A comparative study of two thienopyrimidine Schiff base probes for sequential monitoring of Ga and Pd.

Two Schiff base probes (S1 and S2) were prepared and synthesized by incorporating thienopyrimidine into salicylaldehyde or 3-ethoxysalicylaldehyde individually, with the aim of detecting Ga and Pd sequentially. Upon chelation with Ga, S1 and S2 exhibited fluorescence enhancement in DMSO/HO buffer. Both S1-Ga and S2-Ga were quenched by Pd. The limit of detection for S1 in response to Ga and Pd was 2.86 × 10 and 4.4 × 10 M, respectively. For S2, the limit of detection for Ga and Pd was 4.15 × 10 and 3.0 × 10 M, respectively. Furthermore, the complexation ratios of both S1 and S2 with Ga and Pd were determined to be 1:2 through Job's plots, ESI-MS analysis, and theoretical calculations. Two molecular logic gates were constructed, leveraging the response behaviors of S1 and S2. Moreover, the potential utility of S1 and S2 for monitoring Ga and Pd in domestic water was verified.