Quantum with lanthanide complexes

The main hardware types offered by physics are mentioned, namely trapped ions (or trapped atoms), quantum dots, quantum optical cavities, rf superconducting quantum interference devices (SQUIDs) and nitrogen-vacancy (NV) defects on diamond. Some are important simply as a benchmark to evaluate the quality of the implementations offered by chemistry, whereas others might be combined with lanthanide complexes to produce heterogeneous quantum information processors which combine the advantages of different hardware types. 

An important measure of the luminescence is the quantum yield. In effect, this is the probability that a photon will be emitted by the lanthanide given that one photon has been absorbed by the antenna ligand. Since measurement of absolute quantum yields is particularly difficult, the overall quantum yield ( ) is normally measured with reference to certain standards (26) these are routinely [Ru(bpy)3]2+ in water or SulfoRhodamine 101 in methanol for Eu3 +, and quinoline sulfate in 0.1 M HC1 or fluorescein in 1 N NaOH for Tb3+ (27,28). A method has been developed that measures energy transfer from the lanthanide complex to an acceptor of known quantum yield (28). 

Photophysical studies have been conducted on a number of lanthanide complexes of calix[n]arenes, and a significant number of these are discussed in a recent review (79). The first europium and terbium calixarene complexes showed promising photophysical properties, with terbium luminescence lifetime of 1.5 ms and quantum yield of 0.20 in aqueous solution (80). 

Brunet, E. Juanes, 0. Sedano, R. Rodriguez-Ubis, J.-C. Lanthanide complexes of polycarboxylate-bearing dipyrazolylpyridine ligands with near-unity luminescence quantum yields the effect of pyridine substitution. Photochem. Photobiol. Sci. 2002, 1, 613-618. 

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