Sensitive Luminescent Sensor Research Articles

Structures and Luminescent Sensing Properties of Terbium Metal–Organic Frameworks with Methyl-Decorated Phenanthroline Ligand

Two new Tb(III) metal–organic frameworks based on 4,7-dimethylphenanthroline (dmphen) and flexible ligand trans-1,4-cyclohexanedicarboxylate (chdc2−) were synthesized and characterized. Their crystallographic formulae are [Tb2(dmphen)2(H2O)2(chdc)3]·2DMF (1; DMF = N,N-dimethylformamide) and [Tb2(dmphen)2(NO3)2(chdc)2]·2DMF (2). Among some differences in their synthetic conditions, the most important one is apparently the using of terbium(III) nitrate instead of terbium(III) chloride as a metal precursor in the synthesis of 2, providing a nitrate coordination to Tb3+, and its subsequent notable structural differences to 1. Compound 1 was found to have a layered hcb structure with intralayer windows ca. 10 × 8 Å2 in size. Its layer-to-layer packing leaves narrow channels running across these windows, with 18% as a total solvent-accessible volume in the coordination structure. Compound 2 was found to have a layered sql structure with smaller intralayer windows of ca. 8 × 6 Å2 in size. Methyl substituents on the phen ligands do not affect the topology of the framework but seem to have a substantial effect on the packing density, as well as the pore volume of the resulting MOF. A high 18.4% luminescence quantum yield was found for 2. Its emission lifetime of 0.695(12) ms belongs to a typical range for phosphorescent Tb(III)-carboxylate complexes. A quenching of its emission by different nitroaromatic molecules was found. A linear concentration dependence on 3-nitrotoluene and 4-nitro-m-xylene at micromolar concentrations was found during luminescent titration experiments (LOD values ca. 350 nM), suggesting this MOF to be a viable and highly sensitive luminescent sensor for such substrates.

Fabrication of two 3D Ln-MOFs as highly sensitive luminescent sensors for Fe3+ and Cr3+ ions

Two new isostructural lanthanide(III)−metal organic frameworks (Ln-MOFs), namely [Ln2(FDA)3(TMS)2(H2O)2]·H2O (Ln = Eu 1 and Tb 2, H2FDA = 2,5-furandicarboxylic acid, TMS = tetramethylene sulfone), have been synthesized and characterized. Single-crystal X-ray diffraction analysis reveals that both Ln-MOFs exhibit three-dimensional structures crystallizing in the monoclinic C2/c space group. Luminescent sensing studies indicate that 1 and 2 possess commendable capabilities for detecting Fe3+ and Cr3+, with low detection limits of 20.00 nM and 43.41 nM for 1 and 66.10 nM and 0.37 μM for 2, respectively. Furthermore, the investigation into the mechanism revealed the quenching of Fe3+ can be ascribed to the dual effects of inner filter effect (IFE) and the static quenching. Conversely, the dynamic quenching mechanism has played a predominant role during the sensing process of Cr3+.

Practicality and Compatibility of Cd(II) Coordination Polymer as Luminescent Sensor in Selective and Sensitive Detection of 3‐Nitrotyrosine Biomarker

AbstractBased on the mixed ligands of 1,4‐bis(2,4,6‐tricarboxylpyrid‐5‐yl)benzene (H6BTPB) and 1,4‐bis(imidazol‐1‐yl)benzene (bib), a new cadmium(II) coordination polymer with the molecular formula of {[Cd(bib)(μ2‐H2O)(H2O)2](H4BTPB)0.5(bib)0.5}n (CdCP) was constructed under solvothermal condition, and displayed a 3D supramolecular structure expanded by the hydrogen bonds between the 1D [Cd(bib)(μ2‐H2O)(H2O)2]n ladder chain and the guests. Profiting from its superior stability and inherent luminescence, the prepared CdCP dispalyed great potential as a highly sensitive and selective luminescent sensor in trace detection of 3‐NT biomarker in both water and real bodily fluids through the luminescence quenching effects, with the Ksv and LODs being 2.408×105 M−1 and 30.3 nM in water, 2.230×105 M−1 and 44.7 nM in diluted urine, 2.249×105 M−1 and 43.9 nM in diluted serum, respectively. Subsequent mechanism studies indicated the synergistic effect of internal filtering effect, photo‐induced electron transfer, and fluorescence resonance energy transfer determining the luminescence quenching response of CdCP towards 3‐NT biomarker.

