DOCSLIB.ORG

Appendices Appendix A

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Appendices Appendix A Appendices Appendix A Character Tables* of the More Common Symmetry Point Groups 1. Cyclic Groups A C2 E C2 A 1 1 z R z xz., y2, Z2, xy B 1 -1 x,y Rx' R y YZ, zx 2 C3 E C3 C3 W = exp (2ni/3) A 1 1 1 Z Rz .~ + y2, Z2 1 W w2 xz. - y2, xy, x,y E{ 1 w* W*2 } } Rx' Ry } yz, zx 3 C4 E C4 C2 c4 2 A 1 1 1 1 z R z x + I, Z2 B 1 -1 1 -1 r -I,xy 1 i -1 -i E { x,y Rx' Ry YZ,zx 1 -i -1 i } } } • Adapted from 1. Gutman and O.E. Polansky: Mathematical Concepts in Organic Chemistry. Springer, Berlin Heidelberg New York London Paris Tokyo 1986. Appendix 5, pp. 184-199 284 Appendix A. Character Tables ofthe More Common Symmetry Point Groups Cs E Cs Cs2 Cs3 Cs4 W = exp (271ij5) I A 1 1 1 1 1 - i R% xl +.1, Z2 1 W w2 w3 w4 { } x,y } yz,zx E1 1 w* W*2 W*3 W*4 }R", Ry 1 w2 w4 W w3 } xl -.I, xy E2 { 1 W*2 W*4 w* W*3 2 S C6 E C6 C3 C2 C3 C6 W = exp (271ij6) A 1 1 1 1 1 1 Z R% X2 +.I,z2 B 1 -1 1 -1 1 -1 1 W w1 -1 -w _w2 E1 { 1 w* W*2 -1 -w* _W*2 } x,y } R", Ry } YZ,zx 1 w2 w4 1 w2 w4 Ez { 1 W*2 W*4 1 W*2 W*4 } xl -.I, xy 2. Cnv Groups C2v E C2 U V Ud zx yz Al 1 1 1 1 z xl, y2, Z2 A2 1 1 -1 -1 R% xy B1 1 -1 1 -1 x Ry zx B2 1 -1 -1 I Y R yz " I C3v E 2C3 3uv Al 1 1 1 z xl +.1, Z2 A2 1 I -1 R% -.I, xy E 2 -1 0 {.r x,y I R", Ry yz,zx Appendix A. Character Tables of the More Common Symmetry Point Groups 285 c4V E 2C4 C2 2a v 2ad AI 1 1 1 1 1 Z X2 +/,Z2 A2 1 1 1 -1 -1 Rz 2 8 1 1 -1 1 1 -1 x _/ 8 2 1 -1 1 -1 1 xy E 2 0 -2 0 0 x,y RX,R), YZ,ZX C5v E 2C5 2c; 5a,. <p = 2rr:5 AI 1 1 1 1 Z :xl + /, .::2 A2 1 1 1 -1 R z EI 2 a b 0 x,y Rx ' Ry yz, ZX E2 2 b a 0 :xl -/, xy I a = 2 cos <p = 2 cos 4<p = (0 - 1)/2 = 0.618034, b = 2cos2<p = -(0 + 1)/2 = -1.618034. C6v E 2C6 2C3 C2 3a v 3ad AI 1 1 1 1 1 1 Z :xl + /, Z2 A2 1 1 1 1 -1 -1 R z 8 1 1 -1 1 -1 1 -1 82 1 -1 1 -1 -1 1 EI 2 1 -1 -2 0 0 x,y Rx ' Ry y.::, zx E2 2 -1 -1 2 0 0 xZ-/,xy 3. Cnh Groups C1h E ah Clh = es xy A' 1 1 X,y R x2, y2, Z2, xy AU z 1 -1 z R x ' R y yz,zx 286 Appendix A. Character Tables ofthe More Common Symmetry Point Groups C2h E C2 i (jh 2 Ag 1 1 1 1 R z x , y2, Z2, xy A u 1 1 -1 -1 z 8g 1 -1 1 -1 R x ' Ry yz, zx 8 u 1 -1 -1 1 x,y 2 S2 C3h E C3 C3 (jh S3 3 A' 1 1 1 1 1 1 Rz :x? + f, r A" 1 1 1 -1 -1 -1 z 1 W w2 1 W w2 E' { } x,y }:x? - f, xy 1 w* W*2 1 w* W*2 1 W w2 -1 -w _w2 Eil { } yz, zx 1 w* W*2 -1 -w* _W*2 }Rx' Ry 3 S3 C4h E C4 C2 C4 i 4 (jh S4 Ag 1 1 1 1 1 1 1 1 R z :x? + f, r A u 1 1 1 I -1 -1 -1 -1 z 8 g 1 -1 1 -1 1 -1 1 -1 :x?