Abstract
The geometries and relative energies of the singlet and triplet states of the three didehydrobenzenes (benzynes), six didehydropyridines (pyridynes), and six didehydropyridinium (pyridynium) cations are compared at the density functional, multiconfigurational self-consistent field, and coupled cluster levels of theory. The title Bergman cyclization, which produces a meta diradical, is characterized at the density functional theory level and compared to the analogous Bergman cyclizations generating all of the para diradicals in the subject aryne series. Singlet-triplet splittings in the pyridynium cations and 1H hyperfine couplings in the N-protonated pyridyl radicals are found to be well correlated by proportionality constants determined previously for other arynes. Heats of formation (298 K) are predicted for all six pyridynes. (C) 2000 Elsevier Science B.V.
Original language | English (US) |
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Pages (from-to) | 1-15 |
Number of pages | 15 |
Journal | International Journal of Mass Spectrometry |
Volume | 201 |
Issue number | 1-3 |
DOIs | |
State | Published - 2000 |
Bibliographical note
Funding Information:The authors are grateful for high-performance computing resources, as well as an undergraduate internship, made available by the Minnesota Supercomputer Institute. This work was supported in part by the National Science Foundation, the Alfred P. Sloan Foundation, and the University of Minnesota’s Undergraduate Research Opportunities Program (UROP).
Copyright:
Copyright 2006 Elsevier B.V., All rights reserved.
Keywords
- Aryne
- Biradical
- Didehydroarene
- Enediyne cyclization
- Singlet-triplet splitting