Rapid and reliable ratiometric fluorescence detection of nitro explosive 2,4,6-trinitrophenol based on a near infrared (NIR) luminescent Zn(II)-Nd(III) nanoring.

Rapid and quantitative detection of 2,4,6-trinitrophenol (TNP) is very crucial for homeland security, military application, and environment protection. Herein, a nine-metal Zn(II)-Nd(III) nanoring 1 with a diameter of 2.3 nm was constructed by the use of a long-chain Schiff base ligand, which shows ratiometric fluorescence response to TNP with high selectivity and sensitivity. The fluorescence sensing behavior of 1 to TNP is expressed by a first-order equation I1060nm/I560nm = -0.0128*[TNP] + 0.9723, which can be used to quantitatively analyze TNP concentrations in solution. The limits of detection (LODs) to TNP based on the ligand-centered (LC) and Nd(III) emissions of 1 are 5.93 µM and 3.18 µM, respectively. The fluorescence response mechanism to TNP is attributed to the competitive absorption effect and photoinduced electron transfer (PET). The luminescence quenching of 1 is dominated by static process.

Rapid and reliable ratiometric fluorescence detection of isoquercitrin based on a high-nuclearity Zn(II)-Nd(III) nanomolecular sensor.

Rapid and quantitative detection of isoquercitrin (Isq) has been attracting much attention due to its outstanding pharmacological and physiological activities. Herein, an interesting 48-metal Zn(II)-Nd(III) nanocluster (1, molecular sizes 1.3 × 2.8 × 3.1 nm) with salen-type Schiff base ligand was constructed as molecular sensor for the luminescence detection of Isq. 1 exhibits visible ligand-centered emission and NIR luminescence of Nd(III), and shows ratiometric fluorescence response to Isq with high sensitivity even in the presence of other interferences. The fluorescence sensing behavior can be expressed by a second-order equation I1060nm/I480nm = A*[Isq]2 + B*[Isq] + C, which is used to quantitatively analyze the Isq concentrations in DMF and FCS. The LODs to Isq for the ligand-centered and lanthanide emissions of 1 in DMF are 0.21 µM and 0.11 nM, respectively. The quenching of the ligand-centered emission of 1 caused by Isq is attributed to the competitive absorption of light energy and "inner effect", while, the luminescence enhancement is due to the "antenna effect".

A 20-Metal Zn(II)-Cd(II)-Eu(III) Nanocluster with Qualitative and Quantitative Luminescence Detection of Meloxicam (an Anti-Inflammatory Drug).

Meloxicam (MLX) is a novel nonsteroidal anti-inflammatory drug, but on the other hand, it has become one of the common microcontaminants in surface waters and sewage. Herein, we report the preparation of a ternary-metal Zn(II)-Cd(II)-Eu(III) nanocluster 1 for the response of MLX through the enhancement of lanthanide luminescence. The luminescence sensing behavior of 1 is expressed by the equation I615nm = 3060 × [MLX] + 46,604, which can be used in the quantitative analysis of MLX concentrations in meloxicam dispersible tablets. Filter paper strips bearing 1 can be used to qualitatively detect MLX by a color change to red under a UV lamp. The luminescence response time is no more than five s, and the detection limit is as low as 2.31 × 10-2 nM.

Ratiometric Fluorescence Detection of Levofloxacin Based on a Cube-like Zn(II)-Eu(III) Nanocluster: Functionalized Sodium Alginate Film for the Detection in Serum and Medicine.

A cube-like Zn(II)-Eu(III) nanocluster 1 (molecular sizes: 1.8 × 2.0 × 2.0 nm) was constructed by the use of a new long-chain Schiff base ligand. It shows a ratiometric fluorescence response to levofloxacin (LFX) with high sensitivity and selectivity, which can be expressed as I615 nm/I550 nm = A*[LFX]2 + B*[LFX] + C. It is used to quantitatively detect the LFX concentrations in fetal calf serum (FCS) and tablets sold in pharmacy. Filter paper strips bearing 1 can be used to qualitatively detect LFX by a color change to red under a UV lamp. 1 and its hybrid with sodium alginate (SA), 1@SA, display potential applications in the qualitative detection of LFX in FCS and the medicine. The limit of detection of 1 to LFX is as low as 2.1 × 10-2 nM.

