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A new chiral one-dimensional gadolinium coordination polymer [Gd(HDTTA)3(CH3OH)3]n (1) (D-H2DTTA = (+)-Di-p-toluoyl-D-tartaric acid) was synthesized at room temperature, and fully structurally characterized by Infrared (IR), elemental analysis (EA), single-crystal and powder X-ray diffraction (PXRD). The structure analysis shows that complex 1 belongs to the trigonal system with R3 space group and displays an infinite chain structure along the c axis. In 1, each Gd3+ cation is in the tri-capped trigonal prism geometry, and neighboring Gd3+ cations are connected by three partly deprotonated HDTTA− ligands with the Gd···Gd distance of 7.686(1) Å. The circular dichroism (CD) spectrum demonstrates the chirality of the complex. Magnetic studies reveal that complex 1 displays weak antiferromagnetic interactions between Gd3+ cations and it exhibits a small magnetic entropy change (−ΔSm = 7.26 J kg−1 K−1 with ΔH = 7 T and T = 2.5 K) because of long Gd···Gd distance and relatively low magnetic density. [ABSTRACT FROM AUTHOR]

Herein, a novel and fluorescent zinc-organic framework sensor [Zn3(μ3-Hbptc)2(μ2-4,4′-bpy)2(H2O)4]n·2nH2O (1) (H4bptc = 2,3,3′,4′-biphenyl tetracarboxylic acid, 4,4′-bpy = 4,4′-bipyridine) is synthesized and characterized, demonstrating its excellent fluorescence performance for Cu2+ detection and the enrichment of Cu2+ in aqueous media. The fluorescence intensity of 1 can be selectively quenched by Cu2+ in a linear range of Cu2+ concentrations of 0–0.7 μM. The limit of detection (LOD) value is as low as 32.4 nM, which is superior to those of most of the fluorescent sensors based on metal–organic frameworks (MOFs). It is also far below the maximum allowable concentration of Cu2+ in drinking water as defined by the U.S. Environmental Protection Agency (EPA) and the World Health Organization (WHO), so it is employed for the detection of Cu2+ in actual water samples. More importantly, the nature of the interaction between the active coordination site (COO−) of 1 and Cu2+ determines the quenching mechanism, that is Cu2+ in the analyte is captured by MOF 1, which has been investigated by ICP, luminescence, UV-vis, XPS, and lifetime studies. Besides, the chemosensor shows regeneration performance without the loss of performance in five consecutive cycles. So MOF 1 is a simple and convenient probe used not only for the rapid detection but also for the enrichment of trace amounts of Cu2+ in aqueous media, and the application can be further extended to a variety of environmental and biological analysis processes. [ABSTRACT FROM AUTHOR]

Based on the investigation and analysis of seven soil mineral substance variables, nine vegetation factors, four topographical factors, and ten soil physicochemical factors in the 200 x40 m dynamic monitoring plots in farmland, forest plantation, secondary forest, and primary forest in the depressions between hills in karst region, and by using traditional statistical analysis, principal component analysis (PCA), and canonical correlation analysis (CCA), this paper studied the compositional characteristics and roles of soil mineral substances as well as the coupling relation- ships between the mineral substances and the vegetation, topography, and other soil properties. In the depressions, soil mineral substances were mainly composed of SiO2, Al2O3, K2O, and Fe2O3, whose contents were obviously lower than the mean background values of the soils in the world and in the zonal red soils at the same latitudes. The soil CaO and MgO contents were at medium level, while the soil MnO content was very low. The composition of soil mineral substances and their varia- tion degrees varied with the ecosystems, and the soil development degree also varied. There was a positive correlation between vegetation origin and soil origin, suggesting the potential risk of rock desertification. Due to the high landscape heterogeneity of the four ecosystems, PCA didn't show good effect in lowering dimension. In all of the four ecosystems, soil mineral substances were the main affecting factors, and had very close relationships with vegetation, topography, and other soil properties. Especially for SiO2, CaO, and MnO, they mainly affected the vegetation species diver- sity and the soil organic matter, total nitrogen, and total potassium. This study indicated that soil mineral substances were the one of the factors limiting the soil fertility and vegetation growth in the depressions between hills in karst region. To effectively use the soil mineral resources and rationally apply mineral nutrients would have significances in the restoration and reconstruction of karst degraded ecosystems. [ABSTRACT FROM AUTHOR]

Herein, a novel and fluorescent zinc-organic framework sensor [Zn 3 (μ 3 -Hbptc) 2 (μ 2 -4,4'-bpy) 2 (H 2 O) 4 ] n ·2nH 2 O (1) (H 4 bptc = 2,3,3',4'-biphenyl tetracarboxylic acid, 4,4'-bpy = 4,4'-bipyridine) is synthesized and characterized, demonstrating its excellent fluorescence performance for Cu 2+ detection and the enrichment of Cu 2+ in aqueous media. The fluorescence intensity of 1 can be selectively quenched by Cu 2+ in a linear range of Cu 2+ concentrations of 0-0.7 μM. The limit of detection (LOD) value is as low as 32.4 nM, which is superior to those of most of the fluorescent sensors based on metal-organic frameworks (MOFs). It is also far below the maximum allowable concentration of Cu 2+ in drinking water as defined by the U.S. Environmental Protection Agency (EPA) and the World Health Organization (WHO), so it is employed for the detection of Cu 2+ in actual water samples. More importantly, the nature of the interaction between the active coordination site (COO - ) of 1 and Cu 2+ determines the quenching mechanism, that is Cu 2+ in the analyte is captured by MOF 1, which has been investigated by ICP, luminescence, UV-vis, XPS, and lifetime studies. Besides, the chemosensor shows regeneration performance without the loss of performance in five consecutive cycles. So MOF 1 is a simple and convenient probe used not only for the rapid detection but also for the enrichment of trace amounts of Cu 2+ in aqueous media, and the application can be further extended to a variety of environmental and biological analysis processes.