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Leading by cytotoxicity against HepG2 cells, bioactivity-guided fractionation of the EtOAc fraction from Artemisia atrovirens led to the isolation of 18 new guaianolide dimers, artematrolides A–R and lavandiolides A, B, C, H, and J. Eight compounds (1, 4, 10, 12, 13, and 19–21) were unambiguously confirmed by the single-crystal X-ray diffraction analyses, and the others were elucidated based on IR, UV, HRESIMS, 1D and 2D NMR experiments, and comparison of the experimental and calculated ECD data. Structurally, all of them were [4 + 2] Diels–Alder adducts of two monomeric guaianolides. The isolates were evaluated for their cytotoxicity against three human hepatoma cell lines, and 19 compounds demonstrated cytotoxicity against HepG2, SMMC-7721, and Huh7 cell lines. Especially, compounds 1, 12, 14, and 15 exhibited cytotoxicity with IC50 values of 4.4, 3.8, 7.6, and 6.7 μmol/L (HepG2), 9.6, 4.6, 6.6, and 6.0 μmol/L (SMMC-7721), and 7.6, 4.5, 6.9, and 5.6 μmol/L (Huh7), respectively. Notably, compound 12 showed the most promising activity against three human hepatoma cell lines and dose-dependently inhibited cell migration and invasion, induced G2/M cell cycle arrest and cell apoptosis in HepG2 cells, down-regulated the expression of BCL-2 and PARP-1, and activated PARP-1 to up-regulate the expression of cleaved-PARP-1.

Artatrovirenols A and B (1 and 2), two novel cagelike sesquiterpenoids, possess a unique 5/5/6/5/5-pentacyclic and a 5/5/6/5-tetracyclic system with an unprecedented tetracyclo[5.3.1.1.4,1101,5]dodecane scaffold from Artemisia atrovirens. The structures of compounds 1 and 2 including their absolute stereochemistry were elucidated through extensive spectroscopic analyses, X-ray crystallography, and quantum chemical calculations. Plausible biosynthetic pathways for the new isolates were proposed from the naturally occurring arglabin (3) via the key intramolecular Diels-Alder cycloaddition. Compound 1 showed cytotoxicity against three human hepatoma cell lines (HepG2, SMMC-7721, and Huh7) with half maximal inhibitory concentration values of 123.8, 44.0, and 142.6 μΜ, respectively.

The dried fruits of Amomum tsao-ko were first revealed to have hypoglycemic effects on db/db mice at a concentration of 200 mg/kg. In order to clarify the antidiabetic constituents, 19 new flavanol-fatty alcohol hybrids, tsaokoflavanols A-S (1-19), were isolated and determined by extensive spectroscopic data and ECD calculations. Most of the compounds showed α-glucosidase and PTP1B dual inhibition, among which 1, 2, 6, 11, and 18 exhibited obvious activity against α-glucosidase with IC50 values of 5.2-9.0 μM, 20-35 times stronger than that of acarbose (IC50, 180.0 μM); meanwhile, 6, 10-12, and 19 were PTP1B/TCPTP-selective inhibitors with IC50 values of 56.4-80.4 μM, 2-4 times stronger than that of suramin sodium (IC50, 200.5 μM). Enzyme kinetics study indicated that compounds 1, 2, 6, and 11 were α-glucosidase and PTP1B mixed-type inhibitors with Ki values of 13.0, 11.7, 2.9, and 5.3 μM and 142.3, 88.9, 39.2, and 40.8 μM, respectively. Docking simulations proved the importance of hemiacetal hydroxy, the orientation of 3,4-dihydroxyphenyl, and the length of alkyl in binding with α-glucosidase and PTP1B.