Construction of a Zn(II)-Eu(III) Nanoring with Temperature-Dependent Luminescence for the Qualitative and Quantitative Detection of Neopterin as an Inflammatory Marker.

A nine-metal Zn(II)-Eu(III) nanoring 1 with a diameter of about 2.3 nm was constructed by the use of a long-chain Schiff base ligand. It shows a luminescence response to neopterin (Neo) through the enhancement of lanthanide emission with high selectivity and sensitivity, which can be used to quantitatively analyze the concentrations of Neo in fetal calf serum and urine. The luminescence sensing of 1 to Neo is temperature-dependent, and it displays more obvious response behavior at lower temperatures. Filter paper strips bearing 1 can be used to qualitatively detect Neo by the color change from chartreuse to red under a UV lamp. The limit of detection is as low as 3.77 × 10-2 nM.

A Near-Infrared Luminescent 11-Metal Cd(II)-Nd(III) Nanocluster for the Rapid Excitation Wavelength-Dependent Detection of Rutin.

A near-infrared luminescent Cd(II)-Nd(III) nanocluster 1 (molecular dimensions of 1.0 nm × 2.2 nm × 2.2 nm) was obtained using a Schiff base ligand. It can be used as a sensor for the wavelength-dependent detection of rutin even in the presence of other interference, which can be expressed by the third-order equation IEx470 nm/IEx395 nm = A[Rut]3 + B[Rut]2 + C[Rut] + D. 1 is used to analyze the Rut concentrations quantitatively in CH3CN and fetal calf serum (FCS). For the determination of Rut concentrations in FCS, the ranges of recovery and relative standard deviations are 99.06-104.70% and 2.30-4.15%, respectively.

Rapid and quantitative detection of the inflammatory marker neopterin based on a visible luminescent Zn(II)-Eu(III) nanocluster.

A high-nuclearity Zn(II)-Eu(III) nanocluster was synthesized for the rapid and quantitative luminescence detection of neopterin as an inflammatory marker.

Construction of a Near-IR-Luminescent Rectangular Yb(III) Complex from a Dodecadentate Schiff Base Ligand for the Excitation-Wavelength-Dependent Detection of Aloe Emodin (a Natural Medicinal Ingredient).

A near-IR-luminescent octanuclear Yb(III) complex 1 was constructed from a new dodecadentate Schiff base ligand, which is used in the rapid and reliable wavelength-dependent detection of aloe emodin (AE) with high sensitivity even in the presence of other interferences.

Construction of a Near-Infrared Luminescent 48-Metal Rectangular Zn(II)-Yb(III) Nanocluster with Carbonate Templates for the Dual-Emissive Detection of Rutin as a Medicinal Ingredient.

An interesting 48-metal Zn(II)-Yb(III) nanocluster (1) with a size of about 1.3 × 2.8 × 3.1 nm was constructed by carbonate templates from a Schiff base ligand. It exhibits ligand-centered emission and near-infrared (NIR) luminescence of Yb(III), which are used in the dual-emissive detection of rutin (Rut) with high sensitivity even in the presence of other interferences. The response behavior can be expressed by the second-order equation I980 nm/I510 nm = A*[Rut]2 + B*[Rut] + C, and the limits of detection to Rut for the emissions of 1 are 2.23 µM and 0.20 nM.

Rapid and reliable triple-emissive detection of 2,6-dichloro-4-nitroaniline as a pesticide based on a high-nuclear Cd(II)-Sm(III) nanocluster.

