Sensitization of the NIR emission of Nd(III) by the 4a atropoisomer of a mesotetraphenyl porphyrin bearing four 8-hydroxyquinolinylamide chelates

For many optical devices such as for example amplifiers and lasers, the luminescence properties of lanthanide ions are of particular interest. Indeed, lanthanide ions emit narrow bands ranging from visible to near–infrared. However, owing to the low absorption coefficients of Laporte-forbidden-f-f transitions, the emission must be sensitized by an energy transfer from chromophoric ligands located in the proximity of the lanthanide ion (antenna effect).

A preorganised porphyrin-based ligand bearing four monoanionic chelates on the same face of the backbone (a4 atropoisomer), offers two distinct coordinating poles consisting in the porphyrin macrocyclic core and four 8-hydroxyquinolines organised in a convergent manner. The difference in binding propensity of the two coordinating poles was exploited for the formation of mononuclear Neodymium and heterobinuclear Palladium Neodymium complexes. In both type of complexes, the porphyrin backbone plays the role of sensitizer. Indeed, excitation in the visible region (Soret band of the porphyrin at 429 nm) leads to an efficient NIR emission of Nd(III) at 1070 nm.

 

 

F. Eckes, V. Bulach, A. Guenet, C. Strassert, L. De Cola And M. W. Hosseini, "Sensitization of the NIR emission of Nd(III) by the 4a atropoisomer of a meso-tetraphenyl porphyrin bearing four 8-hydroxyquinolinylamide chelates", Chem. Commun., 2010, DOI: 10.1039/b920676k. Link to article