Synthesis and Characterization of Biphenylene‐Containing Diazaacenes

Abstract

We describe the efficient synthesis of substituted benzo[3,4]cyclobuta[1,2-b]phenazine, benzo[3,4]cyclobuta[1,2]benzo[1,2-i]phenazine, and benzo[3,4]cyclobuta[1,2-b]naphtho[2,3-i]phenazine by a condensation reaction of aromatic diamines with the stable biphenylene-2,3-dione.

Synthesis of Triptycene‐Substituted Azapentacene and Azahexacene Derivatives

“…Cyclic voltammetry measurements show the influence of the structure on the first reduction potential (Table ). The elongation of the acene backbone for 16 results in destabilization of the LUMO owing to the formally anti‐aromatic cyclobutadiene unit in accord with our earlier findings . A higher frontier molecular orbital (FMO) gap results.…”

“…Heating the reaction mixture produced a mixture of unknown compounds with only a small amount of 15 . The coupling of 13 to biphenylene dione gives 16 , featuring an extended π‐system with an anti‐aromatic unit attached to the azaacene core …”

“…Compound 15 is synthesized at room temperature with ay ield of 65 %. Heating the reactionm ixture produced am ixture of unknown compounds with only as mall amount of 15.T he coupling of 13 to biphenylened ione gives 16,f eaturing an extended p-system with an anti-aromatic unit attached to the azaacenec ore. [10] As urprising discoveryi st hat 13 is active in Pd-catalyzed couplings to give the large target 17-H 2 .T his discoveryi si mportant as 1 is reluctant to participate in Pd-catalyzedc ouplings. Surprisingly,t he coupling of 13 to dichloroquinoxaline workedb est if the reaction mixture was stirred in an open(!)…”

A Stable Bis(benzocyclobutadiene)‐Annelated Tetraazapentacene Derivative

“…Both the development of powerful syntheticc oncepts to prepare soluble and processible derivatives of otherwise difficult to dissolve larger azaacenes,b ut also the discoveryo ft heir spectacular nchannel transport properties by Miao has boosted the visibility and utility of these materials. [8] We have already synthesized as eries of unsymmetrical biphenylene-substituted azaacenes, but the synthesis of symmetrical azaacenes is more challenginga nd desirable for their potential applicationi no rganic electronics. [6] While in Vollhardt's phenylenes,t here is as trict sequence of benzenea nd cyclobutadiene units,S wager extended the concept to larger acenes and successfully interspersed cyclobutadienee lements between anthracene units and demonstrated that thesem aterials are attractive emitters.…”

“…[6] While in Vollhardt's phenylenes,t here is as trict sequence of benzenea nd cyclobutadiene units,S wager extended the concept to larger acenes and successfully interspersed cyclobutadienee lements between anthracene units and demonstrated that thesem aterials are attractive emitters. [7][8][9][10] [a] Dr.P . [8] We have already synthesized as eries of unsymmetrical biphenylene-substituted azaacenes, but the synthesis of symmetrical azaacenes is more challenginga nd desirable for their potential applicationi no rganic electronics.…”