Zinc Sensing via Enhancement of Two-Photon Excited Fluorescence

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• 作者：Ajit Bhaskar ; Guda Ramakrishna ; Robert J. Twieg ; Theodore Goodson ; III
• 刊名：Journal of Physical Chemistry C
• 出版年：2007
• 出版时间：October 11, 2007
• 年：2007
• 卷：111
• 期：40
• 页码：14607 - 14611
• 全文大小：178K
• 年卷期：v.111,no.40(October 11, 2007)
• ISSN：1932-7455

文摘

A branched chromophore tris[p-(4-pyridylethynyl)phenyl]amine (TPPA) with pyridine terminal groups isinvestigated for its ability to sense small quantities of Zinc ions via a two-photon excited fluorescence (TPEF)enhancement mechanism. Changes in the linear and nonlinear optical properties upon coordination with Zn²⁺have been studied using steady-state measurements, Two-photon absorption and femtosecond transientabsorption spectroscopy. An order of magnitude increase in the TPEF signal of the Zn-bound chromophorewas observed, thereby rendering our chromophore a "turn-on" sensor for Zn²⁺. The molecule was highlyselective toward Zn²⁺ and was able to detect Zn²⁺ at the ppm level. Transient absorption measurementsrevealed the excited-state dynamics and elucidated the reasons for the observed behavior of the TPPAchromophore. This study provides a guideline along which organic chromophores could be developed for"turn-on" metal ion sensing using multiphoton excitation.