Inductively Coupled Plasma （ICP） Mass Spectrometry （MS） Hyphenated with Atomic Emission Spectrometry（AES） for Simultaneous Determination of Major, Minor and Micro Amounts of Elements in Geochemical Samples

Introduction Geological resource survey demands for determining various constituents including major, minor, micro, trace and ultra-trace levels of elements for preparing the map of resource distribution of our country. As a powerful and popularly used technique for multi-element analysis, inductively coupled plasma（ICP） atomic emission spectrometry （AES） has been applied to this field for a period of time. However, ICP spectrometric determination of those micro, trace and ultratrace elements needs enrichment procedures for improving the detection limit, which is unacceptable in case a great mass of samples should be analyzed as that in the task of geological resource survey. On the other hand, although ICP mass spectrometry （MS） is considered the most powerful method for trace elements determination, it is difficult for ICP-MS to be used to determine the trace and major analytes simultaneously in a spectrum.     

Preconcentration by Using Microcrystalline Phenolphthalein for Determining Trace Molybdenum （Ⅵ） in Water by GFAAS

Molybdenum（ Ⅵ ） is a biologically essential trace element and its role in an extremely wide variety of systems has been reported. Most common methods often fail to determine trace Mo （ Ⅵ ） in the analysis of molybdenum-containing samples, due to limitations such as inadequate detection limits and matrix interference, which make the direct determinations impossible. To solve this problem, various approaches are employed to concentrate and separate Mo（ Ⅵ ） to detectable levels. Concentration and separation methods play a main role in the analysis of trace Mo（Ⅵ）. Therefore, many separation and preconcentration procedures have been developed for the determination of Mo （ Ⅵ ）.     

Thermal,Mechanical and Rheological Properties of Eco-friendly Poly（propylene carbonate）/Poly（1,2-propylene succinate） Blends

In order to improve the flexibility of poly（propylene carbonate） （PPC）, poly（1,2-propylene succinate） （PPSu） was used to plasticize PPC in a batch mixer. The effects of PPSu on the miscibility, thermal stability, mechanical and theological properties of the blends were investigated. PPC was partially miscible with PPSu. It was demonstrated that PPSu decreased the glass transition temperature and melt viscosity of PPC, as shown in the DSC and rheological curves. With the increase in PPSu content, the PPC/PPSu blends showed decreased tensile strength, however, the elongation at break was increased to 1100% for the 70/30 PPC/PPSu blend. The introduction of PPSu provided an efficient and novel plasticization method to extend the application area of PPC.     

Synthesis and blue light-emitting properties of 4,4＇-bis（diphenylamino）-quinque（p-phenyl）s

An excellent organic blue light-emitting diode based on 4,4＇-bis（diphenylamino）-quinque（p-phenylene）s （OPP（5）-NPh） with a maximum luminance of up to 5000 cd/m^2 and a luminanous efficiency of 1.3 cd/A was reported. This diode was made by using a wide band-gap hole-blocking layer, F-TBB instead of PBD in the OLED devices. We attribute the good performance to the one trade-off involved in the use of F-TBB to obtain higher luminance is the increased turn-on voltages and slightly decreased device efficiencies.     

PRELIMINARY INVESTIGATION ON THE MISCIBILITY OF ISOTACTIC POLYPROPYLENE （iPP） AND SYNDIOTACTIC POLYPROPYLENE （sPP） BLENDS

Experimental miscibility studies were performed on different compositions of iPP/sPP blends, where sPP has a low syndiotacticity （[rrrr] = 81%）. Combining optical microscopy, rheology, and solid state NMR spectroscopy, the miscibility of the blends was investigated at different scales in the traditionally thought to be ＂immiscible＂ iPP/sPP blends. For the composition of iPP/sPP （90/10） blend, it shows to be miscible in the melt, and furthermore, the existence of intermolecular chain interactions between sPP and iPP components was detected in the solid state.     

Structures and Aromaticity of Three-membered BeXP （X = C,Si, Ge） and CYP （Y = O,S, Se） Rings

Three-membered BeXP （X = C, Si, Ge） and CYP （Y = O, S, Se） rings are theoretically investigated using density functional theory （DFT） methods at the B3LYP/6-311＋G^＊ and B3PW91/6-311＋G^＊ levels of theory. The research results show that the size of atoms has a great influence on the structural stability of these species. The wiberg bond indexs （WBIs） suggest the existence of delocalization in these structures. Negative nucleus-independent chemical shift （NICS） values for these species indicate that a strong ring current exists in these three-membered structures （Cs symmetry）. A detailed molecular orbital （MO） analysis further reveals that a delocalized π MO strengthens the structural stability and makes these species show strong aromatic characters.     

