Radical Ions of a Bishomobinaphthylene Containing two 1,6-methano[10]annulene moieties: An ESR and ENDOR study

✍ Scribed by Rainer Bachmann; Fabian Gerson; Andreas Kusch; Emanuel Vogel

• Publisher: John Wiley and Sons
• Year: 1993
• Tongue: German
• Weight: 608 KB
• Volume: 76
• Category: Article
• ISSN: 0018-019X
• DOI: 10.1002/hlca.19930760320

✦ Synopsis

In ESR spectroscopy, protons separated by 0,1,2,. .. sp3-hybridized C atoms from the nearest n-centre, are denoted a, p, y . . . Attempts to generate I t from 1 with AICI, or tris(p-bromophenyl)ammoniumyl-SbC16 in CH2C12 failed thus far [15]. Oxidation of 2 by SbClS in CH2C1, yielded a dimeric radical cation 2, ' [I61 [17]. ESR and ENDOR spectra of monomeric 2+ were only observed upon y-irradiation of 2 in a CFCI, matrix [18]. An unsuccessful attempt to produce 4 t from 4 in conc. H2S0, was mentioned in the early publication on 4' [14]. Later on, it was reported [I91 that the 5,6,11,12-tetramethyl derivative of 4 fails to yield its radical cation with AICI, in CH,C12, although substitution by alkyl groups in these four positions is expected to markedly lower the oxidation potential of 4.

Experimental. -The synthesis of 3 has been described in [12]. The ESR spectra were taken on a Varian-E9 instrument, while a Bruker-ESP-300 system served for ENDOR and TRIPLE-resonance studies.