A porphyrin derivative containing 2-(oxymethyl)pyridine units showing unexpected ratiometric fluorescent recognition of Zn with high selectivity

• Published in: Analytica chimica acta Vol. 616; no. 2; pp. 214 - 221
• Main Authors: Li, Chun-Yan, Zhang, Xiao-Bing, Dong, Yan-Yan, Ma, Qiu-Juan, Han, Zhi-Xiang, Zhao, Yan, Shen, Guo-Li, Yu, Ru-Qin
• Format: Journal Article
• Language: English
• Published: 02.06.2008
• ISSN: 0003-2670
• DOI: 10.1016/j.aca.2008.04.024

A porphyrin derivative (1), containing two 2-(oxymethyl)pyridine units has been designed and synthesized as chemosensor for recognition of metal ions. Unlike many common porphyrin derivatives that show response to different heavy metal ions, compound 1 exhibits unexpected ratiometric fluorescence response to Zn2+ with high selectivity. The response of the novel chemosensor to zinc was based on the porphyrin metallation with cooperating effect of 2-(oxymethyl)pyridine units. The change of fluorescence of 1 was attributed to the formation of an inclusion complex between porphyrin ring and Zn2+ by 1:1 complex ratio (K = 1.04 X 105), which has been utilized as the basis of the fabrication of the Zn2+-sensitive fluorescent chemosensor. The analytical performance characteristics of the proposed Zn2+-sensitive chemosensor were investigated. The sensor can be applied to the quantification of Zn2+ with a linear range covering from 3.2 X 10-7 to 1.8 X 10-4 M and a detection limit of 5.5 X 10-8 M. The experiment results show that the response behavior of 1 to Zn2+ is pH-independent in medium condition (pH 4.0-8.0) and show excellent selectivity for Zn2+ over transition metal cations.