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Exploring metal phosphonates with new crystal structures is of significance for the development of metal-organic frameworks (MOFs). In this work, two new copper phosphonates, [tetraauqa-1,4-phenylenebis(hydroxymethylene))bisphosphonate biscopper(II)] bishydrate [Cu2(H2L)(H2O)4]·2H2O (1) and 1,4-phenylenebis(hydroxymethylene))bisphosphonate-(4,4'-bipy) copper(II) [Cu(H4L)(4,4'-bipy)] (2) (4,4'-bipy = 4,4'-bipyridine), have been synthesized from a hydroxy functionalized bisphosphonate ligand, H6L = (1,4-phenylenebis(hydroxymethylene))bis(phosphonic acid). The introduction of a hydroxy group can regulate the crystal structures. The bisphosphonate ligand in 1 is hexadentate, binding six copper ions with its six phosphonate oxygen atoms and two hydroxy oxygen atoms, forming a three-dimensional framework structure with rectangle channels running along the b-direction. For 2, the bisphosphonate ligands are double deprotonated and chelate or bridge two copper ions, showing a two-dimensional layered crystal structure. These compounds have interesting fluorescence properties with emission maxima (307 and 410 nm) lying in the blue region. [ABSTRACT FROM AUTHOR]

Access to lanthanide acetate coordination compounds is challenged by the tendency of lanthanides to coordinate water and the plethora of acetate coordination modes. A straightforward, reproducible synthetic procedure by treating lanthanide chloride hydrates with defined ratios of the ionic liquid (IL) 1‐ethyl‐3‐methylimidazolium acetate ([C2mim][OAc]) has been developed. This reaction pathway leads to two isostructural crystalline anhydrous coordination complexes, the polymeric [C2mim]n[{Ln2(OAc)7}n] and the dimeric [C2mim]2[Ln2(OAc)8], based on the ion size and the ratio of IL used. A reaction with an IL : Ln‐salt ratio of 5 : 1, where Ln=Nd, Sm, and Gd, led exclusively to the polymer, whilst for the heaviest lanthanides (Dy−Lu) the dimer was observed. Reaction with Eu and Tb resulted in a mixture of both polymeric and dimeric forms. When the amount of IL and/or the size of the cation was increased, the reaction led to only the dimeric compound for all the lanthanide series. Crystallographic analyses of the resulting salts revealed three different types of metal‐acetate coordination modes where η2μκ2 is the most represented in both structure types. [ABSTRACT FROM AUTHOR]

One new uranyl tetracarboxylate, [UO2(H2L3)(H2O)]·3H2O, was synthesized hydrothermally from a methyl group decorated semi-rigid tetracarboxylic acid ligand and systematically characterized using powder and single-crystal X-ray diffraction, IR, EA, TGA, and luminescent methods. The four carboxylate groups in the carboxylic ligand were all monodentate bridging and the uranyl cations are linked by tetracarboxylic ligands to form a two-dimensional layered crystal structure. Introduction of methyl groups has a large effect on the speciation of uranyl carboxylates. The thermal behavior and luminescent properties are also investigated. [ABSTRACT FROM AUTHOR]

A series of lanthanide diphosphonates, namely Ln(HL)(H2O)2 (Ln = Nd 1, Eu 2, Tb 3 and Er 4), have been synthesized from a semirigid diphosphonate ligand, (5-methyl-1,3-phenylene)bis(methylene)bisphosphonic acid (H4L). These lanthanide diphosphonates have been systematically characterized by using powder and single-crystal X-ray diffraction, elemental analysis, TGA, IR, UV-vis absorption and luminescence techniques. The single-crystal XRD measurements revealed that these compounds all have two-dimensional layered crystal structures. Among these four compounds, 1, 2 and 4 are isostructural and crystallize in the P21/c space group, whereas compound 3 crystallizes in the P21 space group. These compounds display the characteristic emissions of the respective lanthanide ions. The sensing properties of compound 3 were investigated which revealed that it could be used as a luminescent probe for Fe3+ and Cr2O72− with good selectivity and sensitivity. [ABSTRACT FROM AUTHOR]