-f,xy 8 u 1 -1 1 -1 -1 1 -1 1 1 i -1 -i 1 i -1 -i } YZ,zx Eg { 1 -i -1 i 1 -i -1 i } Rx ' Ry 1 i -1 -i -1 -i 1 i } x, Y Eu { I -i -1 i -1 i 1 -i > 2 3 '0 C5h E C5 C C (J/, S5 S; S3 W = exp (2n i/5) '0 5 5 C! 5 ~ <tl ------~- ::; X 2 +y2,z2 8: A' I I I >< AU ~I --I ~I ~I ~l > 2 3 4 2 3 4 (1 w w w w W w w w R, P"' E; { W*2 w*3 W*4 W*2 W*3 W*4 }:~yl w* I w* ~ ~ w w 2 w 3 w 4 ~I ~(I) ~·ul ~W3 ~W4 M­ <tl } YZ,::X ..., Ei' { w* W*2 W*3 (1)*4 ~I ~w* __ W*2 ~W*3 __ W*4 } Rx ' R y 3 w 2 w 4 W w 3 u/ w 4 w W 0"~ E2 { }X2~y2,XY (0 W*2 W*4 w* W*3 w*Z W*4 w* W*3 cn o w Z w 4 W w 3 ~I --ol ~W4 ~w ~u/ ...., E2' { w*Z W*4 W*3 ~I ~W*2 ~W*4 ~w* ~W*3 ;. w* <tl s;: o -------_. Iil (1 C6h E C C C C5 S2 S5 W = cxp (2n i/6) 6 3 2 C; 6 3 6 (J/, S'" S3 S~ o A ~ Z2 ::; 9 1 R z + jl, r:n A 1 ~I ~I -I ~I ~I --I Z " '<: 8 g ~I ~I ~l I ~l ~I I ~I S S <tl Bu ~l ~I ~I ~I ~l 1 -I M­ ..., w w 2 ~I ~W ~W2 1 (j) U)2 ~l ~w ~wz '<: E 10 { } Rx ' Rr } yz, ZX ""0 w* w*Z ~l ~w* ~W*2 w* (j)*Z ~l ~w* ~w*Z 9. ::; W w Z ~l ~w ~W2 ~l ~w ~W2 w w 2 M- } X, y CJ EI" { w'~ w*Z ~l ~w* ~w*Z ~l ~w* ~w*Z w* w*Z ..., w Z w 4 1 w 2 w 4 w 4 w 2 w 4 g 0./ 2 '0 EZg { } x ~ y2, xy W*2 W*4 W*2 W*4 1 W*2 W*4 W*2 W*4 '" w Z w 4 w 2 w 4 ~l ~wZ ~W4 ~l ~wZ ~W4 E2u { W*2 W*4 W*2 W*4 ~l ~W*2 ~W*4 ~l ~W*2 ~W*4 -l00"-' 288 Appendix A. Character Tables ofthe More Common Symmetry Point Groups 4. S2n Groups S2 E i S2 = Ci Ag 1 1 Rx ' Ry' R. x2,~,z2,xy,yz,zx A u 1 -1 x,y,z S3 S4 E S4 C2 4 A 1 1 1 1 R. _~ +~, Z2 B 1 -1 1 -1 z x2 _ y2, xy 1 i -1 -i } x,y } YZ,zx E{ 1 -i -1 i } Rx' Ry S6 E C3 C32 i S56 S6 I w = exp (2ni/3) A 1 1 1 1 1 1 R x2 + y2, z2 9 Au 1 1 1 -1 -1 -1 z 1 w ai 1 w w2 } x2 -/, xy, yz, zx Eg { 1 w* W*2 1 w* W*2 } Rx ' Ry I W w2 -1 -w -ai { }x,y Eu 1 w* W*2 -1 -w* _W*2 5. Dn Groups D2 E C2 C2 C2 D2 = V Z Y x A 1 1 1 1 x2, y2, Z2 -1 R xy BI 1 1 -1 z % B2 1 -1 1 -1 Y Ry zx B3 1 -1 -1 1 x R x YZ D3 E 2C3 3C2 AI 1 1 1 x2 + /, Z2 A2 1 1 -1 Z Rz 2 E 2 -1 0 x,y Rx' Ry x -/, xy, YZ, zx D4 E 2C~ C2 2C; 2C; AI 1 1 1 1 1 x2 + /, Z2 A2 1 1 1 -1 -1 Z R = 8 1 1 -1 1 1 -1 82 1 -I 1 -1 1 E 2 0 -2 0 0 x,y Rx ' R)' ~ -/, xy, yz, zx Ds E 2Cs 2C; 