A novel nano‐size lanthanum metal–organic framework based on 5‐amino‐isophthalic acid and phenylenediamine: Photoluminescence study and sensing applications

Abstract

In this paper, a novel lanthanum metal–organic framework La‐MOF was prepared via hydrothermal and reflux methods. The La‐MOF was achieved through the reaction of a 5‐amino‐isophthalic acid with 1, 2‐phenylenediamine and lanthanum chloride. The prepared La‐MOF structure was confirmed by XRD, mass spectrometry, IR, UV–Vis and elemental analysis, whereas the size, and morphology was examined by FE‐SEM/EDX and HR‐TEM. The results indicated that the La‐MOF prepared via both methods have the same structure and composition. Meanwhile, the MOF yield, reaction time, morphology, physiochemical and sensing properties were highly depended on the used preparation method. The photoluminescence (PL) study was carried out for the La‐MOF, and the results showed that La‐MOF exhibits strong emission at 558 nm after excitation at 369 nm. Moreover, the PL data indicating that the La‐MOF has highly selective sensing properties for iron (III) competing with different metal ions. The Stern‐Völmer graph shows a linear calibration curve which achieved over a concentration range 1.0–500 μM of Fe3+ with a correlation coefficient, detection, and quantitation limits 0.998, 1.35 μM and 4.08 μM, respectively. According to the remarkable quenching of the PL intensity of La‐MOF using various concentrations of Fe3+, it was successfully used as a sensor for Fe3+detecting in different water resources (pure and waste) samples. The quenching mechanism was studied and it has a dynamic type and due to efficient energy transfer between the La‐MOF and Fe3+.

Promising photoluminescence optical approach for triiodothyronine hormone determination based on smart copper metal–organic framework nanoparticles

“…In offering system, Figure c reveals the standardized absorption, emission, and excitation spectra of Cu‐MOF‐NPs and T3 hormone. From this figure, it noted that there an overlap was observed between the absorption spectrum of quencher (T3) and the excitation, emission, and absorption spectrum of Cu‐MOF‐NPs this signifying of the probability of energy transfer may occur between Cu‐MOF‐NPs and T3 hormone . Moreover, the Cu‐MOF‐NPs acts as donor site and T3 acts as the acceptor site.…”

“…“Where C o is the critical concentration value of T3 hormone, R o is the critical radius (the distance between T3 and Cu‐MOF‐NPs)”. From the overhead calculations that the critical radius was 2.22 A°, this means that the quenching mechanism is an efficient energy transfer between the T3 hormone and Cu‐MOF‐NPs may take place …”

“…The calibration curve “linear correlation” was found between photoluminescence intensity of Cu‐MOF at λ em = 492 nm and concentration of the triiodothyronine hormone (T3) in the range given in 0.0 to 200 ng/dL. The linear correlation was achieved by using the Stern–Völmer equation ( 1 ) at λ em = 492 nm: [(F 0 /F)‐1] = K sv [Q] (1).…”

“…On other hand, coordination polymers (CP) and metal–organic frameworks (MOFs) are considered high research precedency in coordination chemistry and attracted more enormous interest because of their widely applications, fascinating structures and potentially valuable properties It's defined as high molecular weight molecules which designed by the repetition of monomeric units of linked metal ions with organic ligand(s) via coordination bonding . MOFs are hybrid substances have a broad variety of physical and chemical properties like; porosity, photoluminescence, sensing, catalysis, magnetism and conductivity in addition to a lot of technical applications were reported . Accordingly, the multifunctional organic ligands with definite functional groups, like carboxylate, phosphate, and pyridyl, are very important and have been broadly explored, due to they have shown a good building block in the synthesis of MOFs.…”

“…[18,19] MOFs are hybrid substances have a broad variety of physical and chemical properties like; porosity, photoluminescence, sensing, catalysis, magnetism and conductivity in addition to a lot of technical applications were reported. [20][21][22] Accordingly, the multifunctional organic ligands with definite functional groups, like carboxylate, phosphate, and pyridyl, are very important and have been broadly explored, due to they have shown a good building block in the synthesis of MOFs. 5aminoisophthalic acid (AIP), a well-known multipurpose ligand, has been broad uses in the design of the MOFs and polymeric complexes because of its different coordination sites to metal ions and also due to its ability to act as Hbond donor and acceptor.…”