Lanthanide complexes sensing

There has been recent interest in lanthanide complexes of ligands of the type (21). These are in some sense nitrogen analogues of the crown ethers. As Schiff bases, their lanthanide complexes may be synthesized by a template condensation, for example from 2,6-diacetylpyridine, 1,2-diaminoethane and lanthanum nitrate. These components react in alcohols to give [La(N03)3L], where the aza-crown L = (21 R = Me). This compound has a structure (Figure 6), quite analogous to that of [La(N03)3(18-crown-6)], in which La—N... 

Troster, T., 2003. Optical studies of non-metallic compounds under pressure. In Gschneidner Jr., K.A., Biinzli, J.-C.G., Pecharsky, V.K. (Eds.), Handbook on the Physics and Chemistry of Rare Earths, vol. 33. Elsevier, Amsterdam, pp. 515-589 (chapter 217). Tsukube, H., Shinoda, S., 2002. Chem. Rev. 102, 2389. Tsukube, H., Shinoda, S., 2006. Near infrared emissive lanthanide complexes for anion sensing. ICFE 6 Conference, Wroclaw, September 4-9, 2006, paper AI-5. 

Tsukube, H. and Satoshi, S. (2002) Lanthanide complexes in molecular recognition and chirality sensing of biological substrates. Chemical Reviews, 102, 2389—2403. 

Gunnlaugsson, T., Harte, A.J., Leonard, J.R, and Nieuwenhuyzen, M. (2002) Delayed lanthanide luminescence sensing of aromatic carboxylates using heptadentate triamide Tb(III) cyclen complexes the recognition of salicylic acid in water. Chemical Communications, 2134-2135. 

Lanthanide complexes with heterocyclic ligands in molecular recognition and chirality sensing of biological substrates 02CRV2389. 

Pandya S, Yu JH, Parker D (2006) Engineering emissive lanthanide complexes for molecular imaging and sensing. Dalton Trans 2757-2766... 

The detection of DNA strands by NIR luminescent lanthanide complexes is possible through the modulation of Yb luminescence in Pd-porphyrin-containing complexes upon nucleic acid binding [48] or by the sensitivity of the intramolecular energy transfer towards the presence of DNA sensing in coumarin-rhodamine-modified ytterbium complexes [95]. 

Another problem of using lanthanide complexes as luminescent probes is their susceptibility to interferences. This diminishes the selectivity of the response to a certain analyte and impedes analytical applications in complex samples. The incorporation of LLCs in solid state matrices leads to responsive layers that can be integrated in optical devices for continuous sensing. 

The above account has given some insight into the use of lanthanide complexes for sensing. This is a very active area of research and is fast growing, as can be clearly seen from the few examples listed, which have, with a few exceptions, been based on the cyclen structure. As for many of the transition metal ion examples shown above, these have also been used for imaging proposes, particularly within cells, an area recently reviewed by one of the leaders in the field. ... 

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