Lumophore-receptor systems

There have also been some recent developments which promise interesting offshoots. Ca -sensitive 66 has the tried-and-tested features of 65 along with a new twist. The Ca -induced conformational change alters the lumophore structure from resembling a rhodamine to a fluorescein lookalike. Not only does 66 maintain 

The positive electrostatic charge of Ru(II) polypyridyl complexes has been combined with hydrogen-bond donating primary carboxamide groups in Beer s 68 to yield anion-sensitive luminescent systems. Structural variations have allowed strong biasing of Cr/HjPO selectivity in either direction. Macrocyclic 69 also raises interesting questions about PET/EET processes (Section 13) across 

The vibrancy of integrated systems, as illustrated by these diverse examples, serves as a counterpoint to the more overtly supramolecular systems under discussion in this review. 

Section 13) and 64 is successful for Na+.162 All this notwithstanding, several integrated lumophore-receptor systems, e.g. 65,91 have been persuaded to act as cation sensors in physiology with respect to their excitation spectra. The influence of these sensors have been immense and Tsien has been a pioneer in this general area.90,12,163 

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Lumophore-receptor systems where the two components are sterically held orthogonal can be considered to have a virtual Co spacer between the lumophore and receptor. Thus these systems can be approximately considered as a PET system. A deeper analysis would take twisted intramolecular charge transfer (TICT) states [116] into account whose thermodynamics is, unsurprisingly, very similar to that of PET systems. 

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