5C2 rp = 21[/5 AI 1 1 1 1 ~ +/,1 A2 1 1 1 -1 z Rz EI 2 a b 0 x,y Rx' R v yz, zx E2 2 b a 0 x2 -/, xy I a = 2 cos rp = 2 cos 4rp = (Vs - 1)/2 = 0.618034, b = 2 cos 2rp = -(Vs + 1)/2 = -1.618034. D6 E 2C6 2C3 C2 3C; 3C;' AI 1 1 1 1 1 1 x2 + /, Z2 A2 1 1 1 1 -1 -1 Rz 8 1 1 -1 1 -1 1 -1 8 2 1 -1 1 -1 -1 1 Z EI i 2 1 -1 -2 0 0 x,y Rx ' Ry yz, zx 2 Ez I 2 -1 -1 2 0 0 x _ y2, xy I 6. Dnd Groups D2d E 2S4 C2 2C; 2C;' Du = Vd AI 1 1 1 1 1 x 2 + /, Z2 A2 1 1 1 -1 -1 Rz 8 1 1 -1 1 1 -1 x2 -/ 8 2 1 -1 1 -1 1 z xy E 2 0 -2 0 0 x,y Rx' Ry yz, zx 290 Appendix A.
Load more

Recommended publications
  • Triprismane (CH)6
    Triprismane (CH)6 Ein DaMocles Projekt von • Heiko Hofmann • Nina Hundertmark • Fatema Rad • Regina Sander Contents Introduction…………………………………………...page 1 Chemical and physical informations………………...page 2 Stability………………………………………………..page 3 Preparation……………………………………………page 4 - 6 Research and Development…………………………..page 7 - 8 References……………………………………………..page 9 Introduction Triprismane is the smallest and probably most famous member of a class of extraordinary and interesting polyhederanes, the [n]-prismanes. The smallest member of this hydrocarbon family was proposed by Ladenburg in 1869 as structure for benzene, and more than a century ago, the existence of triprimane became part of a discussion about cage compounds. Formally these cage compounds consist of an even number of methine units positioned at the corners of a regular prism. It's very high symmetry and their complex structure makes them not only difficult to preparate, but also highly strained. The conservation of orbital symmetry, publicised by Woodward and Hoffmann, is the most important facet about the durableness of triprismane and its thermodynamic stability. In 1965 Woodward won the nobel prize of chemistry for these rules. Seite 1 von 9 1.) Chemical and physical informations [3]-prismane [4]-prismane [5]-prismane [6]-prismane (ΔHf = 1338,9 kJ/mol) (ΔHf = 719,7 kJ/mol) (ΔHf = 602,5 kJ/mol) (ΔHf = 686,2 kJ/mol) ΔHf(Benzol) = 961,9 kJ/mol) These interpretations have been predicted by MM2 calculations as they are also used by programmes like ChemDraw. Empirical formula C6H6 CAS RN (Registry 650-42-0 N°) Name: IUPAC: teracylo[2.2.0.02,6.03,5]-hexane prismane, [3]-prismane, triprismane, ladenburg-Benzene.