Abstract Two new sesquiterpenoids, artemlavanins A (1) and B (3), together with fifteen known compounds (2 and 4−17) were isolated from the EtOH extract of Artemisia lavandulaefolia. The structures of new compounds were elucidated by extensive spectroscopic analyses (HRESIMS, 1D and 2D NMR) and ECD calculations. Compound 1 was a sesquiterpenoid lactone possessing a rearranged eudesmane skeleton; compounds 2–5, 6–8, 9 and 10–12 belonged to the eudesmane, guaiane, oppositane and farnesane sesquiterpenoids, respectively; compounds 13–17 were the phenyl derivatives with a 4-hydroxyacetophenone moiety. Twelve compounds (1–3, 5–7, 10–12, 14, 15 and 17) displayed cytotoxicity against hepatic stellate cell line LX2 (HSC-LX2) with IC50 values ranging from 35.1 to 370.3 μM. Compounds 2, 7, 10–12 and 17 exhibited the stronger cytotoxicity than silybin (IC50, 169.6 μM) with IC50 values of 82.1, 35.1, 95.0, 83.8, 81.6 and 90.1 μM. Compound 7 as the most active one showed significant inhibition on the deposition of human collagen type I (Col I), human hyaluronic acid (HA) and human laminin (HL) with IC50 values of 10.7, 24.5 and 13.3 μM. Graphic Abstract

Spiroseoflosterol (1), a 7(8→9)-abeo-ergostane steroid with a unique spiro[4.5]decan-6-one system, was isolated from the fruiting bodies of Butyriboletus roseoflavus. Its structure was determined by interpretation of comprehensive spectroscopic, X-ray, and computational data. A plausible biogenetic pathway for spiroseoflosterol (1) was postulated based on a key semipinacol rearrangement. Compound 1 was cytotoxic to HepG2 and Huh7/S (sorafenib-resistant Huh7) with IC50 values of 9.1 and 6.2 μM, respectively.

The biomimetic synthesis of guaianolide dimers lavandiolides H, I, and K and artematrolide F containing a spirolactone moiety has been accomplished for the first time from naturally abundant arglabin in four to six steps with an overall yield up to 60%, and a series of natural product-like guaianolide dimers, trimer, and tetramer were also successfully synthesized. Notably, the trimeric compound exhibited antihepatoma cytotoxicity more potent than that of sorafenib with IC50 values of 6.2 μM (HepG2), 6.8 μM (Huh7), and 7.2 μM (SK-HEP-1).

Ethnopharmacological relevance Artemisia capillaris (Yin-Chen) is a famous traditional Chinese medicine (TCM) for treating acute and chronic hepatitis in China. Enynes are one type of characteristic constituents in this herb, while their anti-hepatitis B virus (anti-HBV) properties have not been systemically investigated. Aim of the study This study is to reveal the active part of A. capillaris, and systemically investigate the enynes and their anti-HBV activity. Materials and methods The total extract and each fraction of A. capillaris were assayed for the anti-HBV activity to reveal the active part. Bioassay-guided fractionation using various chromatographic techniques yielded the enynes, whose structures were elucidated by spectroscopic analyses and ECD calculations. The anti-HBV properties inhibiting HBsAg and HBeAg secretions and HBV DNA replication were evaluated on HepG 2.2.15 cell line in vitro. Results ACT-2 and ACT-3 was revealed to be the respective active and toxic part of A. capillaris. Twelve enynes (1–12) involving four new ones (1–4) and two unusual enyne analogs (13–14) were isolated from the active part (ACT-2). All the isolates were assayed for their anti-HBV activity, and the preliminary structure-activity relationships were summarized based on the structural features. In particular, compound 4 could significantly inhibit the secretions of HBsAg and HBeAg, and HBV DNA replication with IC50 values of 197.2 (SI > 5.1), 48.7 (SI > 20.5) and 9.8 (SI > 102) μM. Conclusions Enynes are responsible for the anti-HBV effects of A. capillaris. Hydroxyl and glycosyl groups are preferable for maintaining activity. This is the first time to systematically investigate the anti-HBV activity of enynes in A. capillaris, which provides valuable information for understanding the ethnopharmacological application of Yin-Chen.

