Water-soluble 2-hydroxyisophthalamides for sensitization of lanthanide luminescence

Samuel, Amanda P. S., Moore, E.van G., Melchior, Marco, Xu, Jide and Raymond, Kenneth N. (2008) Water-soluble 2-hydroxyisophthalamides for sensitization of lanthanide luminescence. Inorganic Chemistry, 47 17: 7535-7544. doi:10.1021/ic800328g

Author Samuel, Amanda P. S.
Moore, E.van G.
Melchior, Marco
Xu, Jide
Raymond, Kenneth N.
Title Water-soluble 2-hydroxyisophthalamides for sensitization of lanthanide luminescence
Journal name Inorganic Chemistry   Check publisher's open access policy
ISSN 0020-1669
Publication date 2008-09-01
Year available 2008
Sub-type Article (original research)
DOI 10.1021/ic800328g
Volume 47
Issue 17
Start page 7535
End page 7544
Total pages 10
Place of publication Washington , D.C., U.S.A.
Publisher American Chemical Society
Language eng
Abstract A series of octadentate ligands featuring the 2-hydroxyisophthalamide (IAM) antenna chromophore to sensitize Tb(III) and Eu(III) luminescence has been prepared and characterized. The length of the alkyl amine scaffold that links the four IAM moieties has been varied to investigate the effect of the ligand backbone on the stability and photophysical properties of the Ln(III) complexes. The amine backbones utilized in this study are N,N,N′,N′-tetrakis-(2-aminoethyl)-ethane-1,2-diamine [H(2,2)-], N,N,N′,N′-tetrakis-(2-aminoethyl)-propane-1,3-diamine [H(3,2)-], and N,N,N′,N′-tetrakis-(2-aminoethyl)-butane-1,4-diamine [H(4,2)-]. These ligands also incorporate methoxyethylene [MOE] groups on each of the IAM chromophores to increase their water solubility. The aqueous ligand protonation constants and Tb(III) and Eu(III) formation constants were determined from solution thermodynamic studies. The resulting values indicate that at physiological pH the Eu(III) and Tb(III)complexes of H(2,2)-IAM-MOE and H(4,2)-IAM-MOE are sufficiently stable to prevent dissociation at nanomolar concentrations. The photophysical measurements for the Tb(III) complexes gave overall quantum yield values of 0.56, 0.39, and 0.52 respectively for the complexes with H(2,2)-IAM-MOE, H(3,2)-IAM-MOE, and H(4,2-IAM-MOE, while the corresponding Eu(III)complexes displayed significantly weaker luminescence, with quantum yield values of 0.0014, 0.0015, and 0.0058, respectively. Analysis of the steady state Eu(III) emission spectra provides insight into the solution symmetries of the complexes. The combined solubility, stability, and photophysical performance of the Tb(III) complexes in particular make them well suited to serve as the luminescent reporter group in high sensitivity time-resolved fluoroimmunoassays.
Keyword Ligands
Q-Index Code C1
Q-Index Status Provisional Code
Institutional Status Non-UQ
Additional Notes Published online 1 August 2008

Document type: Journal Article
Sub-type: Article (original research)
Collection: School of Chemistry and Molecular Biosciences
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Created: Mon, 09 Sep 2013, 10:20:39 EST by Evan Moore on behalf of School of Chemistry & Molecular Biosciences