2D Zn (II) Metal‐Organic Framework as a Highly Sensitive Luminescent Sensor for Detection of the Cr2O72− and Fe3+

AbstractIn this work, NH2‐containing organic ligand 5‐Aminoisophthalic acid (AIPA), and trans‐1,2‐bis(4‐pyridyl)ethene (bpe) were selected as organic ligands to construct a new two‐dimensional luminescent Zn(II) metal‐organic framework [Zn(AIPA)(bpe)1/2]⋅named MOF‐1. It is worth noting that MOF‐1 exhibited excellent thermal stability and chemical stability in common solvents and different pH aqueous solution. As we expected, the luminescence sensing investigations demonstrated that MOF‐1 could be deemed as a multifunctional fluorescence sensor toward Cr2O72− and Fe3+ via a “turn‐off” effect. Notably, MOF‐1 had high selectivity and sensitivity for Fe3+ and Cr2O72− with low detection limits of 9.72×10−5 M and 1.95×10−5 M, respectively. Furthermore, the possible quenching mechanisms were also explored in detail.

Luminescent lanthanide-containing gelatin/polydextran/laponite nanocomposite double-network hydrogels for processing and sensing applications

Lanthanide-containing nanomaterials have gained significant popularity for their utilization in polymeric networks, enabling the creation of luminescent nanocomposites for advanced applications. In this study, we developed a new type of lanthanide-containing nanocomposite hydrogels by incorporating terbium-containing laponite (Tb3+@Lap) into the networks of polyethyleneimine-modified gelatin/polydextran aldehyde (PG/PDA) through dynamic bonds. The structures and properties of the Tb3+@Lap-containing nanocomposite double-network (ncDN) hydrogels were comprehensively investigated in comparison with the DN hydrogels with a pure polymeric network and the Lap-containing ncDN hydrogels. The PG/PDA/Tb3+@Lap ncDN hydrogels with multiple dynamic bonds (i.e., imine bonds, coordination bonds, hydrogen bonds, and electrostatic interactions) exhibited remarkable characteristics of shear-thinning and self-healing, making them suitable for the construction of hydrogel scaffolds on a macroscale using fabrication techniques such as electrospinning and 3D printing. Moreover, the PG/PDA/Tb3+@Lap ncDN hydrogels have been demonstrated to act as sensitive and selective luminescent sensors for detecting copper ions. Taken together, a versatile lanthanide-containing ncDN hydrogel platform capable of dynamic features is developed for processing and sensing applications.

Synthetic Control of Thorium Metal‐Organic Frameworks for Sequencing and Sensing of Radioiodine Species

Comprehensive SummaryExploring the physiochemical properties and expanding the applications of actinide‐containing materials is paramount to address the escalating challenge of radioactive waste accumulation. However, unlocking the full potential of these materials is largely crippled by the radiotoxicity of the actinides. We report here two porous and luminescent thorium‐based metal‐organic frameworks (Th‐BITD‐1 and Th‐BITD‐2) that serve as a bifunctional platform for sequencing and sensing of radioiodine, a much more radioactive fission product discharged during the nuclear fuel reprocessing. In particular, Th‐BITD‐1 displays better iodine uptake performance than Th‐BITD‐2 via the solution‐based process and vapor diffusion with the maximum adsorption capacities of 831 and 1099 mg/g, respectively. Furthermore, Th‐BITD‐1 can function as a highly sensitive luminescence sensor for iodate with a quenching constant (KSV) of 6.6(5) × 103 M−1 and a detection limit of 2.02 μM, respectively, outperforming 2.96(6) × 103 M−1 and 10.5 μM of Th‐BITD‐2. Moreover, a positive correlation between the sensing efficacy and the iodate adsorption capacity has been revealed. This work highlights the opportunity in designing novel actinide‐based MOFs for their potential applications in radiological fields, e.g., radionuclide separation and detection.

