Organic Synthesis Applied to Space Sciences J.-C
Total Page:16
File Type:pdf, Size:1020Kb
Load more
Recommended publications
-
Accurate Enthalpies of Formation of Astromolecules: Energy, Stability and Abundance
Accurate Enthalpies of Formation of Astromolecules: Energy, Stability and Abundance Emmanuel E. Etim and Elangannan Arunan* Inorganic and Physical Chemistry Department, Indian Institute of Science Bangalore, India-560012 *email: [email protected] ABSTRACT: Accurate enthalpies of formation are reported for known and potential astromolecules using high level ab initio quantum chemical calculations. A total of 130 molecules comprising of 31 isomeric groups and 24 cyanide/isocyanide pairs with atoms ranging from 3 to 12 have been considered. The results show an interesting, surprisingly not well explored, relationship between energy, stability and abundance (ESA) existing among these molecules. Among the isomeric species, isomers with lower enthalpies of formation are more easily observed in the interstellar medium compared to their counterparts with higher enthalpies of formation. Available data in literature confirm the high abundance of the most stable isomer over other isomers in the different groups considered. Potential for interstellar hydrogen bonding accounts for the few exceptions observed. Thus, in general, it suffices to say that the interstellar abundances of related species are directly proportional to their stabilities. The immediate consequences of this relationship in addressing some of the whys and wherefores among astromolecules and in predicting some possible candidates for future astronomical observations are discussed. Our comprehensive results on 130 molecules indicate that the available experimental enthalpy -
Possible Gas-Phase Syntheses for Seven Neutral Molecules Studied Recently with the Green Bank Telescope
A&A 474, 521–527 (2007) Astronomy DOI: 10.1051/0004-6361:20078246 & c ESO 2007 Astrophysics Possible gas-phase syntheses for seven neutral molecules studied recently with the Green Bank Telescope D. Quan1 and E. Herbst2 1 Chemical Physics Program, The Ohio State University, Columbus, Ohio 43210, USA e-mail: [email protected] 2 Departments of Physics, Chemistry and Astronomy, The Ohio State University, Columbus, OH 43210, USA Received 9 July 2007 / Accepted 17 August 2007 ABSTRACT Aims. With the Green Bank telescope (GBT), seven neutral molecules have been newly detected or confirmed towards either the cold interstellar core TMC-1 or the hot core source Sgr B2(N) within the last 1–2 years. Towards TMC-1, the new molecules seen are cyanoallene (CH2CCHCN) and methyl triacetylene (CH3C6H) while methyl cyanoacetylene (CH3CCCN) and methyl cyanodiacety- lene (CH3C5N) were confirmed. Towards Sgr B2(N), the three newly detected molecules are cyclopropenone (c-C3H2O), ketenimine (CH2CNH), and acetamide (CH3CONH2); these are mainly seen in absorption and are primarily located in an envelope around the hot core. In this work, we report a detailed study of the gas-phase chemistry of all seven molecules. Methods. Starting with our updated gas-phase chemical reaction network osu.01.2007, we added formation and depletion reactions to treat the chemistry of each of the seven molecules. Some of these were already in our network but with incomplete chemistry, while most were not in the network at all prior to this work. We assumed the standard physical conditions for TMC-1 and assumed that these also hold for the envelope around Sgr B2(N). -
Estimation Of'hetrazan'in Body Fluids
No. 4183 December 31, 1949 NATURE II 35 strated by a coupled oxidation of alcohol in the blank value of about 1 (J.gm.fml. Further, trichlor presence of catalase6 • As an artificial ascorbic oxidase acetic acid precipitation removes about 20 per cent it had a Qo8 ((.Ll. oxygen per mgm. dry weight per hr.) of added 'Hetrazan'. Therefore, although it may at pH 7·2 and 39° C. of about 10,000. Hydrogen be more tedious, it is preferable to extract serum or cyanide inhibited this catalysed oxidation of ascorbic plasma. acid by combining with modified ferricytochrome c, Urines show a blank value of about 5 flgm.fml., thus preventing its reduction, while carbon monoxide, but occasionally, in concentrated urines, the blank by combining with modified ferrocytochrome c, may reach 20 vgm.jml. prevented its oxidation. The