Highly selective and sensitive detection of metal ions and nitroaromatic compounds by an anionic europium(iii) coordination polymer

Abstract

A luminescent Eu(iii)-based coordination polymer, {[Eu(H2O)5(BTEC)][H(C5H6N2)]·3H2O} () has been synthesized under hydrothermal conditions using 1,2,4,5-benzenetetracarboxylic acid (H4BTEC) as a linker. Compound possesses an anionic zig-zag chain constructed from the BTEC ligands and [EuO4(H2O)5] nodes. The protonated 4-aminopyridine groups as guests are located between chains. exhibits the characteristic sharp emission bands of Eu(3+) at 578, 593, 615, 652 and 693 nm upon excitation at 290 nm. The strong emission of could be quenched effectively by trace amounts of Fe(3+) ions even in the presence of other metal ions including Al(3+), Ca(2+), Cd(2+), Co(2+), Cr(3+), Cu(2+), Fe(2+), K(+), Mg(2+), Mn(2+), Pd(2+) and Zn(2+). Similarly, also exhibits superior selectivity and sensitivity towards 4-nitrophenol (4-NP) compared with other competing interfering analytes, such as 2,4,6-trinitrophenol, 2,6-dinitrotolune, 4-nitrotoluene, nitrobenzene, 1,3-dinitrobenzene, o-xylene, nitromethane, nitropropane, phenol, 4-bromophenol and bromobenzene, through a fluorescence quenching mechanism. The possible fluorescence quenching mechanisms are discussed. Moreover, could be used as a visual fluorescent test paper for selectively detecting trace amounts of Fe(3+) and 4-NP.

Synthesis, Crystal Structures and Photoluminescent Properties of One-Dimensional Europium(III)- and Terbium(III)-Glutarate Coordination Polymers, and Their Applications for the Sensing of Fe3+ and Nitroaromatics

“…The Figures S12, S13 depict that the luminescence quenching efficiencies and concentration of Fe 3+ are in good agreement with linear proportion with R values of 0.9949 and 0.9734 for 1 and 2 , respectively. The detection limits for and 1 and 2 , estimated from the linear regression curves, were found to be 4.6565 × 10 −7 M and 1.612 × 10 −7 M, respectively, which is comparable with the reported terbium and europium coordination polymers for the detection of Fe 3+ (Bogale et al, 2016, 2017a,b; Gao et al, 2016). The Stern-Volmer equation I0I=(1+Ksv[Q]) was used; where I 0 and I are luminescence intensity before and after addition of quencher, respectively, Q is the quencher concentration and K sv is the quenching coefficient constant.…”

“…The Stern-Volmer equation I0I=(1+Ksv[Q]) was used; where I 0 and I are luminescence intensity before and after addition of quencher, respectively, Q is the quencher concentration and K sv is the quenching coefficient constant. The value of K sv was found to be 1.31 × 10 5 M −1 and (for 1 ) and 8.07 × 10 4 M −1 (for 2 ), which suggest that the static and dynamic quenching processes are dominant as revealed by the reported studies (Bogale et al, 2016, 2017a,b; Gao et al, 2016).…”

“…The fluorescence emissions of europium and terbium in different compounds have been reported for sensing metal ions (Zhao et al, 2004; Bogale et al, 2016, 2017a), nitro compounds (Bogale et al, 2016, 2017a), and solvent molecules (Li et al, 2013; Wang et al, 2014). The emission behavior of 1 and 2 were investigated in various solvents, such as methanol, ethanol, THF, DMSO, DMF, water, acetone, and dichloromethane.…”

“…From the large number of lanthanide coordination polymers, only some of them have been found active and explored for luminescence changes when brought in contact with some analyte or target molecules, possessing promising application as chemical sensors (Zhao et al, 2004; Zhang et al, 2010; Azab et al, 2013; Wang et al, 2014; Xiang et al, 2017). Thus, the optical properties of lanthanides are a beneficial tool to design new lanthanide based sensors, such as sensing of temperature (Miyata et al, 2013; Rao et al, 2013), cations (Zhao et al, 2004, 2014a; Chen et al, 2009; Zhang et al, 2010; Bogale et al, 2016, 2017a), anions (Wong et al, 2006; Tan and Wang, 2011) nitroaromatics (Bogale et al, 2016, 2017a) and small molecules (Zhou et al, 2013; Zhao et al, 2014b). Such developments also encouraged us to synthesize new lanthanide coordination polymers with characteristic properties to selectively recognize and sense the specific analyte.…”

Luminescent Properties of Lanthanoid-Poly(Sodium Acrylate) Composites: Insights on the Interaction Mechanism

“…The Cu 2+ paramagnetism contributes to the quenching of the fluorescence emission by increasing the intersystem crossing process [ 29 , 41 , 42 , 43 , 44 ]. The higher Tb 3+ /PSA sensitivity to Cu 2+ with respect to that of Eu 3+ /PSA could be partially due to the overlap between the absorption spectra of both Tb 3+ /PSA and Cu 2+ (spectra not shown), which is likely to significantly diminish Tb 3+ /PSA emission intensity [ 28 , 45 , 46 ]. In general, PSA plays an important role in the quenching process, due to its ability to coordinate Cu 2+ ions.…”