Synthesis and Properties of Branched Oligo(2-thienyl)- and Oligo(2,2’-bithien-5-yl)-Substituted Pyridine Derivatives

M. K. Bera, S. L. Gholap, P. Hommes, K. Neuthe, D. Trawny, J. P. Rabe, D. Lentz, R. Zimmer, H.-U. Reissig – 2013

Starting from easily accessible precursors we describe the preparation of a series of branched oligo(2-thienyl)- and oligo(2,2′-bithienyl)-substituted pyridine derivatives. With palladium-catalyzed cross-coupling reactions of pyridyl nonaflates/triflates as key steps we synthesized 2,6-di(2-thienyl)pyridines bridged by thiophene or benzene rings. By selective bromination of 2,6-di(2-thienyl)pyridine and 2,4,6-tri(2-thienyl)pyridine and subsequent coupling reactions an access to oligo(2,2′-bithien-5-yl)-substituted pyridine derivatives was gained. The constitution and solid state conformation of 2,6-bis(2,2’-bithien-5-yl)pyridine was determined by X-ray analysis. This series of new pyridine-thiophene conjugates was systematically investigated by UV/vis spectroscopy. Large Stokes shifts in the neutral and protonated form were observed. The electrochemical oxidation of two typical compounds was studied, however, these oxidations were irreversible forming a polymeric film at the anode. As a selected example, a thiophene-bridged 2,6-di(2-thienyl)pyridine derivative was also investigated by scanning tunneling microscopy showing an interesting self-assembly into a highly ordered monolayer on highly oriented pyrolytic graphite.

Titel
Synthesis and Properties of Branched Oligo(2-thienyl)- and Oligo(2,2’-bithien-5-yl)-Substituted Pyridine Derivatives
Verfasser
M. K. Bera, S. L. Gholap, P. Hommes, K. Neuthe, D. Trawny, J. P. Rabe, D. Lentz, R. Zimmer, H.-U. Reissig
Datum
2013
Kennung
DOI: 10.1002/adsc.201300613
Quelle/n
Zitierweise
Adv. Synth. Catal. 2013, 355, 3463 - 3474
Art
Text
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