208-20-8Relevant academic research and scientific papers
Photodimerization of Solid Pleiadiene; Isomerization and Cycloreversion of the Dimer
Hazell, Alan C.,Pagni, Richard M.,Persy, Gabriele,Rommel, Erika,Wirz, Jakob
, p. 2830 - 2840 (1981)
Irradiation (λ>400 nm) of solid pleiadiene (1) yields a single, head-to-head ?4s+?4s>-photodimer (2) the structure of which was determined by X-ray analysis.The formation of 2 is entirely suppressed at 77 K, since properly oriented pairs of molecules arise only from thermal disorder in crystals of 1.Upon pyrolysis (80 deg), the strained photodimer 2 rearranges to the ?2s+?4s> dimer 3 by a 'forbidden' suprafacial -C-atom migration.Both 2 and 3 are reconverted to 1 by UV. irradiation in solution, but the latter, 'forbidden' photoreaction is suppressed at 77 K.Discrepancies of the experimental observations with the predictive schemes of Kaupp or Michl are discussed.
Synthesis and Properties of Acepleiadylene-1,2-dione
Suzuki, Seiichi,Tanaka, Shinri,Tsunetsugu, Josuke,Higashi, Miwako,Yamaguchi, Hiroyuki
, p. 1601 - 1635 (2007/10/02)
Acepleiadylene-1,2-dione (4) has been synthesized from cycloheptacenaphthene-1,2-dione (11) by bromination with NBS followed by dehydeobromination with triethylamine.Compound (11) was synthesized by Friedel-Crafts acylation of acepleiadane (10) with oxalyl chloride.Compound (10) was prepared from o-pleiadienequinone (6) by reduction with sodium borohydride to diols (7) and successive dehydration with low valent titanium.MNDO calculations indicated that compound (4) is nearly planar.The reduction potentials of dione (4) were determined by cyclic voltammetry which showed that E1 = -0.50 V and E2 = -0.84 V.Spectral and electrochemical data suggest that dione (4) is a annulenedione with a vinyl cross-link.
