Synthesis and Structure of a Longitudinally Twisted Hexacene

Abstract

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 SnCl -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.

Selective access to either a doubly boron-doped tetrabenzopentacene or an oxadiborepin from the same precursor

“…the red screw axis). 52 Starting from the aromatic ring containing C(15), the five annulated rings contribute absolute values of 3.8(4), 12.4(3), 17.8(5), 12.4(3), and 3.8(4)° to the overall absolute twist of 50.2(5)°. 53 The solid-state structures of B 2 -TBPA and TBPA are very much alike, apart from two significant differences: the end-to-end twist in the carbonaceous TBPA (40.9°; Fig.…”

Stabilization by Benzannulation: Butterfly Azaacenes

“…Although Bettinger obtained heptacene via cycloreversion of a precursor in thin films, suitably large silylethynyl groups, as was shown by Anthony, are powerful to protect and solubilize larger acenes. Further published concepts entail addition of aryl and arylthiyl substituents . These strategies are also applicable to larger azaacenes .…”

“…The aqueous layer was extracted twice with dichloromethane. The combined organic layers were washed with saturated NaHCO 3 solution and dried over MgSO 4 .A fter removal of the solvent, the crude product was subjected to column chromatography by given conditions. 11,18-Bis-((triisopropylsilyl)ethynyl)-10,19-dihydro-phenanthro[9,10-b]quinoxalino[2,3-i]phenazine (1-H 2 ) 2,3-Dibromo-6,13-bis((triisopropylsilyl)ethynyl)-5,14-dihydro-quinoxalino[2,3-b]phenazine (72 mg, 89.7 mmol, 1.00 equiv) and Sn,Sn-dimethyl-9-stannafluorene (27 mg, 89.7 mmol, 1.00 equiv) were added to af lame-dried Schlenk under argon.…”

Dodecaphenyltetracene

“…Both molecules are twisted acenes, and 2 displays an end‐to‐end twist of 63°. Much more highly twisted polycycles have since been prepared by benzannulation of the ends of acenes, with the most recent “world record holder” being hexacene 3 , which displays an astonishing 184° end‐to‐end twist …”