@article{FunkenEngelsPeyerimhoffetal.1990,
author = {Funken, K. and Engels, Bernd and Peyerimhoff, S.D. and Grein, F.},
title = {Study of the hyperfine coupling constants of the moleculs NH2, NHD and ND2},
url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-58875},
year = {1990},
abstract = {In the present paper we c:alculate tbe magnetic hyperfine couplina constants (hfcc) ai.ID and A11 of the ground states of the isotopes NH2, NHD and ND2 using truncated MR..CI methods. Differences from other theoretical methocls and shortoominp of the truncated Cl approach in calculating tlj10 are studied. Polarization effects wbich detennirae ailo. as weU as a simple model to describe the dipolar hfcc's, are discussed. All results are in. excellent aareement with experimental data. lt is shown that ab initio methods are able to obtain reliable values for otf-diaaonal values of A41 which are difficult to measure experimentaDy.},
subject = {Organische Chemie},
language = {en}
}
@article{LangHerzogStangletal.1990,
author = {Lang, R. and Herzog, C. and Stangl, R. and Brunn, E. and Braun, M. and Christl, Manfred and Peters, K. and Peters, E.-M. and Schnering, H. G. von},
title = {Reaktionen von Homobenzvalenen mit 4-Phenyl-3H-1,2,4-triazol-3,5(4H)-dion, Tetracyanethylen, Chlorsulfonylisocyanat und Schwefeldioxid. Einige konzertierte 1,4-Additionen an eine Vinylcyclopropan-Einheit},
url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-58527},
year = {1990},
abstract = {No abstract available},
subject = {Organische Chemie},
language = {de}
}
@article{ChristlReuchlein1990,
author = {Christl, Manfred and Reuchlein, H.},
title = {Synthesis and NMR Spectra of 2,3-Dihydro-1,3-methanoindene Derivatives and 1,2,3,5-Tetrahydro-1,3-methanopentalene},
url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-58557},
year = {1990},
abstract = {No abstract available},
subject = {Organische Chemie},
language = {en}
}
@article{ChristlLanzendoerferGroetschetal.1990,
author = {Christl, Manfred and Lanzend{\"o}rfer, U. and Gr{\"o}tsch, M. M. and Ditterich, E. and Hegmann, J.},
title = {Cycloadditionen von 1,3,4-0xadiazin-6-onen (4,5-Diaza-alpha-pyronen), 9 - 6-Oxo-5-phenyl-1,3,4-oxadiazin-2-carbons{\"a}ure-methylester - Synthese und Reaktionen mit Norbornen, Norbornadien, Cyclopropenen, Cyclobuten und Benzvalen},
url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-58569},
year = {1990},
abstract = {No abstract available},
subject = {Organische Chemie},
language = {de}
}
@article{ChristlReuchlein1990,
author = {Christl, Manfred and Reuchlein, H.},
title = {Synthesen und NMR-Spektren von 2,3-Dihydro-1,3-methanoindenderivaten und 1,2,3,5-Tetrahydro-1,3-methanopentalen},
url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-58549},
year = {1990},
abstract = {No abstract available},
subject = {Organische Chemie},
language = {de}
}
@article{EngelsPeyerimhoff1989,
author = {Engels, Bernd and Peyerimhoff, S.D.},
title = {Theoretical study of FC\(_2\)H\(_4\)},
url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-58824},
year = {1989},
abstract = {Large-scale multireference configuration interaction (MRD-CI) calculations in a quite flexible AO basis are employed to study the energy hypersurface for the reaction intermediate FC\(_2\)H\(_4\) • The reaction F + C\(_2\)H\(_4\) -> FC\(_2\)H\(_4\) as weil as the 1,2 migration of the fluorine atom in FC\(_2\)H\(_4\) is investigated. In addition the rotation around the CC bond in the optimum conformation is studied. The absolute minimum in the potential energy is found for the asymmetric structure but the symmetric structure is also found to be stable with respect to the dissociation, so that a shuttling of the fluorine atom is in principle possible but highly unlikely because ( l) the activation energy is high ( II 5-130 kJ fmol) and the saddle point lies only 4(}-50 kJ jmol below the dissociation Iimit of F + C\(_2\)H\(_4\) and (2) the competitive motion, i.e., rotation around the CC axis, is nearly free (I 1-17 kJ/mol).},
