This journal is © The Royal Society of Chemistry and the Centre National de la Recherche Scientifique 2016 New J. Chem., 2016, 40, 8053--8059 | 8053
Cite this: New J. Chem., 2016, 40, 8053
Synthesis of a novel, fluorescent, electroactive
and metal ion sensitive thienylpyrrole derivate
Rukiye Ayranci and Metin Ak*In this study, a novel, fluorescent, metal ion sensitive monomer called (E)-4-(2,5-di(thiophen-2-yl)-1H-pyrrol-1-yl)-N-(pyren-1-ylmethylene)aniline (PR–SNS) was synthesized. Good fluorescence properties for PR–SNS were successfully achieved, which emits blue. Furthermore, PR–SNS shows sensitive fluorescence changes when interacting with metal ions. The electrochemical properties of P(PR–SNS) were studied via spectroelectrochemistry, kinetic studies, and colorimetry measurements. The novel PR–SNS or its polymer might be a good candidate for the selective sensing of metal ions via smart florescent and electrochemical features.
1. Introduction
The synthesis and application of electroactive conjugated poly-mers have attracted a great deal of attention because of their widespread use such as in organic photovoltaics,1charge storage,2
electrochromics3–7 sensors8–10 and solar cells.11 Nowadays,
fluorescent conducting polymers have been studied for a large number of applications such as fluorescent polarizers,12 light-emitting diodes,13,14and chemical biosensors.15,16Fluorescent conducting polymers have considerably responded to inter-action with analytes, such as biomolecules, toxins and metal ions, due to the fact that fluorescent sensing probes have unique sensing capability.17,18
Pyrene derivatives have a high fluorescence quantum yield. They can be selective to specific analytes and their emission wavelengths are observed in the visible region.19There are many reports on pyrene based structures that investigate their fluori-metric features or used as metal-ion sensors.20–22
Schiff bases are one of the most popular classes of organic compounds which are derived from an amino and carbonyl compound. Schiff bases play a significant role as chelating ligands, which coordinate to metal ions via the azomethine nitrogen due to their flexible nature and easy proton donating property.23Besides, since Schiff bases allow geometric and cavity control of host–guest complexation, they have shown exceptional selectivity, sensitivity and stability for a specific ion.24
Furthermore, the study of conjugated Schiff bases has flourished in the last few decades due to their interesting optoelectronic properties. Their simple and clean chemistry make them promising candidates as low cost alternatives to the currently used conjugated materials.25,26
In previous papers our research group have reported the synthesis and application of 2,5-di(2-thienyl)pyrrole (SNS) derivate conjugated polymers.27–30According to our studies, the important requirement in designing molecules for fluorescent conjugated monomers is that the polymerizable electroactive group must react with the florescent group. The synthesis of thienylpyrrole derivate Schiff base electroactive monomers and their electrochemical properties have not been studied as yet to the best of our knowledge.
Herein, to achieve a polymerizable, electrochromic conducting polymer, we synthesize a novel monomer in which 1-pyrene-carboxaldehyde (PR) is incorporated in 4-(2,5-di(thiophen-2-yl)-1H-pyrrol-1-yl)aniline (SNS) via a Schiff base reaction. The monomer PR–SNS is characterized via elemental analyses,1H-NMR and FTIR. Also, metal ion selectivity is obtained via pyrene modified Schiff base based PR–SNS by fluoresce changing. For this purpose, the metal ions, Cd2+, Zn2+, Hg2+, Cu2+ and Fe3+ were activated to interact with PR–SNS. In the presence of Hg2+, the PR–SNS solution showed a strong florescent emission intensity compared with other metals which quenched the fluorescence of PR–SNS through an electron transfer mechanism. After characterization and determi-nation of the sensing features of the PR–SNS monomer, P(PR–SNS) was synthesized via the potentiodynamic technique and character-ized via SEM, cyclic voltammetry and spectroelectrochemistry. Subsequently, the electrochromic properties of the corresponding polymer were investigated. Preliminary results demonstrate that this monomer can be used for sensor applications, and also its polymer can be used electrochromic applications.
2. Experimental
2.1. Chemicals and methods
Thiophene, succinyl chloride, aluminum chloride, toluene, hydro-chloric acid, sodium bicarbonate, magnesium sulphate (anhydrous),
Pamukkale University, Faculty of Art and Science, Chemistry Department, Denizli, Turkey. E-mail: metinak@pau.edu.tr
Received (in Montpellier, France) 27th June 2016, Accepted 25th July 2016 DOI: 10.1039/c6nj02006b www.rsc.org/njc
