Synthesis And Properties Of Sodium And Europium(Iii) Cryptates Incorporating The 4,4'-Substituted-2,2'-Bipyridine Units

A general strategy for the syntheses of 4,4',6,6'-substituted-2,2'-bipyridines starting from aromatic aldehyde is described. A series of sodium cryptates and two europium cryptates [Eu subset of bpy center dot bpy center dot bpy]center dot 2Cl center dot Br (bpy=6,6'-dimethylene2,2'- bipyridine-4,4'-dimethylester) (23) and [Eu subset of bpy(1)bpy(1)center dot bpy(2)]center dot 2Cl center dot Br (bpy(1) = 6,6'-dimethylene-2,2'-bipyridine-4,4'dicarboxylic acid, bpy(2) = 6,6'-dimethylene-2,2'-bipyridine-4,4'-diformylethylenediamine) (24), were synthesized from these compounds. Sodium cryptates have been confirmed by H-1 NMR, C-13 NMR and high resolution mass spectrum (HRMS). The structure of europium cryptate 23 was confirmed by X-ray diffraction (XRD) and HRMS. The photoluminescence (PL) spectra, decay curve and the absolute quantum efficiency (eta) of 23 are presented. 23 can be efficiently excited by near-UV light and presents a bright red luminescence with the lifetime (tau) of 0.32 ms and the. of 70%. It is suggested that 23 is expected to be a potential efficient phosphor for lighting and display.