Phosphoreszenzeigenschaften von [2,2](1,4)Naphthalinoparacyclophan und [2,2](1,4)Chrysenoparacyclophan und deren Grundzustandskomplexen mit Silberperchlorat

Abstract

Due to the cyclophane structure the energies of the lowest triplet state, phosphorescence lifetimes and phosphorescence/fluorescence quantum yield ratios of [2,2](l,4)naphthalenoparacyclophane (2) and [2,2](1.4)chrysenoparacyclophane (4) differ markedly from the data of 1,4-dimethyl naphthalene and chrysene respectively. By ground state complexation of 2 and 4 with silver Perchlorate the transannular interaction in the cyclophanes is reduced. In contrast to naphthalene. 2 does not effectively quench the benzophenone phosphorescence in benzophenone/ 2 mixed crystals at 77 K. It is shown, however, that this cannot be regarded as a specific property of 2 but rather as an example of the more general phenomenon that steric or stereoelectronic factors can play a considerable role in intermolecular triplet-triplet energy transfer.

Oxidative Carbon−Carbon Bond Cleavage of a [2.2]Paracyclophane Derivative − Efficient Intramolecular Trapping of the Radical Cation

“…the 1 H NMR spectrum of 5, the structure of which was unambiguously established by the X-ray crystallographic data). The oxidative cleavage with ceric ammonium nitrate (another wellknown electron transfer oxidant) of the ethano bridge in parent [2.2]paracyclophane (7) has been studied previously by Adam and co-workers. [5] For comparison, we oxidized 7 with NOBF 4 and isolated two major products, identified as bibenzyl-4,4Ј-dicarbaldehyde (8) and the corresponding monooxime 9 (Scheme 1).…”