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Azapropellanes have been extensively studied for their special application. Debenzylation of pentabenzylpentaaza[3,3,3]propellane was studied in this paper. The N-benzyl groups were removed by catalytic hydrogen transfer under the mild conditions with simple process. The yield of the debenzylation product was lower. Their structures of all compounds were confirmed by spectra.

The heterogeneous photo-Fenton process is still inhabited by the poor recycling of Fe(III)/Fe(II). Therefore, a visible light active α-FeOOH/BiOI catalyst was prepared by facile precipitation method. The synthesized photocatalysts were characterized by different methods, such as XRD, SEM, HR-TEM, XPS. Results showed that the loose flocculent of α-FeOOH covered on the BiOI particle. Rhodamine B was selected to evaluate the photocatalytic performance under visible-light irradiation in the presence of H2O2. The superior photocatalytic activity of 0.5M-FeOOH/BiOI was obtained that 100% of RhB can be degraded within 20 min illumination. UV–vis diffuse reflectance spectra and the photoluminescence measurements revealed that the 0.5M-FeOOH/BiOI composite enhanced charge carrier separation in the way of Fe(III) consumed photo electron to form Fe(II). Simultaneously, the acceleration of Fe(III)/Fe(II) recycling is beneficial to catalyze H2O2 to form hydroxide radical (·OH). Photo stability further revealed that the 0.5M-FeOOH/BiOI composite could be a promising material in wastewater treatment and other environmental remediation applications.

Four new triterpene glycosides, named salaciacochinosides A-D (1–4) were isolated from the 90% ethanol extract of Salacia cochinchinensis, together with five known compounds 2α,3β,23-trihydroxyurs-12,18-dien-28-oic acid 28-O-β- d -glucopyranoside (5), racemiside (6), alangiplatanoside (7), acantrifoside E (8), and syringin (9). The structures of the four new triterpenoids were characterized by chemical methods and MS, IR, 1D and 2D NMR spectral analyses. The α-glucosidase inhibitory activities of the nine compounds were assessed, compounds 6 and 7 showed remarkable α-glucosidase inhibitory activities, with IC50 values of 0.44 and 0.75 μM, respectively. Compounds 1–5 exhibited moderate α-glucosidase inhibitory activities, and compounds 8 and 9 showed none α-glucosidase inhibitory activity in our current experiments.

Two novel terpenoids, named norperovskatone (1), biperovskatone (2) were isolated from the cultured Perovskia atriplicifolia, together with five known compounds. Compound 1 was a novel C18 nor-diterpenoid featuring a unique seco-ring C. Compound 2 was an unusual dimer including two different diterpenoid units. The structures of the two novel compounds were established by comprehensive spectroscopic analysis, as well as by crystal X-ray diffractions. All of the isolates were evaluated for their anti-HBV activities. Compounds 1 and 2 were found to possess remarkable anti-HBV activity.

In order to understanding of the fate and transport of TiO2 nanoparticles (NPs) in the water treatment process, this study focused on the particle surface characteristics and hydrodynamic properties at different humic acid (HA) concentration, using aluminum sulfate (AS) as a coagulant. The changes of zeta potential of humic acid capped TiO2 NPs and flocs were measured by Malvern Zetasizer nanoZS. The surface functional group of flocs was investigated using FT-IR spectra. The growth velocity of alum-TiO2 NPs flocs were determined using a small-angle light scattering technique during the coagulation process.Experimental results indicated that the zeta potential of alum-TiO2 NPs flocs surface after adsorption of humic acid was related with humic acid concentration. Adsorption of humic acid resulted in more negative electrophoresis on the surface. Size and growth velocity of alum-TiO2 NPs flocs were estimated at different humic acid concentration. It was found that the flocs growed were faster in the presence of humic acid, while humic acid had adverse influences on the growth of alum-TiO2 NPs flocs.

In order to understanding of the fate and transport of TiO2 nanoparticles (Nps) in the water treatment process, this study focused on the impact of humic acid (HA) on the aggregation and charge behavior of TiO2 Nps, and investigated the removability of TiO2 Nps stabilized by HA during the coagulation process. Malvern Zetasizer nanoZS measured the changes of size and zeta potential of HA capped TiO2 Nps (HA-TiO2). Uv-vis spectrometer examined the aggregation behavior of TiO2 and HA-TiO2 NPs at different pH value. Jar tests were conducted to evaluate the removal efficiency of TiO2 NPs. HA adsorbed on the surface of TiO2 Nps could decrease the zeta potential values and enhance the stability of TiO2 Nps. TiO2 Nps could be effectively removed by aluminum sulfate (AS) under favorable condition. HA could influence the removal of TiO2 Nps during the coagulation processes. Low concentration of HA rejected the removal efficiency of TiO2 Nps, however, high concentration of HA promoted removing effectiveness.