Liver fibrosis is a final result of extensive deposition of extracellular matrix (ECM) and starts with the activation and proliferation of hepatic stellate cells (HSCs). Our previous study showed that eudesmane sesquiterpenoid santamarin had cytotoxicity against hepatic stellate cell line LX2 (HSC-LX2) with IC50 values of 16.5 ± 0.7 μM. To explore the structure–activity relationships, twenty-six derivatives were synthesized by modifying the hydroxyl group, double-bond and unsaturated lactone. Cytotoxicity evaluation suggested that eight derivatives (6, 9, 13, 17, 20 and 25–27) increased activity against HSC-LX2. Especially, derivatives 17, 20 and 25 displayed obvious cytotoxicity with IC50 values of 6.4 ± 0.4, 4.6 ± 0.1, and 3.5 ± 0.1 μM, which were 3 to 5-fold higher than santamarin. Preliminary mechanisms study revealed that the active compound 20 exhibited more than 8-fold and 6-fold enhancement of inhibitory effect on the deposition of human hyaluronic acid (HA) and human laminin (HL) with IC50 values of 7.6 ± 0.6 and 3.3 ± 1.2 μM.

As a successful anti-tumor drug target, the family of histone deacetylases (HDACs) is also a critical player in immune response, making the research of anti-inflammatory HDAC inhibitors an attractive new focus. In this report, triterpenoids nigranoic acid (NA) and manwuweizic acid (MA) were identified as HDAC inhibitors through docking-based virtual screening and enzymatic activity assay. A series of derivatives of NA and MA were synthesized and assessed for their biological effects. As a result, hydroxamic acid derivatives of NA and MA showed moderately increased activity for HDAC1/2/4/6 inhibition (the lowest IC50 against HDAC1 is 1.14 μM), with no activity against HDAC8. In J774A.1 macrophage, compound 1–3, 13 and 17–19 demonstrated inhibitory activity against lactate dehydrogenase (LDH) and IL-1β production, without affecting cell viability. Compound 19 increased the histone acetylation level in J774A.1 cells, as well as inhibited IL-1β maturation and caspase-1 cleavage. These results indicated that compound 19 blocks the activation of NLRP3 inflammasome, probably related to HDAC inhibition. This work provided a natural scaffold for developing low-cytotoxic and anti-inflammatory HDAC inhibitors, as well as a class of tool molecules for studying the relationship between HDACs and NLRP3 activation.

Depression is associated with high mortality and morbidity rates worldwide. By our random screening, it was first revealed that 23 magnolol derivatives were synthesized followed by in vitro and in vivo evaluation of their antidepressive potential. Compound 7c was found to be the most promising compound, with EC50 values of 396.5 and 383.0 μM agitating on MT1 and MT2 receptors, respectively. Additionally, we carried out in vivo experiments to confirm the efficacy and safety of compound 7c; the compound was found to be orally bioavailable and highly effective, leading to a significant reduction of immobility time in a mouse model of depression (forced swimming test and tail suspension test); the acting mechanism was explored by determining its effect on the levels of monoamine neurotransmitters and their metabolites in different mice brain regions; the acute toxicity study showed that the 50% lethal dose (LD50) of 7c was higher than 2000 mg/kg, p. o. A total of 25 metabolites of 7c were identified, including 5 metabolites in phase I and 20 metabolites in phase II. Altogether, these results indicate that magnolol derivative 7c is a promising lead compound for the development of a new chemical class of antidepressant drugs.

Under the guidance of bioassay against HSC-LX2, the EtOH extract and the EtOAc fraction of Artemisia capillaris (Yin-Chen) exhibited cytotoxic activity against HSC-LX2 with inhibitory ratios of 39.7% and 68.7% at the concentration of 400.0 μg/mL. Bioassay-guided investigation of Fr. D (the active fraction) yielded 14 new coumaric acid analogues, artemicapillasins A–N (1–14). The structures of the isolates were elucidated by spectroscopic analyses involving UV, IR, MS, 1D and 2D NMR spectra and ECD calculations. Cytotoxic activity against HSC-LX2 cells of these isolates was performed to reveal that 12 compounds demonstrated cytotoxicity with inhibitory ratios more than 50% at 400 μM. The most active artemicapillasin B (2) gave an IC50 value of 24.5 μM, which was about 7 times more toxic than the positive drug silybin (IC50, 162.3 μM). Importantly, artemicapillasin B (2) showed significant inhibition on the deposition of human collagen type I (Col I), human laminin (HL) and human hyaluronic acid (HA) with IC50 values of 11.0, 14.4 and 13.8 μM, which was about 7, 11 and 5 times more active than silybin. Artemicapillasin B (2) as an interesting antihepatic fibrosis candidate is worth in-depth study.

