Synthesis, Crystal Structure, and Physical Properties of 7,14-Disubstituted Pentacene-5,12-diones Containing a Methylenequinoid Structure

5,7,12,14-Tetrafunctionalized 6,13-Diazapentacenes

The synthesis, property evaluation, and single crystal X-ray structures of four 5,7,12,14-tetrafunctionalized diazapentacenes are presented. The synthesis of these compounds either starts from tetrabromo-N,N-dihydrodiazapentacene or from a diazapentacene tetraketone. Pd-catalyzed coupling or addition of a lithium acetylide gave the precursors that furnish, after further redox reactions, the diazapentacenes as stable crystalline materials. The performance of the tetraphenyl-substituted compound as n-channel semiconductor was evaluated in organic field effect transistors.

2,3-Dihalo- and 2,3,6,7-Tetrahaloanthracenes by Vollhardt Trimerization

We efficiently synthesized otherwise difficult to obtain 2,3- and 2,3,6,7-halogenated anthracenes with diverse east/west substituents. Key steps involve the (i) Vollhardt cyclization of bis(propargyl)benzenes with bis(trimethylsilyl)acetylene, (ii) halo-desilylation introducing chlorine, bromine, or iodine substituents, and (iii) dehydrogenation. Pd catalysis allows selective functionalization at the anthracenes' east/west positions. A tetrahydropentacene is synthesized and derivatized via the same strategy, employing tetrapropargylbenzene.

Improvement of the electrochemical and singlet fission properties of anthraquinones by modification of the diradical character

Quantum chemistry is employed to estimate the effects that the structural modification of 1,5- and 9,10-anthraquinones produces in their electronic structure, in the pursuit of a common strategy to improve the electrochemical and singlet fission features on conjugated quinones.

Functionalization of pentacene-5,7,12,14-tetraone with geminal enediyne and 1,3-dithiole groups

Pentacene-5,7,12,14-tetraone was subjected to selective olefination and cross-coupling reactions to yield a new class of pentacene-based π-conjugated systems with intriguing structural, electronic, and redox properties.

Synthesis, crystal structure, and electron-accepting property of the BF2 complex of a dihydroxydione with a perfluorotetracene skeleton

A BF(2) complex containing an octafluorotetracene moiety was synthesized as a new type of electron acceptor. This compound exhibits a long-wavelength absorption based on the perfluorotetracene skeleton and high electron affinity due to its quadrupolar structure enhanced by fluorination. In the crystal, the molecules are arranged with short F...pi and F...F contacts affording a dense crystal packing. The BF(2) complex exhibited n-type semiconducting behavior.