Are N,N-dihydrodiazatetracene derivatives antiaromatic?
The synthesis and X-ray characterization of two new dialkynylated diazatetracenes and the corresponding N, N-dihydrodiazatetracenes are reported. The dialkynylated heteroacenes are packed in a brick-wall motif that enforces significant overlap of their pi-faces. Cyclic voltammetry indicates that the dehydrogenated forms are easily reduced to their radical anions in solution. The planarity of these species validates the discussion of their aromaticity. Nucleus Independent Chemical Shift (NICS) computations demonstrate that both of these 20 pi and 24 pi electron systems are aromatic. Both experimental and computational results suggest that the aromaticity of the dihydroheteroacenes is reduced.
Miao
Shaobin
S
School of Chemistry and Biochemistry and Center for Organic Photonics and Electronics, Georgia Institute of Technology, Atlanta, Georgia 30332-0400, USA.
Brombosz
Scott M
SM
Schleyer
Paul V R
PV
Wu
Judy I
JI
Barlow
Stephen
S
Marder
Seth R
SR
Hardcastle
Kenneth I
KI
Bunz
Uwe H F
UH