Herein a nano-scale bimetallic Fe/Eu-MOF with a regular octahedral structure was synthesized for the first time. The synthesized Fe/Eu-MOF has both peroxidase-like activity and fluorescence properties. Fe/Eu-MOF can catalyze H2O2 to oxidize the chromogenic substrate TMB to produce blue oxTMB, which has ultraviolet absorption at 652 nm. Unexpectedly, the generated oxTMB can effectively quench the fluorescence of the catalyst Fe/Eu-MOF at 450 nm. The quenching mechanism is mainly the internal filtration effect (IFE), accompanied by static quenching (SQE), Forster resonance energy transfer (FRET) and photoelectron transfer (PET). Fe/Eu-MOF has a high affinity for sodium pyrophosphate (PPi). PPi can be adsorbed to the surface of Fe/Eu-MOF, destroying the structure of Fe/Eu-MOF and inhibiting its catalytic activity, resulting in a decrease in UV absorbance and the decline of fluorescence quenching. In contrast, phosphoric acid (Pi) has almost no effect on the reaction system. Alkaline phosphatase (ALP) can catalyze the hydrolysis of PPi to Pi, thereby reducing the inhibitory effect of PPi. Based on this, we successfully constructed a dual-mode ALP sensor with high selectivity. The linear ranges based on the 652 nm absorption or the fluorescence detection are from 1 to 200 U/L, and the detection limits are 0.6 for the absorption method and 0.9 U/L for the fluorescence method, respectively.

Carbon nanofibers embedded with ultrafine zirconia nanoparticles (ZrO2-CNFs) are fabricated via a new methodology. Polyvinylpyrrolidone (PVP) and polymethylmethacrylate (PMMA) binary polymers containing zirconium n-butoxide are first dissolved in dimethylformamide, and the resulting solution is electrospun and heat-treated. The tetragonal zirconia nanoparticles formed, with a size of 5±2nm in diameter, are uniformly distributed in the carbon nanofibres. Using Nafion as an additive, ZrO2-CNFs are drop-cast onto the glassy carbon electrode (ZrO2-CNF/GCE) and the modified electrode is then applied to detect methyl parathion (MP) using differential pulse voltammetry. Two linear relationships are found at the concentration ranges of 1×10−9–2×10−8g/L and 2×10−8–2×10−7g/L, with a detection limit of 3.4×10−10g/L (S/N>3). The electrospun-based ZrO2-CNF is a very promising coating material for electrochemical sensing of organophosphorus compounds. Keywords: Zirconia nanoparticles, Electrospinning, Carbon nanofiber, Methyl parathion, Electrochemical sensor

Twenty-four gramine derivatives were synthesized and evaluated on MT1 and 5-HT1A receptors in vitro. Among them, seven derivatives (7, 8, 16, 19, 20, 21, and 24) exhibited higher agonisting activities on MT1 or 5-HT1A receptors. Compared with gramine, derivatives 7, 8, 16, 19, 20, 21, and 24 displayed 1.6–3.5-fold increase in agonistic rates on 5-HT1A receptor. Particularly, derivatives 7, 19, and 21 exhibited significant agonistic activities on MT1 and 5-HT1A receptors with EC50 values of 0.51, 0.39, 0.50 mΜ and 0.28, 0.46, 0.23 mΜ, respectively. The preliminary structure–activity relationships of gramine derivatives were summarized for further investigation on MT1 and 5-HT1A receptors as new potential agonists.

The EtOH extracts of the dried seeds of Alpinia katsumadai were revealed with hypoglycemic effects on db/db mice at the concentration of 200 mg/kg. In order to clarify the antidiabetic constituents, 16 new diarylheptanoid-chalcone hybrids, katsumadainols A1−A16 (1–16), together with 13 known analogues (17–29), were isolated from A. katsumadai under the guidance of bioassay. Most of the compounds showed α-glucosidase and PTP1B dual inhibition, among which compounds 1–3, 5–7, 11–14, 21–25, and 27 showed PTP1B/TCPTP selective inhibition with IC50 values ranging from 22.0 to 96.7 μM, which were 2–10 times more active than sodium orthovanadate (IC50, 215.7 μM). All compounds exhibited obvious inhibition against α-glucosidase with IC50 values of 2.9–29.5 μM, indicating 6–59 times more active than acarbose (IC50, 170.9 μM). Study of enzyme kinetics indicated compounds 1, 3, and 12 were PTP1B and α-glucosidase mixed-type inhibitors with Ki values of 13.1, 12.9, 21.6 μM, and 4.9, 7.4, 3.4 μM, respectively.