carbon monoxide The method is sufficiently sensitive to measure a inhibition was somewhat light-sensitive. This reaction blood concentration of 'Hetrazan' of 1 (J.gm.jml. Like was also inhibited by methyl isocyanide and nitroso most of these methods, it lacks specificity, but has benzene. Modified cytochrome c also catalysed the been found useful in following the concentration jn decomposition of hydrogen peroxide, being itself blood and urine after oral administration of the drug. destroyed in this reaction. Cyanide inhibited this A full account of the results of these experiments catalysed decomposition of hydrogen peroxide. will be published later. Typically, ingestion of The result of this experiment agrees with an 10 mgm.jkgm. body-weight of the hydrochloride observation of Keilin and Hartrees that when cyto results in a maximum plasma concentration of about chrome c is made autoxidizable it loses its catalytical 5-7 [lgm.jml., reached in three hours. -
Interferometric Observations of Large Biologically Interesting Interstellar and Cometary Molecules
SPECIAL FEATURE: PERSPECTIVE Interferometric observations of large biologically interesting interstellar and cometary molecules Lewis E. Snyder* Department of Astronomy, University of Illinois, 1002 West Green Street, Urbana, IL 61801 Edited by William Klemperer, Harvard University, Cambridge, MA, and approved May 26, 2006 (received for review March 3, 2006) Interferometric observations of high-mass regions in interstellar molecular clouds have revealed hot molecular cores that have sub- stantial column densities of large, partly hydrogen-saturated molecules. Many of these molecules are of interest to biology and thus are labeled ‘‘biomolecules.’’ Because the clouds containing these molecules provide the material for star formation, they may provide insight into presolar nebular chemistry, and the biomolecules may provide information about the potential of the associated inter- stellar chemistry for seeding newly formed planets with prebiotic organic chemistry. In this overview, events are outlined that led to the current interferometric array observations. Clues that connect this interstellar hot core chemistry to the solar system can be found in the cometary detection of methyl formate and the interferometric maps of cometary methanol. Major obstacles to under- standing hot core chemistry remain because chemical models are not well developed and interferometric observations have not been very sensitive. Differentiation in the molecular isomers glycolaldehdye, methyl formate, and acetic acid has been observed, but not explained. The extended source structure for certain sugars, aldehydes, and alcohols may require nonthermal formation mechanisms such as shock heating of grains. Major advances in understanding the formation chemistry of hot core species can come from obser- vations with the next generation of sensitive, high-resolution arrays. -
Hydroxyacetonitrile (HOCH2CN) As a Precursor for Formylcyanide (CHOCN), Ketenimine (CH2CNH), and Cyanogen (NCCN) in Astrophysical Conditions
A&A 549, A93 (2013) Astronomy DOI: 10.1051/0004-6361/201219779 & c ESO 2013 Astrophysics Hydroxyacetonitrile (HOCH2CN) as a precursor for formylcyanide (CHOCN), ketenimine (CH2CNH), and cyanogen (NCCN) in astrophysical conditions G. Danger1, F. Duvernay1, P. Theulé1, F. Borget1, J.-C. Guillemin2, and T. Chiavassa1 1 Aix-Marseille Univ, CNRS, PIIM UMR 7345, 13397 Marseille, France e-mail: [email protected] 2 Institut des Sciences Chimiques de Rennes, École Nationale Supérieure de Chimie de Rennes, CNRS, UMR 6226, Avenue du Général Leclerc, CS 50837, 35708 Rennes Cedex 7, France Received 8 June 2012 / Accepted 19 November 2012 ABSTRACT Context. The reactivity in astrophysical environments can be investigated in the laboratory through experimental simulations, which provide understanding of the formation of specific molecules detected in the solid phase or in the gas phase of these environments. In this context, the most complex molecules are generally suggested to form at the surface of interstellar grains and to be released into the gas phase through thermal or non-thermal desorption, where they can be detected through rotational spectroscopy. Here, we focus our experiments on the photochemistry of hydroxyacetonitrile (HOCH2CN), whose formation has been shown to compete with aminomethanol (NH2CH2OH), a glycine precursor, through the Strecker synthesis. Aims. We present the first experimental investigation of the ultraviolet (UV) photochemistry of hydroxyacetonitrile (HOCH2CN) as a pure solid or diluted in water ice. Methods. We used Fourier transform infrared (FT-IR) spectroscopy to characterize photoproducts of hydroxyacetonitrile (HOCH2CN) and to determine the different photodegradation pathways of this compound. To improve the photoproduct identifications, irradiations of hydroxyacetonitrile 14N and 15N isotopologues were performed, coupled with theoretical calculations. -
