Ortho-Diethynylbenzene Dianion† Cite This: Chem

Total Page:16

File Type:pdf, Size:1020Kb

Ortho-Diethynylbenzene Dianion† Cite This: Chem Chemical Science View Article Online EDGE ARTICLE View Journal | View Issue Preparation of an ion with the highest calculated proton affinity: ortho-diethynylbenzene dianion† Cite this: Chem. Sci.,2016,7,6245 Berwyck L. J. Poad,ab Nicholas D. Reed,b Christopher S. Hansen,b Adam J. Trevitt,b Stephen J. Blanksby,a Emily G. Mackay,c Michael S. Sherburn,c Bun Chan‡d and Leo Radomd Owing to the increased proton affinity that results from additional negative charges, multiply-charged anions have been proposed as one route to prepare and access a range of new and powerful “superbases”. Paradoxically, while the additional electrons in polyanions increase basicity they serve to diminish the electron binding energy and thus, it had been thought, hinder experimental synthesis. We report the synthesis and isolation of the ortho-diethynylbenzene dianion (ortho-DEB2À) and present observations of this novel species undergoing gas-phase proton-abstraction reactions. Using a theoretical model based on Marcus–Hush theory, we attribute the stability of ortho-DEB2À to the Received 20th April 2016 presence of a barrier that prevents spontaneous electron detachment. The proton affinity of 1843 kJ Creative Commons Attribution 3.0 Unported Licence. Accepted 17th June 2016 molÀ1 calculated for this dianion superbase using high-level quantum chemistry calculations significantly DOI: 10.1039/c6sc01726f exceeds that of the lithium monoxide anion, the most basic system previously prepared. The ortho- www.rsc.org/chemicalscience diethynylbenzene dianion is therefore the strongest base that has been experimentally observed to date. Introduction solvent interaction, provides an ideal way to investigate the fundamental basicity of these highly reactive systems.7 Exploration of the fundamental thermochemistry of acids and In the gas phase, the proton affinity of an anion is equivalent D bases informs our understanding of chemical transformations to the enthalpy of deprotonation ( acidH298) of the conjugate This article is licensed under a À ¼ D and can drive innovation in the design of new reactions and acid (i.e., PA[X ] acidH298[XH]). The strongest base prepared À 8 reagents.1–3 The hydroxide anion has the largest proton affinity to date is the lithium monoxide anion (LiO ). With an esti- À À possible in an aqueous environment, since any base with mated proton affinity of 1782 Æ 8 kJ mol 1, LiO supplanted the Open Access Article. Published on 20 June 2016. Downloaded 10/5/2021 7:08:50 AM. À À a larger PA will abstract a proton from H2O (PA[OH ] ¼ 1633.14 methide anion (CH3 ) at the top of the basicity scale in 2008, À Æ 0.04 kJ mol 1).4 To generate stronger bases in solution, non- exceeding the proton affinity of the carbanion by approximately À 4,9,10 aqueous solvents are required. For example lithium diisopro- 40 kJ mol 1. More recently, computational studies have pylamide, which is oen employed in organic synthesis as proposed extending this framework to even more basic ions À 11 a deprotonating agent, must be used in an aprotic solvent such such as OLi3O . However no clear synthetic route to form as tetrahydrofuran.5 Such extremely strong bases are referred to these ions in the gas phase has been demonstrated. Anionic 6 À À as superbases. Owing to these environmental factors, investi- superbases such as LiO and CH3 necessarily satisfy two gation and comparison of the intrinsic basicity of compounds essential requirements: they are the conjugate bases of very in solution is limited. Probing the reactivity of high proton weak gas-phase acids and their neutral radicals have low elec- affinity species in the gas phase, an environment free from any tron affinities (EAs). Multiply-charged anions can also full these thermochemical requirements, as the gas-phase acidity of ffi aCentral Analytical Research Facility, Institute