Ligand-to-metal energy transfer

Figure 5 Triplet-mediated ligand-to-metal energy transfer in lanthanide complexes.

Zucchi, G. Scopelliti, R. Biinzli, J.-C. G. Importance of the chromophore orientation to the ligand-to-metal energy transfer in lanthanide complexes with pendant-arm fitted cyclen derivatives. J. Chem. Soc., Dalton Trans. 2001, (13), 1975-1985. 

TABLE 5. Absorption Data and Ligand-to-Metal Energy-Transfer Efficiencies11... 

After this first report of NIR electroluminescence using Er hydroxyquinolinate, H. Suzuki et al. investigated the luminescence characteristics of this complex under different sample forms which can further be used as NIR emissive materials. Three types of samples have been prepared vacuum-deposited thin-films, doped spin-coated IR polymer films and doped polymer microparticles (Suzuki et al., 2003). Typical NIR luminescence of the Er ion was observed at 1.55 pm for each sample form and with higher intensities when excitation was performed in the ligand absorption bands instead of directly in the Er excited levels. This clearly indicates that sensitization of Er -centered luminescence occurs through ligand-to-metal energy transfer. For the doped monodispersed PMMA microparticles the lower lumi-... 

In general, all of the fundamental principles concerning spectral overlap, absorption strength, etc., that are critical to understanding the ligand to metal energy transfer process in the design of luminescent lanthanide complexes, also apply to the luminescence from chiral complexes. 

Mameri et al. developed acyclic ligand 51 containing bipyridine carboxylic moieties, which gave high stabihty and hydrophihcity of the lanthanide complex [131]. This formed luminescent 1 1 complexes with Eu " and Tb cations, where two water molecules located in the first coordination sphere of the lanthanide centers. The efficient ligand-to-metal energy transfer was ensured by the bipyridine photoantenna. Upon addition of ATP anion, the Eu luminescence intensity decreased to 20% of its initial value. Since the luminescence lifetime increased from 0.28 to 0.58 and 0.65 ms with the addition of 10 and 20 equivalents of ATP anion, the two boimd water molecules were replaced by the external ATP anion. In contrast, ADP, AMP, and NOs an-... 

FIAs fluoroimmunoassays en tr. ligand-to-metal energy-transfer... 

The efficiency of the ligand-to-metal energy transfer, hen.tr., can be obtained from the ratio between the quantum yield upon ligand excitation, (P, and the quantum yield upon... 

---