Metal-ion sensing fluorophores with large two-photon absorption cross sections: aza-crown ether substituted donor-acceptor-donor distyrylbenzenes.
Chromophores based on a donor-acceptor-donor structure possessing a large two-photon absorption cross section and one or two mono-aza-15-crown-5 ether moieties, which can bind metal cations, have been synthesized. The influence of Mg(2+) binding on their one- and two-photon spectroscopic properties has been investigated. Upon binding, the two-photon action cross sections at 810 nm decrease by a factor of up to 50 at high Mg(2+) concentrations and this results in a large contrast in the two-photon excited fluorescence signal between the bound and unbound forms, for excitation in the range of 730 to 860 nm. Experimental and computational results indicate that there is a significant reduction of the electron donating strength of the aza-crown nitrogen atom(s) upon metal ion binding and that this leads to a blue shift in the position as well as a reduction in the strength of the lowest-energy two-photon absorption band. The molecules reported here can serve as models for the design of improved two-photon excitable metal-ion sensing fluorophores.
Department of Chemistry, University of Arizona, Tucson, Arizona 85721, USA.
Stephanie J K
SJ
Pond
Osamu
O
Tsutsumi
Mariacristina
M
Rumi
Ohyun
O
Kwon
Egbert
E
Zojer
Jean-Luc
JL
Brédas
Seth R
SR
Marder
Joseph W
JW
Perry
D001372:Aza Compounds / Q000138:chemical synthesis / Q000737:chemistry*; D001555:Benzene Derivatives / Q000737:chemistry*; D043844:Crown Ethers / Q000138:chemical synthesis / Q000737:chemistry*; D005456:Fluorescent Dyes / Q000138:chemical synthesis / Q000737:chemistry*; D008670:Metals / Q000737:chemistry*; D018613:Microscopy, Confocal; D008956:Models, Chemical; D017785:Photons; D013050:Spectrometry, Fluorescence
D001372:Aza Compounds; D001555:Benzene Derivatives; D043844:Crown Ethers; D005456:Fluorescent Dyes; D008670:Metals