Oligofluorene Antennae for Luminescent Lanthanide Cations: Synthesis and Characterization
Lanthanide complexes emit as sharp emission bands, have long luminescence lifetimes for temporal discrimination from background fluorescence and strong resistance to photobleaching. These attractive properties make lanthanide compounds potentially applicable in a variety of devices, including optical displays and sensors. However, luminescent lanthanide cations weakly absorb light, and require proximal chromophores to absorb excitation light. Energy is subsequently transferred to the lanthanide cations, resulting in the sensitization of their emission.
Usually, the energy levels in a given chromophore are fixed and cannot be adjusted. In this thesis, oligofluorene ligands, comprised of either one (mono) or three (ter) fluorene units in the backbone, exhibited a tunable nature of their electronic levels directly controlled by the number of fluorene units. By varying the length of the fluorene backbone in these ligands, the donating level(s) of the chromophore was (were) discretely tuned to the accepting level(s) of a particular lanthanide (Eu and Tb). Furthermore, the lanthanide cation was coordinated to a cage-like polyaminocarboxylate moiety within the ligand, which protected the cation from non-radiative deactivation. Matching the energies of the donating electronic states of an oligofluorene ligand with the appropriate accepting levels of a lanthanide cation lead to efficient oligofluorene to lanthanide energy transfer with quantum yields of 7%, such as in the TF1:Eu3+ complex. The efficiency in these novel lanthanide complexes is comparable to established lanthanide compounds used today in fluoroimmunoassays.
Advisor:Alexander Star; Stephane Petoud; Tara Y. Meyer
School:University of Pittsburgh
School Location:USA - Pennsylvania
Source Type:Master's Thesis
Date of Publication:09/19/2007