Quinoline-attached triazacyclononane (TACN) derivatives as fluorescent zinc sensors.
TACN (1,4,7-triazacyclononane) derivatives with three 6-methoxy-2-quinolylmethyl or 1-isoquinolylmethyl moieties were examined as fluorescent zinc sensors. Upon the addition of zinc, 6-MeOTQTACN (5) exhibited a 9-fold fluorescence increase at 420 nm (λex = 341 nm, ϕZn = 0.070). Fluorescence enhancement is specific for zinc and cadmium, although cadmium induces smaller increases (ICd/I0 = 3.6 and ICd/IZn = 40%). The isoquinoline analog 1-isoTQTACN (6) exhibits minimal fluorescence enhancement upon zinc binding. TPEN (N,N,N',N'-tetrakis(2-pyridylmethyl)ethylene-diamine) does not extract zinc from the 6-MeOTQTACN-Zn complex (5-Zn). The quantum yield, metal ion selectivity and metal binding affinity differences between TACN and ethylenediamine (EN) skeletons in quinoline-based ligands are discussed based on the X-ray crystallographic analysis of zinc and cadmium complexes, demonstrating the superiority of quinoline-TACN conjugates.
KYOUSEI Science Center, Nara Women's University, Nara 630-8506, Japan. mikata@cc.nara-wu.ac.jp.
Yuji
Y
Mikata
Yuki
Y
Nodomi
Asako
A
Kizu
Hideo
H
Konno
D001372:Aza Compounds / Q000737:chemistry*; D002104:Cadmium / Q000737:chemistry; D018360:Crystallography, X-Ray; D005456:Fluorescent Dyes / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D008958:Models, Molecular; D010880:Piperidines / Q000737:chemistry*; D011804:Quinolines / Q000737:chemistry*; D021241:Spectrometry, Mass, Electrospray Ionization; D015032:Zinc / Q000032:analysis*
D001372:Aza Compounds; D005456:Fluorescent Dyes; D010880:Piperidines; D011804:Quinolines; C482777:triazacyclononane; D002104:Cadmium; D015032:Zinc