Premium
Multicolor Fluorescence of a Styrylquinoline Dye Tuned by Metal Cations
Author(s) -
Shiraishi Yasuhiro,
Ichimura Chizuru,
Sumiya Shigehiro,
Hirai Takayuki
Publication year - 2011
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201101048
Subject(s) - homo/lumo , quinoline , chemistry , fluorescence , photochemistry , intramolecular force , metal , moiety , acetonitrile , acceptor , stereochemistry , molecule , organic chemistry , physics , quantum mechanics , condensed matter physics
A styrylquinoline dye with a dipicolylamine (DPA) moiety ( 1 ) has been synthesized. The dye 1 in acetonitrile demonstrates multicolor fluorescence upon addition of different metal cations. Compound 1 shows a green fluorescence without cations. Coordination of 1 with Cd 2+ shows a blue emission, while with Hg 2+ and Pb 2+ exhibits yellow and orange emissions, respectively. The different fluorescence spectra are due to the change in intramolecular charge transfer (ICT) properties of 1 upon coordination with different cations. The DPA and quinoline moieties of 1 behave as the electron donor and acceptor units, respectively, and both units act as the coordination site for metal cations. Cd 2+ coordinates with the DPA unit. This reduces the donor ability of the unit and decreases the energy level of HOMO. This results in an increase in HOMO–LUMO gap and blue shifts the emission. Hg 2+ or Pb 2+ coordinate with both DPA and quinoline units. The coordination with the quinoline unit decreases the energy level of LUMO. This results in a decrease in HOMO–LUMO gap and red shifts the emission. Addition of two different metal cations successfully creates intermediate colors; in particular, the addition of Cd 2+ and Pb 2+ at once creates a bright white fluorescence.