Syntheses and Structures of 6,13-Dihydro-6,13-diborapentacenes: π-Stacking in Heterocyclic Analogues of Pentacene

6,13-Dibromo-6,13-dihydro-6,13-diborapentacene (1) has been prepared by the reaction of 2,3-bis(trimethylsilyl)naphthalene with BBr3. The reaction of 1 with Me4Sn or mesityllithium afforded the dimethyl derivative 2 or the dimesityl derivative 3, respectively. In the solid state compounds 1 and 2 form cofacial π-stacks along the a crystal axes, albeit in slightly different ways.