Zinc-specific intramolecular excimer formation in TQEN derivatives: fluorescence and zinc binding properties of TPEN-based hexadentate ligands.
Dalton Trans
; 43(43): 16377-86, 2014 Nov 21.
Article
em En
| MEDLINE
| ID: mdl-25247241
ABSTRACT
Zn(2+)-induced fluorescence enhancement of the TPEN (N,N,N',N'-tetrakis(2-pyridylmethyl)ethylenediamine)-based ligand, N,N-bis(1-isoquinolylmethyl)-N',N'-bis(pyridylmethyl)ethylenediamine (N,N-1-isoBQBPEN, 1b), has been investigated. Upon Zn(2+) binding, 1b shows a fluorescence increase (ÏZn = 0.028) at 353 and 475 nm. The fluorescence enhancement at longer wavelengths is due to intramolecular excimer formation of two isoquinolines and is specific for Zn(2+); Cd(2+) induces very small fluorescence at 475 nm (ICd/IZn = 10%). The excimer formation of the [Zn(1b)](2+) complex in the excited state is supported by the time-dependent DFT calculation. Neither long-wavelength fluorescence nor excimer formation is observed in the Zn(2+) complex of N,N'-1-isoBQBPEN (2b). The quinoline analog N,N-BQBPEN (1a) exhibits similar but significantly smaller excimer formation. Thermodynamic and kinetic comparisons of Zn(2+) binding properties of ethylenediamine-based hexadentate ligands with pyridines and (iso)quinolines are comprehensively discussed.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Zinco
/
Etilenodiaminas
/
Complexos de Coordenação
Idioma:
En
Revista:
Dalton Trans
Assunto da revista:
QUIMICA
Ano de publicação:
2014
Tipo de documento:
Article
País de afiliação:
Japão