Amino acid and acetone fluorescence sensors based on a stable light-emitting Cd(II) metal-organic framework with derivatives of isonicotinic acid

As one of the most promising category of functional materials, luminescent metal–organic frameworks (LMOFs) have been widely investigated as fluorescence chemical sensors which can offer a reliable diagnostic tools in biomedical research. Herein, a luminescent Cd-MOF [Cd2(L)2(H2O)]n (Cd-MOF) (H2L = 3-(3-carboxylphenyl) isonicotinic acid), was synthesized by and characterized in detail. Single-crystal structure determination reveals that Cd-MOF crystalizes in the monoclinic crystal system with C2/c space group. Experimental results show that Cd-MOF is a highly selective and sensitive luminescent sensor for rapidly detecting acetone, l-Tryptophane (L-Trp) and l- Aspartic acid (L-Asp) in water. It can significantly test acetone in common solvents, selectively identify l-Trp-and l-Asp-in 12 amino acid aqueous solutions, and enhance the fluorescence signal of Tryptophan and quench l-Asp-with the detection limit of 17.6 μM and 68.8 μM respectively. However, upon the interaction with electron rich amino acid (L-Trp), the Cd-MOF shows the selective “Turn-On” behavior, which may also be supported by the DFT studies.

A 2D mixed-lanthanide metal‒organic framework as dual-emitting luminescent sensor for ratiometric detection of tetracycline and nitrophenols

Solvothermal treatment of Gd(III)/Eu(III) salts with 2,3,5,6-tetrachloroterephthalic acid (H2tClbdc) and 1,10-phenanthroline (phen) afforded three two-dimensional lanthanide metal‒organic frameworks (MOFs), [Ln(tClbdc)(phen)(H2O)(NO3)]n (1-Ln, Ln = Gd, Eu, Eu0.03Gd0.97). The dual-emitting characteristic along with the excellent solution and photophysical stability of the mixed-lanthanide MOF 1-Eu0.03Gd0.97 make it a highly sensitive luminescent sensor to ratiometrically detect tetracycline (TC), picric acid (PA) and 4-nitrophenol (4-NP), with the limits of detection of 0.38 μM, 0.75 μM and 1.49 μM for TC, PA and 4-NP, respectively. The significant luminescence quenching of the lanthanide-based sensor by these organic pollutants might be ascribed to inner filtration effect (IFE), fluorescence resonance energy transfer (FRET) and hydrogen-bonding and/or electrostatic interactions between the sensor and phenolic analytes. More significantly, 1-Eu0.03Gd0.97 filled mixed-matrix membranes could be employed as an easy-to-use sensory tool for visual recognition of TC by the turn-off red emission signal.

A cobalt-coordination polymer as a highly selective and sensitive luminescent sensor for detecting 2,4,6-trinitrophenol

In this paper, a new three-dimensional network coordination polymer {[Co(TPTC)(HBPDPE)2·2H2O]·3H2O} n [[[(1:1′:4′,1″-terphenyl)-3,3″,5,5″-tetracarboxylic cobalt (II)] dipyridine dihydrate] trihydrate] (Complex 1) was generated under solvothermal synthesis by rigid conjugated ligand H4TPTC ([1:1′:4′,1″-terphengl]-3,3″,5,5″-tetracarboxylic), V-shaped BPDPE (4,4′-bis (pyridyl) diphenyl ether) and Co(II) ion. In complex 1, the neighboring Co(II) ions are linked by deprotonated TPTC4- to achieve a 1D zigzag chain [Co(TPTC)(HBPDPE)2] n , then the adjacent [Co(TPTC)(HBPDPE)2] n chains linked each other by various H-bondings to extend the structure from 1D chain to 3D network. Complex 1 has excellent fluorescence sensing performance and exhibits high sensitivity and selectivity for detecting 2,4,6-trinitrophenol (TNP), the quenching constant K sv is up to 2.08 × 105 M−1 along with the correlation coefficient R 2 of 0.993. Furthermore, the quench mechanisms of this Co-MOF as a sensor to detect nitro- aromatic explosives were studied as well.