CARRIER PHOTOGENERATION IN POLY（N-VINYL-CARBAZOLE）-BASED PHOTOCONDUCTIVE THIN-FILM DEVICES

In this paper, photoexcitation processes in the bilayer devices based on inorganic materials and poly（N-vinylcarbazole） （PVK） were investigated. In order to clarify the roles of inorganic materials in photoconductive properties of bilayer devices, TiO2 and ZnS were chosen to combine with PVK. A model for generation of photocurrent （Iph） in single layer device of PVK was obtained. It is deduced that the recombination rate constant （Pcomb） and the ionization rate constant （y） ofexcitons should be considered as the most important factors for Iph. For inorganic materials （TiO2 or ZnS）/PVK bilayer devices, in reverse bias of-4 V, the photocurrent of 115 mA/cm^2 in the TiO2/PVK device was observed, but the photocurrent in the ZnS/PVK device was only 10 mA/cma under the illumination light of 340 nm and the light intensity of 14.2 mW/cm^2. The weaker photocurrent is attributed to the absorption of ZnS within UV region and the energy offset at the interface between PVK and ZnS, which impedes the transport of charge carriers.     

Theoretical Investigation on the Absorption and Emission Properties of the Three Isomers of Bis（thiocyanato）（2,2^1-bipyridyl）platinum（ll）

This paper presents a Density Functional or Time Dependent Density Functional （DFT/TDDFT） study of the molecular and electronic structures, optical absorption and emission spectra of three linkage isomers： bis（isothiocyanato-S）（2,2^1-bipyridyl） platinum（II） （[Pt（SCN）2（bpy）]）, （isothiocyanato-S）（thiocyanato-N）-（2,2^1-bipy- ridyl） platinum（II） （[Pt（SCN）（NCS）（bpy）]）, and bis（thiocyanato-N）（2,2^1）-bipyridyl）platinum（II） （[Pt（NCS）2（bpy）]）, in which different coordination ligands based on the N- and S-coordination of the thiocyanato ligands control the luminescent color. The electronic structures were studied using the B3LYP functional. Optimized geometries Were compared to the experimentally observed structures. TDDFT calculation was carded out to investigate the excited singlet and triplet states. Calculations have been performed both in vacuo and in solvents, using a polarized continuum model （PCM） to account for solute-solvent interactions. Inclusion of the solvent led to a significant energy change, and as a consequence, the computed spectrum calculated in the presence of the solvent was in good agree- ment with the experimental determinations. The first two absorptions were found to originate from mixed plati- num-SCN （or NSC） to bipyridyl-n＊ transitions rather than pure metal-to-ligand-charge-transfer （MLCT） transitions, whereas the higher-energy bands arose from intraligand n→π＊ transitions. The stretching frequencies of C≡N have been calculated both in the ground and excited states, which are relative to the charge transition during the excitation. In addition, different sizes of basis sets were also discussed in this paper.     

FRACTAL CHARACTER OF PHASE MORPHOLOGY OF HIGH IMPACT POLYSTYRENE/POLY（cis-BUTADIENE） RUBBER BLENDS

Evolution and fractal character of the phase morphology of high impact polystyrene/poly（cis-butadiene） rubber （HIPS/PcBR） blends during melting and mixing were investigated using scanning electron microscopy （SEM）. The characteristic length L was defined as the size of particles of the dispersed phase in blends. Different fractal dimensions, Df and Din, were introduced to study the distribution width of phase dimensions in the dimensionless region and the uniformity of the spatial distribution of particles, respectively. The results showed that the average characteristic length Lm and Df increase as the volume fraction of the dispersed phase increases, when the volume fraction of the dispersed phase is lower than 50%. In other words, the size of particles increases and their distribution in the dimensionless region becomes more uniform. Meanwhile, the uniformity of the spatial distribution becomes more perfect as the volume fraction increases. At a certain composition, Lm decreases in the initial stage of the mixing and levels off in the late stage. In the initial stage, Df becomes large rapidly with the process of blending, which means that the distribution of L in the dimensionless region becomes more uniform. Meanwhile, the spatial distribution tends to be ideal rapidly in the early stage and fluctuates in a definite range in the late stage of the mixing.     

Preparation and Properties of Poly（vinyl alcohol）/Chitosan Blend Bio-nanocomposites Reinforced by Cellulose Nanocrystals

The aim of this paper is to report the effect of the addition of cellulose nanocrystals（CNCs） on the mechanical, thermal and barrier properties of poly（vinyl alcohol）/chitosan（PVA/Cs） bio-nanocomposites films prepared through the solvent casting process. The characterizations of PVA/Cs/CNCs films were carried out in terms of X-ray diffraction（XRD）, transmission electron microscopy（TEM）, scanning electron microscopy（SEM）, thermogravimetric analysis（TGA and DTG）, oxygen transmission rate（OTR）, and tensile tests. TEM and SEM results showed that at low loading levels, CNCs were dispersed homogenously in the PVA/Cs matrix. The tensile strength and modulus in films increased from 55.1 MPa to 98.4 MPa and from 395 MPa to 690 MPa respectively, when CNCs content went from 0 wt% to 1.0 wt%. The thermal stability and oxygen barrier properties of PVA/Cs matrix were best enhanced at 1.0 wt% of CNCs loading. The enhanced properties attained by incorporating CNCs can be beneficial in various applications.     

