Al3+ enhanced room temperature phosphorescence of Pd-porphyrin resided in hybrid supramolecular gels and used for detection of trace Hg2+ ions

Ruru Xue; Lu Feng; Saisai Wei; Xuelin Dong; Qin Wang; Yajiang Yang; Yonggui Liao; Hong Wang

doi:10.1016/j.talanta.2018.10.018

Al³⁺ enhanced room temperature phosphorescence of Pd-porphyrin resided in hybrid supramolecular gels and used for detection of trace Hg²⁺ ions

Talanta. 2019 Mar 1:194:183-188. doi: 10.1016/j.talanta.2018.10.018. Epub 2018 Oct 12.

Authors

Ruru Xue¹, Lu Feng¹, Saisai Wei¹, Xuelin Dong², Qin Wang¹, Yajiang Yang¹, Yonggui Liao¹, Hong Wang³

Affiliations

¹ Key Laboratory of Materials Chemistry for Energy Conversion and Storage of the Ministry of Education, School of Chemistry and Chemical Engineering, Huazhong University of Science and Technology, Wuhan 430074, China.
² Key Laboratory of Rare Mineral Exploration and Utilization, Ministry of Land and Resources, Geological Experimental Testing Center of Hubei Province, Wuhan 430034, China.
³ Key Laboratory of Materials Chemistry for Energy Conversion and Storage of the Ministry of Education, School of Chemistry and Chemical Engineering, Huazhong University of Science and Technology, Wuhan 430074, China. Electronic address: hongwzy@hust.edu.cn.

PMID: 30609520
DOI: 10.1016/j.talanta.2018.10.018

Abstract

Micelle-hybridized supramolecular hydrogels were constructed through the self-assembly of gelator N,N-dibenzoyl-L-cystine (DBC) and micelles formed from a Gemini surfactant (G_12-8-12). A phosphor, palladium meso-tetra (4-carboxyphenyl) porphyrin (Pd-TCPP) and Al³⁺ ions were loaded within the hybrid system. Interestingly, the room temperature phosphorescence (RTP) of Pd-TCPP can be efficiently enhanced and modulated by the concentration of Al³⁺ ions. The enhancement effect could be attributed to the interactions between Al³⁺ and DBC as well as porphyrin, which verified by ¹H NMR analysis. The study of transmission electron microscopy and scanning electron microscopy indicated that a more compact 3D network structure of the gel system was formed upon the addition of Al³⁺. In addition, measurement of critical micelle concentration indicated that Al³⁺ ions increase the surface activity of G_12-8-12 to promote micelle formation, thereby increasing the dispersion of Pd-TCPP in the hybrid gels. Based on the synergistic effect of these results, the non-radiative transition of Pd-TCPP was efficiently inhibited, resulting in highly efficient RTP. Furthermore, the enhanced RTP of as-prepared gel system shows potential application to detect trace Hg²⁺ ions because the RTP can be quenched by Hg²⁺. A linear relationship between RTP against the logarithmic concentration of Hg²⁺ was found over the range of 6 × 10^-8 and 1 × 10^-6 mol/L. The detection limit was found to be 0.017 nmol/L.

Keywords: Aluminum ions; Hybridized supramolecular gels; Pd-porphyrin; Room temperature phosphorescence; Trace mercury ions.