus adopts an sp2 hybridization Ethene (common name ethylene) has a molecular formula of CH2CH2 Each carbon is sp2 hybridized with a σ bond to two hydrogens and the other carbon Hybridized orbital allows stronger bonds due to more overlap H H C C H H Structure of Ethylene In addition to the σ framework of ethylene, each carbon has an atomic p orbital not used in hybridization The two p orbitals (each with one electron) overlap to form a π bond (p bonds are not symmetric about the internuclear axis) π bonds are not as strong as σ bonds (in ethylene, the σ bond is ~90 Kcal/mol and the π bond is ~66 Kcal/mol) Thus while σ bonds are stable and very few reactions occur with C-C bonds, π bonds are much more reactive and many reactions occur with C=C π bonds Nomenclature of Alkenes August Wilhelm Hofmann’s attempt for systematic hydrocarbon nomenclature (1866) Attempted to use a systematic name by naming all possible structures with 4 carbons Quartane a alkane C4H10 Quartyl C4H9 Quartene e alkene C4H8 Quartenyl C4H7 Quartine i alkine → alkyne C4H6 Quartinyl C4H5 Quartone o C4H4 Quartonyl C4H3 Quartune u C4H2 Quartunyl C4H1 Wanted to use Quart from the Latin for 4 – this method was not embraced and BUT has remained Used English order of vowels, however, to name the groups
  • C11 Aromatic and N-Alkane Hydrocarbons on Crete, in Air from Eastern Europe During the MINOS Campaign

    C11 Aromatic and N-Alkane Hydrocarbons on Crete, in Air from Eastern Europe During the MINOS Campaign

    Atmos. Chem. Phys., 3, 1461–1475, 2003 www.atmos-chem-phys.org/acp/3/1461/ Atmospheric Chemistry and Physics GC×GC measurements of C7−C11 aromatic and n-alkane hydrocarbons on Crete, in air from Eastern Europe during the MINOS campaign X. Xu1, J. Williams1, C. Plass-Dulmer¨ 2, H. Berresheim2, G. Salisbury1, L. Lange1, and J. Lelieveld1 1Max Planck Institute for Chemistry, Mainz, Germany 2German Weather Service, Meteorological Observatory Hohenpeissenberg, Germany Received: 23 January 2003 – Published in Atmos. Chem. Phys. Discuss.: 17 March 2003 Revised: 8 August 2003 – Accepted: 2 September 2003 – Published: 23 September 2003 Abstract. During the Mediterranean Intensive Oxidant campaign are estimated using the sequential reaction model Study (MINOS) campaign in August 2001 gas-phase or- and related data. They lie in the range of about 0.5–2.5 days. ganic compounds were measured using comprehensive two- dimensional gas chromatography (GC×GC) at the Finokalia ground station, Crete. In this paper, C7−C11 aromatic 1 Introduction and n-alkane measurements are presented and interpreted. The mean mixing ratios of the hydrocarbons varied from Atmospheric volatile organic compounds (VOCs) are recog- 1±1 pptv (i-propylbenzene) to 43±36 pptv (toluene). The nized as important atmospheric species affecting air chem- observed mixing ratios showed strong day-to-day variations istry on regional and global scales. Photochemical reactions and generally higher levels during the first half of the cam- of hydrocarbons in the atmosphere lead to the formation of paign. Mean diel profiles showed maxima at local mid- ozone, oxygenates and organic aerosols (Fehsenfeld et al., night and late morning, and minima in the early morning 1992; Andreae and Crutzen, 1997; Limbeck and Puxbaum, and evening.
  • Reactions of Alkenes and Alkynes