Synthesis of (-)-fortamine and (+)-2-deoxyfortamine from resolved 3S,4S-N-carbomethoxy-3-aminocyclohexen-4-ol

A three step sequence (Scheme I) starting with racemic 3,4-epoxycyclohexene (5) and (S)-α-methylbenzylamine gave 3S,4S-N-carbomethoxy-3-aminocydohexen-4-ol (10) with chromatographic removal of the undesired 3R,4R byproduct. The absolute configuration of 10 was established by x-ray crystallographic analysis of its precursor, 6 (as the HCl salt). Resolved 10 was converted to the aminocyditols (-)-fortamine (1) and (+)-2-deoxyfortamine (2) by efficient routes which parallel those previously developed in the racemic series.     

Studies on organophosphorus compounds: Thiation of 3,1-benzoxathian-4-ones. New routes to 1,2-benzisothiazole-3(2H)-thiones and 3H-1,2-benzodithiol-3-imines

3,1-Benzoxathian-4-ones, 2, when heated with 2,4-bis(4-methoxyphenyl)-1,3,2,4-dithiadiphosphetane-2, 4-disulfide, 1, or with P₄S₁₀ give one or more of the following products 3,1-benzoxathian-4-thione, 3, 1,3-benzodithian-4-one, 4, 1,3-benzodithian-4-thione, 5, and 3H-1,2-benzodithiole-3-thione, 6. Compounds 2, when heated with primary and secondary amines and with hydrazines, give 2-mercaptobenzamides, 7, and 2-mercaptobenzohydrazides, 8, or their corresponding disulfides, 7' and 8'. 3H-1, 2-Benzodithiol-3-immes, which are in equilibrium with 1,2-benzisothiazole-3(2H)-thiones, (9A ? 9B), are prepared by two new routes (a) by allowing 3 or 5 to react with primary amines or hydrazines, (b) by allowing 7, 8, 7' or 8' to react with 1.     

Synthesis of new 3-substituted-2H-1,2-naphthothiazin-4(3H)-one 1,1-dioxides via directed ortho-metalation reaction

The reaction of compounds 6a–i, readily available from α-amino acids, with an excess of lithium diisopropylamide, leads to new 3-substituted-2H-1,2-naphthothiazin-4(3H)-one 1,1-dioxides 7a–i, with yields ranging between 21 and 70%. The key steps are: the naphthylsulfonyl ortho-deprotonation based on the directed ortho-metalation reaction followed by a regiospecific intramolecular cyclisation reaction. Lithiation–deuteration experiments carried out on the naphthylsulfonamides 8 and 9 using n-BuLi and LDA demonstrated the regioselectivity of the deprotonation of the H-3 over the H-1 one of the naphthalene ring.     

Studies on organophosphorus compounds—XXVIII: Syntheses of 3H-1,2-dithiole-3-thiones and 4H-1,3,2,-oxazaphosphorine derivatives from the dimer of p-methoxyphenyl-thionophosphine sulfide and der

Unsubstituted and 2-monosubstituted 3-oxo esters react with the dimer of p-methoxyphenyl-thionophosphine sulfide (1) and elemental sulfur in anhydrous toluene at 110° to give the corresponding 3H-1,2-dithiole-3-thiones (2) in nearly quantitative yields (90–95%). Ethyl 2,2-dimethyl 3-oxo-butanoate, failing to react in toluene at 110°, decomposes into a complex mixture at 140° in anhydrous xylene. Also secondary and tertiary 3-oxo-amides such as acetoacetanilide and N,N-dimethylacetoacetamide produce the corresponding 3H-1,2-dithiole-3-thiones (2) upon treatment with 1 and elemental sulfur. Primary 3-oxo-amides and 3-oxo-nitriles react with 1 in anhydrous toluene at 110° giving in all cases investigated, derivatives of 2,3-dihydro-2(4-methoxyphenyl)-4H-1,3,2-oxazaphosphorine-4-t as main products (70–95%). ¹H, ¹³C and ³¹P NMR data are tabulated and reaction mechanisms are suggested.     