The Prebiotic Molecular Inventory of Serpens SMM1
Astronomy & Astrophysics manuscript no. SMM1_C2H3NO_isomers ©ESO 2021 January 1, 2021 The prebiotic molecular inventory of Serpens SMM1 I. An investigation of the isomers CH3NCO and HOCH2CN N.F.W. Ligterink1, A. Ahmadi2, A. Coutens3, Ł. Tychoniec2 H. Calcutt4; 5, E.F. van Dishoeck2; 6, H. Linnartz7, J.K. Jørgensen8, R.T. Garrod9, and J. Bouwman7 1 Physics Institute, University of Bern, Sidlerstrasse 5, 3012 Bern, Switzerland e-mail: [email protected] 2 Leiden Observatory, Leiden University, PO Box 9513, 2300 RA Leiden, The Netherlands 3 Laboratoire d’Astrophysique de Bordeaux, Univ. Bordeaux, CNRS, B18N, allée Geoffroy Saint-Hilaire, 33615 Pessac, France 4 Department of Space, Earth and Environment, Chalmers University of Technology, 41296, Gothenburg, Sweden 5 Institute of Astronomy, Faculty of Physics, Astronomy and Informatics, Nicolaus Copernicus University, Grudziadzka 5, 87-100 Torun, Poland 6 Max-Planck Institut für Extraterrestrische Physik (MPE), Giessenbachstr. 1, 85748 Garching, Germany 7 Laboratory for Astrophysics, Leiden Observatory, Leiden University, PO Box 9513, 2300 RA Leiden, The Netherlands 8 Centre for Star and Planet Formation, Niels Bohr Institute & Natural History Museum of Denmark, University of Copenhagen, Øster Voldgade 5–7, 1350 Copenhagen K., Denmark 9 Departments of Chemistry and Astronomy, University of Virginia, Charlottesville, VA 22904, USA Received October 8, 2020; accepted December 22, 2020 ABSTRACT Aims. Methyl isocyanate (CH3NCO) and glycolonitrile (HOCH2CN) are isomers and prebiotic molecules that are involved in the formation of peptide structures and the nucleobase adenine, respectively. These two species are investigated to study the interstellar chemistry of cyanides (CN) and isocyanates (NCO) and to gain insight into the reservoir of interstellar prebiotic molecules. -
H2CS) and Its Thiohydroxycarbene Isomer (HCSH
A chemical dynamics study on the gas phase formation of thioformaldehyde (H2CS) and its thiohydroxycarbene isomer (HCSH) Srinivas Doddipatlaa, Chao Hea, Ralf I. Kaisera,1, Yuheng Luoa, Rui Suna,1, Galiya R. Galimovab, Alexander M. Mebelb,1, and Tom J. Millarc,1 aDepartment of Chemistry, University of Hawai’iatManoa, Honolulu, HI 96822; bDepartment of Chemistry and Biochemistry, Florida International University, Miami, FL 33199; and cSchool of Mathematics and Physics, Queen’s University Belfast, Belfast BT7 1NN, Northern Ireland, United Kingdom Edited by Stephen J. Benkovic, The Pennsylvania State University, University Park, PA, and approved August 4, 2020 (received for review March 13, 2020) Complex organosulfur molecules are ubiquitous in interstellar molecular sulfur dioxide (SO2) (21) and sulfur (S8) (22). The second phase clouds, but their fundamental formation mechanisms have remained commences with the formation of the central protostars. Tempera- largely elusive. These processes are of critical importance in initiating a tures increase up to 300 K, and sublimation of the (sulfur-bearing) series of elementary chemical reactions, leading eventually to organo- molecules from the grains takes over (20). The subsequent gas-phase sulfur molecules—among them potential precursors to iron-sulfide chemistry exploits complex reaction networks of ion–molecule and grains and to astrobiologically important molecules, such as the amino neutral–neutral reactions (17) with models postulating that the very acid cysteine. Here, we reveal through laboratory experiments, first sulfur–carbon bonds are formed via reactions involving methyl electronic-structure theory, quasi-classical trajectory studies, and astro- radicals (CH3)andcarbene(CH2) with atomic sulfur (S) leading to chemical modeling that the organosulfur chemistry can be initiated in carbonyl monosulfide and thioformaldehyde, respectively (18). -
