Terbium emission

Ligands L33 and L34 are both good sensitizers of europium, whilst the former also efficiently sensitizes terbium emission (29). The quantum yield of [EuL34]3+ in aqueous solution, 0.247, is among the highest reported for any europium complex. The lower triplet energy of L34 results in back transfer of energy from the terbium excited state to... 

The excitation spectra of Nao.5Gdo.5WO4 singly and doubly doped with terbium and europium is shown in Fig. 42. One notes the appearance of terbium lines in the europium excitation spectrum in the doubly doped compound. The fact that there is essentially no terbium emission in this sample is also quite evident. 

A terbium complex (Figure 5.13) is a molecular logic gate corresponding to a two-input INHIBIT function the output (a terbium emission line) is observed only when the inputs , the presence of proteins and the absence of oxygen, are both satisfied. 

Fig. 17. Fluorescence emission spectra of DM-CCK (6 pM, 10 mM MOPS, pH 7.0, 30° C) in absence (curve a) and presence (curve b) of Tb3. Spectra were recorded with 284 nm exitation. Terbium emission was monitored at 549 nm.

With respect to luminescence, the most used lanthanides are europium and terbium. They have red (europium) and green (terbium) emissions. They are applied in additive color synthesis where all colors are reproduced by combinations of red, green and blue. Dysprosium (yellow) and samarium (orange) are also interesting for their luminescence, but the emissions are weaker than for europium and terbium. Other REEs exhibiting luminescence are thulium (red, blue, NIR), and praseodymium, but they have not been fully investigated (Andres and Chauvin 2012). 

The terbium complexes allow more flexibility in the choice of suitable acceptors and more particularly of multiple acceptors in the scope of multiplexing, since the terbium emission lines are more evenly disposed in the emission spectrum (compared to europium emission) displaying lines at 490, 545, 585, and 620 nm. Thus, either fluorescein, rhodamin, or indocyanines derived acceptors can be used, their respective emission falling in workable windows between successive emission lines or in the NIR window. Furthermore, green fluorescent protein (GFP) or GFP-like acceptors have been recently used to design assay involving a fusion protein substrate [17]. 

Figure 2 Stern-Volmer plot for the dependence of the terbium emission intensity in 4b upon the concentration of dissolved molecular oxygen 370, 545 nm, emission measured 0.1 ms...

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