Design and synthesis of 4,4′-π-conjugated[2,2′]-bipyridines: a versatile class of tunable chromophores and fluorophores

New Journal of Chemistry Pub Date: 2001-12-07 DOI: 10.1039/B106096C

Abstract

A series of 4,4′-disubstituted[2,2′]-bipyridines, featuring π-conjugated substituents such as donor-(acceptor-) substituted styryl, thienylvinyl, phenylimino and phenylazo groups, have been synthesized. X-Ray structures are provided for three ligands containing –C[double bond, length half m-dash]C–, –C[double bond, length half m-dash]N– and –N[double bond, length half m-dash]N– linkers, respectively. These chromophores display good to excellent thermal stabilities with decomposition temperatures of up to 350?°C. The strong influence of the nature of the endgroups and π-linkers on the optical properties is discussed. The stepwise protonation of 4,4′-dibutylaminostyryl-[2,2′]-bipyridine and its coordination behavior to different metallic moieties [Zn(II), Hg(II), Pd(II), Re(I), Re(VII)] have also been investigated. It is found that the absorption and emission maxima can be easily tuned by these exogenous additives over a wide range of wavelengths (360?<?λabs?<?560 nm ; 482?<?λem?<?646 nm).

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