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Dianions from Cyclophanes with Unsaturated Bridges; Cyclic Conjugation in 22-38 n-Electron Perimeter Systems

Ulf Norinder ; Department of Organic Chemistry, Chalmers University of Technology and University of Goteborg, S-412 96 Goteborg, Sweden
David Tanner ; Department of Organic Chemistry, Chalmers University of Technology and University of Goteborg, S-412 96 Goteborg, Sweden
Olof Wennerstrom ; Department of Organic Chemistry, Chalmers University of Technology and University of Goteborg, S-412 96 Goteborg, Sweden


Puni tekst: engleski pdf 8.086 Kb

str. 269-280

preuzimanja: 64

citiraj


Sažetak

A series of. new c:yclophanes with unsaturated bridges, formally
containing it-systems with 18-48 it-electrons was synthesized.
Several of these cyclophanes containing 4n perimeters can be reversibly
reduced to their dianions with 4n + 2 perimeters. This
reversible two-electron process can conveniently be studied by
cyclic voltammetry. The electrochemical data reveal a chemically
significant difference between the neutral 4n and 4n+2 systems
even for large n. A good correlation between calculated energies
of the LUMO orbitals and the reversible reduction potentials has
been obtained. Recent theories of resonance energies in neutral
molecules and dianions with conjugated perimeters have been
tested. The question whether resonance energies or more simply
the frontier orbitals should be used to rationalize the behavior of
the cyclophanes and their dianions is discussed.

Ključne riječi

Hrčak ID:

194232

URI

https://hrcak.srce.hr/194232

Posjeta: 129 *