for Future Environments, Queensland an anion is inherently low while the electron a nity of an anion University of Technology, Brisbane, QLD 4001, Australia. E-mail: berwyck.poad@ (i.e., the affinity for addition of a second electron to produce qut.edu.au a dianion) can be low or even negative. Despite their potential bSchool of Chemistry, University of Wollongong, Gwynneville, NSW 2522, Australia instability, such dianion systems have been observed because of cResearch School of Chemistry, Australian National University, Canberra, ACT 2601, a repulsive Coulomb barrier (RCB) that arises from the inter- Australia action between the local bound-potential of the functional dSchool of Chemistry, University of Sydney, Sydney, NSW 2006, Australia † group carrying the charge (e.g., a carboxylate group) and the Electronic supplementary information (ESI) available: Synthesis of precursor 12,13 compounds, detailed experimental and theoretical procedures, 3 supporting repulsive Coulomb potential between like charges. This RCB gures, 4 supporting tables, NMR spectra of synthesised compounds. See DOI: can stabilise multiply-charged anions and, in some cases, 10.1039/c6sc01726f allows for the generation and isolation of polyanions despite ‡ Present address: Graduate School of Engineering, Nagasaki University, Bunko their negative electron binding energies.14,15 Based on these 1-14, Nagasaki 852-8521, Japan. This journal is © The Royal Society of Chemistry 2016 Chem. Sci.,2016,7,6245–6250 | 6245 View Article Online Chemical Science Edge Article À considerations, the 1,3-diethynylbenzene dianion (meta-DEB2 ) was postulated to be a gas-phase superbase with a calculated PA À À of 1796.6 kJ mol 1, approximately 15 kJ mol 1 greater than that of the lithium monoxide anion.8 Thus far, no experimental studies have been reported on this gas-phase dianion – presumably due to the expectation that Coulomb repulsion between the proximate negative charges would destabilise the dianion and thus pose a challenge to its generation and isolation. À In this article, we outline the synthesis of meta-DEB2 in the gas phase along with the isomeric 1,2- and 1,4-dieth- À ynylbenzene dianions (ortho- and para-DEB2 , respectively). Observation of proton-transfer reactions between these dia- nions and a number of weak acids demonstrates their behav- Fig. 1 Mass spectra illustrating the synthesis of the ortho-DEB dianion ffi iour as gas-phase bases. The calculated proton a nity of each of base. The mass-isolated dicarboxylate anion at m/z 106 (a) is observed À the DEB2 isomers exceeds that of the lithium monoxide anion, to decarboxylate under CID to yield m/z 84 (b). Subsequent isolation À with ortho-DEB2 representing the strongest gas-phase base and activation of this m/z 84 ion yields a second decarboxylation m z meta synthesised to date. product at / 62 and associated reaction products (c). The - and para-DEB dianions were synthesised using the same approach. Results and discussion À diacids (i.e., ortho, meta and para-DEB2 ). This is strongly sup- 2À Synthesis of the ortho-DEB dianion at a mass-to-charge ratio ported by the differences in product ions and product ion Creative Commons Attribution 3.0 Unported Licence. (m/z) of 62 was performed using tandem mass spectrometry in abundances observed in the mass spectra at each step of the À À a linear quadrupole and followed the process outlined in gas-phase preparation (cf. ortho-DEB2 in Fig. 1 and para-DEB2 Scheme 1 and Fig. 1. Negative ion electrospray ionisation of the in ESI Fig. S1†). Moreover, the pseudo rst-order decay of diacid precursor generated the dicarboxylate dianion (m/z 106), each of the m/z 62 ion populations is consistent with only which was mass-selected and subjected to successive collisional a single isomer in each instance (Fig. 2). Full experimental activation steps to remove the carboxylate groups while retaining both charges. Such decarboxylation processes that are accom- panied by retention