New and highly stable Eu(III) and Tb(III) complexes based on two triarylborane functionalized cyclen derivative ligands L1 and L2, have been achieved. The Eu(III) and Tb(III) lanthanide compounds have been found to display highly distinct and contrasting temperature-dependent dual emission and decay lifetimes, rendering them as potential sensitive temperature probes. The emission colors of the new lanthanide complexes can be tuned by controlling the ratio of the Eu(III) and Tb(III) complexes in a binary composite and the temperature. Bright white light emission based on the new binary Eu(III) and Tb(III) complexes has been achieved. Furthermore, the triarylborane functionality of the new complexes enables their use as effective probes for anions such as fluoride ions, allowing the further tuning of the lanthanide emission.

Seven new phenolic glycosides including two heterocyclic phenolic derivatives orcinosides I-J (1-2) and five chlorophenolic glycosides curculigines J-N (3-7), together with nineteen known compounds were isolated from the rhizome of Curculigo orchioides. Based on extensive spectroscopic analyses (UV, IR, HRESIMS, 1D and 2D NMR), the structures of the new compounds were identified. Orcinoside I (1) and J (2) displayed xanthine oxidase inhibitory activities with IC50 values 0.25 and 0.62mM respectively.

Different dimensional siliciferous particles including silica (0D), halloysite nanotubes (HNTs,1D) and montmorillonite (MMT,2D) were melt blending with certain amount of melamine cyanurate and polyamide 6(PA6) by a twin-screw extruder. Characterization of the PA6 composites has been investigated using scan electron microscopy (SEM), thermal gravimetric analyzer (TGA), universal testing machine and limiting oxygen index instrument. SEM images indicate that the nanoparticles were uniformly dispersed in the PA6 but there was some aggregation of MCA in the composites. The incorporation of silica exerted a negative effect on the flame retardancy of PA6/MCA composite, whereas adding HNTs and MMT lead to the improvements of LOI value of 30.4 and 30.9 respectively. TGA results show that PA6/MCA/silica, PA6/MCA/HNTs and PA6/MCA/OMMT exhibit two degradation stages. Higher Tmax1 and Tmax2 appeared comparing with PA6/MCA. Char residue of PA6/MCA/OMMT at 600°C were elevated most. HNTs and OMMT can increase the tensile strength and elongation of PA6/MCA by universal testing machine results, even higher than pure PA6, showing enhanced effects of these 1D and 2D fillers. These could enhance strength of the char and finally increase the flame retardancy of PA6.

Sixteen tropinone derivatives were prepared, and their antitumor activities against five human cancer cells (HL-60, A-549, SMMC-7721, MCF-7 and SW480) were evaluated with MTS [3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxy methoxyphenyl)-2-(4-sulfopheny)-2H-tetrazolium] assay. Most of the derivatives exhibited better activities compared with tropinone at the concentration of 40 μM. Particularly, derivative 6 showed significant activities with IC50 values of 3.39, 13.59, 6.65, 13.09 and 12.38 μM respectively against HL-60, A-549, SMMC-7721, MCF-7 and SW480 cells, which suggested more potent activities than that of cis-dichlorodiamineplatinum (DDP). Graphical Abstract

The first total synthesis of rhuscholide A, a benzofuran lactone possessing anti-HIV-1 activity, had been accomplished in 14 linear steps with 10.6% overall yield. In this synthesis, base-mediated phenol ortho-alkylation and piperidine promoted aldol condensation were exploited as key steps. The synthesis was flexible and allowed for the convenient preparation of two analogous natural products glabralide B and denudalide.

The enantioselective addition of alcohols to isatin-derived N -Boc ketimines was investigated for the first time. Isatin-derived N , O -aminals were obtained in excellent yields with moderate-to-good enantioselectivities (up to 78% ee) in the presence of a quinine-based bifunctional catalyst.