    Reactions of Alkenes and Alkynes

    05 Reactions of Alkenes and Alkynes Polyethylene is the most widely used plastic, making up items such as packing foam, plastic bottles, and plastic utensils (top: © Jon Larson/iStockphoto; middle: GNL Media/Digital Vision/Getty Images, Inc.; bottom: © Lakhesis/iStockphoto). Inset: A model of ethylene. KEY QUESTIONS 5.1 What Are the Characteristic Reactions of Alkenes? 5.8 How Can Alkynes Be Reduced to Alkenes and 5.2 What Is a Reaction Mechanism? Alkanes? 5.3 What Are the Mechanisms of Electrophilic Additions HOW TO to Alkenes? 5.1 How to Draw Mechanisms 5.4 What Are Carbocation Rearrangements? 5.5 What Is Hydroboration–Oxidation of an Alkene? CHEMICAL CONNECTIONS 5.6 How Can an Alkene Be Reduced to an Alkane? 5A Catalytic Cracking and the Importance of Alkenes 5.7 How Can an Acetylide Anion Be Used to Create a New Carbon–Carbon Bond? IN THIS CHAPTER, we begin our systematic study of organic reactions and their mecha- nisms. Reaction mechanisms are step-by-step descriptions of how reactions proceed and are one of the most important unifying concepts in organic chemistry. We use the reactions of alkenes as the vehicle to introduce this concept. 129 130 CHAPTER 5 Reactions of Alkenes and Alkynes 5.1 What Are the Characteristic Reactions of Alkenes? The most characteristic reaction of alkenes is addition to the carbon–carbon double bond in such a way that the pi bond is broken and, in its place, sigma bonds are formed to two new atoms or groups of atoms. Several examples of reactions at the carbon–carbon double bond are shown in Table 5.1, along with the descriptive name(s) associated with each.
  • INVESTIGATION of POLYCYCLIC AROMATIC HYDROCARBONS (Pahs) on DRY FLUE GAS DESULFURIZATION (FGD) BY-PRODUCTS

    INVESTIGATION of POLYCYCLIC AROMATIC HYDROCARBONS (Pahs) on DRY FLUE GAS DESULFURIZATION (FGD) BY-PRODUCTS

    INVESTIGATION OF POLYCYCLIC AROMATIC HYDROCARBONS (PAHs) ON DRY FLUE GAS DESULFURIZATION (FGD) BY-PRODUCTS DISSERTATION Presented in Partial Fulfillment of the Requirements for the Degree Doctor of Philosophy in the Graduate School of The Ohio State University By Ping Sun, M.S. ***** The Ohio State University 2004 Dissertation Committee: Approved by Professor Linda Weavers, Adviser Professor Harold Walker Professor Patrick Hatcher Adviser Professor Yu-Ping Chin Civil Engineering Graduate Program ABSTRACT The primary goal of this research was to examine polycyclic aromatic hydrocarbons (PAHs) on dry FGD by-products to determine environmentally safe reuse options of this material. Due to the lack of information on the analytical procedures for measuring PAHs on FGD by-products, our initial work focused on analytical method development. Comparison of the traditional Soxhlet extraction, automatic Soxhlet extraction, and ultrasonic extraction was conducted to optimize the extraction of PAHs from lime spray dryer (LSD) ash (a common dry FGD by-product). Due to the short extraction time, ultrasonic extraction was further optimized by testing different organic solvents. Ultrasonic extraction with toluene as the solvent turned out to be a fast and efficient method to extract PAHs from LSD ash. The possible reactions of PAHs under standard ultrasonic extraction conditions were then studied to address concern over the possible degradation of PAHs by ultrasound. By sonicating model PAHs including naphthalene, phenanthrene and pyrene in organic solutions, extraction parameters including solvent type, solute concentration, and sonication time on reactions of PAHs were examined. A hexane: acetone (1:1 V/V) ii mixture resulted in less PAH degradation than a dichloromethane (DCM): acetone (1:1 V/V) mixture.
  • Synthesis of Bowl-Shaped Polycyclic Aromatic Compounds and Homo-Bi-Dentate 4,5-Diarylphenanthrene Ligands

    Synthesis of Bowl-Shaped Polycyclic Aromatic Compounds and Homo-Bi-Dentate 4,5-Diarylphenanthrene Ligands

    Graduate Theses, Dissertations, and Problem Reports 2008 Synthesis of bowl-shaped polycyclic aromatic compounds and homo-bi-dentate 4,5-diarylphenanthrene ligands Daehwan Kim West Virginia University Follow this and additional works at: https://researchrepository.wvu.edu/etd Recommended Citation Kim, Daehwan, "Synthesis of bowl-shaped polycyclic aromatic compounds and homo-bi-dentate 4,5-diarylphenanthrene ligands" (2008). Graduate Theses, Dissertations, and Problem Reports. 4391. https://researchrepository.wvu.edu/etd/4391 This Dissertation is protected by copyright and/or related rights. It has been brought to you by the The Research Repository @ WVU with permission from the rights-holder(s). You are free to use this Dissertation in any way that is permitted by the copyright and related rights legislation that applies to your use. For other uses you must obtain permission from the rights-holder(s) directly, unless additional rights are indicated by a Creative Commons license in the record and/ or on the work itself. This Dissertation has been accepted for inclusion in WVU Graduate Theses, Dissertations, and Problem Reports collection by an authorized administrator of The Research Repository @ WVU. For more information, please contact [email protected]. Synthesis of Bowl-shaped Polycyclic Aromatic Compounds and Homo-bi-dentate 4,5-Diarylphenanthrene Ligands Daehwan Kim Dissertation Submitted to the Eberly College of Arts and Sciences at West Virginia University in partial fulfillment of the requirements for the degree of Doctor of Philosophy in Organic Chemistry Kung K. Wang, Ph. D., Chair Peter M. Gannett, Ph. D. John H. Penn, Ph. D. Michael Shi, Ph. D. Björn C.
  • Gas Phase Synthesis of Interstellar Cumulenes. Mass Spectrometric and Theoretical Studies."