Colloidal suspensions of totally inorganic perovskites nanoparticles: A new photoluminescent emission in the near-IR

Luminescent materials have attracted great attention due to the amazing applications. In this sense, perovskite halide materials have shown promising luminescent properties which allows them to be useful in various applications such as LEDs, sensors. In this work, colloidal suspensions of CsPbI3 and Pd-doped CsPbI3 perovskite nanoparticles were prepared at different temperatures, and their structure and luminescence properties were characterized to analyse the effect of the synthesis temperature and the Pd-doping. With the increase of temperature, the main photoluminescence band of perovskite nanoparticles are slightly red-shifted. But the most amazing result is that the Pd-doped CsPbI3 shows a new emission band at 877 nm under excitation at 785 nm. Therefore, this compound may be used as a highly sensitive luminescent sensor in several applications, such as in biosystems due to their emission in the first biological window under NIR excitation.

New 3D Cd (II) metal-organic framework as a highly sensitive luminescent sensor for detection of the 4-nitrophenol and nitrofuran antibiotics

The overused of nitroaromatic explosives and antibiotics had led to severe environment and health issues. The detection on nitroaromatic explosives and antibiotics with high selective and sensitive is pressing need. Herein, a new cadmium-based metal–organic framework (MOF), namely {[(CH3)2NH2]2[Cd3(TCPPDA)2]·5DMF·8H2O}nMOF-1 (H4TCPPDA = N,N,N’,N’-Tetrakis(4-carboxyphenyl)-1,4-phenylenediamine) had been successfully synthesized and characterized. Single crystal X-ray diffraction analysis displayed that MOF-1 possesses 3D (4,8)-connected framework with the Schläfli symbol of {42.6}2{44.62.87.102} comprising trinuclear [Cd3(COO)8] SBUs. The detection ability of MOF-1 toward nitroaromatic explosives and antibiotics were evaluated. Notably, MOF-1 had high selectivity and sensitivity for 4-Nitrophenol (4-NP) and nitrofuran antibiotics (nitrofurazone, NFZ, nitrofurantoin, NFT) with low detection limits of 7.5, 1.39 and 1.23 μM. Furthermore, the possible quenching mechanisms were also explored by calculations and experiments.

Sensitive ratiometric sensor for Al(III) detection in water samples using luminescence or eye-vision

A facile, quick, and sensitive ratiometric luminescence sensor is designed for detection aluminum ions in water samples using luminescence or eye-vision. This approach relies on the emission change of the europium(III) complex with 3-(2-naphthoyl)-1,1,1,-trifluoro acetone (3-NTA) after interaction with various concentration of aluminum ions. The addition of aluminum ions suppressed the Eu(III) emission at 615 nm under 333 nm excitation, while simultaneously enhancing the ligand emission at 480 nm. Optimum detection was obtained in methanol. The quantification of aluminum ions using ratiometric method was determined by plotting the luminescence ratio (F480nm/F615nm) versus aluminum ions concentration. The calibration plot was obtained within the range 0.1–100 µM with LOD = 0.27 µM. Additionally, the concentration of aluminum ions can be estimated semi-quantitatively by visually observing the luminescence colour change of the probe from red to light green and then to dark green after being excited by a UV lamp with 365 nm. As far as we are aware, this is the first luminescent lanthanide complex-based ratiometric probe for the detection of aluminum ions. The probe showed remarkable aluminum ions selectivity relative to that of other metal ions. The suggested sensor was used effectively to identify aluminum ions in water samples with good results.Graphical

Three new Zn(ii) coordination polymers for highly selective and sensitive detection of Fe3+

In this work, three novel Zn(ii)-CPs with diverse structures and fascinating topologies can be highly selective and sensitive luminescent sensors for detection of Fe3+.

