Synthesis, ionisation potentials and electron affinities of hexaazatrinaphthylene derivatives.
Several hexaazatrinaphthylene derivatives and a tris(thieno)hexaazatriphenylene derivative have been synthesised by reaction of the appropriate diamines with hexaketocyclohexane. The crystal structure of 2,3,8,9,14,15-hexachloro-5,6,11,12,17,18-hexaazatrinaphthylene has been determined by X-ray diffraction; this reveals a molecular structure in good agreement with that predicted by density functional theory (DFT) calculations and pi-stacking with an average spacing between adjacent molecular planes of 3.18 A. Solid-state ionisation potentials have been measured by using UV photoelectron spectroscopy and fall in the range of 5.99 to 7.76 eV, whereas solid-state electron affinities, measured using inverse photoelectron spectroscopy, vary in the range -2.65 to -4.59 eV. The most easily reduced example is a tris(thieno)hexaazatriphenylene substituted with bis(trifluoromethyl)phenyl groups; DFT calculations suggest that the highly exothermic electron affinity is due both to the replacement of the outermost phenylene rings of hexaazatrinaphthylene with thieno groups and to the presence of electron-withdrawing bis(trifluoromethyl)phenyl groups. The rather exothermic electron affinities, the potential for adopting pi-stacked structures and the low intramolecular reorganisation energies obtained by DFT calculations suggest that some of these molecules may be useful electron-transport materials.
Barlow
Stephen
S
School of Chemistry and Biochemistry and Center for Organic Photonics and Electronics, Georgia Institute of Technology, Atlanta, GA 30332, USA.
Zhang
Qing
Q
Kaafarani
Bilal R
BR
Risko
Chad
C
Amy
Fabrice
F
Chan
Calvin K
CK
Domercq
Benoit
B
Starikova
Zoya A
ZA
Antipin
Mikhail Yu
MY
Timofeeva
Tatiana V
TV
Kippelen
Bernard
B
Brédas
Jean-Luc
JL
Kahn
Antoine
A
Marder
Seth R
SR