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Nanododecahedral ZIF-67 crystals were successfully synthesized by a simple coprecipitation method at room temperature and constructed with graphene oxide (GO) and Nafion as an electrochemical sensing platform for Cu2+. The properties of the electrode and the modified materials were analysed by cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), square wave stripping voltammetry (SWSV), scanning electron microscopy (SEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). The experimental results show that the ZIF-67/GO/Nafion/GCE sensor platform has a stronger adsorption effect on Cu2+. It has high sensitivity (101.29 μA·μM−1) and a low detection limit (7.55 nM) in the linear range of 0.01 to 1.0 μM, as well as long-term stability, good repeatability and selectivity. The recovery rate was between 95.7 and 102.7% for real water samples. The method can be used for the trace analysis of Cu2+, which is valuable for the detection of trace metal ions in real water samples. [ABSTRACT FROM AUTHOR]

DNA has long been used as a template for the construction of helical assemblies of inorganic nanoparticles.sup.1-5. For example, gold nanoparticles decorated with DNA (or with peptides) can create helical assemblies.sup.6-9. But without such biological ligands, helices are difficult to achieve and their mechanism of formation is challenging to understand.sup.10,11. Atomically precise nanoclusters that are protected by ligands such as thiolate.sup.12,13 have demonstrated hierarchical structural complexity in their assembly at the interparticle and intraparticle levels, similar to biomolecules and their assemblies.sup.14. Furthermore, carrier dynamics can be controlled by engineering the structure of the nanoclusters.sup.15. But these nanoclusters usually have isotropic structures.sup.16,17 and often assemble into commonly found supercrystals.sup.18. Here we report the synthesis of homodimeric and heterodimeric gold nanoclusters and their self-assembly into superstructures. While the homodimeric nanoclusters form layer-by-layer superstructures, the heterodimeric nanoclusters self-assemble into double- and quadruple-helical superstructures. These complex arrangements are the result of two different motif pairs, one pair per monomer, where each motif bonds with its paired motif on a neighbouring heterodimer. This motif pairing is reminiscent of the paired interactions of nucleobases in DNA helices. Meanwhile, the surrounding ligands on the clusters show doubly or triply paired steric interactions. The helical assembly is driven by van der Waals interactions through particle rotation and conformational matching. Furthermore, the heterodimeric clusters have a carrier lifetime that is roughly 65 times longer than that of the homodimeric clusters. Our findings suggest new approaches for increasing complexity in the structural design and engineering of precision in supercrystals. Ligand-protected gold nanoclusters are engineered to form complex arrangements of double and quadruple helices, which are based on the pairing of motifs on neighbouring enantiomers, akin to the base pairing seen in DNA double helices., Author(s): Yingwei Li [sup.1] , Meng Zhou [sup.2] , Yongbo Song [sup.3] , Tatsuya Higaki [sup.1] , He Wang [sup.2] , Rongchao Jin [sup.1] Author Affiliations: (1) Department of Chemistry, [...]

Objective: To explore the relationship between the expressions of P21, P27 and proliferating cell nuclear antigen (PCNA) in glomerular mesangial tissue and poor renal prognosis in patients with immunoglobulin A (IgA) nephropathy. Methods: A total of 145 patients with IgA nephropathy treated in Xiaogan Central Hospital from April 2017 to August 2019 were selected as the research object. The expressions of P21, P27 and PCNA in glomerular mesangial tissue were detected by immunohistochemistry. All patients were followed up for 24 months, and the prognosis were counted. The expressions of P21, P27 and PCNA in glomerular mesangial tissue of patients with different prognosis were compared and the influencing factors of poor prognosis in patients with IgA nephropathy were analyzed by Logistic regression analysis. Results: The expression rates of P21, P27 and PCNA positive cells in glomerular mesangial tissue of patients with IgA nephropathy were (38.69±6.83)%, (55.94±8.08)%, (33.47±5.72)%, respectively. The incidence rete of poor prognosis in patients with IgA nephropathy was 17.24%, and the expression rates of P21 and PCNA positive cells in glomerular mesangial tissue of patients with poor prognosis were higher than those in good prognosis group (P<0.05), while the expression rate of P27 positive cells was lower than that in good prognosis group (P<0.05). Logistic multiple regression analysis showed that elevated diastolic blood pressure, increased 24 h proteinuria, mesangial cell proliferation, segmental glomerulosclerosis, renal tubular atrophy/interstitial fibrosis, crescentic body, increased expression rates of P21 and PCNA positive cells and decreased expression rate of P27 positive cells were all risk factors affecting the poor prognosis of patients with IgA nephropathy (P<0.05). Conclusion: There are positive expressions of P21, P27 and PCNA in glomerular mesangial tissue of IgA nephropathy. The expression rates of P21 and PCNA positive cells in glomerular mesangial tissue of of patients with poor prognosis of IgA nephropathy are higher than those with good prognosis, while the expression rate of P27 protein positive cells is lower than those with good prognosis, which are risk factors for poor prognosis of patients with IgA nephropathy. [ABSTRACT FROM AUTHOR]

