Synthesis and Structure of a Longitudinally Twisted Hexacene.

The addition of phenyllithium to a polycyclic quinone, 9,11,12,21,22,24-hexaphenyltetrabenzo[a,c,n,p]hexacene-10,23-dione (10), followed by SnCl2 -mediated reduction of the diol intermediate, yielded 9,10,11,12,21,22,23,24-octaphenyltetrabenzo-[a,c,n,p]hexacene (4). Crystallographic analysis of hexacene 4 showed it to possess a longitudinal twist of 184°, which was in good agreement with AM1 calculations. In addition to being the most twisted acene synthesized to this point, compound 4 contains within its substructure the most twisted naphthalene, anthracene, tetracene, and pentacene moieties described.