Issue 25, 2014

8-TQEN (N,N,N′,N′-tetrakis(8-quinolylmethyl)ethylenediamine) analogs as fluorescent cadmium sensors: strategies to enhance Cd2+-induced fluorescence and Cd2+/Zn2+ selectivity

Abstract

In order to exploit the untapped sensing potential of the TQEN (N,N,N′,N′-tetrakis(2-quinolylmethyl)ethylenediamine) family of fluorescent probes, 8-TQEN (N,N,N′,N′-tetrakis(8-quinolylmethyl)ethylenediamine) analogs were designed and characterized. Although 8-TQEN lacks practicality owing to poor solubility in both aqueous media and organic solvents, 6-MeO-8-TQEN (N,N,N′,N′-tetrakis(6-methoxy-8-quinolylmethyl)ethylenediamine, 1b) exhibits Cd2+-selective fluorescence enhancement at 395 nm in DMF–HEPES buffer (1 : 1), (ICd/I0 = 25, λex = 332 nm, ϕCd = 0.025). Zn2+ induces weaker fluorescence (IZn/I0 = 9, IZn/ICd = 0.35). In contrast, both the parent probes TQEN (IZn/I0 = 23, ICd/IZn = 0.64) and 6-MeOTQEN (IZn/I0 = 11, ICd/IZn = 1.29 exhibit higher sensitivity toward Zn2+. When the quinoline groups were replaced with 8-hydroxyquinoline different responses were observed. The propanediamine derivative, 8-TQOEPN (N,N,N′,N′-tetrakis(8-quinolyloxyethylene)propanediamine, 2c) exhibits significant fluorescence enhancement at 423 nm upon Cd2+ binding (λex = 325 nm, ICd/I0 = 19, ϕCd = 0.31). Fluorescence enhancement is Cd2+-specific as Zn2+ induces only more modest emission increases (IZn/I0 = 8.8, IZn/ICd = 0.45).

Graphical abstract: 8-TQEN (N,N,N′,N′-tetrakis(8-quinolylmethyl)ethylenediamine) analogs as fluorescent cadmium sensors: strategies to enhance Cd2+-induced fluorescence and Cd2+/Zn2+ selectivity

Supplementary files

Article information

Article type
Paper
Submitted
01 ⵉⵏⵏ 2014
Accepted
20 ⴱⵕⴰ 2014
First published
24 ⴱⵕⴰ 2014

RSC Adv., 2014,4, 12849-12856

8-TQEN (N,N,N′,N′-tetrakis(8-quinolylmethyl)ethylenediamine) analogs as fluorescent cadmium sensors: strategies to enhance Cd2+-induced fluorescence and Cd2+/Zn2+ selectivity

Y. Mikata, A. Takekoshi, A. Kizu, Y. Nodomi, M. Aoyama, K. Yasuda, S. Tamotsu, H. Konno and S. C. Burdette, RSC Adv., 2014, 4, 12849 DOI: 10.1039/C4RA00010B

To request permission to reproduce material from this article, please go to the Copyright Clearance Center request page.

If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given.

If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page.

Read more about how to correctly acknowledge RSC content.

Social activity

Spotlight

Advertisements