of charge have previously been noted for several organolithium compounds.8,16 The same method was This article is licensed under a deployed successfully for the generation of both meta-andpara- À DEB2 , using the appropriate isomeric diacid precursor. In À addition to the DEB2 dianion (m/z 62) and its associated proton- Open Access Article. Published on 20 June 2016. Downloaded 10/5/2021 7:08:50 AM. transfer product (m/z 125) observed in Fig. 1c, the main product ions following the nal collisional activation step arise from loss of CO2 and loss of an electron from m/z 84 (m/z 124), accompa- nied by a small amount of C2 loss from this ion (m/z 100). Decarboxylation of carboxylate anions upon collision- induced dissociation has previously been demonstrated as an effective means to prepare regiospecic anions in the gas phase.17 Such precedent strongly suggests that regiochemistry of the three m/z 62 dianions is retained from their precursor À Fig. 2 (a) Evidence for proton abstraction by ortho-DEB2 . Mass Scheme 1 Gas-phase synthesis of the ortho-DEB isomer. Negative spectra acquired by isolating ortho-diethynylbenzene dianion (m/z 62) ion electrospray ionisation produces the dicarboxylate dianion and monitoring the production of the proton-transfer product (m/z 106). Subjecting this ion to successive stages of collisional (m/z 125) for increasing trapping times in the presence of background activation results in the loss of two carbon dioxide molecules, with water show that the ion signal intensity growth for the proton-transfer retention of both negative charges, yielding the ortho-DEB2À dia- product is clearly coupled to the decay of the dianion superbase ion nion (m/z 62). Synthesis of the meta-andpara-DEB2À isomers signal. (b) Decay plots showing the decrease in integrated ion signal proceeds in an analogous manner, using the appropriate diacid intensity with increased trapping time for m/z 62 for all three DEB2À precursor. dianions. 6246 | Chem. Sci.,2016,7,6245–6250 This journal is © The Royal Society of Chemistry 2016 View Article Online Edge Article Chemical Science details, including preparation of the diacid precursors, are l DG 2 DG* ¼ 1 þ presented in the ESI.† 4 l (1) À Mass selection allowed isolation of the ortho-DEB2 dia- nion within the ion trap and an investigation of its fate over D * time.
Recommended publications
  • WO 2017/106925 Al 29 June 2017 (29.06.2017) P O P C T
    (12) INTERNATIONAL APPLICATION PUBLISHED UNDER THE PATENT COOPERATION TREATY (PCT) (19) World Intellectual Property Organization International Bureau (10) International Publication Number (43) International Publication Date WO 2017/106925 Al 29 June 2017 (29.06.2017) P O P C T (51) International Patent Classification: BZ, CA, CH, CL, CN, CO, CR, CU, CZ, DE, DJ, DK, DM, C22B 26/12 (2006.01) C22B 3/06 (2006.01) DO, DZ, EC, EE, EG, ES, FI, GB, GD, GE, GH, GM, GT, HN, HR, HU, ID, IL, IN, IR, IS, JP, KE, KG, KH, KN, (21) International Application Number: KP, KR, KW, KZ, LA, LC, LK, LR, LS, LU, LY, MA, PCT/AU20 16/05 1278 MD, ME, MG, MK, MN, MW, MX, MY, MZ, NA, NG, (22) International Filing Date: NI, NO, NZ, OM, PA, PE, PG, PH, PL, PT, QA, RO, RS, 22 December 2016 (22. 12.2016) RU, RW, SA, SC, SD, SE, SG, SK, SL, SM, ST, SV, SY, TH, TJ, TM, TN, TR, TT, TZ, UA, UG, US, UZ, VC, VN, (25) Filing Language: English ZA, ZM, ZW. (26) Publication Language: English (84) Designated States (unless otherwise indicated, for every (30) Priority Data: kind of regional protection available): ARIPO (BW, GH, 20159053 17 22 December 201 5 (22. 12.2015) AU GM, KE, LR, LS, MW, MZ, NA, RW, SD, SL, ST, SZ, 2016900774 2 March 2016 (02.03.2016) AU TZ, UG, ZM, ZW), Eurasian (AM, AZ, BY, KG, KZ, RU, TJ, TM), European (AL, AT, BE, BG, CH, CY, CZ, DE, (72) Inventor; and DK, EE, ES, FI, FR, GB, GR, HR, HU, IE, IS, IT, LT, LU, (71) Applicant : HUNWICK, Richard [AU/AU]; 59 Abing LV, MC, MK, MT, NL, NO, PL, PT, RO, RS, SE, SI, SK, don Road, Roseville, New South Wales 2069 (AU).