    Gas Phase Synthesis of Interstellar Cumulenes. Mass Spectrometric and Theoretical Studies."

    rl ì 6. .B,1l thesis titled: "Gas Phase Synthesis of Interstellar Cumulenes. Mass Spectrometric and Theoretical studies." submitted for the Degree of Doctor of Philosophy (Ph.D') by Stephen J. Blanksby B.Sc.(Hons,) from the Department of ChemistrY The University of Adelaide Cì UCE April 1999 Preface Contents Title page (i) Contents (ii) Abstract (v) Statement of OriginalitY (vi) Acknowledgments (vii) List of Figures (ix) Phase" I Chapter 1. "The Generation and Characterisation of Ions in the Gas 1.I Abstract I 1.II Generating ions 2 t0 l.ru The Mass SPectrometer t2 1.IV Characterisation of Ions 1.V Fragmentation Behaviour 22 Chapter 2 "Theoretical Methods for the Determination of Structure and 26 Energetics" 26 2,7 Abstract 27 2.IT Molecular Orbital Theory JJ 2.TII Density Functional Theory 2.rv Calculation of Molecular Properties 34 2.V Unimolecular Reactions 35 Chapter 3 "Interstellar and Circumstellar Cumulenes. Mass Spectrometric and 38 Related Studies" 3.I Abstract 38 3.II Interstellar Cumulenes 39 3.III Generation of Interstellar Cumulenes by Mass Spectrometry 46 3.IV Summary 59 Preface Chapter 4 "Generation of Two Isomers of C5H from the Corresponding Anions' 61 ATheoreticallyMotivatedMassSpectrometricStudy.'. 6l 4.r Abstract 62 4.rl Introduction 66 4.III Results and Discussion 83 4.IV Conclusions 84 4.V Experimental Section 89 4.VI Appendices 92 Chapter 5 "Gas Phase Syntheses of Three Isomeric CSHZ Radical Anions and Their Elusive Neutrals. A Joint Experimental and Theoretical Study." 92 5.I Abstract 93 5.II Introduction 95 5.ru Results and Discussion t12 5.IV Conclusions 113 5.V Experimental Section ttl 5.VI Appendices t20 Chapter 6 "Gas Phase Syntheses of Three Isomeric ClHz Radical Anions and Their Elusive Neutrals.
  • Physical Organic Chemistry

    Physical Organic Chemistry

    PHYSICAL ORGANIC CHEMISTRY Yu-Tai Tao (陶雨台） Tel: (02)27898580 E-mail: [email protected] Website:http://www.sinica.edu.tw/~ytt Textbook: “Perspective on Structure and Mechanism in Organic Chemistry” by F. A. Corroll, 1998, Brooks/Cole Publishing Company References: 1. “Modern Physical Organic Chemistry” by E. V. Anslyn and D. A. Dougherty, 2005, University Science Books. Grading: One midterm (45%) one final exam (45%) and 4 quizzes (10%) homeworks Chap.1 Review of Concepts in Organic Chemistry § Quantum number and atomic orbitals Atomic orbital wavefunctions are associated with four quantum numbers: principle q. n. (n=1,2,3), azimuthal q.n. (m= 0,1,2,3 or s,p,d,f,..magnetic q. n. (for p, -1, 0, 1; for d, -2, -1, 0, 1, 2. electron spin q. n. =1/2, -1/2. § Molecular dimensions Atomic radius ionic radius, ri：size of electron cloud around an ion. covalent radius, rc：half of the distance between two atoms of same element bond to each other. van der Waal radius, rvdw：the effective size of atomic cloud around a covalently bonded atoms. - Cl Cl2 CH3Cl Bond length measures the distance between nucleus (or the local centers of electron density). Bond angle measures the angle between lines connecting different nucleus. Molecular volume and surface area can be the sum of atomic volume (or group volume) and surface area. Principle of additivity (group increment) Physical basis of additivity law: the forces between atoms in the same molecule or different molecules are very “short range”. Theoretical determination of molecular size：depending on the boundary condition.