Optimization of Eu3+-to-Host Emission Ratio in Double-Perovskite Molybdenites for Highly Sensitive Temperature Sensors

Double-perovskite phosphors exhibit unusual thermal and luminescent behavior and could potentially be applied as efficient and sensitive luminescent temperature sensors. Four double perovskite hosts─Ba2MgMoO6 (BMM), Sr2MgMoO6 (SMM), Ba2ZnMoO6 (BZM), and Sr2ZnMoO6 (SZM)─are studied for the correlations between the symmetry, energetic structure, luminescence, and thermometric performance. The quantum yield of Eu3+ emission in those hosts is higher for the samples with high cubic symmetry and ranges up to over 20% for Ba2MgMoO6. The Eu3+ ions can be excited indirectly by the host absorption bands in the UV and charge transfer band (CTB) in the blue range. The symmetry of the host plays a crucial role in the thermal stability of the host emission, which together with varying activation energy of Eu3+ luminescence provides a basis for thermometric sensitivity optimization. The relative sensitivities (Sr) obtained by the Eu-doped molybdenite hosts are 3.2% at 75 °C for Sr2MgMoO6 and 9.2% at −196 °C for Ba2ZnMoO6. It is also demonstrated that the sensing performance is higher in hosts with a uniform quenching profile of host luminescence and steep quenching of Eu3+ luminescence.

An Adenine‐Based Biological Metal‐Organic Framework as an Efficient Luminescent Sensor for Tetracycline Detection

AbstractBecause of their misuse and poor management, antibiotics pose a significant threat to the ecological environment and human health. The development of highly sensitive and effective sensors to detect such environmental contaminants is a crucial and challenging task. As a new class of desirable biocompatible materials, biological metal‐organic frameworks are considered as a viable platform for sensing applications. Herein, we report the synthesis of biological luminescent metal‐organic framework [Zn6Ad4(BPDC‐(OH)2)4]n (JNU‐104) using adenine (Ad) and 2,2′‐dihydroxy‐1,1′‐biphenyl‐4,4′‐dicarboxylic acid [BPDC‐(OH)2] as organic linkers. JNU‐104 serves as a robust and sensitive luminescent sensor for detecting tetracycline antibiotics in aqueous media with low limits of detection (LODs) of 0.023, 0.029 and 0.024 μM for tetracycline (TC), oxytetracycline (OTC), and chlortetracycline (CTC), respectively. Furthermore, the MOF‐based test strips show a rapid and visualizable luminescence response to tetracycline antibiotics, making JNU‐104 a promising candidate for practical applications in sensing.

Functional groups assisted-photoinduced electron transfer-mediated highly fluorescent metal-organic framework quantum dot composite for selective detection of mercury (II) in water

The presence of toxic mercury (II) in water is an ever-growing problem on earth that has various harmful effect on human health and aquatic living organisms. Therefore, detection of mercury (II) in water is very much crucial and several researches are going on in this topic. Metal-organic frameworks (MOFs) are considered as an effective device for sensing of toxic heavy metal ions in water. The tunable functionalities with large surface area of highly semiconducting MOFs enhance its activity towards fluorescence sensing. In this study, we are reporting one highly selective and sensitive luminescent sensor for the detection of mercury (II) in water. A series of binary MOF composites were synthesized using in-situ solvothermal synthetic technique for fluorescence sensing of Hg2+ in water. The well-distributed graphitic carbon nitride quantum dots on porous zirconium-based MOF improve Hg2+ sensing activity in water owing to their great electronic and optical properties. The binary MOF composite (2) i.e., the sensor exhibited excellent limit of detection (LOD) value of 2.4 nmol/L for Hg2+. The sensor also exhibited excellent performance for mercury (II) detection in real water samples. The characterizations of the synthesized materials were done using various spectroscopic techniques and the fluorescence sensing mechanism was studied.

MOF-based sensor platforms for rapid detection of pesticides to maintain food quality and safety

Pesticides are primarily used in agriculture to increase crop yield because of their highly lucrative, stable structure and agricultural benefits such as eliminating fungi, plant diseases, pests and insects to regulate the growth of crops. Apart from their rebel design and agricultural benefits, pesticides have severe toxicity to a variety of other living organisms. Therefore, developing effective pesticide detection systems is an ongoing challenge. Multiple technologies that for the rapid, easy, sensitive, and selective detection of these neurotoxic compounds are in demand. This paper reviews the recent advances in sensing assays based on the metal-organic framework (MOF) structure for pesticide detection. We have reviewed state-of-the-art optical biosensors for in-place sensing that have the advantages of a simple protocol, simple manipulation, super sensitivity, wide linear range, and cost-effectiveness. These biosensors use chemiluminescence with a short sensing time and a highly sensitive luminescence sensor that enables real-time detection by easy smartphone pairing. For profitable platforms, the obstacles related to sample preparation and equipment cost can be overcome by employing electrochemical sensors. The intensity, impedance, and potential difference measurement techniques used in these biosensors allow for low detection limits and observable durations in water, agricultural, and food samples containing high levels of pesticides.