    [Show full text]
  • Superhalogen and Superacid. Superalkali and Superbase
    Superhalogen and Superacid. Superalkali and Superbase Andrey V. Kulsha,1 Dmitry I. Sharapa2,3 Correspondence to: Andrey V. Kulsha [email protected]; Dmitry I. Sharapa [email protected] 1 Andrey V. Kulsha Lyceum of Belarusian State University, 8 Ulijanauskaja str., Minsk, Belarus, 220030 2 Dmitry I. Sharapa Chair of Theoretical Chemistry and Interdisciplinary Center for Molecular Materials, Friedrich-Alexander-Universitat Erlangen-Nürnberg, Egerlandstraße 3, 91058 Erlangen, Germany 3 Institute of Catalysis Research and Technology (IKFT), Hermann-von-Helmholtz-Platz 1, Eggenstein-Leopoldshafen, Germany, D-76344 ABSTRACT A superhalogen F@C20(CN)20 and a superalkali NC30H36 together with corresponding Brønsted superacid and superbase were designed and investigated on DFT and DLPNO-CCSD(T) levels of theory. Calculated compounds have outstanding properties (electron affinity, ionization energy, deprotonation energy, and proton affinity, respectively). We consider superacid H[F@C20(CN)20] to be able to protonate molecular nitrogen, while NC30H35 superbase should easily deprotonate SiH4. Neutral NC30H36 should form a metallic metamaterial with extreme properties like remarkable transparency to visible light due to infrared plasmonic wavelength. The stability of these structures is discussed, while some of the previous predictions concerning Brønsted superacids and superbases of record strength are doubted. The proton affinity limit was suggested for stable neutral Brønsted superbases. Introduction Traditionally, a superhalogen is a molecule with However, few of the known superhalogen and high electron affinity, which forms a stable superalkali neutral molecules are stable in 5-7 anion. A good example is AuF6 with electron condensed phase. For example, some anions affinity of about 8.2 eV.1 Just in the same way a were predicted to have vertical electron superalkali is a molecule with low ionization detachment energies above 13 eV,8,9 but the energy, which forms a stable cation.
    [Show full text]
  • Proton Affinity Changes Driving Unidirectional Proton Transport In
    doi:10.1016/S0022-2836(03)00903-3 J. Mol. Biol. (2003) 332, 1183–1193 Proton Affinity Changes Driving Unidirectional Proton Transport in the Bacteriorhodopsin Photocycle Alexey Onufriev1, Alexander Smondyrev2 and Donald Bashford1* 1Department of Molecular Bacteriorhodopsin is the smallest autonomous light-driven proton pump. Biology, The Scripps Research Proposals as to how it achieves the directionality of its trans-membrane Institute, 10550 North Torrey proton transport fall into two categories: accessibility-switch models in Pines Road, La Jolla, CA 92037 which proton transfer pathways in different parts of the molecule are USA opened and closed during the photocycle, and affinity-switch models, which focus on changes in proton affinity of groups along the transport 2Schro¨dinger Inc., 120 West chain during the photocycle. Using newly available structural data, and Forty-Fifth Street, 32nd Floor adapting current methods of protein protonation-state prediction to the Tower 45, New York, NY non-equilibrium case, we have calculated the relative free energies of pro- 10036-4041, USA tonation microstates of groups on the transport chain during key confor- mational states of the photocycle. Proton flow is modeled using accessibility limitations that do not change during the photocycle. The results show that changes in affinity (microstate energy) calculable from the structural models are sufficient to drive unidirectional proton trans- port without invoking an accessibility switch. Modeling studies for the N state relative to late M suggest that small structural re-arrangements in the cytoplasmic side may be enough to produce the crucial affinity change of Asp96 during N that allows it to participate in the reprotonation of the Schiff base from the cytoplasmic side.
