A Cl- anion-responsive luminescent Eu3+ complex with a chiral tripod: ligand substituent effects on ternary complex stoichiometry and anion sensing selectivity.
A new series of N3,O-mixed donor tripods was prepared for luminescent Eu3+ complexes, in which the soft quinoline nitrogen, tertiary amine nitrogen, and hard amide oxygen donors were cooperatively involved. The mixed donor tripods formed more stable 1 : 1 complexes with Eu(NO3)3, La(NO3)3 and Tb(NO3)3 than the corresponding N4 donor tripods, and their Eu3+ complexes particularly exhibited anion-responsive luminescence properties. NMR, UV, and luminescence spectroscopic characterizations revealed that -CH3 substitution on the tripod skeleton remarkably altered the preferred stoichiometry of the "tripod-Eu3+-anion" ternary complex and gave anion-dependent europium luminescence. Although the disubstituted tripod preferred to form non-luminescent 2 : 1 (tripod : Eu3+) complexes with Eu(NO3)3 and other salts, it formed a luminescent 1 : 1 complex with EuCl3. Thus, this type of tripod offered Cl- anion-selective luminescence enhancement that was easily observed by the naked eye.
Kataoka
Yumiko
Y
Department of Chemistry, Graduate School of Science, Osaka City University, 3-3-138 Sugimoto, Osaka 558-8585, Japan.
Paul
Dharam
D
Miyake
Hiroyuki
H
Shinoda
Satoshi
S
Tsukube
Hiroshi
H
D000838:Anions / Q000032:analysis; D002712:Chlorides / Q000032:analysis*; D005063:Europium / Q000737:chemistry*; D005456:Fluorescent Dyes / Q000138:chemical synthesis / Q000737:chemistry*; D008024:Ligands; D049449:Luminescence; D009682:Magnetic Resonance Spectroscopy; D009584:Nitrogen / Q000737:chemistry; D009942:Organometallic Compounds / Q000138:chemical synthesis / Q000737:chemistry*; D010100:Oxygen / Q000737:chemistry; D013050:Spectrometry, Fluorescence; D013056:Spectrophotometry, Ultraviolet
D000838:Anions; D002712:Chlorides; D005456:Fluorescent Dyes; D008024:Ligands; D009942:Organometallic Compounds; D005063:Europium; D009584:Nitrogen; D010100:Oxygen