20380-31-8Relevant academic research and scientific papers
Synthesis and properties of the first Moebius annulenes
Ajami, Dariush,Hess, Kirsten,Koehler, Felix,Naether, Christian,Oeckler, Oliver,Simon, Arndt,Yamamoto, Chiyo,Okamoto, Yoshio,Herges, Rainer
, p. 5434 - 5445 (2006)
Heilbronner in 1964 predicted that annulenes with "... a planar perimeter of N = 4r AO's. which would yield an open shell configuration when occupied by 4r electrons, can be twisted into a closed shell Moebius strip perimeter without loss in π electron energy". We have been able to synthesize the first [4n]annulene with such a Moebius topology and now present further Moebius isomers and the details of their preparation as stable compounds. To address the question whether the twist in the π system has an effect on the properties we systematically investigate energy, geometry and magnetic parameters of a large number isomers of [16]annulenes. The Moebius twisted annulenes are consistently more aromatic than the non-twisted isomers. This is true for the parent as well as our benzoannelated systems. Our results are in contrast to those published recently by C. Castro, W. L. Karney, P. von R. Schleyer et al.
The radical cation of anti-tricyclooctadiene and its rearrangement products
Bally, Thomas,Bernhard, Stefan,Matzinger, Stephan,Truttmann, Leo,Zhu, Zhendong,Roulin, Jean-Luc,Marcinek, Andrzej,Gebicki, Jerzy,Williams, Ffrancon,Chen, Guo-Fei,Roth, Heinz D.,Herbertz, Torsten
, p. 849 - 857 (2000)
The anti dimer of cyclobutadiene (anti-tricyclo[4.2.0.02,5]octa-3,7- diene, TOD) is subjected to ionization by γ-irradiation in Freon matrices, pulse radiolysis in hydrocarbon matrices, and photoinduced electron transfer in solution. The resulting species are probed by optical and ESR spectroscopy (solid phase) as well as by CIDNP spectroscopy (solution). Thereby it is found that ionization of anti-TOD invariably leads to spontaneous decay to two products, that is bicyclo[4.2.0]octa-2,4,7-triene (BOT) and 1,4- dihydropentalene (1,4-DHP), whose relative yield strongly depends on the conditions of the experiment. Exploration of the C8H8.+ potential energy surface by the B3LYP/631G* density functional method leads to a mechanistic hypothesis for the observed rearrangements which involves a bifurcation between a pathway leading to the simple valence isomer, BOT·+, and another one leading to an unprecedented other valence isomer, the anti form of the bicyclo[3.3.0]octa-2,6-diene-4,8-diyl radical cation (anti-BOD·+). The latter product undergoes a very facile H-shift to yield the radical cation of 1,3a-dihydropentalene (1,3a-DHP·+) which ultimately rearranges by a further H-shift to the observed product, 1,4-DHP·+.
THE DIOXYGENATION OF EPOXIDES WITH PHOSPHINES. I. PHOTOCHEMICAL FORMATION OF THE anti-DIMER OF CYCLOBUTADIENE FROM FURAN AND TRIPHENYLPHOSPHINE
Condeiu, Christian,Dinulescu, Ilie G.,Marton, George,Badea, Florian
, p. 733 - 734 (2007/10/02)
The formation of anti-dimer of cyclobutadiene from furan is presented.
