Fluorescent chemosensors containing a Ru(tpy)2 2+ core and open-chain polyazaalkanes

4-4-(Bromomethyl)phenyl]-2,2:6,2-terpyridine reacts with triethylenetetraamine or tetraethylenepentaamine in CH₂Cl₂ to yield the ligands L¹ and L², respectively. Reaction of L¹ and L² with Ru(mtpy)Cl₃ (mtpy = 4-methyl-2,2:6,2-terpyridine) in MeOH yielded, after column chromatography and precipitation with NH₄]PF₆], the compounds Ru(L¹)(mtpy)]PF₆]₂ and Ru(L²)(mtpy)]PF₆]₂. These metallo-receptors contain triethylenetetraamine or tetraethylenepentaamine recognition sites and Ru(tpy)₂]²⁺ cores as fluorescent signalling subunits. The fluorescent behaviour of Ru(L¹)(mtpy)]²⁺ and Ru(L²)(mtpy)]²⁺ in the presence of metal ions and anions has been studied in MeCN:H₂O (70:30 v/v) as a function of the pH.