With the widespread application of neonicotinoid insecticides, Clothianidin has received much attention due to the potential harm to human health and ecological environment. However, the mechanism of Clothianidin's underlying toxicity to organisms remains unclear. In this work, the interaction between Clothianidin and human serum albumin was investigated and the intrinsic fluorescence of human serum albumin got quenched via static mechanisms upon the addition of Clothianidin. The binding constants between Clothianidin and human serum albumin at three different temperature were obtained to be 3.543 × 104, 2.995 × 104, and 2.490 × 104 M−1, respectively. Based on the van't Hoff equation, the thermodynamic parameters, ΔH0 and ΔS0 were estimated to be −53.885 KJ mol−1 and −110.535 J mol−1K−1, respectively. A single binding site was predicted from the binding constants at different temperatures by multiple spectroscopic techniques and the negative values of ΔH0 and ΔS0 indicated the binding of human serum albumin with Clothianidin was driven by hydrogen bonds or van der Waals forces. Furthermore, the loose and unfolded secondary structure of human serum albumin along with the addition of clothianidin had been observed through ultraviolet-visible absorption and circular dichroism spectra. In addition, it was also found that Clothianidin had polar effects of structural microenviroment not only on Trp but also Tyr residues from synchronous fluorescence analysis. This study illuminates the molecular mechanism of the interaction between human serum albumin and clothianidin for the first time and helps to construct a specific pesticide biosensor system of human health. [ABSTRACT FROM AUTHOR]

Catalytic depolymerization of lignin is still a challenge due to its low conversion and repolymerization of the reactive intermediates. Reductive depolymerization over supported nickel catalysts with probable surface acidic and basic properties is a very promising process. It is therefore very important to investigate the effect of acidity and basicity of the supports on catalytic reactivity. In this paper, we synthesized a series of nickel based catalysts supported on ZnO-Al 2 O 3 composites with varying Zn/Al atom ratios (Zn/Al = 2, 3, 5, ∞) and tested their catalytic performances over a model compound 2-phenoxy-1-phenylethanone containing β-O-4 bond. All these catalysts showed 100% conversion by reacting at 250 °C for 2 h under 2 MPa of H 2 . Higher selectivity towards ethylcyclohexane could be obtained over the catalyst Ni/ZnO-Al 2 O 3 -5. The possible cleavage pathways of selective oxidized β-O-4 ether linkage have been proposed. [ABSTRACT FROM AUTHOR]

Abstract: Nickel phosphides supported on HZSM‐5 zeolite with different initial P/Ni molar ratios were prepared for catalytic hydrodeoxygenation (HDO) of eugenol to produce hydrocarbons. When P/Ni<0.5, the increase of P content gave smaller and more uniform particles which was helpful for hydrogenation of aromatic ring, while the total acid sites of the catalyst decreased due to the coverage of more acid sites of HZSM‐5 by adding P which was unfavourable for the removal of oxygen. At P/Ni=0.5, the active phase supported on HZSM‐5 was mainly Ni3P with the smallest average particle size and minimum amount of acid sites which could account for the best hydrogenation activity and the lowest selectivity of hydrocarbons, respectively. Further increasing the P/Ni ratio up to 1 and 2, the active phase became Ni2P and a lot of nonuniform Ni2P nanorod crystals appeared on and out of the support HZSM‐5 which caused a sharp drop in the hydrogenation activity of the catalyst. For a combination of hydrogenation and deoxygenation considerations, The P/Ni=0.25 is the best ratio for nickel phosphides supported on HZSM‐5 zeolite to HDO of lignin‐related phenols. [ABSTRACT FROM AUTHOR]

By employing an aromatic methyl substituted V-shaped diphosphonic acid as a ligand, a series of metal diphosphonates, namely [Cu3(HL)2(H2O)2][(H2O)2] (1), [Cu(H2L)(pyz)(H2O)2][(H2O)2] (2), [Cu(H2L)(2,2′-bipy)] (3), [Cu(H2L)(4,4′-bipy)(H2O)2] (4), [Zn(H2L)(2,2′-bipy)] (5) and [Cd(H2L)(2,2′-bipy)(H2O)][(H2O)6] (6), have been synthesized. The structural studies reveal that these compounds exhibit diverse crystal structures. The introduction of the methyl group and pyridine derived auxiliary ligands results in the formation of plenty of C–H…O, C–H…π and π…π interactions, which contribute to the crystallization of metal diphosphonates. It was found that the Zn and Cd containing compounds showed intense intraligand emissions. [ABSTRACT FROM AUTHOR]