    [Show full text]
  • Proton Affinity of SO3
    View metadata, citation and similar papers at core.ac.uk brought to you by CORE provided by Elsevier - Publisher Connector Proton Affinity of SO3 Cynthia Ann Pommerening, Steven M. Bachrach, and Lee S. Sunderlin Department of Chemistry, Northern Illinois University, DeKalb, Illinois, USA ϩ Collision-induced dissociation (CID) of the radical cation H2SO4 gives the product pairs ϩ ϩ ϩ ϩ H2O SO3 and HO HSO3 with a 1:3 ratio that is essentially independent of collision energy. Statistical analysis of the two channels indicates that the proton affinity of HO is 3 Ϯ ϭ Ϯ 4 kJ/mol lower than that of SO3. This can be used to derive PA(SO3) 591 4 kJ/mol at 0 K and 596 Ϯ 4 kJ/mol at 298 K. Previously, Munson and Smith bracketed the proton affinity as PA(HBr) ϭ 584 kJ/mol Ͻ PA(SO ) Ͻ PA(CO) ϭ 594 kJ/mol. The threshold of 152 Ϯ 16 ϩ 3 kJ/mol for formation of H O ϩ SO indicates that the barrier to CID is small or nonexistent, 2 3 ϩ in contrast to the substantial barriers to decomposition for H3SO4 and H2SO4. (JAmSoc Mass Spectrom 1999, 10, 856–861) © 1999 American Society for Mass Spectrometry he development of extensive scales of proton this work provide an independent measurement of the ⌬ affinity (PA), gas basicity (GB), and acidity ( Ha) PA of SO3. values has provided a framework for the quanti- The gas-phase addition of H2OtoSO3 to form T ϭϪ⌬ tative understanding of ion properties. (PA H for sulfuric acid has a substantial barrier, as indicated by addition of a proton, GB ϭϪ⌬G for addition of a reaction rate measurements [4–6] and computational ⌬ ϭ⌬ proton, and Ha H for deprotonation.) The history results [7, 8].
    [Show full text]
  • WO 2014/138933 Al 18 September 2014 (18.09.2014) P O P C T
    (12) INTERNATIONAL APPLICATION PUBLISHED UNDER THE PATENT COOPERATION TREATY (PCT) (19) World Intellectual Property Organization International Bureau (10) International Publication Number (43) International Publication Date WO 2014/138933 Al 18 September 2014 (18.09.2014) P O P C T (51) International Patent Classification: Jersey 08873 (US). LANGEVIN, Marie-Eve; 20 Worlds C25B 1/16 (2006.01) C25B 9/00 (2006.01) Fair Dr., Somerset, New Jersey 08873 (US). BOW 61/46 (2006.01) (74) Agent: BERESKIN & PARR LLP/S.E.N.C.R.L., S.R.L.; (21) International Application Number: 40th Floor, 40 King Street West, Scotia Plaza, Toronto, PCT/CA20 14/000264 Ontario M5H 3Y2 (CA). (22) International Filing Date: (81) Designated States (unless otherwise indicated, for every 17 March 2014 (17.03.2014) kind of national protection available): AE, AG, AL, AM, AO, AT, AU, AZ, BA, BB, BG, BH, BN, BR, BW, BY, (25) Filing Language: English BZ, CA, CH, CL, CN, CO, CR, CU, CZ, DE, DK, DM, (26) Publication Language: English DO, DZ, EC, EE, EG, ES, FI, GB, GD, GE, GH, GM, GT, HN, HR, HU, ID, IL, IN, IR, IS, JP, KE, KG, KN, KP, KR, (30) Priority Data: KZ, LA, LC, LK, LR, LS, LT, LU, LY, MA, MD, ME, 61/788,292 15 March 2013 (15.03.2013) US MG, MK, MN, MW, MX, MY, MZ, NA, NG, NI, NO, NZ, (71) Applicant: NEMASKA LITHIUM INC. [CA/CA]; 450 OM, PA, PE, PG, PH, PL, PT, QA, RO, RS, RU, RW, SA, rue de la Gare-du-Palais, ler etage, Quebec, Quebec G1K SC, SD, SE, SG, SK, SL, SM, ST, SV, SY, TH, TJ, TM, 3X2 (CA).
