Acenes are popular organic semiconducting materials. For example, tetracenes and pentacenes are excellent
semiconductor candidates in organic field-effect transistor devices due to their high charge carrier mobilities
(4‒25 S.cm-1s-1).1 These linear acenes are especially benefited from (i) extended π-conjugation, (ii)
favourable π-π stacking interactions and (iii) enhanced overlapping integrals.2 On the flip side, oligoacenes
seriously suffer from poor solubility and high photoreactivity.3 To put such reactive molecules into use and
to tap their beneficial charge transport properties to the fullest extent, several modifications were attempted
on tetracene and pentacene by Bao et al., Anthony et al. and others.4,5 Besides these important breakthroughs,
several other reports appeared on the modification of pentacenes via introduction of heteroatoms, halogens,
dissymmetry, etc.6 This thesis work focuses on the idea of linearly π-extending coumarins, beyond
benzo[g]coumarins. The synthesis, photophysical, thermal and electrochemical properties of the novel
coumarinacenes and their photostability aspects will be presented. The potential of these coumarinacenes as
stable semiconductors in thin film transistor devices has been evaluated. Besides, the synthesis and
photophysical properties of another series of linearly extended coumarin derivatives, i.e.,
coumarinacenequinone and tetracyanocoumarinacenequino-dimethane, which may act as potential electron
acceptors in systems, such as, batteries and photovoltaic cells,7 will also be discussed.
References:
1) Meng, Q.; Dong, H.; Hu, W.; Zhu, D. J. Mater. Chem. 2011, 21, 11708-11721.
2) Wang, C.; Dong, h.; Hu, W.; Liu, Y.; Zhue, D. Chem. Rev. 2012, 112, 2208-2267
3) Dong, S.; Ong, A.; Chi, C. J. Photochem. Photobio. C: Photochem. Rev. 2019, 38, 27-46.
4) Tang, M. L.; Okamoto, T.; Bao, Z. J. Am. Chem. Soc. 2006, 128, 16002-16003
5) (a) Kim, Y.; Whitten, J. E.; Swager, T. M. J. Am. Chem. Soc. 2005, 127, 12122-12130; (b) Anthony, J. E.;
Brooks, J. S.; Eaton, D. L.; Parkin, S. R. J. Am. Chem. Soc. 2001, 123, 948
6) Lakshminarayana, A. N.; Ong, A.; Chi, C. J. Mater. Chem. C. 2018, 6, 3551-3563
7) Gomez, R.; Seoane, C.; Segura, J. L. Chem. Soc. Rev. 2007, 36, 1305-1322