Spectral luminescence characteristics, viz., quantum yields and luminescence lifetime, of the Yb3+ and Nd3+ ions in aqueous-methanolic solutions of their complexes with chromophoric benzo-15-crown-5 derivatives were determined. The efficient 4f-luminescence (lambda(exc) = 337 nm) is due to the intramolecular transfer of the excitation energy from the chromophoric moiety of the molecule to the Ln(3+) ion.
Composition de teinture des fibres kératiniques comprenant un colorant direct monohétéroyldiarylméthane ou un précurseur leuco de celui-ci et procédé de teinture la mettant en oeuvre
Crown ether dyes were synthesized in order to develop photometric reagents which are highly selective to alkali and alkaline earth metals. They contain dissociable protons attached to the chromophores of crown ether molecule. Their extraction behavior for alkali and alkaline earth metal ions as neutral complex was examined. The dyes extract potassium and alkaline earth metals, respectively. Dyes with
Spectral luminescence characteristics, viz., quantum yields and luminescence lifetime, of the Yb3+ and Nd3+ ions in aqueous-methanolic solutions of their complexes with chromophoric benzo-15-crown-5 derivatives were determined. The efficient 4f-luminescence (lambda(exc) = 337 nm) is due to the intramolecular transfer of the excitation energy from the chromophoric moiety of the molecule to the Ln(3+) ion.