A luminescent 56-metal Cd(II)-Sm(III) nanocluster (1, molecular sizes: 4.5 × 2.7 × 2.7 nm) was constructed from a flexible Schiff base ligand, and its crystal structure was determined using the X-ray diffraction method. It shows a rapid triple-emissive response to 2,6-dichloro-4-nitroaniline (DCN, a common pesticide) with high sensitivity and selectivity, which can be used to quantitatively analyze the DCN concentrations in fruit extracts. The limits of detection (LODs) of 1 to DCN for the visible ligand-centered and Sm(III) emissions and NIR Sm(III) luminescence are from 0.95 µM to 2.81 µM.

Rapid and Reliable Excitation Wavelength-Dependent Detection of 2,6-Dipicolinic Acid Based on a Luminescent Cd(II)-Tb(III) Nanocluster.

A Cd(II)-Tb(III) nanocluster {[Cd10Tb9L8(OH)16(OAc)23(H2O)3][Cd10Tb9L8(OH)16(OAc)23(H2O)4]}·3H2O (1), which contains two crystallographically independent components, was constructed from a tridentate ligand (HL, 3-ethoxysalicylaldehyde). It exhibits rapid and reliable excitation wavelength-dependent luminescence response to 2,6-dipicolinic acid (DPA) [limit of detection = 0.23 nM], which is not influenced by aromatic carboxylates, amino acids, and ions. The test papers of 1 can be used to check DPA in solution. The equation IEx272nm/IEx329nm = 0.0109 × [DPA]2 + 0.106 × [DPA] + 2.39 of 1 for the luminescence response could be used to quantitatively measure the concentration of DPA in tap water. 1 displays rapid and stable luminescence response to DPA, with the sensing times shorter than 5 s and no changes for the lanthanide luminescence over 24 h.

Regulatable Detection of Antibiotics Based on a Near-IR-Luminescent Tubelike Zn(II)-Yb(III) Nanocluster.

A tubelike Zn(II)-Yb(III) cluster, [Zn6Yb5L5(HL)(NO3)4(DMF)6(EtOH)4(H2O)4] (1; DMF = N,N-dimethylformamide and EtOH = ethanol; molecular size 1.5 × 1.8 × 2.9 nm), was synthesized from a new long-chain Schiff base ligand. 1 exhibits a regulatable near-IR-luminescent response to nitrofuran antibiotics (NFAs) and fluoroquinolones with high sensitivity, which is not influenced by other antibiotics. The quenching constants of NFAs and fluoroquinolones range from 0.55 × 104 to 8.8 × 104 M-1, and the detection limits of 1 to them are from 4.2 × 10-4 to 2.6 × 10-5 M. It also shows a luminescent response to real antibiotic drugs containing NFAs and fluoroquinolones.

Ratiometric fluorescent detection of dipicolinic acid as an anthrax biomarker based on a high-nuclearity Yb18 nanoring.

An 18-metal lanthanide nanoring [Yb18(L1)8(HL2)2(OAc)20(MeOH)8(EtOH)6(H2O)4] (1), which shows a ratiometric fluorescent response to DPA, was constructed through the strategy of using two types of polydentate organic ligands. The addition of DPA increases the visible ligand-centered emission, but decreases the NIR lanthanide luminescence of 1. The limit of luminescent detection of 1 for DPA is 1.5 µM. The high fluorescence sensitivity of 1 to DPA is not affected by the existence of interferents such as aromatic carboxylates and ions.

One high-nuclearity Eu18 nanoring with rapid ratiometric fluorescence response to dipicolinic acid (an anthrax biomarker).

One 18-metal Eu(iii) nanoring (size: 1.0 × 2.7 × 2.7 nm) was constructed as a rapid ratiometric fluorescent probe for the detection of dipicolinic acid with high sensitivity and selectivity, by using two types of polydentate organic ligands.

Construction of a high-nuclearity Nd(III) nanoring for the NIR luminescent detection of antibiotics.