    [Show full text]
  • Acid Dissociation Constant - Wikipedia, the Free Encyclopedia Page 1
    Acid dissociation constant - Wikipedia, the free encyclopedia Page 1 Help us provide free content to the world by donating today ! Acid dissociation constant From Wikipedia, the free encyclopedia An acid dissociation constant (aka acidity constant, acid-ionization constant) is an equilibrium constant for the dissociation of an acid. It is denoted by Ka. For an equilibrium between a generic acid, HA, and − its conjugate base, A , The weak acid acetic acid donates a proton to water in an equilibrium reaction to give the acetate ion and − + HA A + H the hydronium ion. Key: Hydrogen is white, oxygen is red, carbon is gray. Lines are chemical bonds. K is defined, subject to certain conditions, as a where [HA], [A−] and [H+] are equilibrium concentrations of the reactants. The term acid dissociation constant is also used for pKa, which is equal to −log 10 Ka. The term pKb is used in relation to bases, though pKb has faded from modern use due to the easy relationship available between the strength of an acid and the strength of its conjugate base. Though discussions of this topic typically assume water as the solvent, particularly at introductory levels, the Brønsted–Lowry acid-base theory is versatile enough that acidic behavior can now be characterized even in non-aqueous solutions. The value of pK indicates the strength of an acid: the larger the value the weaker the acid. In aqueous a solution, simple acids are partially dissociated to an appreciable extent in in the pH range pK ± 2. The a actual extent of the dissociation can be calculated if the acid concentration and pH are known.
    [Show full text]
  • The Pennsylvania State University
    The Pennsylvania State University The Graduate School Department of Chemical Engineering A SOLID CATALYST METHOD FOR BIODIESEL PRODUCTION A Dissertation in Chemical Engineering by Dheeban Chakravarthi Kannan Submitted in Partial Fulfillment of the Requirements for the Degree of Doctor of Philosophy August 2009 The dissertation of Dheeban Chakravarthi Kannan was reviewed and approved* by the following: Jack V. Matson Professor of Environmental Engineering Dissertation Adviser Themis Matsoukas Associate Professor of Chemical Engineering Chair of Committee Joseph M. Perez Senior Research Scientist, Department of Chemical Engineering Wallis A. Lloyd Adjunct Professor of Chemical Engineering Brian A. Dempsey Professor of Environmental Engineering Thomas P. Hettmansperger Professor of Statistics Andrew Zydney Professor of Chemical Engineering Head of the Department of Chemical Engineering *Signatures are on file in the Graduate School ABSTRACT Biodiesel has considerable production potential as a renewable source of energy. The conventional processes use soluble alkali catalysts that contaminate the biodiesel and glycerol products, and present separation problems. An efficient and clean process is crucial for large scale commercial production. Solid catalysts have the potential to eliminate these problems. A method has been developed to produce biodiesel using a solid catalyst. The reaction is carried out at high temperature and pressure conditions (260 °C, 70 atm). The high temperature is not a problem since the solid catalyst is part of a continuous process in which heat energy can be recovered. The reaction time is short (15 minutes) compared to that of the conventional processes (~ 100 minutes). Promising catalysts were identified from batch tests; and MnO was found to be the most effective catalyst from the lab-scale packed-bed reactor tests.
