Application and recognition behaviors of TPA-cored probes with subtle structural change.

Two new triphenylamine-cored probes (L1, L2) with different receptor units have been synthesized and fully characterized by IR, NMR and MS spectra. Their photophysical properties have been investigated in detail. The recognition abilities of two probes were evaluated by a series of metal ions, which showed that L1 could recognize Cu(2+) over other metal ions. L2 could respond to Cu(2+), Hg(2+) in a short time, which interferes with a little each other. The Job's plot and (1)H NMR titration of L1 with Cu(2+) and L2 with Cu(2+) (Hg(2+)) in CD3CN verified the coordination mode of complexes L1-Cu(2+), L2-Cu(2+) and L2-Hg(2+), respectively. The limit of detection of L2 for Cu(2+) was lower than that of L1 towards Cu(2+). The results demonstrated that the receptor units in the probes had remarkable effect on recognizing metal ions. Meanwhile, L1 and L2 showed potential application in bio-imaging after mixing with Cu(2+).