Synthesis of 8-heteroatom-substituted 4,4-difluoro-4-bora-3a,4a-diaza-s-indacene dyes (BODIPY)

Thioketones, bis-(5-R-1H-pyrrol-2-yl)-methanethiones (R=H, Me, Et), 4 react with methyl iodide or isopropyl triflate to give the pyrrolium salts, which are treated with tertiary amine and boron trifluoride to produce the 8-(thiomethyl/thioisopropyl) 4,4-difluoro-3,5-di-R-4-bora-3a,4a-diaza-s-indacenes 6a-6c and 8a-8c. The reaction of the methyl thioether group of 6a and 6b with aniline gives the substitution products whose structure corresponds to formula 10. The structures of the thioethers 6a-6c and compound 10a were determined by X-ray diffraction. The thiomethyl groups in 6a-6c are close to be coplanar to the flat ring system, the strain due to the interaction of methyl with the hydrogen at C1 is released by shifting of the sulfur atom away from carbon C1 and opening of the angle C8-S-methyl. This coplanarity of the thiomethyl group with ring system agrees with the preference of the syn conformation of methyl vinyl thioether. In the structures of the aniline compound 10a the length of the nitrogen to C8 is close to that of NC double bond. Thioethers 6a-6c show high wavelength absorption at 523-530 nm and fluorescence with a Stokes shift of 12-24 nm and with a quantum yield of 0.15-0.37. In contrast the aniline substituted compounds 10a and 10b showed absorption at 410 and 430 nm, respectively, with no fluorescence. According to their spectral properties they are better described by structure 10 than 7.     

Studies on the sequential claisen rearrangement of methyl-3-arlyloxy- 2-(aryloymethyl)prop-2-enolates

Claisen rearrangement of methyl-3-aryloxy-2-(aryloxymethyl)prop-2-enoates (4) in refluxing N,N-diethylaniline gave 3-(2-hydroxyphenylmethylene) -3,4-dihydro-2H-1-benzopyran-2-ones (6) and 3-methoxycarbonyl-2H-1-benzopyrans(7).     

Chemoenzymatic synthesis of (3R,4S)- and (3S,4R)-3-methoxy-4-methylaminopyrrolidine

An efficient and a convenient enantioselective synthesis of (3R,4S)-3-methoxy-4-methylaminopyrrolidine has been carried out by a lipase-mediated resolution protocol. This method describes the preparation of (±)-1-Cbz-cis-3-azido-4-hydroxypyrrolidine starting from commercially available diallylamine followed by ring-closing metathesis (RCM) via S_N2 displacement reactions. Pseudomonas cepacia lipase immobilized on diatomaceous earth (Amano PS-D) provides (3R,4S)-11 and (3S,4R)-12 in an excellent enantiomeric excess.     

Synthesis,anti-angiogenic and DNA cleavage studies of novel <Emphasis Type="Italic">N</Emphasis>-(4-methyl-3-((4-(pyridin-3-yl)pyrimidin-2-yl)amino)phenyl)piperidine-4-carboxamide derivatives

A series of novel N-(4-methyl-3-((4-(pyridin-3-yl)pyrimidin-2-yl)amino)phenyl)piperidine-4-carboxamide derivatives 10(a–f), 12(a–c) and 14(a–c) were synthesized and characterized by FTIR, ¹H-NMR, mass spectral and elemental analysis. The efficacy of these derivatives to inhibit in vivo angiogenesis was evaluated using chick chorioallantoic membrane (CAM) model and their DNA cleavage abilities were evaluated after incubating with calf thymus DNA followed by gel electrophoresis. These novel piperidine analogues efficiently blocked the formation of blood vessels in vivo in CAM model and exhibited differential migration and band intensities in DNA binding/cleavage assays. Among the tested compounds 10a, 10b, 10c, 12b, 14b and 14c showed significant anti-angiogenic and DNA cleavage activities compared to their respective controls and the other derivatives used in this study. These observations suggest that the presence of electron donating and withdrawing groups at positions 2, 3 and 4 of the phenyl ring of the side chain may determine their potency and as anticancer agents by exerting both anti-angiogenic and cytotoxic effects

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Configuration and conformational equilibrium of (±)-trans-1-oxo-3-thiophen-2-yl-isochroman-4-carboxylic acid methyl ester

The X-ray analysis of 1-oxo-3-thiophen-2-yl-isochroman-4-carboxylic acid methyl ester 1 confirmed its trans-configuration and a conformation with diaxial H-3 and H-4 atoms in solid state. NMR experiments indicated that trans-1 exists in solution in both expected conformers. In CDCl₃ and especially in CD₃OD or DMSO, the conformational equilibrium is shifted towards the conformer with diequatorial H-3 and H-4, which was also determined by 2D NOESY experiments. The shift is due to the greater polarity of that conformer deduced by ab initio calculations.