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.

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.

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.

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.

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.

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.

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).

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.

Construction of a 18-Metal Neodymium(III) Nanoring with NIR Luminescent Sensing to Antibiotics.

One 18-metal Nd(III) nanoring, [Nd18(L1)8(HL2)2(OAc)20(MeOH)8(EtOH)6(H2O)4]·2(MeOH)·6(H2O) (1), was constructed by the use of a hexadentate Schiff base ligand. For 1, the near-infrared (NIR) luminescence of Nd(III) was detected under the excitation of absorption band at 371 nm. The study of luminescent sensing properties exhibits that, even with the existence of other antibiotics, this Nd(III) nanoring displays high sensitivity and selectivity to nitrofuran antibiotics (NFAs). The luminescence quenching constants and limits of detection of 1 to NFAs are found to be 1.4 × 104 to 3.5 × 104 M-1 and 0.9-2.2 µM, respectively.

Construction of Chiral "Triple-Decker" Nd(III) Nanocluster with High NIR Luminescence Sensitivity toward Co(II).

One Nd(III) complex [Nd3L3(OAc)3] (1) was synthesized from a conjugate Schiff base ligand H2L. It shows a chiral "triple-decker" structure (1.1 × 1.2 × 1.8 nm) with Nd(III) ions sandwiched between the Schiff base ligands. 1 exhibits NIR Nd(III) luminescence, and the LMET efficiency is calculated to be 13.8%. It displays high luminescence sensitivity and selectivity to Co(II). The KSV value and LOD of 1 to Co(II) are 9.96 × 104 M-1 and 0.97 µM, respectively.

Synthesis of Hexagonal FeMnP Thin Films from a Single-Source Molecular Precursor.

The first heterobimetallic phosphide thin film containing iron, manganese, and phosphorus, derived from the single-source precursor FeMn(CO)8 (µ-PH2 ), has been prepared using a home-built metal-organic chemical vapor deposition apparatus. The thin film contains the same ratio of iron, manganese, and phosphorus as the initial precursor. The film becomes oxidized when deposited on a quartz substrate, whereas the film deposited on an alumina substrate provides a more homogeneous product. Powder X-ray diffraction confirms the formation of a metastable, hexagonal FeMnP phase that was previously only observed at temperatures above 1200 °C. Selected area electron diffraction on single crystals isolated from the films was indexed to the hexagonal phase. The effective moment of the films (µeff =3.68 µB ) matches the previously reported theoretical value for the metastable hexagonal phase, whereas the more stable orthorhombic phase is known to be antiferromagnetic. These results not only demonstrate the successful synthesis of a bimetallic, ternary thin film from a single-source precursor, but also the first low temperature approach to the hexagonal phase of FeMnP.

New Main-Group-Element-Rich nido-Octahedral Cluster System: Synthesis and Characterization of [Et4N][Fe2(CO)6(µ3-As){µ3-EFe(CO)4}2].

A series of clusters of the form [Et4N][Fe2(CO)6(µ3-As)}(µ3-EFe(CO)4)], where E is either P or As, were synthesized from [Et4N]2[HAs{Fe(CO)4}3] and ECl3. AsCl3 gives the As-only compound; PCl3 produces compounds having two As atoms with one P atom, or one As atom and two P atoms, and they can exist as two possible isomers, one of which is chiral. The As2P and AsP2 clusters cocrystallize, and their structure as determined by single-crystal X-ray diffraction is given along with the structure of the As-only cluster. Analytical data as well as density functional theory calculations support the formation and geometries of the new molecules.

Anionic Bismuth-Oxido Carboxylate Clusters with Transition Metal Countercations.

Six new anionic bismuth-oxido clusters containing trifluoroacetate ligands were prepared. These include two new Bi6O8 clusters: [M(NCMe)2(H2O)4]3[Bi6(µ3-O)4(µ3-OH)4(CF3CO2)12] with an octahedral Bi6O4(OH)4 core (M = Ni, 1a; Co, 1b) and four Bi4O2 clusters, {[Co(NCMe)6][Bi4(µ3-O)2(CF3CO2)10]}n (2a), {[Co{HC(MeCO)2(MeCNH)}2][Bi4(µ3-O)2(CF3CO2)10]·2[CF3CO2]·2[CF3CO2H]·2[H2O]}n (2b), {[Cu(NCMe)4]2[Bi4(µ3-O)2(CF3CO2)10]·2[CF3CO2H]}n (2c), and {[Me4N]2[Bi4(µ3-O)2(CF3CO2)10]·2[CF3CO2H]}n (2d). These are among the first bismuth-oxido anionic clusters synthesized, and the first to have transition metal countercations. The Bi6O8 anion in 1a and 1b is a high-symmetry octahedron. Additionally, two of the new Bi4O2 clusters are arranged in 1D polymeric structures via bridging carboxylate ligands. The cation in compound 2c had not been previously characterized and was also observed in the synthesis of [Co{HC(MeCO)2(MeCNH)}2][Bi(NO3)6] (3). The new compounds were characterized using single crystal X-ray crystallography and elemental analysis.

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".

Anion-dependent self-assembly of near-infrared luminescent 24- and 32-metal Cd-Ln complexes with drum-like architectures.

Two series of 4d-4f clusters [Ln8Cd24L12(OAc)48] and [Ln6Cd18L9Cl8(10)(OAc)28(26)] (Ln = Nd, Gd, Er, and Yb) with novel drum-like structures were prepared using a flexible Schiff base ligand. Their NIR luminescence properties were determined.

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.