Changes in future climate will have an important impact on biodiversity. Taiwania cryptomerioides has important scientific value for the study of paleogeography, paleoclimate and paleobotany. Based ...on the environmental data and future scenarios provided by previous studies, the present and future suitable habitat for Taiwania cryptomerioides was modeled, and the significance of environmental factors that shape its distribution were evaluated in this study. Furthermore, a maximum entropy model (MaxEnt) and geographical information system (ArcGIS) were used to identify suitable regions under climate change scenarios in China. The 112 occurrence records and nine environmental factors were further analyzed in this work. Our results show that Taiwania cryptomerioides has a suitable habitat of 211.21 × 104 km2 across most of northeast China. Moreover, the altitude, annual mean temperature, precipitation of the driest month and precipitation of the wettest quarter were identified as the essential factors shaping habitat availability for Taiwania cryptomerioides. Furthermore, the area under the curve (AUC) of the train was 0.944, placing the model in the “excellent” category. As predicted by concentrations of four greenhouse gases from increasing emissions, ranges of species may decrease as global warming intensifies. Overall, the range shift to higher latitudes would gradually become significant. Our research offers suggestions for conservation both in theory and in application, as well as long-term management strategies for the species.
A simple multifunctional Schiff base fluorescence probe (E)-
N
′-(2,4-dihydroxybenzylidene)-2-hydroxybenzohydrazide (
NDH
) was designed and synthesized by the reaction of 2,4-dihydroxybenzaldehyde ...and salicylhydrazide.
NDH
acts as a “off–on” logic gate fluorescence probe for Al
3+
, Zn
2+
and La
3+
ions, providing different colors and detection limits of 1.22 μM, 2.47 μM and 2.94 μM, respectively. Moreover, the binding stoichiometry of
NDH
to Zn
2+
was 2:1, but to other metal ions was 1:1, and was confirmed by Job’ plot,
1
H NMR and ESI–MS. Furthermore, the probe
NDH
was applied to detect Al
3+
, Zn
2+
and La
3+
ions in real water samples and Hela cells. This work might provide a new evidence that the fluorescent probe with “off–on” logic gate can serve as an economical and efficient strategy for simultaneous sensing multiple metal ions.
Graphical abstract
A novel, highly sensitive and selective fluorescent probe was developed to trace Al
3+
, Zn
2+
and La
3+
in real water samples and live cells.
The North and South Mountains of Lanzhou City are the ecological protection barriers and an important part of the ecological system of Lanzhou City. This study takes the North and South Mountains as ...the study area, calculates the soil erosion modulus of the North and South Mountains of Lanzhou City based on the five major soil erosion factors in the RUSLE model, and analyses the spatial and temporal dynamics of soil erosion in the North and South Mountains of Lanzhou City and the soil erosion characteristics under different environmental factors. The results of the study show that: The intensity of soil erosion is dominated by slight erosion, which was distributed in the northwestern and southeastern parts of the North and South Mountains in 1995, 2000, 2005, 2010, 2015 and 2018. Under different environmental factors, the soil erosion modulus increased with elevation and then decreased; the soil erosion modulus increased with a slope; the average soil erosion modulus of grassland was the largest, followed by forest land, cultivated land, unused land, construction land, and it was the smallest for water; except for bare land, the average soil erosion modulus decreases with the increase of vegetation cover; Soil erosion modulus was the greatest in the pedocal of the North and South Mountains, and the least in the alpine soil.
Two 3D functional coordination polymers based on the rigid 1,3,5-tris(1-imidazolyl)benzene ligand and cobalt transition metal have been successively synthesized. Complex 2 shows good photo-catalysis ...properties for the photo-catalytic degradation of mixed organic dyes (MB/MV/RhB).
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Two novel coordination polymers (CPs) based on cobalt transition metal, namely {Co(tib)2·2HNO3}n (1) and {Co(tib)(4,4′-sbdc)·H2O}n (2) (tib = 1,3,5-tris(1-imidazolyl)benzene, H2sbdc = 4,4′-stilbenedicarboxylic), have been designed and successfully synthesized under solvothermal conditions, which were characterized by elemental analysis, infrared spectra, powder X-ray diffraction (PXRD), thermogravimetric (TG) analysis and single-crystal X-ray diffraction. Single-crystal X-ray diffraction analysis reveals that complex 1 features a stable 2D → 3D supramolecular frameworks through H-bonds with a rare (3,6)-connected kgd topology and complex 2 displays a 2-fold interpenetrating (2,4)-connected new topology with the point Schläfli of (44·62)(42). Importantly, the photo-catalytic properties of complexes 1–2 have been investigated, and then complex 2 is a good photo-catalyst for the degradation of mixed organic dyes (MB/MV/RhB).