    [Show full text]
  • MCSCF Study of S1 and S2 Photochemical Reactions of Benzene
    J. Am. Chem. Soc, 1993,11S, 673-682 673 for correcting for the change in charge distribution, and the present known experimental data. In calculating AGo(soln) for the neutral approach represents the most accurate method of obtaining an radicals from eq 8, the solution free energies are partitioned as estimate of Eo(S).The resulting values of Eo(s)were -1.19, -1.73, the sum of hydrogen-bonding (AGo(HB)) and non-hydrogen- -1.05, and -0.94 V for methylamine, ethylamine, dimethylamine, bonding (AGo(NHB)) terms, and the latter is treated as a constant and trimethylamine, respectively. Likewise, utilizing the values which depends on the number of CH2units in the molecule. It of AGO(,) derived above, one can estimate that Eo(I)has values was argued that the difference in AGo(soln) between a-carbon of about -1.5, -1.9, -1.5, and -1.4 V for the same amines, re- radicals, R'R2NCR3H', and the parent molecules, R1R?NCR3H2, spectively. The large negative values of Eo(I)confirm the strong is less than 2 kJ mol-' and can be neglected. For the charged reductive power of these R1R2NCR3H'radicals. Previous esti- species, the difference between trimethylaminium ((CH,),N'+) mates of Eo(])in aqueous solution have been in the region of -1.0 and trimethylammonium ((CH3),NH+) could be derived from V.@ Equilibrium measurements of these quantities in water will experimental estimates of AGO(so1n) of the two species. The be very difficult because of the transitory nature of both the increase in magnitude of the solution free energy of (CH3),N'+ radicals and the iminium products.
    [Show full text]
  • A Procedure for Computing Hydrocarbon Strain Energies Using Computational Group Equivalents, with Application to 66 Molecules
    Swarthmore College Works Chemistry & Biochemistry Faculty Works Chemistry & Biochemistry 2020 A Procedure For Computing Hydrocarbon Strain Energies Using Computational Group Equivalents, With Application To 66 Molecules Paul R. Rablen Swarthmore College, prablen1@swarthmore.edu Follow this and additional works at: https://works.swarthmore.edu/fac-chemistry Part of the Organic Chemistry Commons Let us know how access to these works benefits ouy Recommended Citation Paul R. Rablen. (2020). "A Procedure For Computing Hydrocarbon Strain Energies Using Computational Group Equivalents, With Application To 66 Molecules". Chemistry. Volume 2, Issue 2. 347-360. DOI: 10.3390/chemistry2020022 https://works.swarthmore.edu/fac-chemistry/252 This work is licensed under a Creative Commons Attribution 4.0 License. This work is brought to you for free by Swarthmore College Libraries' Works. It has been accepted for inclusion in Chemistry & Biochemistry Faculty Works by an authorized administrator of Works. For more information, please contact myworks@swarthmore.edu. Article A Procedure for Computing Hydrocarbon Strain Energies Using Computational Group Equivalents, y with Application to 66 Molecules Paul R. Rablen Department of Chemistry and Biochemistry, Swarthmore College, Swarthmore, PA 19081, USA; prablen1@swarthmore.edu Dedication: This paper is dedicated to Professor Bernd Giese on the occasion of his 80th birthday. It was a y pleasure and an honor to work with you on the question of electron conduction in peptides a few years ago. Received: 4 April 2020; Accepted: 27 April 2020; Published: 30 April 2020 Abstract: A method is presented for the direct computation of hydrocarbon strain energies using computational group equivalents. Parameters are provided at several high levels of electronic structure theory: W1BD, G-4, CBS-APNO, CBS-QB3, and M062X/6-31+G(2df,p).