United States Patent Office Patented Jan
3,712,911 United States Patent Office Patented Jan. 23, 1973 1. 2 Another possibility is for R1 and R2 to jointly form an 3,712,911 alkylidene radical, as in the compound METALLIZED SOCYANDES Ulrich Schoellkopf, Bovenden, and Fritz Gerhart, Gottin EC-CEI-CE=C-N=C gen, Germany, assignors to Badische Anilin- & Soda Fabrik Aktiengesellschaft, Ludwigshafen (Rhine), Ger Me many or to denote a carboxylic radical together with the alpha No Drawing. Filed Oct. 20, 1969, Ser. No. 867,941 carbon atom of the isocyanide, as in cyclohexylisocyanide. Int, C. C07c 119/02 The radicals R in the ROOC- and ROC-groups may U.S. C. 260-464 8 Claims in principle have the same meanings as the radicals R and R. In ROOC-R may also be a metal ion (Me) and in O ov-ROC-hydrogen. ABSTRACT OF THE DISCLOSURE Me in the first-mentioned general formula stands for ov-Metalated isocyanides containing the radical alkali metal, i.e. lithium, sodium or potassium, or an equivalent of magnesium, zinc or cadmium. 5 As can be seen from the details given above, the metal lized isocyanides of this invention constitute a new class Me of compounds characterized by the as an essential portion of the molecule. Me stands for alkali or an equivalent of magnesium, zinc or cadmium. Their manufacture is accomplished by replacing hydrogen 20 on the cy-carbon of an isocyanide with said metals. The portion of the molecule. compounds open up new routes for organic synthesis and Examples of individual compounds of this class are therefore have outstanding importance as intermediates, c-metal methyl isocyanide, a-metal ethyl isocyanide, c e.g. -
A Study of the C3H2 Isomers and Isotopologues: first Interstellar Detection of HDCCC?
A&A 586, A110 (2016) Astronomy DOI: 10.1051/0004-6361/201527460 & c ESO 2016 Astrophysics A study of the C3H2 isomers and isotopologues: first interstellar detection of HDCCC? S. Spezzano1;3, H. Gupta2;??, S. Brünken3, C. A. Gottlieb4, P. Caselli1, K. M. Menten5, H. S. P. Müller3, L. Bizzocchi1, P. Schilke3, M. C. McCarthy4, and S. Schlemmer3 1 Max-Planck-Institut für extraterrestrische Physik, Giessenbachstr. 1, 85748 Garching, Germany e-mail: [email protected] 2 California Institute of Technology, 770 S. Wilson Ave., M/C 100-22, Pasadena, CA 91125, USA 3 I. Physikalisches Institut, Universität zu Köln, Zülpicher Str. 77, 50937 Köln, Germany 4 Harvard-Smithsonian Center for Astrophysics, and School of Engineering & Applied Sciences, Harvard University, Cambridge, MA 02138, USA 5 Max-Planck Institut für Radioastronomie, Auf dem Hügel 69, 53121 Bonn, Germany Received 28 September 2015 / Accepted 12 November 2015 ABSTRACT The partially deuterated linear isomer HDCCC of the ubiquitous cyclic carbene (c-C3H2) was observed in the starless cores TMC- 1C and L1544 at 96.9 GHz, and a confirming line was observed in TMC-1 at 19.38 GHz. To aid the identification in these narrow line sources, four centimetre-wave rotational transitions (two in the previously reported Ka = 0 ladder and two new ones in the Ka = 1 ladder) and 23 transitions in the millimetre band between 96 and 272 GHz were measured in high-resolution laboratory spectra. Ten spectroscopic constants in a standard asymmetric top Hamiltonian allow the main transitions of astronomical interest −1 in the Ka ≤ 3 rotational ladders to be calculated to within 0.1 km s in radial velocity up to 400 GHz. -
Abstract Book
Our Astro-Chemical History Past, Present, and Future Sept. 10-14 2018 Assen, The Netherlands Abstract Book Program Monday 12:30-14:00 Lunch 14:00-15:25 14:00 Welcome and logistics 14:10 Summary of activities/results from the Action (Laurent Wiesenfeld) 14:40 The Future of Astrochemistry - Farid Salama (NASA) 15:25-16:00 Coffee break 16:00-17:30 Formation of COMs: surface routes vs new gas-phase routes 16:00 Audrey Coutens (Bordeaux, FR) 16:30 Dimitrios Skouteris (Pisa, IT) 17:00 Alexey Potapov (University ofJena, DE) 17:30-18:30 Welcome reception/posters 19:00-20:00 Dinner Tuesday 9:00-10:30 Low temperature chemistry and kinetics and processes (gas & solid) 9:00 Sergiy Krasnokutskiy (Jena, DE) 9:30 Johannes Kästner (Stuttgart, DE) 10:00 Stanka Jerosimić (Belgrade, RS) 10:30-11:00 Coffee break 11:00-12:30 Isotopic fractionation