Basic fibroblast growth factor (bFGF) plays an important role in angiogenesis. However, the underlying mechanisms are not clear. Mg(2+) is the most abundant intracellular divalent cation in the body and plays critical roles in many cell functions. We investigated the effect of bFGF on the intracellular Mg(2+) concentration ([Mg(2+)](i)) in human umbilical vein endothelial cells (HUVECs). bFGF increased [Mg(2+)](i) in a dose-dependent manner, independent of extracellular Mg(2+). This bFGF-induced [Mg(2+)](i) increase was blocked by tyrosine kinase inhibitors (tyrphostin A-23 and genistein), phosphatidylinositol 3-kinase (PI3K) inhibitors (wortmannin and LY294002) and a phospholipase Cgamma (PLCgamma) inhibitor (U73122). In contrast, mitogen-activated protein kinase inhibitors (SB202190 and PD98059) did not affect the bFGF-induced [Mg(2+)](i) increase. These results suggest that bFGF increases the [Mg(2+)](i) from the intracellular Mg(2+) stores through the tyrosine kinase/PI3K/PLCgamma-dependent signaling pathways.

The first enantioselective aza-Morita—Baylis—Hillman reaction of acrylates with ketimines derived from isatins is developed.

The first enantioselective vinylogous aldol–cyclization cascade reaction of allyl pyrazoleamides with isatins is reported. With 1 mol% of Takemoto catalyst, optically active spirocyclic oxindole–dihydropyranones were obtained in excellent yields (93–99%) and good-to-excellent enantioselectivities (82–97% ee).

The first organocatalytic Mannich coupling of pyrazoleamides with ketimines of type (I)/(VI) is reported.

A efficient procedure using a bifunctional squaramide catalyst is presented for the domino Mannich cyclization of isatin imines and 1,3-dicarbonyl compounds (II) and (IV) to produce 3-amino-2-oxindoles in high yields and excellent stereoselectivities.

The first enantioselective aza-Morita–Baylis–Hillman reaction of acrylates with ketimines derived from isatins has been developed. With 2 mol% of chiral bifunctional phosphine-squaramide 4e, optically active 3-substituted-3-amino-2-oxindoles were obtained in excellent yields with up to 91% ee.

The first organocatalytic enantioselective Mannich reaction of pyrazoleamides with isatin-derived N-Boc ketimines has been developed to afford 2-oxindole-based chiral β-amino amides in good yields (84–97%) with excellent diastereo- and enantioselectivities (up to 99:1 dr and >99% ee).

The enantioselective addition of alcohols to isatin-derived N-Boc ketimines is investigated for the first time.

Large-scale tetracene-doped anthracene nanowire arrays were prepared, and the doping effects were studied. The high doping concentration up to 10% (molar ratio) has been achieved, attributed to both the unique long-nanowire geometry and the excellent structural compatibility of anthracene and tetracene. The incorporation of long tetracene molecules into the matrix of short anthracene molecules induced an enlarged interlayer thickness, a decreased nanowire thickness, and an expanded nanowire width. The tetracene molecules were homogeneously embedded into the anthracene matrix at low doping concentrations (

Previously, we found that a furocoumarin derivative, psoralen (7H-furo[3,2-g][1]benzopyran-7-one), blocked a human Kv1.5 potassium channel (hKv1.5) and has a potential antiarrhythmic effect. In the present study, to develop more potent hKv1.5 blockers or antiarrhythmic drugs, we synthesized ten psoralen derivatives and examined their blocking effects on hKv1.5 stably expressed in Ltk cells. Among the newly synthesized psoralen derivatives, three derivatives (Compounds 5, 9 and 10) showed the open channel-blocking effect. Compound 9 among them was the most potent in blocking hKv1.5. We found that compound 9, one of the psoralen derivatives, inhibited the hKv1.5 current in a concentration-, use- and voltage-dependent manner with an IC50 value of 27.4 +/- 5.1 nM at +60 mV. Compound 9 accelerated the inactivation kinetics of the hKv1.5 channel, slowed the deactivation kinetics of hKv1.5 current resulting in a tail crossover phenomenon. Compound 9 inhibited hKv1.5 current in a use-dependent manner. These results indicate that compound 9, one of psoralen derivatives, acts on hKv1.5 channel as an open channel blocker and is much more potent than psoralen in blocking hKv1.5 channel. If further studies were done, compound 9 might be an ideal antiarrhythmic drug for atrial fibrillation.

