Jump to main content
Jump to site search

Issue 36, 2013
Previous Article Next Article

Theoretical studies on the structural and spectroscopic properties of an iminocoumarin-based probe and its metal complexation: an implication for a fluorescence probe

Author affiliations

Abstract

To understand the sensing behaviors of molecular fluorescent probes, an N,N-di(picolyl)aminoethyl-iminocoumarin probe (L) and its complexation with metal(II) ions (ML, M = Mg, Ca, Zn, Cd and Hg) were examined by relativistic density functional theory (DFT). Four stable conformational isomers (labeled as g1g1g1, g2g2, a1a1 and a2a2) for each of them have been optimized, except for CaL having only three without the g2g2 isomer. All of these structures have been confirmed by frequency calculations. In the aqueous solution, the a2a2 isomer of the L probe was calculated to be the most stable, while the g1g1g1 isomer turns out to be energetically favorable upon binding with metal ions. At these isomeric geometries, the experimentally obtained absorption was well reproduced by calculations of time-dependent DFT (TD-DFT) and a conductor-like polarized continuum model (CPCM). A slight red-shifting from L (508 nm) to ML (516–528 nm) was found. This is due to the metal affinity that stabilizes the LUMOs of ML greater than the HOMOs. Singlet excited-state structures of L and ML (M = Zn, Cd and Hg) were fully optimized using the TD-DFT approach, giving more relaxed geometries than their respective ground-state ones. Their fluorescent emissions in the aqueous solution were calculated to be 543 and 551–560 nm, respectively, agreeing with experimental values of 543 nm for L and 558 nm for ZnL. The present study also presents theoretical support for a sensing mechanism of photo-induced charge transfer of the L probe that was proposed in the previous experiment.

Graphical abstract: Theoretical studies on the structural and spectroscopic properties of an iminocoumarin-based probe and its metal complexation: an implication for a fluorescence probe

Back to tab navigation

Supplementary files

Publication details

The article was received on 27 May 2013, accepted on 10 Jun 2013 and first published on 10 Jun 2013


Article type: Paper
DOI: 10.1039/C3DT51367J
Citation: Dalton Trans., 2013,42, 13004-13013
  •   Request permissions

    Theoretical studies on the structural and spectroscopic properties of an iminocoumarin-based probe and its metal complexation: an implication for a fluorescence probe

    Y. Guo, X. Li, M. Zhang, Q. Pan and Z. Sun, Dalton Trans., 2013, 42, 13004
    DOI: 10.1039/C3DT51367J

Search articles by author

Spotlight

Advertisements