Metal–organic frameworks (MOFs) have exhibited appreciable potential as catalytic agents in the field of material science. The research of new MOFs with dual functions in electrocatalysis and ...photocatalysis under ultraviolet (UV) irradiation is extremely pivotal for renewable energy applications. Hence, we synthesized a series of three-dimensional MOFs, namely, Cd(bimb)2(HITA)2n (Cd-MOF 1), {Cd(bimb)6(NO3)2}n (Cd-MOF 2), and Cd(bimb)4(ONO2)2n (Cd-MOF 3) (bimb = 1,4-bis(imidazol-1-ylmethyl)benzene; H2ITA = 5-hydroxyisophthalic acid), with applicability in the oxygen evolution reaction process and Fenton-like photocatalysis. The obtained results show that Cd-MOF 1 exhibited the most remarkable catalytic performance, affording a current density of 10 mA cm–2 at a very low overpotential of 279 mV and the smallest Tafel slope of 85.13 mV dec–1. Meanwhile, these MOFs can generate hydroxyl radicals (•OH) under UV light irradiation with the existence of H2O2, enabling the rapid degradation of organic pollutants. This study provides a valuable direction for producing multifunctional and environmentally friendly catalysts.
Two novel cobalt(II)-based metal–organic frameworks (MOFs), namely, {Co3(TTHA)(bibp)2(H2O)} n (1) and {Co2(H2TTHA)(bidpe)2} n (2) (H6TTHA = 1,3,5-triazine-2,4,6-triamine hexaacetic acid, bibp = ...4,4′-bis(imidazolyl)biphenyl, bidpe = 4,4-bis(imidazoly)diphenyl ether), were hydrothermally prepared based on the mixed ligands strategy and fully characterized. Due to the rich coordination modes of the carboxylic acid ligand, 1 possesses a three-dimensional (3D) structure with two secondary building units (Co3N3(CO2)4(CO)4 and Co2N2(CO2)4), whereas 2 exhibits a tangled one-dimensional (1D) chain structure and further forms a 3D structure assembled by weak interactions. Interestingly, 1 can serve as an unusual turn-on sensor for the detection of trivalent metal ions (Al3+, Cr3+, and Fe3+) in an aqueous solution with a low detection limit, and 2 shows high-sensitivity fluorescence turn-off behavior toward polystyrene and styrene biomarker phenylglyoxylic acid (PGA). Significantly, 2 can effectively sense the PGA in complicated biological environments. The mechanism study indicated that the absorbance-caused enhancement mechanism is responsible for the fluorescence turn-on phenomena of 1 induced by trivalent metal ions, while the occurrence of the structural collapse of 2 leads to a turn-off effect toward PGA.
Three novel Mn(II)/Co(II)-based 3D metal-organic frameworks (MOFs), namely {Mn2(L)(tib)(H2O)·3DMA·4H2O}n (1), {Co2(L)(bipd)2·3H2O}n (2) and {Co(L)0.5(bimb)·3H2O·0.5O2}n (3) ...(H4L = 5,5'-(1,4-xylylenediamino) diisophthalic acid, tib = 1,3,5-tris(1-imidazolyl)benzene, bipd = 3,5-bis(1-imidazoly)pyridine, and bimb = 1,4-bis(lmidazol)-butane), have been successfully synthesized using the mixed-ligand as functionalized organic linker. The structural characterization revealed that both MOFs 1 and 2 exhibited an unprecedented 4-nodal 3D framework that enriching crystal engineering, while MOF 3 featured a 2-nodal three-interpenetrating bbf topology framework with a Schläfli symbol of (64·82)(66)2. The title MOFs have been exploited as photocatalysts for degradation of methylene blue (MB), methyl violet (MV) and malachite green (MG). The photocatalytic results demonstrated that MOFs 2 and 3 exhibited efficient photocatalytic abilities to degrade the three aromatic dyes under UV irradiation. The possible catalytic mechanism was also explored and discussed in detail. Moreover, the variable-temperature magnetic analyses indicated that MOFs 1–3 exhibited weak antiferromagnetic behavior between Mn(II)/Co(II) ions.
