N,N-di(2-pyridylmethyl)amino-modified porphyrinato zinc complexes. The "ON-OFF" fluorescence sensor for Fe3+.

Two porphyrinato-zinc derivatives modified with two and four N,N-di(2-pyridylmethyl)amino groups, namely Zn-Porphyrin-2-DPA (1) and Zn-Porphyrin-4-DPA (2), have been designed, synthesized, and characterized. Systemic studies over a series of metal ions reveal that binding with Fe(3+) for the former compound induces the decrease of fluorescence emission intensity by 37.2%, while for the latter one results in a more remarkable decrease in the fluorescence emission intensity by 90.3%, rendering compound 2 the first example of DPA-modified porphyrin fluorescence ON-OFF sensor for Fe(3+).