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Abstracts: Lectures
LECT-15
Multicoloured luminescent lanthanide complexes:
From nanoparticles to biomolecule recognition
S. P. Hammond, D. J. Lewis, P. B. Glover, M. Solomons and Z. Pikramenou*
School of Chemistry, The University of Birmingham, Edgbaston, Birmingham, B15 2TT (UK).
E-mail:
We are interested in ligand design for the assembly of luminescent lanthanide complexes with recognition
features that allow probing of interactions in sensing schemes, biomolecules or nanoscale systems. [1-3] In
one approach we use ligands based on bis-amides of diethylene triamine pentaacetic acid (bis-DTPA).
Upon complexation to the lanthanide ion they form a rigid hairpin structure with pendant arms that can be
modified to target specific recognition sites.
Red-emissive, water-soluble nanoscale labels
have been prepared based on europium
complexes. [4-5] Bis-DTPA ligands with thiol
arms have been used. The binding of the
Eu(III) complexes to platinum or gold
nanoparticles (NPs) has been demonstrated
by different techniques. Results suggest that
the system can be optimised to allow
minimum quenching of the luminescence by
the surface of NPs.
O
H
N
C
O
N O
O
O
N Eu
O O
N O
C
N
H
SH
SH
Au NP
The thiol active bis-DTPA system sensitizes visible and near infra-red emission from many lanthanide ions.
Its versatile nature has allowed the formation of bi-colour emissive lanthanide compounds. [5]
To address DNA recognition using the lanthanide metal as a reporter luminescent probe we have
incorporated platinum terpyridyl units as arms in the lanthanide bis-DTPA complex. Luminescent Ln-Pt 2
metallohairpin complexes have been developed and their intercalative recognition with DNA has been
demonstrated with linear dichroism spectroscopy. [5-6] The heterotrimetallic complexes were formed in onestep
reaction, by assembly of a derivative of a DTPA bisamide, a platinum terpyridine unit and the
lanthanide salt. The metallohairpin complexes bear a neutral lanthanide moiety and two positively charged
platinum containing intercalating units. The Nd(III) and Eu(III) analogues are luminescent in the near infra–
red and the visible respectively.
References: [1] P.B. Glover et al., Chem. Eur. J. (2007) in press. [2] M. M. Castaño-Briones et al., Chem. Comm.
(2004) 2832. [3] A. P. Bassett et al. Inorg. Chem. 44 2005 6410. [4] D. J. Lewis et al., Chem. Commun. (2006) 1433.
[5] unpubl. results [6] P. B. Glover et al., J. Am. Chem. Soc. 125 (2003) 9918.
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