Issue 42, 2018

Luminescent Zn(ii) coordination polymers as efficient fluorescent sensors for highly sensitive detection of explosive nitroaromatics

Abstract

The hydro(solvo)thermal reactions of Zn(NO3)2·6H2O, N-(pyridin-3-yl)-4-(pyridin-4-yl)-1,8-naphthalimide (NI-bpy-34) and aromatic polycarboxylic acids afforded the corresponding zinc coordination polymers (CPs) [Zn2(1,4-bdc)(1,4-Hbdc)2(NI-bpy-34)2] (1, 1,4-H2bdc = benzene-1,4-dicarboxylic acid), [Zn2(2,6-ndc)(2,6-Hndc)2(NI-bpy-34)2]·H2O (2, 2,6-H2ndc = naphthalene-2,6-dicarboxylic acid), and [Zn(Hbtc)(NI-bpy-34)(H2O)]·H2O (3, H3btc = benzene-1,3,5-tricarboxylic acid). CP 1 features a 1D ladder structure with lateral arms which expands into a two-fold interweaved supramolecular 2D + 2D → 2D network through H-bonds. CP 2 adopts a complicated 2D thick-layer structure which expands into a 3D H-bonded (4,6)-connected net with a (4462)(44611) topology with three-fold interpenetration. CP 3 adopts a 2D grid-like (4,4)-layer structure. The three CPs all emit strong blue fluorescence in toluene suspension which is effectively turned off in the presence of a variety of electron-deficient aromatic nitro compounds. The quenching efficiencies and the Stern–Volmer quenching constants (Ksv) both indicate that 1,4-dinitrobenzene (79% quenching, Ksv = 2.11 × 103 M−1), 3-nitrophenol (95% quenching, Ksv = 1.61 × 104 M−1), and nitrobenzene (87% quenching, Ksv = 3.91 × 103 M−1) represent the highest quenching responses for CPs 1–3, respectively, for which the limits of detection were calculated to be 8.45 (1.42), 2.47 (0.34), and 5.14 (0.63) μM (ppm), respectively. Thus, CPs 1–3 can be used as promising fluorescence sensors for the highly selective and sensitive detection of aromatic nitro compounds. The mechanism of the quenching sensing of aromatic nitro compounds can mainly be explained by a photoinduced electron transfer process. On the other hand, through metal-ion exchange, the framework Zn2+ ions in CP 3 were partially substituted by Cu2+ ions by about 45% via single-crystal to single-crystal (SCSC) transformations. The resulting Cu2+-exchanged material 3-(Cu : Zn) displays decreased fluorescence emission due to paramagnetic fluorescence quenching caused by d9 configuration Cu2+ ions. Further, the exchange kinetics have been studied.

Graphical abstract: Luminescent Zn(ii) coordination polymers as efficient fluorescent sensors for highly sensitive detection of explosive nitroaromatics

Supplementary files

Article information

Article type
Paper
Submitted
14 Aug 2018
Accepted
24 Sep 2018
First published
24 Sep 2018

CrystEngComm, 2018,20, 6762-6774

Luminescent Zn(II) coordination polymers as efficient fluorescent sensors for highly sensitive detection of explosive nitroaromatics

M. Tsai, C. Li and J. Wu, CrystEngComm, 2018, 20, 6762 DOI: 10.1039/C8CE01371C

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