Single- and Multiphoton Turn-on Fluorescent Fe³⁺ Sensors Based on Bis(rhodamine)
Selective and sensitive turn-on fluorescent Fe 3+ sensors based on novel bis(rhodamine) dye molecules are reported. The compounds are synthesized with very high yields and characterized with NMR, ESI mass spectrometry, and elemental analysis. Single- and two-photon fluorescence enhancement is observed for both molecules in the presence of Fe 3+. High selectivity and sensitivity is observed over other metal ions and is shown to be due mainly to the spirolactam ring-opening power of Fe 3+. All measurements are made in buffer environments simulating biological conditions to facilitate single- and multiphoton fluorescence imaging of Fe 3+ in vivo and in vitro. Larger enhancement of fluorescence for both one- and two-photon excitation makes them suitable candidates for fluorescent labeling of biological systems. Two photon cross-section and time-resolved fluorescence measurements are utilized to understand the selectivity of the present sensors for Fe 3+-sensing. © 2010 American Chemical Society.
A. J. Weerasinghe et al., "Single- and Multiphoton Turn-on Fluorescent Fe³⁺ Sensors Based on Bis(rhodamine)," Journal of Physical Chemistry B, American Chemical Society (ACS), Jan 2010.
The definitive version is available at http://dx.doi.org/10.1021/jp1034568
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