    [Show full text]
  • Symmetry 2010, 2, 1745-1762; Doi:10.3390/Sym2041745 OPEN ACCESS Symmetry ISSN 2073-8994
    Symmetry 2010, 2, 1745-1762; doi:10.3390/sym2041745 OPEN ACCESS symmetry ISSN 2073-8994 www.mdpi.com/journal/symmetry Review n– Polyanionic Hexagons: X6 (X = Si, Ge) Masae Takahashi Institute for Materials Research, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577, Japan; E-Mail: masae@bios.tohoku.ac.jp; Tel.: +81-22-795-4271; Fax: +81-22-795-7810 Received: 16 August 2010; in revised form: 7 September 2010 / Accepted: 27 September 2010 / Published: 30 September 2010 Abstract: The paper reviews the polyanionic hexagons of silicon and germanium, focusing on aromaticity. The chair-like structures of hexasila- and hexagermabenzene are similar to a nonaromatic cyclohexane (CH2)6 and dissimilar to aromatic D6h-symmetric benzene (CH)6, although silicon and germanium are in the same group of the periodic table as carbon. Recently, six-membered silicon and germanium rings with extra electrons instead of conventional substituents, such as alkyl, aryl, etc., were calculated by us to have D6h symmetry and to be aromatic. We summarize here our main findings and the background needed to reach them, and propose a synthetically accessible molecule. Keywords: aromaticity; density-functional-theory calculations; Wade’s rule; Zintl phases; silicon clusters; germanium clusters 1. Introduction This review treats the subject of hexagonal silicon and germanium clusters, paying attention to the two-dimensional aromaticity. The concept of aromaticity is one of the most fascinating problems in chemistry [1,2]. Benzene is the archetypical aromatic hexagon of carbon: it is a planar, cyclic, fully conjugated system that possesses delocalized electrons. The two-dimensional aromaticity of planar monocyclic systems is governed by Hückel’s 4N + 2 rule, where N is the number of electrons.
    [Show full text]
  • Durham E-Theses
    Durham E-Theses The photochemistry of highly uorinated pyridines Middleton, Roderick How to cite: Middleton, Roderick (1977) The photochemistry of highly uorinated pyridines, Durham theses, Durham University. Available at Durham E-Theses Online: http://etheses.dur.ac.uk/8331/ Use policy The full-text may be used and/or reproduced, and given to third parties in any format or medium, without prior permission or charge, for personal research or study, educational, or not-for-prot purposes provided that: • a full bibliographic reference is made to the original source • a link is made to the metadata record in Durham E-Theses • the full-text is not changed in any way The full-text must not be sold in any format or medium without the formal permission of the copyright holders. Please consult the full Durham E-Theses policy for further details. Academic Support Oce, Durham University, University Oce, Old Elvet, Durham DH1 3HP e-mail: e-theses.admin@dur.ac.uk Tel: +44 0191 334 6107 http://etheses.dur.ac.uk UNIVERSITY OF DURHAM A THESIS entitled THE PHOTOCHEMISTRY OF HIGHLY FLUORINATED PYRIDINES Submitted by RODERICK MIDDLETON, B.Sc.(DUNELM) (Van Mlldert College) The copyright of this thesis rests with the author. No quotation from it should be published without his prior written consent and information derived from it should be acknowledged. A candidate for the degree of Doctor of Philosophy . 1977 To My Mother MEMORANDUM This work was carried out at the University of Durham between October 1973 and October 1976. It is the original work of the author unless indicated by reference and has no been submitted for any other degree.
    [Show full text]
  • Reactions of Benzvalene with Tetracyanoethylene, 2,3-Dichloro-5, 6-Dicyano-P-Benzoquinone, Chlorosulfonyl Isocyanate, and Sulfur Dioxide
    J. Am. Chem. Soc. 1984, 106, 373-382 373 Reactions of Benzvalene with Tetracyanoethylene, 2,3-Dichloro-5, 6-dicyano-p-benzoquinone, Chlorosulfonyl Isocyanate, and Sulfur Dioxide. Evidence for Concerted 1,4-Cycloadditions to a Viny1cyclopropane System 1 Manfred Cbrist!, * Ericb Brunn, and Franz Lanzendorfer Contribution from the Inslitul fur Organische Chemie der Universiliit Wurzburg, Am Hubland, D-8700 Wurzburg, Federal Republic of Germany. Received June 17, 1983 Abstract: The reaction of benzvalene (4) with tetracyanoethylene (TCNE) affords a mixture of tetracyclo[3.3.0.02.4.0J·6]octane derivative 5, tricyclo[3.3.0.02•6]oct-7-ene derivative 6, and tricyclo[3.3.0.02•8]oct-6-ene derivative 7. By means of dideuterated benzvalene 4a and the solvent effect on the ratio of the products the mechanisms have been studied. Accordingly, the formation of the main products 5 and 6 involves zwitterionic intermediates, which arise from electrophilic attack of TCNE at the olefinic portion of 4. The third compound 7 is thought to be produced in a concerted 1,4-addition of TCNE to the vinylcyclopropane moiety of benzvalene (4). Treatment of 4 with 2,3-dichloro-5,6-dicyano-p-benzoquinone gives rise to a 1: 1 adduct, which is structurally analogous to TCNE adduct 7 and which is most probably formed in a one-step process as evidenced by the positions of the deuterons when 4a was utilized. In a reinvestigation of the reaction between chlorosulfonyl isocyanate and 4 the new compounds 18a, a 4-azatricyclo[3.3.0.02,8]oct-6-en-3-one derivative, and 19, an 8-azatetracyclo[ 4.2.0.02,4.0J·l]octan-7-one derivative, have been discovered in addition to the known products 2a and 3a.