subject = {Organische Chemie},
language = {en}
}
@article{EngelsPeyerimhoff1989,
author = {Engels, Bernd and Peyerimhoff, S.D.},
title = {The hyperfine coupling constants of the X\(^3\)Σ\(^-\) state of NH : Influence of polarization functions and configuration space on the description of spin polarization},
url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-58832},
year = {1989},
abstract = {The hyperfine coupling constants for the \(^3\)Σ\(-\) ground state of the NH molecule are determined by configuration interaction calculations whereby the infl.uence of polarization functions as weil as of the configuration space on the spin polarization mechanism is analysed. The dipolar part Au(N) and Au(H) can be obtained very reliably without much computational effort (A .. (N) == -45·3 MHz and A"(H) = -62·3 MHz). The value for the isotropic contribution a1.., in the best AO basis and MRD-CI treatment is - 64·5 MHz for H and 16·6 MHz for nitrogen compared to the corresponding experimental quantities of -66 MHz and 19 MHz respectively. Their determination depends on a subtle balance of the lu, 2u and 3u shell correlation description, whereby the dominant contribution to a1..,(H) results from the 2u shell. It is shown that the often good agreement of a110 values with experiment in a small basis singledouble configuration interaction treatment results from a cancellation of two errors.},
subject = {Organische Chemie},
language = {en}
}
@article{EngelsPeyerimhoff1989,
author = {Engels, Bernd and Peyerimhoff, S.D.},
title = {Study of orbital transformations in configurational interaction calculation of hyperfine coupling in nitrogen and CH molecule},
url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-58847},
year = {1989},
abstract = {Multi-reference configuration interaction calculations employing various orbital transformations are undertaken to obtain the isotropic hyperfine coupling constant a\(_{iso\) in nitrogen and a\(_{iso\) (H) in the CH molecule. The natural orbital (NO) basis is found to be more effective than the simple RHF-MO basis; the most obvious is a basis of spin natural orbitals (SNO). It is found that a\(_{iso\) is approached from opposite sides in the NO and 2s shell SNO basis if the CI expansion is increased. Both results are within a few percent of the full CI Iimit for the nitrogen atorn (in the given AO basis) and the experimental value for Hin the CH radical. Various features ofthe SNO are discussed.},
subject = {Organische Chemie},
language = {en}
}
@article{KarnaGreinEngelsetal.1989,
author = {Karna, S. and Grein, F. and Engels, Bernd and Peyerimhoff, S.D.},
title = {The hyperfine coupling constants of \(^{19}\)F\(_2\)},
url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-58817},
year = {1989},
abstract = {The isotropic (a\(_{iso}\)) and dipolar (A\(_{dip}\)) hyperfine coupling constants of 19F2 were obtained from MRD-CI wave functions using a variety of basis sets. In series I, increasing numbers of d functions were added to a 5s4p contracted Huzinaga!Dunning basis. In series II, the 5s3p basis set was uncontracted in several steps until 9s5p was reached, to which were added from one to three d-polarization functions. Cl parameters (selectioo threshoids and the number of reference coofiguratioos) were also varied. A study of the R dependence of aiso and Adip was perfonned. The best values obtained at R\(_e\) are 260 G for a\(_{iso}\) and 308 G for A\(_{dip}\)• compared with experimental values of about 280 G for a;10 and 320 G for A\(_{dip}\)·},
