Self-assembly lanthanides synthesis

For phosphorescence, lanthanide metal ions can be used in a similar manner. Lanthanide ions have very interesting photophysical properties, but often exhibit weak absorption bands, and aggregate to form clusters, which limit their applications. Thus, a dendrimer that can provide a protective shell to isolate a cation and at the same time enhance the emission by transfer from the periphery to the lanthanide ion at the core could be of great interest. Self-assembled lanthanide-cored dendrimers have been prepared to prove such an assumption synthesis was carried out by mixing three equivalents of polyaryl ether dendrons bearing carboxylic acid entity at the focal point with Ln(III) cations [Er(III), Tb(III), and Eu(III)] (Fig. 5.4) [34]. The authors demonstrated that the enhancement of the lanthanide cation emission associated with the dendritic core shell was observed, and an antenna effect from the periphery to the core was shown to promote this process. 

The similarities in chemical behaviour across the lanthanides mean that kinetically stable lanthanide complexes offer a degree of control that cannot readily be achieved through selective self-assembly of small building blocks. Azamacrocycle complexes derived from cyclen amino-carboxylates are particularly suited to this, and ternary complexes can be used to study the photophysical behaviour of lanthanide complexes. We initially used such an approach to probe the effectiveness of chromophores as sensitizers for lanthanides without recourse to extensive synthesis (as illustrated in Fig. 7). This approach can be used with simple chromophores to probe the mechanism of energy transfer. For instance, tetrathiafulvalene... 

Chen XY, Bretonniere Y, Pecaut D, Imbert D, Biinzli JCG, Mazzanti M (2007) Selective self-assembly of hexameric homo- and heteropolymetallic lanthanide wheels synthesis, structure, and photophysical properties. Inorg Chem 46 625-637... 

A.-S. Chauvin,F. Thomas,B. Song,C.D.B. Vandevyver and J.-C. G. Bunzh, Synthesis and Cell Localization of Self-assembled Dinuclear Lanthanide Bioprobes, submitted to Philosophical Transactions A. 

Lincheneau C, Destribats C, Barry DE, Kitchen JA, Peacock RD, Gunnlaugsson T. Lanthanide Directed Self-Assembly Synthesis and Photophysical Evaluation of Chiral Eu(III) Luminescent Half-Helicates . Dalton Trans 2011 40 12056-12059. 

Piguet C., A. F. Williams, G. Bemardinelli, The First Self-Assembled Dinuclear Triple-Helical Lanthanide Complex Synthesis and Structure. Angew. Chem. Ira. Ed. 31, 1622—1624 (1992). 

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