    [Show full text]
  • Third Millennium Ideal Gas and Condensed Phase Thermochemical Database for Combustion with Updates from Active Thermochemical Tables
    ANL-05/20 TAE 960 Third Millennium Ideal Gas and Condensed Phase Thermochemical Database for Combustion with Updates from Active Thermochemical Tables Alexander Burcat Faculty of Aerospace Engineering, Technion – Israel Institute of Technology Branko Ruscic Chemistry Division, Argonne National Laboratory September 2005 Argonne National Laboratory is managed by The University of Chicago for the U. S. Department of Energy About Argonne National Laboratory Argonne is managed by The University of Chicago for the U.S. Department of Energy under contract W-31-109-Eng-38. The Laboratory’s main facility is outside Chicago, at 9700 South Cass Avenue, Argonne, Illinois 60439. For information about Argonne and its pioneering science and technology programs, see www.anl.gov. Availability of This Report This report is available, at no cost, at http://www.osti.gov/bridge. It is also available on paper to U.S. Department of Energy and its contractors, for a processing fee, from: U.S. Department of Energy Office of Scientific and Technical Information P.O. Box 62 Oak Ridge, TN 37831-0062 phone (865) 576-8401 fax (865) 576-5728 reports@adonis.osti.gov Disclaimer This report was prepared as an account of work sponsored by an agency of the United States Government. Neither the United States Government nor any agency thereof, nor The University of Chicago, nor any of their employees or officers, makes any warranty, express or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, or represents that its use would not infringe privately owned rights.
    [Show full text]
  • AND 7-PH!NTLCTCLOHIPTA-1,3,5-TRIIN!S FRON B!NZVAL!NI VIA 3,3A,,,5,5, &A­ 4 H!XAHYDRO·•,S,&-M!TH!NOCYCLOPBNTAPYRAZOLIS and TBTRACYCLO[ •
    Tetrahedron Vol. 45, No. 10, pp. 2905 to 2915, 1989 0040-4020/89 $3.00+.00 Printed in Great Britain. © 1989 Pergarnon Press plc 7-M!THYL- AND 7-PH!NTLCTCLOHIPTA-1,3,5-TRIIN!S FRON B!NZVAL!NI VIA 3,3a,,,5,5, &a­ 4 H!XAHYDRO·•,s,&-M!TH!NOCYCLOPBNTAPYRAZOLIS AND TBTRACYCLO[ •. 1. 0.01 ' • 0~' 1 lHIPTAHIS MANFRED CHRIStL••, ERICH BRUNN•, WOLFGANG R. ROTH~, AND HANS-WERHER LENNARTZ' Institut für Organische Chemie der Universität Würzburg•, Am Hubland, D-8700 Würzburg, Federal Republ ic of Germany Fakultät für Chemie der Universität Bochum~, Postfach 102148, D-4630 Bochum 1, Federal Republic of Germany (Received in Belgium 8 August 1988) Abstract: The addition of benzvalene < n to diazomethane, diazoethane, 2- diazopropane, phenyldiazomethane, and diphenyldiazomethane afforded the 1-pyrazolines 2a-; in good yields. By means of competition experiments, the relative reactivities of benzvalene 111 and norbornene with regard to diazomethane and 2-diazopropane have been determined. The fact that benz­ valene reacts about twice as fast as norbornene with both diazoalkanes cannot be rationalized on the basis of frontier orbital energies. On direct photolysis, the pyrazolines 2a-; were converted into the tetracy­ 2 4 3 clo[ 4. 1. 0. 0 • • 0 •., l heptanes 4a-; exclusi vely. These compounds gave the 1,3,5-cycloheptatrienes !5a,b,d,t,; in high yields on treatment with sil­ ver ions, thus providing better access to 7, 7-dimethyl-( Sdl and 7.7- diphenylcycloheptatriene C 5;1 than before. Su1•prisingly. the latter com­ pound is in equilibrium with a substantial Quantity of the norcaradiene form.
