The structural properties of 5-methyl-2-phenyl-2H-1,2,3-triazole-4- carboxylic acid and chromogenic mechanism on its rhodamine B derivatives to Hg2+ ions

Jianling Li; Guohua Ding; Yanyan Niu; Luyong Wu; Huajie Feng; Wenying He

doi:10.1016/j.saa.2018.04.009

The structural properties of 5-methyl-2-phenyl-2H-1,2,3-triazole-4- carboxylic acid and chromogenic mechanism on its rhodamine B derivatives to Hg²⁺ ions

Spectrochim Acta A Mol Biomol Spectrosc. 2018 Jul 5:200:127-135. doi: 10.1016/j.saa.2018.04.009. Epub 2018 Apr 11.

Authors

Jianling Li¹, Guohua Ding¹, Yanyan Niu¹, Luyong Wu², Huajie Feng³, Wenying He⁴

Affiliations

¹ College of Chemistry and Chemical Engineering, Hainan Normal University, Haikou 571158, China.
² Key Laboratory of Tropical Medicinal Plant Chemistry of Ministry of Education, Haikou 571158, China.
³ College of Chemistry and Chemical Engineering, Hainan Normal University, Haikou 571158, China. Electronic address: 110204286@qq.com.
⁴ Key Laboratory of Tropical Medicinal Plant Chemistry of Ministry of Education, Haikou 571158, China. Electronic address: hewenying@hainnu.edu.cn.

PMID: 29677499
DOI: 10.1016/j.saa.2018.04.009

Abstract

5-Methyl-2-phenyl-2H-1,2,3-triazole-4-carboxylic acid (MPTC), a newly synthesized compound, was explored to study the structural properties and theoretical spectra by using GaussView5.0 program package and the time dependent density functional theory (TD DFT). The calculated quantum chemical values suggested that it is easy for MPTC to lose electron with weak electron accepting ability. And the results of experimental measurements on fluorescence and absorption spectra were consistent with that of the calculated spectra in great degree. In addition, MPTC was successfully used and synthesized a novel rhodamine B derivative RMPTC containing 1,2,3-triazole unit. It is found that there is special chromogenic response of RMPTC to Hg²⁺ ions in N, N-dimethylformamide (DMF)-H₂O (v/v=1/1, Tris-HCl, pH7.4) with the triazole appended colorless chemosensor turned to pink and enabled naked-eye detection. The fluorescence signal for RMPTC-Hg²⁺ system was not affected by other coexisting metal ions. The 1:2 stoichiometric structure of RMPTC and Hg²⁺ is confirmed using a Job's plot estimation and TD DFT calculations. The corresponding "off-on" fluorescence mechanism of RMPTC binding to Hg²⁺ which were ascribed to Hg²⁺ inducing the ring-opened rhodamine B moiety were proposed. This study was an advancement for the application of 1,2,3-triazole compound in photophysical chemistry field and provides guidance for exploring simple and high-selectivity Hg²⁺ probes in aqueous solutions under physiological conditions.

Keywords: 5-Methyl-2-phenyl-2H-1,2,3-triazole-4-carboxylic acid; Chromogenic mechanism; Hg(2+) ion; Rhodamine B; Structural properties; Synthesis.