A metal organic framework [Ni1.5(4,4′-bipy)1.5(H3L)(H2O)3]·[H2O]7 where H6L = 2,4,6-trimethylbenzene-1,3,5-triyl tris(methylene)triphosphonic acid and 4,4′-bipy = 4,4′-bipyridine has been prepared. The structures of [Ni1.5(4,4′-bipy)1.5(H3L)(H2O)3]·[H2O]7 and the desolvated form [Ni1.5(4,4′-bipy)1.5(H3L)(H2O)3] have been determined by single crystal X-ray diffraction and the framework structures are virtually identical with the former having disordered water molecules in the pores. The framework structure comprises of two-dimensional Ni1.5(H3L) layers and 4,4′-bipy linkers acting as pillars with an unusual framework topology of a (3, 3, 6) net that can be denoted as: {4·62}2{63}2{68·85·102}. The framework has one-dimensional channels decorated with acidic O–H groups with irregular shape varying from narrow windows (cross section: 4.2 × 4.2 Å) to pore cavities (diameter: ∼12 Å). Thermogravimetric studies showed that both coordinated and lattice water molecules adsorbed in pores were removed in ultra-high vacuum to give [Ni1.5(4,4′-bipy)1.5(H3L)]. The water vapor adsorption isotherm for [Ni1.5(4,4′-bipy)1.5(H3L)] showed that 3 coordinated and ∼7 pore lattice water molecules were adsorbed and the framework structure was reformed. The desorption isotherm showed that the lattice water was easily desorbed in vacuum at 20 °C to form [Ni1.5(4,4′-bipy)1.5(H3L)(H2O)3]. The ethanol adsorption isotherms for [Ni1.5(4,4′-bipy)1.5(H3L)] for temperature range 20–50 °C were markedly hysteretic. The stoichiometry was [Ni1.5(4,4′-bipy)1.5(H3L)]·[1.11C2H5OH] at p/p0 = 0.97 and 20 °C gave a total pore volume approximately half that of [Ni1.5(4,4′-bipy)1.5(H3L)(H2O)3]. The desorption isotherms show that ethanol is strongly retained with decreasing pressure indicating a stable framework structure. The kinetic profiles for oxygen, nitrogen, carbon dioxide, and water and ethanol vapors, can be described by Fickian, combined barrier resistance/diffusion (CBRD), and stretched exponential models for both adsorption and desorption. Gas adsorption studies for [Ni1.5(4,4′-bipy)1.5(H3L)] reveal kinetic molecular sieving occurs with very high kinetic selectivity for O2/N2 at 0 °C. Carbon dioxide adsorption has intermediate rates of adsorption between oxygen and nitrogen. The isosteric enthalpy for CO2 adsorption at zero surface coverage was 30.7 ± 2.4 kJ mol−1. The corresponding activation energy for diffusion of CO2 into the framework was ∼48 kJ mol−1. Narrow constrictions in the porous structure of [Ni1.5(4,4′-bipy)1.5(H3L)] give rise to kinetic molecular sieving effects and do not allow adsorption of molecules such as methane, which has a larger cross-section. The selectivity for CO2/CH4 was very high (x1000) at 30 °C. The adsorption results are discussed in terms of diffusion, thermodynamics and surface interactions in pores. [ABSTRACT FROM AUTHOR]

One series of isostructural lanthanide phosphonates, namely [Ln2(H2L)3][(H2O)5] (H4L = (5-methyl-1,3-phenylene)bis(phosphonic acid); Ln = Eu (1), Gd (2), Tb (3), and Dy (4)), have been successfully synthesized from a V-shaped rigid ligand. Systematic characterizations using single-crystal and powder X-ray diffraction (XRD), thermogravimetric analyses (TGA), and photoluminescence spectroscopy were accomplished. It was found that these compounds all crystallize in the cubic I213 space group, showing three-dimensional framework structures. The frameworks are stable up to 350 °C and show their respective characteristic metal-centered emissions. The photoluminescence properties were also theoretically investigated by using a newly developed software program – LUMPAC. The energy transfer and back energy transfer rates were estimated, and the T1→5D1 and T1→5D0 channels were revealed to be the dominant pathways. The combination of experimental and theoretical studies on the photoluminescence properties substantially supports the understanding and design of highly luminescent inorganic–organic hybrid materials. [ABSTRACT FROM AUTHOR]