Metal–organic frameworks (MOFs) are typically built by assembly of metal centres and organic linkers, and have emerged as promising crystalline materials in a variety of fields. However, the stability of MOFs is a key limitation for their practical applications. Herein, we report a novel Sr 2+ -MOF [Sr 4 (Tdada) 2 (H 2 O) 3 (DMF) 2 ] (denoted as NKU- 105 , NKU = Nankai University; H 4 Tdada = 5,5'-((thiophene-2,5-dicar bonyl)bis(azanediyl))diisophthalic acid; DMF = N,N -dimethylformamide) featuring an open square channel of about 6 Å along the c -axis. Notably, NKU- 105 exhibits much outstanding chemical stability against common organic solvents, boiling water, acids and bases, relative to most MOF materials. Furthermore, NKU- 105 is an environment-friendly luminescent material with a bright cyan emission. This article is part of the themed issue ‘Coordination polymers and metal–organic frameworks: materials by design’.

The microtopography of manganese dioxide formed in situ was captured by AFM. The adsorptive properties of manganese dioxide formed in situ were evaluated for trace organic pollutants' removal with four different organic pollutants as the model organics which have different functional groups on aromatic ring. Several factors, such as the structure of manganese dioxide formed in situ , the adsorption time, the adsorbent concentration, and the background constituents (Ca 2+ , Mg 2+ , fulvic acid, etc.) in natural water, were investigated to evaluate their effects on adsorption. Results showed that manganese dioxide formed in situ had smaller particle size and higher adsorption capacity than the coagulated one. Ca 2+ and Mg 2+ added to the aqueous solution decreased the organics' removal significantly by accelerating the coagulation of manganese dioxide formed in situ and competing the adsorption sites with organics. The presence of fulvic acid had little impact on organic removal though it competes for the surface sites of manganese dioxide with organics. The four organics adsorbed on manganese dioxide formed in situ are listed in the order of decreasing reactivity: aniline > phenol > nitrobenzene > benzoic acid. The relative reactivity of organics was discussed in terms of electrostatic interaction between organics and adsorbent.

A new diferric complex, Fe2Lb, in which a DNA intercalator (acridine) is linked to a precursor diferric complex (Fe2La), has been designed and synthesised as a hydrolytic cleaving agent of DNA. Compared with Fe2La (without the DNA intercalator) (La: 2,6-bis{[(2-hydroxybenzyl)(pyridin-2-yl)methylamino]methyl}-4-methylphenol), Fe2Lb [Lb: 5-(acridin-9-yl)-N-(3,5-bis{[(2-hydroxybenzyl)(pyridin-2-yl)methylamino]methyl}-4-hydroxybenzyl)pentanamide] leads to a 14-fold increase in the cleavage efficiency of plasmid DNA due to the binding interaction between DNA and the acridine moiety. The interaction has been demonstrated by UV/Vis absorption, CD spectroscopy, viscidity experiments and thermal denaturation studies. The hydrolytic mechanism is supported by evidence from T4 DNA ligase assay, reactive oxygen species (ROS) quenching and BNPP [bis(4-nitrophenyl) phosphate, a DNA model] cleavage experiments. The pH dependence of the BNPP cleavage by Fe2La in aqueous buffer media shows a bell-shaped pH–kobs profile with an optimum point around a pH of 7.0 which is in good agreement with the maximum point of the pH-dependent relative concentration curve of active species from the pH titration experiments. The determination of the initial rates at a pH of 7.36 as a function of substrate concentration reveals saturation kinetics with Michaelis–Menten-like behaviour and Fe2La shows a rate acceleration increase of 4.7 × 106 times in the hydrolysis of BNPP. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)

Three new compounds, atriplicone A (I), B (II), and C (III) are isolated together with five known compounds.

As DNA cleavage agent, a new diiron(III) complex (Fe 2 L b ), in which a DNA-intercalator (pyrene) is covalently linked to a diferric moiety, has been synthesized and characterized. The DNA-binding property and DNA cleavage activity of the complex have also been investigated.