Search

The synthesis, structural, and magnetic features of novel oxime-bridged polynuclear complexes Ni(II) and Cu(II) are presented. Rough models are employed to fit the magnetic susceptibilities of the two antiferromagnetic complexes.

An end-on azide-bridged dimeric [Mn.sup.III] complex is synthesized by using the tridentate N-isonicotinamidosalicylaidimine ligand. Magnetic studies show that the complex has a high-spin ground state of S=4 and is ac out-of-phase frequency-dependent.

A newly discovered easy and simple four-component domino reaction via combination of four common reactants and [Cs.sub.2]C[O.sub.3] in ethylene glycol under microwave heating is described. The resulting tricyclo[6.2.2.01,6]dodecane derivatives could find important application for organic and medicinal research.

Concise and efficient six-component and four-component domino methods to anti-1,2-diarylethylbenzamides and highly substituted 2-(2'-azaaryl)imidazoles developed under solvent-free and microwave-irradiation conditions are presented. The reactions involving new mechanism of microwave enabled umpulong showed a broad scope of substrates in which a wide range of common commercial aromatic aldehydes and heteroaryl nitriles could be used.

The article discusses the newly developed four-component domino reaction, which is used for the synthesis of the multifunctionalized quinazolines. The results demonstrate that these quinazolines are widely used in various organic and medical research applications.

The article explains the structure and the isolation of parnafungins, the antifungal natural products that inhibit mRNA polyadenylation. The fungal polyadenosine polymerase is shown to act as the biochemical target of these natural products.

The design and synthesis of a new cyanide-containing building block K[Fe(pcq)(CN)3]; [pcq = 8-(pyridine-2-carboxamido)quinoline anion] containing a low spin Fe(super III) center with three cyanides groups in a meridional arrangement is discussed. Three cyanide-bridged FeIII2MnII clusters were observed as a result of the reaction of K[Fe(pcq)(CN)3] with Mn(ClO4)2.6H2O, Mn(bipy)2Cl2 and Mn(phen)2Cl2.

Two unique cynano-bridged 2D coordination polymers have been synthesized and characterized structurally and magnetically. The structures are composed of two isomeric polyaza Cu(II) units and one novel macromolecular metallic compound.

In this study, a wave rectified alternating current (RAC) electrocoagulation process was developed for the oxidative sequestration of As(III) via simultaneous generating Fe(II) and O2 in the synthesized anoxic groundwater. The optimal TFe-anode/TMMO-anode:Tpower-off ratio (T is the time-taken in corresponding stage) and reaction period for As(III) sequestration were 1:2:1 and 24 s, respectively. Elevating electric current applied on the alternate iron/MMO anodes (30–50 mA) and solution pH (6.0–9.0) promoted As(III) sequestration, whereas the presence of HCO3– and PO43– deteriorated As(III) sequestration. The intermediate Fe(IV) primarily accounted for the oxidation of As(III) to As(V), which can be readily sequestrated by the freshly generated Fe(III) (oxyhydr)oxides. The energy required for As(III) sequestration in the RAC electrocoagulation process was only 0.11 kW·h m–3, which is much less than those in the traditional DC/AC electrocoagulation processes. Generally, this study offers an energy-efficient strategy to improve access to safe groundwater for millions of people. [ABSTRACT FROM AUTHOR]

Relaxor ferroelectrics exhibit superior properties for converting mechanical energy into electrical energy, and vice versa, but the structural disorder hampers an understanding of structure-property relationships and impedes rational design of new, lead-free materials. Bi0.5K0.5TiO3 (BKT) is a prototypical lead-free relaxor ferroelectric, but the microscopic origins of polarization, nature of the ferroelectric transition (TC), and structural changes across the tetragonal to pseudocubic transition (T2) are poorly understood. Here the local and intermediate structure of BKT is studied from room temperature to above TC by pair distribution functions (PDFs) from synchrotron X-ray total scattering experiments and complemented by ab initio molecular dynamics (AIMD) simulations. The local structure varies smoothly across T2 as well as TC, in contrast to the abrupt changes at TC inferred from conventional diffraction. Ferroelectric distortions are larger on the local scale than in the average structure, with polar Ti4+ displacements prevailing above TC. We find that local polar regions partly cancel each other below TC, while completely averaging out above, implying that BKT goes through a transition from partial to complete disorder across TC. [ABSTRACT FROM AUTHOR]

