Concentration-Independent Ph Detection with a Luminescent Dimetallic Eu(Ⅲ)-Based Probe

摘要

A pH-responsive, luminescent, dimetallic Eu(Ⅲ)-containing complex has been synthesized and exhibits a unique mechanism of response. The luminescence-decay rate of the complex is slow, due to a lack of water molecules coordinated to the Eu(Ⅲ) ions. However, the luminescence-decay rate decreases with increasing pH over a biologically relevant range of 4-8. Physical characterization and computational analysis suggest that the pH response is due to protonation of a bridging alkoxide at lower pH values. Modulation of the luminescence-decay rate is independent from the concentration of Eu(Ⅲ), which we expect to be useful in the non-invasive imaging of in vivo pH.