Using the classic UiO-66 MOF as platform, three terbium-doped zirconium-based MOFs (UiO-66@Tb, UiO-66-OH@Tb and UiO-66-2OH@Tb) were prepared by introducing hydroxyl groups into the terephthalic acid ligand and partial replacement of the Zr(IV) ions with Tb(III), and employed for the sensing of His. It is found that the introduction of hydroxyl group has a significant impact on the fluorescence properties of these functionalized MOFs and leading to different sensing performances. With one hydroxyl group introduced, UiO-66-OH@Tb displays both the ligand-centered and characteristic emissions of Tb(III), and can function as a ratiometric fluorescence sensor toward histamine with improved sensing performance, showing wide detection range of 0–120 mg/L, low detection limit of 0.13 mg/L and excellent anti-interference ability. In addition, UiO-66-OH@Tb could also be prepared into composite film that realized the rapid visual detection of histamine. [Display omitted] • UiO-66 type MOFs were explored as probes for the sensing of histamine. • By introduction of hydroxyl group to the ligand, the energy levels can be altered. • Terbium (III) ions are doped to introduce additional emitting centers. • Ratiometric fluorescent probe with improved performance can be developed. • Composite film can be fabricated to function as visual fluorescence sensor. Food safety is a common concern among people, and the development of high-performance food freshness detection technology is crucial, but is still highly challenging. Fluorescent sensing based on metal organic frameworks is a promising technology to tackle this issue. In this work, three UiO-66 type Zirconium organic frameworks (ZrOFs) which are functionalized with varying numbers of hydroxyl groups to alter the energy levels, and partial replacement of Zirconium(IV) by Terbium(III) ions to introduce additional emitting centers, were explored as probes for the sensing of Histamine (His). With one hydroxyl group introduced, UiO-66-OH@Tb can be developed as ratiometric fluorescent probe with improved sensing performance, showing a wide detection range of 0 to 120 mg/L, and a low detection limit of 0.13 mg/L. UiO-66-OH@Tb can also be fabricated into composite film to function as visual sensing material of His. This work can provide instructions for the development of other fluorescent sensors. [ABSTRACT FROM AUTHOR]

A series of lanthanide diphosphonates, namely Ln(HL)(H2O)2 (Ln = Nd 1, Eu 2, Tb 3 and Er 4), have been synthesized from a semirigid diphosphonate ligand, (5-methyl-1,3-phenylene)bis(methylene)bisphosphonic acid (H4L). These lanthanide diphosphonates have been systematically characterized by using powder and single-crystal X-ray diffraction, elemental analysis, TGA, IR, UV-vis absorption and luminescence techniques. The single-crystal XRD measurements revealed that these compounds all have two-dimensional layered crystal structures. Among these four compounds, 1, 2 and 4 are isostructural and crystallize in the P21/c space group, whereas compound 3 crystallizes in the P21 space group. These compounds display the characteristic emissions of the respective lanthanide ions. The sensing properties of compound 3 were investigated which revealed that it could be used as a luminescent probe for Fe3+ and Cr2O72− with good selectivity and sensitivity. [ABSTRACT FROM AUTHOR]

Sensitive, rapid and convenient sensing of 2,6-pyridinedicarboxylic acid (DPA, a biomarker for Bacillus anthracis ) is crucial for the screening and diagnosis of anthrax. Metal organic framework (MOF)-based sensors are very promising for sensing DPA; however, the design and construction of high-performance sensors with high specificity and sensitivity is still challenging. In this work, a novel luminescent carboxylate MOF (TTCA-Zn) was assembled and employed specifically for the recognition of DPA. We found that it has a three-dimensional anionic framework structure with sqc topology and uses [NH 2 (CH 3 ) 2 ] + as the counter ions. The fluorescence intensity of TTCA-Zn displays a "turn-on" response to the addition of DPA and can function as a high-performance fluorescent sensor of DPA over a wide detection range of 0 to 70 μM, with a low detection limit of 14 nM. The sensing mechanism is also systematically investigated. This work not only reports a new fluorescence sensing material for DPA, but also provides a strategy for the structural design, assembly, and application of such sensors.

Two zero-dimensional inorganic-organic hybrids, namely, [C 4 mim][Cd(TCDPPA) 3 ] ( 1 ) and [C 4 mpy][Cd(TCDPPA) 3 ] ( 2 ), where (TCDPPA) - = 2,2,2-trichloro- N -(di(pyrrolidin-1-yl)phosphoryl)acetamide, (C 4 mim) + = 1-butyl-3-methylimidazolium, and (C 4 mpy) + = 1-butyl-4-methylpyridinium, have been synthesized via metathesis reactions and characterized systematically. These ionic cadmium-containing inorganic-organic hybrid compounds are assembled from a bulky organic cation and a complex anion constructed from the chelation of three TCDPPA ligands to one cadmium ion. These compounds possess wide band gaps and emit in the deep-blue region intensely with a quantum yield as high as 34.04%. The success of this work provides a new method for the design and fabrication of high-efficiency blue-emitting materials.

Lanthanide-uranyl phosphonates possess intriguing crystal structures and huge application prospects, but the construction of these materials remains challenging. In this work, we demonstrate that new uranyl and lanthanide-uranyl sulfonylphosphonates with elegant crystal structures and photophysical properties can be assembled hydrothermally by employing the heterofunctional diethyl phosphonate (diethyl ((phenylsulfonyl)methyl)phosphonate, Et 2 L) as a precursor ligand, which provides an effective strategy for the construction of lanthanide-uranyl phosphonates.