pathways in space 11:00 Kenji Furuya (Tsukuba, JP) 11:30 Eva Wirström (Chalmers, SE) 12:00 Olli Sipilä (Helsinki, FI; MPE, DE) 12:30-14:00 Lunch 14:00-15:30 Nanoparticles: Condensation, reactivity and diffusion 14:00 Herma Cuppen (Nijmegen, NL) 14:30 David Gobrecht (Leuven, BE) 15:00 Antoni Macià Escatllar (Barcelona, ES) 15:30-16:30 Coffee break/poster session 16:30-18:00 16:30 Chemistry of Planetary Atmospheres - Christiane Helling (St Andrews, UK) 17:15 Comet chemistry - Kathrin Altwegg (Bern, CH) 19:00-20:00 Dinner Wednesday 9:00-11:00 Hydrocarbon chains and rings in space 9:00 Ricardo Urso (INAF, IT) 9:30 Maria Luisa Senent (CSIC, ES) 10:00 Thomas Pino (ISMO Paris, FR) 10:30 Sandra Wiersma (Amsterdam, NL) 11:00-11:30 -
Arxiv:1802.10216V1 [Physics.Chem-Ph] 28 Feb 2018 They Play an Important Role in Their Spectroscopic Characteriza- Not Been Systematically Investigated
Bound and continuum-embedded states of cyanopolyyne anions† Wojciech Skomorowski, Sahil Gulania, and Anna I. Krylova Cyanopolyyne anions were among the first anions discovered in the interstellar medium. The discovery have raised questions about routes of formation of these anions in space. Some of the proposed mechanisms assumed that anionic excited electronic states, either metastable or weakly bound, play a key role in the formation process. Verification of this hypothesis requires detailed knowledge of the electronic states of the anions. Here we investigate bound and continuum states of four cyanopolyyne anions, CN−,C3N−,C5N−, and C7N−, by means of ab initio calculations. We employ the equation-of-motion coupled-cluster method augmented with complex absorbing potential. We predict that already in CN−, the smallest anion in the family, there are several low-lying metastable states of both singlet and triplet spin symmetry. These states, identified as shape resonances, are located between 6.3–8.5 eV above the ground state of the anion (or 2.3–4.5 eV above the ground state of the parent radical) and have widths of a few tenths of eV up to 1 eV. We analyze the identified resonances in terms of leading molecular orbital contributions and Dyson orbitals. As the carbon chain length increases in the C2n+1N− series, these resonances gradually become stabilized and eventually turn into stable valence bound states. The trends in energies of the transitions leading to both resonance and bound excited states can be rationalized by means of the Hückel model. Apart from valence excited states, some of the cyanopolyynes can also support dipole bound states and dipole stabilized resonances, owing to a large dipole moment of the parent radicals in the lowest 2S+ state. -
Stellar Metamorphosis: Carbon
Stellar Metamorphosis: Carbon Jeffrey J. Wolynski May 11, 2019 [email protected] Rockledge, FL 32955 Abstract: All stars contain carbon and it is the main building block for all life in the universe. In the general theory, the carbon of a star combines with hydrogen, oxygen and nitrogen (as well as many others) in various combinations during its evolution, forming all biological molecules. This of course takes billions of years (alongside the evolution of life itself, which happens later on) and the carbon molecules increase in complexity as the stars' interiors evolve. For this paper some new ideas that have never been considered before are presented using the general theory. Carbon composes all life. It is also the fourth most abundant element in the universe by mass. One doesn't have to go too far to reason how much life exists in the universe. That aside, the total estimated mass of carbon in the Sun is about 957 Earth masses. That is a lot of carbon to work with to form life. Another wild statistic is that the number of carbon compounds described to date is about 10 million, more than any other element. It is extremely versatile due to its unique properties such as an electronegativity of 2.5 on the Pauling scale. As well it has only 4 valence electrons, meaning to satisfy the shell of 8 it can combine with a wide range of other elements. Long polymers are formed naturally in stars as they evolve and cool, such as hydrocarbons (hydrogen-carbon chains). The basics for understanding how a star forms life, is to reason that the carbon required to form it exists in huge quantities in young stars, as do all other elements required to form life.