Transition metal ions fluorescent signaling

Fan L-J, Zhanga Y, Murphy CB, Angell SE, Parker MFL, Flynn BR, Jones WE Jr (2009) Fluorescent conjugated polymer molecular wire chemosensors for transition metal ion recognition and signaling. Coord Chem Rev 253 401 122... 

Just as the sulfur-based signaling systems have been successful at achieving clear fluorescence enhancements with intrinsically quenching transition metal ions since 1993, there is a growing body of literature on a parallel development with aliphatic amine-based compounds. Bharadwaj and coworkers... 

Once the importance of the nature of the spacer unit in the PET process was realized, it was natural to probe a few more systems with different spacer units to understand the effect of M-F and M-R communications on the PET process and their photophysical behavior. Thus, the systems shown in Fig. 33 were designed (129) with the aim to understand the PET process and its manipulation to create new fluorescent signaling systems for transition metal ions. An examination of Table VIII shows that the efficiency of the PET process in the metal-free state depends on the nature of spacer and the amount of fluorescence recovery varies not only with the metal ion but with the spacer as well. In the case of Lg, the fluorescence enhancement is negligible as the fluorophore can come close to the metal center through rotation of the ethylene bonds. In Lio, the fluorophore is integrated with the receptor and the enhancement is slightly higher only in case of Zn(II) ion as input. 

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