DOES THE AROMATIC DIANION OF 1,2-DI-C-13-[8]ANNULENE AUTOMERIZE AS DOES 1,2-DI-C-13-BENZENE

The solid dianion salt of 1,2-di-C-13-cyclooctatetraene was synthesize d in order to measure the first C-13-C-13 NMR coupling in an aromatic annulene other than benzene and to find out if this dianion will under go high-temperature automerizations analogous to those previously obse rved in the benzene system. The solid potassium salt was heated to ove r 600 degrees C for 2 h, and although decomposition with Hz and CH4 ev olution takes place, there is no observable scrambling of the C-13's. The positions of the C-13's were monitored via NMR, which necessitated a rather complete understanding of the NMR couplings for the cyclooct atetraene dianion system. Interestingly, the (1)J(CH) and (1)J(CC) cou plings for the aromatic COT2- system of 145.9 and 55.8 Hz are all quit e comparable to those recently reported for the 1,2-di-C-13-benzene sy stem (158.6 and 55.8 Hz, respectively).