subject = {Organische Chemie},
language = {en}
}
@article{ChristlBrunnRothetal.1989,
author = {Christl, Manfred and Brunn, E. and Roth, W. R. and Lennartz, H.-W.},
title = {7-Methyl- and 7-Phenylcyclohepta-1,3,5-trienes from Benzvalene Via 3,3a,4,5,6,6a-Hexahydro-4,5,6-methenocyclopentapyrazoles and Tetracyclo[4.1.0.0\(^{2,4}\).0\(^{3,5}\)]heptanes},
url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-58471},
year = {1989},
abstract = {No abstract available},
subject = {Organische Chemie},
language = {en}
}
@article{ChristlBrunnKraftetal.1989,
author = {Christl, Manfred and Brunn, E. and Kraft, A. and Irngartinger, H. and Huber-Patz, U.},
title = {Nichtbindende Wechselwirkungen in zwei 7-Spirotetracyclo[4.1.0.0\(^{2,4}\).0\(^{3,5}\)]heptanen},
url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-58489},
year = {1989},
abstract = {Die Reaktion von Tetrachlordiazocyclopentadien mit Be.nzvalen (2) ergab das Fulven-Derivat 3. Dagegen f{\"u}hrten die Umsetzungen von Diazoßuoren und 5-Diazo-10,1 1-dihydro-SH-dibenzo[ a.d]cyclohepten mit 2 zu den erwarteten Spiro-1-pyrazolinen 4 bzw. 5. Die photolytische Abspaltung von Stickstoff aus 4 und 5 lieferte die Spirotetracycloheptane 6 bzw. 7. Die R{\"o}ntgenstrukturanalyse von 6 beweist einen engen Kontakt zwischen je eineßl Wasserstoffatom der Tetracycloheptan- und der Fluoren-Einheit. Dieser kurze Abstand (2.15 A) ruft Winkelaufweitungen hervor und wird auch als Grund f{\"u}r starke Entschirmungen der betreffenden Protonen und eine formal {\"u}ber sieben Bindungen reichende 0.6-Hz-Kopplung zwischen ihnen angesehen. 7 ist das erste chiralc Tetracyclohcptan. Ursache daf{\"u}r ist eine nichtebene Konformation des Siebenrings, der bei Raumtemperatur nicht invertiert. Auf der Basis von NOE-Messungen gelang die Zuordnung der tH-NMR-Signale von 6 und 7.},
subject = {Organische Chemie},
language = {de}
}
@article{ChristlBraun1989,
author = {Christl, Manfred and Braun, Max},
title = {Photocycloadditionen des Benzvalens},
url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-58492},
year = {1989},
abstract = {No abstract available},
subject = {Organische Chemie},
language = {de}
}
@article{ChristlBraun1989,
author = {Christl, Manfred and Braun, Max},
title = {Photocycloadditions of Benzvalene},
url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-58506},
year = {1989},
abstract = {No abstract available},
subject = {Organische Chemie},
language = {en}
}
@article{ChristlBraun1989,
author = {Christl, Manfred and Braun, Martin},
title = {Freisetzung und Abfangreaktionen von 1-Oxa-2,3-cyclohexadien},
url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-58517},
year = {1989},
abstract = {Umsetzung von 6,6-Dichlor-2-oxabicyclo[3.1.0)hexan (4a) in Styrol mit n-Butyllithium lieferte neben Polystyrol und t-Chlor-1- pbenylhexan (6) in geringer Ausbeute die Tet~hydrocyclobutapyrane 5, die Abfangprodukte des aus 4a generierten t-Oxa-2,3- cyclobexadiens (3). Das unbest{\"a}ndige 6,6-Dibrom-2-oxabicyclo( J.l.O]hexan (4b) wurde bei -60°C erzeugt un~ bei -30°C mit Methyllithium in Gegenwart von Styrol umgesetzt, woraus die Produkte 5 mit 24\% Ausbeute hervorgingen. Als bei 20°C best{\"a}ndige Quelle f{\"u}r 3 erwies sich exo-6-Brom-e~o-6-fluor-2-oxabicyclo[ J.t.O]bexan (9), das aus 2,3-Dihydrofuran und Bromßuorcarben mit 25\% Ausbeute bereitet wurde. Behandlung von 9 in Styrol,