Highly selective detection of Fe3+ and nitro explosives by a bifunctional sensor based on Cd(II) complex

A cadmium fluorescence framework [Cd(sip)(dpa)(H2O)] n (1) (NaH2sip = sodium 5-sulfoisophthalate; dpa = 4,4’-dipyridylamine) has been successfully synthesized and characterized. Single crystal X-ray diffraction analysis reveals that complex 1 exhibits an infinite 1D double chain, the H-bonds extend the 1D chains into a 3D supermolecular framework. Fluorescent studies reveal that 1 can be used as a highly sensitive luminescent sensor for detecting Fe3+ ion in H2O and 4-nitrophenol (4-NP) in DMF within a few seconds through fluorescence quenching. The sensing mechanism for Fe3+ can be explained in terms of synergistic competitive absorption and coordination interactions between Fe3+ and the framework, while the mechanism for detecting 4-NP is mainly attributed to the competitive absorption between the excitation/emission of 1 and analytes.

Hydrolytically Stable Zr-Based Metal-Organic Framework as a Highly Sensitive and Selective Luminescent Sensor of Radionuclides.

Effective detections of radionuclides including uranium and its predominant fission products, for example, iodine, are highly desired owing to their radiotoxicity and potential threat to human health. However, traditional analytical techniques of radionuclides are instrument-demanding, and chemosensors targeted for sensitization of radionuclides remain limited. In this regard, we report a sensitive and selective sensor of UO22+ and I- based on the unique quenching behavior of a luminescent Zr-based metal-organic framework, Zr6O4(OH)4(OH)6(H2O)6(TCPE)1.5·(H2O)24(C3H7NO)9 (Zr-TCPE). Immobilization of the luminescent tetrakis(4-carboxyphenyl)ethylene (TCPE4-) linkers by Zr6 nodes enhances the photoluminescence quantum yield of Zr-TCPE, which facilitates the effective sensing of radionuclides in a "turn-off" manner. Moreover, Zr-TCPE can sensitively and selectively recognize UO22+ and I- ions with the lowest limits of detection of 0.67 and 0.87 μg/kg, respectively, of which the former one is much lower than the permissible value (30 μg/L) defined by the U.S. EPA. In addition, Zr-TCPE features excellent hydrolytic stability and can withstand pH conditions ranging from 3 to 11. To facilitate real-world applications, we have further fabricated polyvinylidene fluoride-integrating Zr-TCPE as luminescence-based sensor membranes for on-site sensing of UO22+ and I-.

Three Cd(II) coordination polymers containing phenylenediacetate isomers: Luminescence sensing and adsorption antibiotics performance in water

Three new Cd(II) coordination polymers (CPs) [Cd(opda) (tib)]·H2O (1), [Cd4(mpda)4(tib)2(dib)2]·7H2O (2), [Cd(ppda) (tib)]·4H2O (3), have been synthesized by using isomeric phenylenediacetates (H2pda) and 1,3,5-tris(1-imidazolyl)benzene (tib) ligand under hydrothermal condition. Single crystal X-ray structures showed that CP 1 constitutes 3,5-connected 2-nodal net with a three-dimensional (3D) structure, while CP 2 forms an ring 1D chain, CP 3 has a interpenetrated 2D structure. The structural diversity of these CPs is mainly attributed to the different coordination modes and isomer conformations of the flexible phenylenediacetic acids. Three CPs are highly selective and sensitive luminescent sensors toward tetracycline (TEC). Compared with CPs 2 and 3, CP 1 has higher quenching percentage and adsorption capacities (64.493 mg g−1) for TEC due to its large specific surface area (171.72 m2 g−1) and pore volume (0.31 cm3 g−1). The main adsorption mechanisms are physisorption and chemisorption, including pore filling effect and π-π interaction. This study provides new insights into the design of 3D CPs for removing pollutants from industrial wastewaters, with the potential to mitigate health risks to humans and natural ecosystems.