DOI: 10.1002/chem.201303863
Communication
&
Lanthanide Probes
Highly Selective and Responsive Visible to Near-IR Ytterbium
Emissive Probe for Monitoring Mercury(II)
Tao Zhang,[a, b] Chi-Fai Chan,[a] Rongfeng Lan,[c] Wai-Kwok Wong,*[a] and Ka-Leung Wong*[a, c]
the detection of heavy Hg2+ ions.[7] In fact, problems with re-
Abstract: A new lanthanide probe based on the fluores-
gards to the selectivity, sensitivity, and survivability for their
cence resonance energy transfer (FRET) process with the
real application do still exist.
combination of ytterbium porphyrinate complex and
Given that bichromophoric sensing systems of rhodamine-
a rhodamine B derivative unit was synthesized to detect
based units with organic chromophores and luminescent tran-
the Hg2+ ion with responsive emission in the visible and
sition-metal complexes have been reported, and that an yt-
near-IR region with a detection limit of 10 mM
terbium porphyrinate complex has recently been reported to
be stable with impressive NIR luminescence in water, we
would like to further explore the application of the latter lan-
To the detriment of public health, global mercury contamina-
tion has long been a great concern. Concerted attempts have
been made, over the past few decades, to develop fluorescent
probes for the Hg2+ ions found environmentally and biologi-
cally.[1,2] Of all sensing systems reported, the use of a rhoda-
mine-based off–on functionality (by a metal-induced ring-
opening process) is a most spectacular design due to its high
sensitivity and selectivity, readiness for modification, and possi-
bility of real-time monitoring.[3] Despite this, biological applica-
tions of the sensor, similar to other organic probes, are still lim-
ited significantly by the fact that its short-lived (ns) visible re-
sponse signals (500–600 nm) are easily absorbed by vascular-
ized tissues (e.g. skin).[4]
thanide complex by amalgamating it with the rhodamine sens-
ing unit.[8,9]
Herein, we report the design and synthesis of a conjugated
probe YbPor-L, a combination of an ytterbium porphyrinate
and a new rhodamine sensing unit, which exhibits both metal-
ion sensing photophysical properties and energy-transferring
properties in a buffer solution (Figure 1) and displays selective-
ly responsive luminescence in visible and NIR regions in the
presence of the Hg2+ ion on the basis of fluorescence reso-
nance energy transfer (FRET).[10]
YbPor-L was synthesized as a final product through an inter-
mediate YbPor-SS (as control, Figure 1) prepared by a series of
With unique photophysical properties, such as line emission
spectra and long luminescence lifetimes (micro- to millisecond
scale), lanthanide-based probes and sensors, which are more
recognizable from the autofluorescent noises generated by the
matrices, become the rising star, in particular, for those being
able to emit in the near-IR (NIR) region and penetrate deep
into biological issues.[5,6] Recently, some visible-emitting Tb/Eu
sensors and NIR-emitting Nd/Yb sensors have been used for
[a] Dr. T. Zhang, C.-F. Chan, Prof. W.-K. Wong, Dr. K.-L. Wong
Institute of Molecular Functional Materials
(Areas of Excellence Scheme University Grants Committee Hong Kong)
and Department of Chemistry and Institute of Advanced Materials
Hong Kong Baptist University
Waterloo Road, Hong Kong (P.R. China)
Fax: (+852)3411-7348
[b] Dr. T. Zhang
MOE key Laboratory of Laser Life Science &
Institute of Laser Life Science, College of Biophotonics
South China Normal University
Guangzhou, 510631 (P.R. China)
[c] Dr. R. Lan, Dr. K.-L. Wong
Hong Kong Baptist University Institute of Research
and Continuing Education, Shenzhen (P.R. China)
Supporting information for this article is available on the WWW under
http://dx.doi.org/10.1002/chem.201303863.
Figure 1. Chemical structures of YbPor-SS and YbPor-L.
Chem. Eur. J. 2014, 20, 970 – 973
970
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