Boronate affinity materials have been successfully used for the selective recognition of glycoproteins. However, by such materials, the large-scale glycoproteins enrichment from human plasma under physiological conditions is rarely reported. In this work, 3-carboxybenzoboroxole (CBX) functionalized polyethylenimine (PEI) modified magnetic graphene oxide nanocomposites were synthesized. Benefitting from the low pKa value of CBX (~6.9) and PEI dendrimer-assisted multivalent binding, the Freundlich constant (KF) for the adsorption of horseradish peroxidase (HRP) was 3.0-7.3 times higher than that obtained by previous work, displaying the high enrichment capacity. Moreover, PEI could improve the hydrophilicity of nanocomposites and reduce nonglycoprotein adsorption. Therefore, such nanocomposites were successfully applied to the analysis of human plasma glycoproteome under physiological conditions, and the identified glycoproteins number and recognition selectivity was increased when compared to the results obtained by previous boronic acid-functionalized particles (Sil@Poly(APBA-co-MBAAm)) under common alkaline condition (137 vs 78 and 67.8% vs 57.8%, respectively). In addition, thrombin (F2), an important plasma glycoprotein, labile under alkaline conditions, was specifically identified by our method, demonstrating the great promise of such nanocomposites in the deep-coverage glycoproteome analysis. [ABSTRACT FROM AUTHOR]

Mesoporous metals are useful for heterogeneous catalysis because their ultrapermeable architecture promotes mass transport to abundant active sites. Our group recently developed a method to manipulate the interior space of nanocrystals by synthesizing mesoporous Rh nanospheres that serve as high performance catalysts for methanol oxidation and nitric oxide (NO) remediation (Jiang, B.; et al. Nat. Commun. 2017, 8, 15581). Here, we extend this concept and propose a sophisticated soft-templating strategy to synthesize three-dimensional mesoporous bimetallic RhCu nanospheres. The nanospheres are alloys of Rh and Cu, and their compositions can be continuously tuned by varying the amount of metal precursors. The mesoporous RhCu nanospheres were examined for catalytic remediation of NO and show good catalytic performance considering the reduced economic cost of the alloyed material. This method offers a general approach for the precise design of high surface area Rh-based metal catalysts. [ABSTRACT FROM AUTHOR]

We investigate A-site cation ordering in the ferroelectric perovskite Bi0.5K0.5TiO3 (BKT) by density functional theory (DFT) calculations and synchrotron X-ray total scattering. Using BKT as a prototypical lead-free ferroelectric perovskite with mixed A-site cations, we use a combination of theory and experiments to assess the energetics and resulting physical properties of cation ordering. Ten different Bi/K configurations in a 2 × 2 × 2 supercell were assessed by real space pair distribution functions (PDFs) and DFT calculations. None of these configurations were identified as particularly favorable from experiment or theory. Ferroelectric polarization calculated by the Berry phase method for all ten configurations yields values of 50-105 μC/cm². This is significantly larger than previously reported experimental results in the range of 22-49 μC/cm², indicating that BKT does not possess long-range A-site cation order. Reverse Monte Carlo (RMC) modeling of the total scattering data with a 12 × 12 × 12 supercell also supports substantial A-site disorder in BKT. A 4 × 4 × 4 supercell with local cation displacements in a pseudodisordered A-site sublattice reproduces the experimentally observed polarization, implying that in a real material there are multiple local polar regions which partly cancel each other. The combination of RMC modeling of PDFs with DFT calculations should be highly applicable to other crystalline materials with sublattice disorder. [ABSTRACT FROM AUTHOR]