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•Three novel Mn(II)/Co(II)-based 3D MOFs under solvothermal or hydrothermal condition in one-step, for the first time, were synthesized.•The MOFs 2 and 3 act as efficient heterogeneous photocatalyst for degradation of three aromatic dyes.•The possible catalytic mechanism was explored and discussed in detail.•MOFs 1–3 exhibit antiferromagnetic coupling between neighboring central ions.
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•Six new Zn-MOFs were prepared, and there were four Zn-MOFs showing unparalleled topologies frameworks.•The six Zn-MOFs displayed fluorescence quenching effect on Fe3+ ions and ...tetracycline antibiotic in aqueous solution.•Complex 1 as a bifunctional fluorescent probe material, showed highly sensitive and selective fluorescence quenching property.
Either reduced or excessive metal ions level in biological systems might induce serious metabolic diseases, and the abuse of antibiotics has seriously affected the environment. Despite the significant progress in the development of fluorescence probes over the past decade, the ability to sensitively and selectively detect these metal ions and antibiotics remains a pressing problem. Herein, we demonstrated some effective fluorescence probes for sensing metal ions and antibiotics, six novel and stable Zn(II) metal-organic frameworks (Zn-MOFs), namely Zn3(L)2(1,4-bimb)3n (1), Zn3(L)2(4,4′-bbibp)2(H2O)2n·2(CH3CN) (2), Zn(HL)(4,4′-bidpe)n (3), Zn(HL)(4,4′-bibp)n (4), Zn(HL)(3,5′-bip)n (5) and Zn(HL)(1,3′-bit)n (6) (flexible H3L = 5-(2-carboxylphenoxy)isophthalic acid, semi-flexible 1,4-bimb = 1,4-bis(imidazol-l-ylmethyl) benzene, rigid 4,4′-bbibp = 4,4′-bis(benzoimidazo-1-ly)biphenyl, semi-flexible 4,4′-bidpe = 4,4′-bis(imidazolyl)diphenyl ether, rigid 4,4′-bibp = 4,4′-bis(imidazolyl)biphenyl, rigid 3,5′-bip = bis(1-imidazoly)pyridine and rigid 1,3-bit = 1,3-bis(l-imidazoly)toluene) have been successfully synthesized via solvothermal conditions and further characterized by IR spectra, elemental analysis, powder X-ray diffraction (PXRD), single-crystal X-ray diffraction, and thermogravimetric (TG) analysis. These Zn MOFs have exhibited diversely architectural frameworks via the assistant N-donor ligands: 1, 2, 5 and 6 show unprecedented topological networks, 1 affords a 3-nodal (3, 4, 4)-connect 2-fold interpenetrating topology structure with the Point Schläfli symbol of (5·6·7·92·10)2(5·6·7)2(5·73·82), 2 shows a 3-nodal (3, 4, 6)-c topology with (4·82)2(42·811·10·12)(86), 5 and 6 display 3-nodal (2, 2, 4)-c topology with (2·44·6)(2)(4). 3 and 4 show 4-connected sql topology with (44·62). As expected, Zn MOFs 1-6 not only revealed a highly sensitive and selective fluorescence quenching effect on Fe3+ ions in aqueous solution, but also toughed the interference of a myriad of other metal ions. It is noteworthy that they could also be used as luminescent sensors for detection of tetracycline antibiotic.
Two novel Ni(II)-based monomeric complexes are applied to the UV-light-driven degradation of methyl violet (MV).
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Two Ni(II)-based monomeric complexes with the formulas of ...Ni(dbb)(H2O)2 (1) and Ni2(H2dbb)2(xda)(H2O)2 (2) (H2dbb = 6,6′-di(benzimidazol-2-yl)-2,2′-bipyridine, H4xda = 5,5′-(1,4-xylylenediamino) diisophthalic acid) have been successfully synthesized under solvothermal conditions. Structural analysis revealed that the discrete monomers of 1 and 2 extend into high-dimensional networks through intermolecular hydrogen bonds, π···π stacking interactions and weak intermolecular interactions. As novel photocatalyst materials, 1 and 2 exhibited active performance towards the degradation of methyl violet (MV) under UV irradiation. Besides, the cyclic experiments indicated that 2 was stable and reusable, enabling it to be potential candidates for dye-containing wastewater treatment. The possible mechanism of the photocatalytic performance was also investigated in detail. Moreover, the magnetic susceptibility measurements of 1 and 2 demonstrated that week antiferromagnetic interactions were operative between the Ni(II) ions.
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