Regiocontrolled synthesis of ethene-bridged para-phenylene oligomers based on PtII- And RuII-catalyzed aromatization

Abstract

We report the regiocontrolled syntheses of ethene-bridged paraphenylene oligomers in three distinct classes by using PtII- and Ru II-catalyzed aromatization. This synthetic approach has been developed based on twofold aromatization of the 1-aryl-2-alkynylbenzene functionality, which proceeds by distinct regioselectivity for platinum and ruthenium catalysts. Variable-temperature NMR spectra provide evi-dence that large arrays of these oligomers are prone to twist from planarity. The UV/Vis and photoluminescence (PL) spectra as well as the band gaps of these regularly growing arrays show a pattern of extensive π conjugation with increasing array sizes, except for in one instance. © 2010 Wiley-VCH Verlag GmbH & Co. KGaA.