    [Show full text]
  • High-Temperature Isomerization of Benzenoid Polycyclic Aromatic Hydrocarbons
    Article Cite This: J. Org. Chem. 2018, 83, 3299−3304 pubs.acs.org/joc High-Temperature Isomerization of Benzenoid Polycyclic Aromatic Hydrocarbons. Analysis through the Bent Bond and Antiperiplanar Hypothesis Orbital Model Jean-Francoiş Parent and Pierre Deslongchamps* Departement́ de Chimie, Facultédes Sciences et de Genie,́ 1045 avenue de la medecine,́ UniversitéLaval, Quebec,́ QC G1 V 0A6, Canada *S Supporting Information ABSTRACT: L. T. Scott has discovered the 1,2-swapping of carbon and hydrogen atoms which is known to take place on benzenoid aromatics (up to ∼1000 °C range). For example, 13C-1-naphthalene is specifically converted to 13C-2-naphthalene, and there is evidence that this occurs through the formation of benzofulvene and a naphthalene−carbene intermediate. Application of the bent bond/antiperiplanar hypothesis leads to the postulate that higher in energy pyramidal singlet diradical intermediates can be used to propose a mechanism that rationalizes various atom rearrangements on benzenoid aromatics and related isomeric compounds. he specific 1,2-swapping of carbon and hydrogen atoms at was then postulated that the benzene isomerization must be T high temperature (≥1000 °C) on benzenoid aromatic taking place through the intermediate formation of the isomeric hydrocarbons was discovered by Scott and co-workers.1 One of benzvalene 7, a hypothesis supported by the thermal isomer- their initial investigations2 reported the selective thermal ization of d-1,d-2-benzvalene, which gave 1,2-deuteriobenzene isomerization of 13C-1-labeled naphthalene 1 to produce 13C- quantitatively.4 2 isomer 2 without any appearance of the 13C-8a isomer 3 It was thus believed that the carbon isomerization of (Figure 1).
    [Show full text]
  • Stress Tensor Eigenvector Following with Next-Generation
    Heriot-Watt University Research Gateway Stress Tensor Eigenvector Following with Next-Generation Quantum Theory of Atoms in Molecules: Excited State Photochemical Reaction Path from Benzene to Benzvalene Citation for published version: Malcomson, T, Azizi, A, Momen, R, Xu, T, Kirk, SR, Paterson, MJ & Jenkins, S 2019, 'Stress Tensor Eigenvector Following with Next-Generation Quantum Theory of Atoms in Molecules: Excited State Photochemical Reaction Path from Benzene to Benzvalene', Journal of Physical Chemistry A, vol. 123, no. 38, pp. 8254-8264. https://doi.org/10.1021/acs.jpca.9b07519 Digital Object Identifier (DOI): 10.1021/acs.jpca.9b07519 Link: Link to publication record in Heriot-Watt Research Portal Document Version: Peer reviewed version Published In: Journal of Physical Chemistry A Publisher Rights Statement: This document is the Accepted Manuscript version of a Published Work that appeared in final form in The Journal of Physical Chemistry A, copyright © American Chemical Society after peer review and technical editing by the publisher. The final authenticated version is available online at: https://doi.org/10.1021/acs.jpca.9b07519 General rights Copyright for the publications made accessible via Heriot-Watt Research Portal is retained by the author(s) and / or other copyright owners and it is a condition of accessing these publications that users recognise and abide by the legal requirements associated with these rights. Take down policy Heriot-Watt University has made every reasonable effort to ensure that the content in Heriot-Watt Research Portal complies with UK legislation. If you believe that the public display of this file breaches copyright please contact open.access@hw.ac.uk providing details, and we will remove access to the work immediately and investigate your claim.
