Issue 9, 2017

Pd2+ fluorescent sensors based on amino and imino derivatives of rhodamine and improvement of water solubility by the formation of inclusion complexes with β-cyclodextrin

Abstract

Mono- and bis-rhodamine derivatives appended with amino (RhB1) and imino (BRI) groups, respectively, have been designed as colorimetric and fluorescent sensors for the selective detection of Pd2+. In addition, an attempt has been made to improve the water solubility of the probe by synthesizing inclusion complexes of RhB1 with β-cyclodextrin as the host molecule. The resulting probe, RhB1-CD, exhibited exactly the same physicochemical phenomena as the guest molecule RhB1, indicating that complexation with β-CD improved the water solubility of RhB1 without affecting its sensing ability. With increasing concentrations of Pd2+, the absorption (556 nm) and emission (591 nm) intensities of BRI as well as the absorption intensities of RhB1/RhB1-CD (563 nm) increase, whereas the emission intensities of RhB1/RhB1-CD decrease due to fluorescence quenching. Therefore, BRI can act as an “OFF–ON” fluorescent probe switch in CH3CN/H2O (3 : 2 v/v) with a detection limit of 1 μM in solution, whereas RhB1 and RhB1-CD act as “ON–OFF” fluorescent probes in EtOH/H2O (1 : 1 v/v) and water, respectively, with a detection limit of 10 μM. All these probes exhibited high selectivity for Pd2+ and reversibility by treatment with Na2S. In the presence of commonly coexisting metal ions, such as Hg2+, Fe3+, Cu2+ and Al3+, BRI undergoes either catalytic Schiff base hydrolysis or it is unaffected by its affinity to the metal ions. However, Pd2+ can be effectively distinguished by a 12–15 nm bathochromic shift in its emission spectrum when compared with that of other metal ions. A Job's plot revealed that BRI forms 1 : 2 complexes by a spirolactam ring opening mechanism, whereas RhB1/RhB1-CD form 2 : 1 complexes by a ring opening mechanism followed by Pd2+-induced dimerization; the proposed binding mechanisms are presented.

Graphical abstract: Pd2+ fluorescent sensors based on amino and imino derivatives of rhodamine and improvement of water solubility by the formation of inclusion complexes with β-cyclodextrin

Supplementary files

Article information

Article type
Paper
Submitted
07 Dec 2016
Accepted
18 Mar 2017
First published
20 Mar 2017

Analyst, 2017,142, 1536-1544

Pd2+ fluorescent sensors based on amino and imino derivatives of rhodamine and improvement of water solubility by the formation of inclusion complexes with β-cyclodextrin

Y. Zhang, R. Balamurugan, J. Lin, S. Fitriyani, J. Liu and A. Emelyanenko, Analyst, 2017, 142, 1536 DOI: 10.1039/C6AN02594C

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