One NIR luminescent 14-metal Nd(iii) nanoring (1, molecular size: 1.0 × 2.2 × 2.6 nm) was obtained from a rigid tridentate ligand, which can absorb and transfer light energy to the Nd(iii) ions. 1 shows interesting luminescence sensing activity to antibiotics, in particular to NFAs with high sensitivity due to the inner filter effect. The quenching constants and the limits of detection of 1 to NFAs are 1.05 × 104 M-1-2.33 × 104 M-1 and 3.05 µM-6.75 µM, respectively. The high fluorescence sensitivities of 1 to NFAs are not changed by the existence of other antibiotics. It also exhibits high sensitivity in the luminescent detection of NFAs contained in real antibiotic drugs.

Construction of Zn(II)/Cd(II)-Yb(III) Schiff Base Complexes for the NIR Luminescent Sensing of Fluoroquinolone Antibiotics.

Two NIR luminescent Zn(II)/Cd(II)-Yb(III) complexes were obtained by the use of a Schiff base ligand with a binaphthyl backbone. Cd(II)-Yb(III) complex 2 has a triangular structure and exhibits interesting luminescent sensing activity to antibiotics, in particular to ciprofloxacin (CPFX) and norfloxacin (NFX) due to the inner filter effect. The limits of the detection of 2 to CPFX and NFX are 0.18 and 0.36 µM, respectively, and the fluorescence sensitivity is not changed with the existence of other antibiotics tested in this study.

Triangular Cd(II)-Sm(III) Schiff Base Complex with Dual Visible and Near-Infrared Luminescent Responses to Nitro Explosives.

Two d-4f complexes [Zn2NdL2(OAc)2]·OH (1) and [Cd3Sm3L3(OAc)6(OH)3] (2) with a designed Schiff base ligand N,N'-bis(3-methoxysalicylidene)(binaphthyl)-1,4-diamine (H2L) were synthesized. The Schiff base ligands coordinate with metal ions by µ2(η1:η2:η1:η1:η2:η1) and µ2(η1:η2:η1:η1:η2:η1) modes in the complexes, which show typical lanthanide emissions. The triangular Cd-Sm complex 2 shows both visible and NIR luminescent responses to nitrobenzene explosive 2,4,6-trinitrophenol (PA).

NIR luminescent detection of quercetin based on an octanuclear Zn(ii)-Nd(iii) salen nanocluster.

A NIR luminescent octanuclear Zn(ii)-Nd(iii) nanocluster 1 was constructed by the use of a salen-type Schiff base ligand. 1 exhibits a lanthanide luminescent response to Que with high sensitivity. The quenching constant of Que to the lanthanide emission is 2.6 × 104 M-1, and the detection limit of 1 to Que is 2.5 µM. The response behavior of 1 to Que is not affected by the existence of some potential interferents such as biomolecules.

Correction: Synthesis and structural characterization of CO2-soluble oxidizers [Bu4N]BrO3 and [Bu4N]ClO3 and their dissolution in cosolvent-modified CO2 for reservoir applications.

[This corrects the article DOI: 10.1039/D0RA09563J.].

One High-Nuclearity Cd(II)-Yb(III) Nanoring with Near-IR Luminescent Sensing to Antibiotics.

One 12-metal Cd(II)-Yb(III) nanoring, [Cd8Yb4L8(OAc)8]·4OH (1), with a size of 1.2 × 2.8 × 2.8 nm was obtained from a designed flexible salen-type ligand that has eight coordination sites (O and N atoms). The near-IR emission of Yb(III) at 983 nm was detected upon the excitation of ligand-central absorption at 386 nm. This Cd(II)-Yb(III) nanoring exhibits high sensitivity to nitrofuran antibiotics (NFAs) even in the presence of other antibiotics. The quenching constants and limits of detection of NFAs are 2.5 × 104-4.5 × 104 M-1 and 1.5-2.8 µM, respectively.