ABSTRACT
The next contribution from Munich has as its target the continuing need for fluorescent sensors for various heavy metals. Heavy atom effects, intramolecular charge transfer, and magnetic interactions can often lead to fluorescence quench ing in these situations. 16 [60] is capable of complexing over 25 metal ions. Nevertheless, some degree of selectivity can be achieved by varying pH, although no fluorescence can be observed at low pH values. Complexation of metal ions causes both a hypsochromic shift of emission and fluorescence quenching. The exception to this is the complexation of Cu2+, which produces a bathochromic shift in emission in addition to quenching.