    [Show full text]
  • A Procedure for Computing Hydrocarbon Strain Energies Using Computational Group Equivalents, † with Application to 66 Molecules
    Article A Procedure for Computing Hydrocarbon Strain Energies Using Computational Group Equivalents, y with Application to 66 Molecules Paul R. Rablen Department of Chemistry and Biochemistry, Swarthmore College, Swarthmore, PA 19081, USA; prablen1@swarthmore.edu Dedication: This paper is dedicated to Professor Bernd Giese on the occasion of his 80th birthday. It was a y pleasure and an honor to work with you on the question of electron conduction in peptides a few years ago. Received: 4 April 2020; Accepted: 27 April 2020; Published: 30 April 2020 Abstract: A method is presented for the direct computation of hydrocarbon strain energies using computational group equivalents. Parameters are provided at several high levels of electronic structure theory: W1BD, G-4, CBS-APNO, CBS-QB3, and M062X/6-31+G(2df,p). As an illustration of the procedure, strain energies are computed for 66 hydrocarbons, most of them highly strained. Keywords: strain; strain energy; group equivalents; strained hydrocarbons; calculated strain; quadricyclane; cubane; prismane; fenestranes; propellanes; spiroalkanes 1. Introduction The concept of strain has long held interest for organic chemists, going back all the way to Baeyer [1–5]. Strain refers to the amount by which the energy of a molecule exceeds that which one would expect if all bond lengths, bond angles, and dihedral angles could simultaneously hold their ideal values, and if no repulsive nonbonded interactions (steric repulsions) were present. As such, strain is generally assumed to be absent in molecules such as straight-chain alkanes in which the bond lengths, angles, and dihedral angles are not geometrically constrained, and in which the extended conformation avoids repulsive nonbonded interactions.
    [Show full text]
  • Nsu-Ehs-Chemical-Hygiene-Plan-2018
    ENVIRONMENTAL NOVA SOUTHEASTERN HEALTH AND SAFETY UNIVERSITY POLICY/PROCEDURE TITLE: POLICY/PROCEDURE Chemical Hygiene Plan NUMBER: 3 DOCUMENT HISTORY OWNER: Facilities Management/AHIS Date: 1 Sept 2011 APPROVED: NSU EHS Committee Date: 1 Sept 2013 IMPLEMENTED: Date: 1 Oct 2010 RETIRED: Date: Date: Revision No. Review / Changes Reviewer 7 August 2013 none 11 May 2018 1.0 Added EHS instead of EH&S and replaced MSDS with C. St Louis SDS CHEMICAL HYGIENE PLAN TABLE OF CONTENTS Section 1: Introduction Page 4 Section 2: Chemical Safety Guidelines Page 7 Section 3: Chemical Hygiene Responsibilities Page 9 Section 4: Exposure Assessments and Medical Surveillance Page 12 Section 5: Safety Data Sheets - SDS Page 16 Section 6: Chemical Labels Page 17 Section 7: Hazard Communication Page 18 Section 8: Permissible Exposure Limits Page 21 Section 9: Engineering Controls Page 22 Section 10: Classification of Hazardous Substances Page 32 Section 11: Chemical Handling Labeling and Storage Page 47 Section 12: Chemical Inventory Page 61 Section 13: Compressed Gas Safety Page 62 Section 14: Spill Response and Clean-up Guidelines Page 65 Section 15: Shipping / Receiving Chemicals Page 69 Section 16: Training Page 70 Section 17: Record Keeping Page 72 Section 18: Chemical Waste Disposal Page 73 Tables and Illustrations Table A: General Classes of Fires and Fire Extinguishers Page 23 Table B: Flammable and Combustible Liquids Class Characteristics Page 35 Table C: Solvent Substitutions Page 37 Table D: Common Cleaning Agents/Hazards/Precautions Page 45 Table
    [Show full text]