The influence of substituents on the luminescence properties of the Eu(III) and Tb(III) chelates of 4-(phenylethynyl)pyridine derivatives

Abstract

42 differently substituted 2,2′,2″,2‴-“[4-(phenylethynyl)pyridine-2,6-diyl]bis(methylenenitrilo)”tetrakis(acetic acids) ( 1–42) were synthesized with the purpose of studying the influence of substituents on the luminescence properties of the Eu(III) and Tb(III) chelates. With the Eu(III) ion, all derivatives (amides, ketones, esters, acids, ethers, halides and nitriles), with the exception of amines, gave a strong emission with suitable excitation wavelengths while, with the Tb(III) ion, only metasubstituted carbonyl derivatives had moderate luminescence properties.