    [Show full text]
  • Lithium Resources and Requirements by the Year 2000
    Lithium Resources and Requirements by the Year 2000 GEOLOGICAL SURVEY PROFESSIONAL PAPER 1005 Lithium Resources and Requirements by the Year 2000 JAMES D. VINE, Editor GEOLOGICAL SURVEY PROFESSIONAL PAPER 1005 A collection of papers presented at a symposium held in Golden, Colorado, January 22-24, 1976 UNITED STATES GOVERNMENT PRINTING OFFICE, WASHINGTON : 1976 UNITED STATES DEPARTMENT OF THE INTERIOR THOMAS S. KLEPPE, Secretary GEOLOGICAL SURVEY V. E. McKelvey, Director First printing 1976 Second printing 1977 Library of Congress Cataloging in Publication Data Vine, James David, 1921- Lithium resources and requirements by the year 2000. (Geological Survey Professional Paper 1005) 1. Lithium ores-United States-Congresses. 2. Lithium-Congresses. I. Vine, James David, 1921- II. Title. HI. Series: United States Geological Survey Professional Paper 1005. TN490.L5L57 553'.499 76-608206 For sale by the Superintendent of Documents, U.S. Government Printing Office Washington, D.C. 20402 Stock Number 024-001-02887-5 CONTENTS Page 1. Introduction, by James D. Vine, U.S. Geological Survey, Denver, Colo ______________-_______-_-- — ------- —— —— ——— ---- 1 2. Battery research sponsored by the U.S. Energy Research and Development Administration, by Albert Landgrebe, Energy Research and De­ velopment Administration, Washington, D.C., and Paul A. Nelson, Argonne National Laboratory, Argonne, Ill-__- —— -____.—————— 2 3. Battery systems for load-leveling and electric-vehicle application, near-term and advanced technology (abstract), by N. P. Yao and W. J. Walsh, Argonne National Laboratory, Argonne, 111___.__________________________________-___-_________ — ________ 5 4. Lithium requirements for high-energy lithium-aluminum/iron-sulfide batteries for load-leveling and electric-vehicle applications, by A.
    [Show full text]
  • Probing the Structure and Reactivity of Gaseous Ions a DISSERTATION
    Probing the Structure and Reactivity of Gaseous Ions A DISSERTATION SUBMITTED TO THE FACULTY OF THE GRADUATE SCHOOL OF THE UNIVERSITY OF MINNESOTA BY Matthew Michael Meyer IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF DOCTOR OF PHILOSOPHY Professor Steven R. Kass Febuary 2010 © Matthew Meyer 2010 Acknowledgements I want to express my gratitude to my advisor Dr. Steven Kass for the opportunity to work with him during my time at Minnesota. I am grateful for his willingness to share not only his vast knowledge of chemistry, but his approach to addressing problems. I also would like to acknowledge professors, John Anthony and Mark Meier for their mentorship while I was at the University of Kentucky that led me to a career in chemistry. Due to the broad nature of the research contained herein I am grateful for the contributions of the many collaborators I had the opportunity to work with while at Minnesota. In particular, I would like to thank Professors Richard O’Hair, Steven Blanksby, and Mark Johnson for their wiliness to allow me to spend time in their labs. During my course of studies I have also had the opportunities to interacts with a variety of other scientist that have contributed greatly to my development and completing this document, including Dr. Dana Reed, Dr. Mark Juhasz, Dr. Erin Speetzen, Dr. Nicole Eyet and Mr. Kris Murphy. I am also grateful for the support of my brother and sister through out this process. Lastly, I want to expresses gratitude to my parents for their support in all my pursuits and encouraging my incessant asking why probably since I could talk.
    [Show full text]
  • Using Tourmaline As an Indicator of Provenance
    Louisiana State University LSU Digital Commons LSU Master's Theses Graduate School 2016 Using Tourmaline As An Indicator Of Provenance: Development And Application Of A Statistical Approach Using Random Forests Erin Lael Walden Louisiana State University and Agricultural and Mechanical College, [email protected] Follow this and additional works at: https://digitalcommons.lsu.edu/gradschool_theses Part of the Earth Sciences Commons Recommended Citation Walden, Erin Lael, "Using Tourmaline As An Indicator Of Provenance: Development And Application Of A Statistical Approach Using Random Forests" (2016). LSU Master's Theses. 4490. https://digitalcommons.lsu.edu/gradschool_theses/4490 This Thesis 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 Master's Theses by an authorized graduate school editor of LSU Digital Commons. For more information, please contact [email protected]. USING TOURMALINE AS AN INDICATOR OF PROVENANCE: DEVELOPMENT AND APPLICATION OF A STATISTICAL APPROACH USING RANDOM FORESTS A Thesis Submitted to the Graduate Faculty of the Louisiana State University and Agricultural and Mechanical College in partial fulfillment of the requirements of the degree of Master of Science in The Department of Geology and Geophysics by Erin Lael Walden B.S., Louisiana State University, 2008 December 2016 In memory of Wayne Douglas Walden ii ACKNOWLEDGMENTS My sincere and endless gratitude goes to Darrell Henry, who provided funding for two years and saw me through personal and academic hurdles with tireless patience and understanding. His insight and communication improved this manuscript greatly. I must also thank Barbara Dutrow for her suggestions and contributions, and Brian Marx for his expertise in statistics and help with programming.
