Supramolecular Dimer as High-Performance pH Probe: Study on the Fluorescence Properties of Halogenated Ligands in Rigid Schiff Base Complex
The development of high-performance fluorescence probes has been an active area of research. In the present work, two new pH sensors <i>Zn-3,5-Cl-saldmpn</i> and <i>Zn-3,5-Br-saldmpn</i> based on a halogenated Schiff ligand (<i>3,5-Cl-saldmpn</i> = N, N<inline-...
| Main Authors: | , , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
MDPI AG
2023-05-01
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| Series: | International Journal of Molecular Sciences |
| Subjects: | |
| Online Access: | https://www.mdpi.com/1422-0067/24/11/9480 |
| Summary: | The development of high-performance fluorescence probes has been an active area of research. In the present work, two new pH sensors <i>Zn-3,5-Cl-saldmpn</i> and <i>Zn-3,5-Br-saldmpn</i> based on a halogenated Schiff ligand (<i>3,5-Cl-saldmpn</i> = N, N<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msup><mrow></mrow><mo>′</mo></msup></semantics></math></inline-formula>-(3,3<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msup><mrow></mrow><mo>′</mo></msup></semantics></math></inline-formula>-dipropyhnethylamine) bis (3,5-chlorosalicylidene)) with linearity and a high signal-to-noise ratio were developed. Analyses revealed an exponential intensification in their fluorescence emission and a discernible chromatic shift upon pH increase from 5.0 to 7.0. The sensors could retain over 95% of their initial signal amplitude after 20 operational cycles, demonstrating excellent stability and reversibility. To elucidate their unique fluorescence response, a non-halogenated analog was introduced for comparison. The structural and optical characterization suggested that the introduction of halogen atoms can create additional interaction pathways between adjacent molecules and enhance the strength of the interaction, which not only improves the signal-to-noise ratio but also forms a long-range interaction process in the formation of the aggregation state, thus enhancing the response range. Meanwhile, the above proposed mechanism was also verified by theoretical calculations. |
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| ISSN: | 1661-6596 1422-0067 |