As heterogeneous catalysts, nanoclusters have been extensively investigated because of their exceptional catalytic performance. In this work, we propose an electrostatic attraction strategy to immobilize atomically precise positively charged [Au52Cu72(SR)55]+ (denoted as Au52Cu72(SR)55) nanoclusters supported onto negatively charged SBA‐15. As expected, the Au52Cu72(SR)55/SBA‐15 catalysts display outstanding activity for driving the benzyl azide‐phenylacetylene cycloaddition reaction (called as click reaction). In comparison to Au11/SBA‐15 and Cu13/SBA‐15 catalysts, the bimetallic Au52Cu72(SR)55/SBA‐15 catalysts exhibit the highest catalytic activity for click reaction. Moreover, to explore the effect of ligands on the catalytic performance of Au52Cu72(SR)55/SBA‐15 catalysts, Au52Cu72(SR)55/SBA‐15‐X (X is the heat treatment temperature, X=120, 250, 300) catalysts are obtained by calcining at different temperatures. Compared with Au52Cu72(SR)55/SBA‐15‐X (X=120, 250, 300), the uncalcined Au52Cu72(SR)55/SBA‐15 catalysts show the best recyclability for click reaction. The structural integrity of the Au52Cu72(SR)55 nanoclusters is a key factor contributing to their exceptional cyclic performance. This work will be valuable for designing an ideal ligand‐protected clusters‐based catalysts with superior performance for organic reactions. [ABSTRACT FROM AUTHOR]

Elucidating the structure–property relationships of ultra-small metal nanocluster with basic nuclear is of great significance for understanding the evolution mechanism in both the structures and properties of polynuclear metal nanoclusters. In this study, an ultra-small copper hydride (CuH for short) nanocluster was simply synthesized with high yield, and the large-scale preparation was also achieved. Single crystal X-ray diffractometer (SC-XRD) analysis shows that this copper NC contains a tetrahedral Cu4 core co-capped by four PPh2Py ligands and two Cl in which the existence of the central H atom in tetrahedron was further identified experimentally and theoretically. This CuH nanocluster exhibits bright yellow emission, which is proved to be the mixture of phosphorescence and fluorescence by the sensitivity of both emission intensity and lifetime to O2. Furthermore, the temperature-dependent emission spectra and density functional theory (DFT) calculations suggest that the luminescence of CuH mainly originates from the metal-to-ligand charge transfer and cluster-centered triplet excited states. This work offers new insights into understanding the structure–property relationship of basic nuclear CuH nanocluster. [ABSTRACT FROM AUTHOR]

The structure/composition of nanoclusters has a decisive influence on their physicochemical properties. In this work, we obtained two different Au–Ag nanoclusters, [Au9Ag12(SAdm)4(dppm)6Cl6]3+ and Au11Ag6(dppm)4(SAdm)4(CN)4, via controlling the Au/Ag molar ratios by a one-pot synthetic approach. The structure of nanoclusters was confirmed and testified by single-crystal x-ray diffraction, electrospray ionization time-of-flight mass spectrometry, XPS, powder x-ray diffraction, and electron paramagnetic resonance. The Au11Ag6 nanocluster possessed a M13 core caped by four Au atoms and four dppm and four AdmS ligands. Interestingly, four CN are observed to locate at the equator of the M13 core. Both nanoclusters contain a similar icosahedral M13 core, whereas their surface structures are totally different. However, the Au11Ag6 nanocluster exhibits good stability and strong red photoluminescence in solution. [ABSTRACT FROM AUTHOR]