An enantioselective domino reaction of 4-bromo-3-oxobutanoates with isatin-derived ketimines was developed to construct 3-amino-2-oxindoles with a quaternary stereocentre. In the presence of 1 mol-% of a bifunctional squaramide organocatalyst, the desired products were achieved in high yields (90–97 %) and with excellent enantioselectivities (92–99 % ee).

Radially oriented anthracene nanowires and their self-assembled concentric ring arrays were prepared through a facial solvent-evaporation method. The successful growth of anthracene nanowires can be attributed to a combined mechanism of molecular self-assembly facilitated by strong π-π intermolecular interactions together with evaporation-induced capillary flow and fingering instability. Their radial orientation is determined by the capillary flow; their shape (either straight or curved nanowires) is governed by the competition between the capillary and Marangoni convectional flows. The self-assembly of nanowires into large-scale concentric ring arrays can be interpreted in terms of the repeated slipping-and-sticking motions of the contact line. The high-quality crystalline anthracene nanowire arrays exhibit size-dependent fluorescence emission with high-degree anisotropy.

A solvent-soluble membrane filter is proposed for the simple and rapid preconcentration and spectrophotometric determination of ascorbic acid based on the reduction of 1, 10-phenanthroline (phen)-iron (III), which is collected on a nitrocellulose membrane filter as an ion-associate of the cationic complex of tri,phen-iron (II) [ferroin, Fe(phen)(2+)(3)] with an anionic surfactant (of dodecyl sulfate). The ion-associate collected is dissolved in a small volume of 2-methoxyethanol together with the filter. The colour intensity is measured at 510 nm against the reagent blank and is proportional to the content of ascorbic acid in the range 2.5-50 microg ascorbic acid in 5 ml of solvent with excellent reproducibility (RSD 3.2% for 200 microg 1(-1) ascorbic acid), the enrichment factor achieves 100-fold and detection limits better than 2.0 microg 1(-1) can be obtained. Diverse components of organic and inorganic compounds normally present in fruits, vegetable, beverages and urine do not interfere. The recoveries of the ascorbic acid added to the samples are quantitative.

An improved rapid method of extraction-photometric determination of trace amounts of nitrate and nitrite in water has been developed. In this method, nitrate is quickly reduced to nitrite at pH 3.0 in 5 min with freshly prepared cadmium sponge, which is produced in situ by action of zinc powder in dilute solution of cadmium chloride in presence of ammonium chloride. At pH 2.0, nitrous acid diazotizes with p-amino-acetophenone, which is then coupled with N-(1-naphthyl)-ethylenediamine. The azodye formed is extracted into n-butanol at pH 2.0 in the presence of β-naphthyl sulfonic acid and aluminium nitrate. The absorbance is measured at 550 nm. The molar absorptivity of the extract is about 4.8 × 104 1 · mol−1 · cm−1. The ions normally present in water do not interfere when sodium metaphosphate is added as a masking agent. Water from several sources has been analyzed by this method, and results found are satisfactory.

A new simple and sensitive procedure for spectrophotometric determination of traces of arsenic has been developed. At pH 5.3, arsine generated usually reacts with silver acetate in the aqueous solution in the presence of Tween-80 to form yellow silver sol, which has an absorption maximum at 420 nm. The molar absorptivity at the wave is found to be 4.8 × 104 l·mole−1 · cm−1. Beer's law is obeyed for 0.3-5.0 μg of arsenic in 20 ml absorbing solution. This method has been used in the determination of arsenic in water and wastewater samples and results are found satisfactory.

Techniques have been developed which allow HPLC (high performance liqid chromatography) to be used for the quantitative determination of [ 99m Tc]pertechnetate in radiopharmaceuticals and biological samples. An instrumental technique accounts for 99m Tc species which do not elute from the HPLC column, while a chemical technique obviates interferences caused by Sn(II). These two techniques are incorporated into an anion exchange HPLC procedure which is applied to the determination of [ 99m Tc]pertechnetate in 99m Tc-diphosphonate radiopharmaceuticals and biological samples.