Matches in UGent Biblio for { <https://biblio.ugent.be/publication/498131#aggregation> ?p ?o. }
Showing items 1 to 31 of
31
with 100 items per page.
- aggregation classification "A1".
- aggregation creator B170167.
- aggregation creator B170168.
- aggregation creator person.
- aggregation date "2002".
- aggregation hasFormat 498131.bibtex.
- aggregation hasFormat 498131.csv.
- aggregation hasFormat 498131.dc.
- aggregation hasFormat 498131.didl.
- aggregation hasFormat 498131.doc.
- aggregation hasFormat 498131.json.
- aggregation hasFormat 498131.mets.
- aggregation hasFormat 498131.mods.
- aggregation hasFormat 498131.rdf.
- aggregation hasFormat 498131.ris.
- aggregation hasFormat 498131.txt.
- aggregation hasFormat 498131.xls.
- aggregation hasFormat 498131.yaml.
- aggregation isPartOf urn:issn:0947-6539.
- aggregation language "eng".
- aggregation publisher "WILEY-V C H VERLAG GMBH".
- aggregation subject "Chemistry".
- aggregation title "Mechanism of the forbidden [3s,5s]-sigmatropic shift: orbital symmetry influences stepwise mechanisms involving diradical intermediates".
- aggregation abstract "The mechanisms of [3s,5s]sigmatropic shifts of octa-1,3,7-triene and 7-methylenenona-1.3,8-triene have been elaborated using B3LYP and BPW91 density functional theory and CASPT2 methods. These orbital symmetry forbidden rearrangements are stepwise, involving diradical intermediates. A comparison with several [3.3]sigmatropic shifts of substituted hexadienes and of [5,5]-sigmatropic shifts that are allowed. but nevertheless follow stepwise paths, shows that the activation barrier for the disallowed [3,51 shift is significantly larger than that for the stepwise reactions that are orbital symmetry allowed. Cyclic diradicals that have an aromatic circuit of electrons including the two radical centers and conjugated pi or sigma bonds are stabilized as compared to cyclic diradicals with an antiaromatic circuit of electrons. This applies to the transition states leading to and from the diradicals and influences the activation energies of stepwise sigmatropic shifts. The magnitudes of these effects are small but will have a significant influence on the rates of competing processes. This series of calculations has been used to assess the relative capabilities of the two functionals. We find that BPW91 underestimates the endothermicity of diradical formation and the barrier to diradical formation whereas B3LYP overestimates these quantities.".
- aggregation authorList BK419312.
- aggregation endPage "1299".
- aggregation issue "6".
- aggregation startPage "1290".
- aggregation volume "8".
- aggregation isDescribedBy 498131.
- aggregation similarTo LU-498131.