    [Show full text]
  • Gas-Phase Hydrogen/Deuterium Exchange As a Molecular Probe for the Interaction of Methanol and Protonated Peptides
    View metadata, citation and similar papers at core.ac.uk brought to you by CORE provided by Elsevier - Publisher Connector Gas-Phase Hydrogen/Deuterium Exchange as a Molecular Probe for the Interaction of Methanol and Protonated Peptides Eric Gard, M. Kirk Green, Jennifer Bregar, and Carlito B. Lebrilla Departmentof Chemistry, University of California, Davis, California, USA The gas-phase hydrogen/deuterium (H/D) exchange kinetics of several protonated amino acids and dipeptides under a background pressure of CH,OD were determined in an external source Fourier transform mass spectrometer. H/D exchange reactions occur even when the gas-phase basicity of the compound is significantly larger (>20 kcal/mol) than methanol. In addition, greater deuterium incorporation is observed for compounds that have multiple sites of similar basicities. A mechanism is proposed that involves a structurally specific intermediate with extensive interaction between the protonated compound and methanol. (r Am Sot Mass Spectrom 1994,5, 623-631) he production of ionic gas-phase macro- [ 10, 11,18,19]. Investigations by Ausloos and L.ias [lOI molecules allows the possibility of studying these have shown that for protonated compounds H/D ex- T complex systems in the absence of solvent. Al- change reactions do not occur when the proton affinity though the gas and solvated phases are intrinsically of the neutral base is greater than the deuterated different, there is evidence to suggest that conforma- reagent by more than 20 kcal/mol. The correlation tion may be retained by the molecule even in the gas between basicity and reactivity has led many people to phase [l-5].
    [Show full text]
  • Zonation in Tourmaline from Granitic Pegmatites & the Occurrence of Tetrahedrally Coordinated Aluminum and Boron in Tourmaline
    ZONATION IN TOURMALINE FROM GRANITIC PEGMATITES & THE OCCURRENCE OF TETRAHEDRALLY COORDINATED ALUMINUM AND BORON IN TOURMALINE by Aaron J. Lussier A Thesis submitted to the Faculty of Graduate Studies of The University of Manitoba in partial fulfilment of the requirements of the degree of DOCTOR OF PHILOSOPHY Department of Geological Sciences University of Manitoba Winnipeg Copyright © 2011 by Aaron J. Lussier ABSTRACT [1] Four specimens of zoned tourmaline from granitic pegmatites are characterised in detail, each having unusual compositional and/or morphologic features: (1) a crystal from Black Rapids Glacier, Alaska, showing a central pink zone of elbaite mantled by a thin rim of green liddicoatite; (2) a large (~25 cm) slab of Madagascar liddicoatite cut along (001) showing complex patterns of oscillatory zoning; and (3) a wheatsheaf and (4) a mushroom elbaite from Mogok, Myanmar, both showing extensive bifurcation of fibrous crystals originating from a central core crystal, and showing pronounced discontinuous colour zoning. Crystal chemistry and crystal structure of these samples are characterised by SREF, EMPA, and 11B and 27Al MAS NMR and Mössbauer spectroscopies. For each sample, compositional change, as a function of crystal growth, is characterised by EMPA traverses, and the total chemical variation is reduced to a series of linear substitution mechanisms. Of particular interest are substitutions accommodating the variation in [4]B: (1) TB + YAl ↔ TSi + Y(Fe, Mn)2+, where T Y T Y transition metals are present, and (2) B2 + Al ↔ Si2 + Li, where transition metals are absent. Integration of all data sets delineates constraints on melt evolution and crystal growth mechanisms.
    [Show full text]