The influences of solid-phase organic constituents on the partition of aliphatic and aromatic organic contaminants

The influence of natural organic matter (NOM) constituents on contaminant distribution coefficients was evaluated by determining the Koc values of aromatic and aliphatic organic compounds (solutes) with clays modified with both aromatic- and aliphatic-rich organic constituents. The studied compounds consisted of naphthalene, phenanthrene, n-pentane, and 2,3,4-trimethylmethane; the solid samples comprised two clays with little organic content, kaolinite and Ca-montmorillonite. Two aliphatic surfactants and three aromatic dyes, sorbed to the clays, served as reference NOM constituents. For solutes of comparable water solubilities, the organic-carbon normalized distribution coefficients (Koc) of the aliphatic solutes between sorbed aliphatic organic matter and aqueous solution slightly exceed those of the aromatic solutes. By contrast, the aromatic solutes exhibited higher Koc values than did the aliphatic compounds with sorbed aromatic-rich organic matter. The difference in Koc values could be attributed to either comparable solubility parameters or the difference in the chemical structure between nonionic organic solutes and specific components of the simulated NOM. The much higher Koc values observed for the aromatic solutes indicate that the NOM composition is a major factor determining the NOC environmental distribution.     

Synthesis and Structure of 2‐Substituted Thieno[3′,2′:5,6]pyrido[4,3‐d]pyrimidin‐4(3H)‐one Derivatives

A series of new 2‐substituted 3‐(4‐chlorophenyl)‐5,8,9‐trimethylthieno[3′,2′: 5,6]pyrido[4,3‐d]pyrimidin‐4(3H)‐ones 8 were synthesized via an aza‐Wittig reaction. Phosphoranylideneamino derivatives 6a or 6b reacted with 4‐chlorophenyl isocyanate to give carbodiimide derivatives 7a or 7b , respectively, which were further treated with amines or phenols to give compounds 8 in the presence of a catalytic amount of EtONa or K₂CO₃. The structure of 2‐(4‐chlorophenoxy)‐3‐(4‐chlorophenyl)‐5,8,9‐trimethylthieno[3′,2′: 5,6]pyrido[4,3‐d]pyrimidin‐4(3H)‐one ( 8j ) was comfirmed by X‐ray analysis.     

Syntheses and Characterizations of Two Palladium(II) Complexes of 5‐Mercapto‐1‐methyltetrazole

Reaction of PdCl₂(CH₃CN)₂ with the sodium salt of 5‐mercapto‐1‐methyltetrazole (MetzSNa) in methanol solution affords an interesting dinuclear palladium complex [Pd₂(MetzS)₄ ] ( 1 ). However, treatment of PdCl₂(CH₃CN)₂ with neutral MetzSH ligand in methanol solution produces a mononuclear palladium complex [Pd(MetzSH)₄]Cl₂ ( 2 ). Both complexes were characterized by IR, ¹HNMR, UV‐Vis spectroscopy as well as X‐ray crystallography. Single‐crystal X‐ray diffraction analyses of two complexes lead to the elucidation of the structures and show that 1 possesses an asymmetric structure: one Pd atom is tetracoordinated by three sulfur atoms and one nitrogen atom to form PdS₃N coordination sphere, the other Pd atom is tetracoordinated by three nitrogen atoms and one sulfur atom to form PdSN₃ coordination sphere. The molecules of 1 are associated to 1‐D infinite linear chain by weak intermolecular Pd···S contacts in the crystal lattice. In 2 , the Pd atom lies on an inversion center and has a square‐planar coordination involving the S atoms from four MetzSH ligands. The two chloride ions are not involved in coordination, but are engaged in hydrogen bonding.     

A new diarylheptanoid and a new diarylheptanoid glycoside isolated from the roots of Juglans mandshurica and their anti-inflammatory activities

A new diarylheptanoid, (2S,3S,5S)-2,3,5-trihydroxy-1,7-bis(4-hydroxy- 3-methoxyphenyl)heptane (1), and a new diarylheptanoid glycoside, (2S,3S,5S)-2,3-dihydroxy-5-O-β-d-xylopyranosyl-7-(4-hydroxy-3-methoxyphenyl)-1-(4-hydroxyphenyl)heptane (2), together with three known compounds, rhoiptelol C (3), rhoiptelol B (4) and 3′,4″-epoxy-2-O-β-d-glucopyanosyl-1-(4-hydroxyphenyl)- 7-(3-methoxyphenyl)heptan-3-one (5) were isolated from the roots of Juglans mandshurica (Juglandaceae). The structures of compounds 1 and 2 were identified based on HR-ESI-MS, 1D and 2D NMR spectroscopic methods. Compounds 1–5 were assayed for their inhibitory effects on the production of NO, TNF-α and IL-6 in LPS-stimulated RAW264.7 cells.     

Three New Triterpenoids from Lycopodium japonicum Thunb

Three new triterpenoids, (3β,8β,14α,21α)‐26,27‐dinoronocerane‐3,8,14,21‐tetrol ( 1 ), (3β,8β,14α,21β)‐26,27‐dinoronocerane‐3,8,14,21‐tetrol ( 2 ), and lycopodiin A ( 3 ), together with four known compounds, lycoclavanol ( 4 ), lycoclaninol ( 5 ), α‐onocerin ( 6 ), and 3‐epilycoclavanol ( 7 ), were isolated from Lycopodium japonicum Thunb (Lycopodiaceae). Their structures were established by means of spectroscopic analyses. Compounds 3 and 7 showed moderate antitumor activity. Compounds 4 and 6 exhibited acetylcholinesterase inhibition activity.     

一类新型的双β-氨基醇的合成及催化硼烷对芳酮的不对称还原反应

以L-半胱氨酸盐酸盐出发，经与二卤代烷偶联，成酯和格氏反应制得三种双手性β-氨基醇，1,2-双[R-2-氨基-3-羟基-3,3-二苯基丙硫基]乙烷(4a)，1,3-双[R-2-氨基-3-羟基-3,3-二苯基丙硫基]丙烷(4b)，1,4-双[R-2-氨基-3-羟基-3,3-二苯基丙硫基]丁烷(4c)。将此类双手性β-氨基醇与硼烷在THF溶液中反应，in situ制备双手性恶唑硼烷催化硼烷对芳酮的不对称还原，产物苯乙醇的光学收率达72.8%、α-溴代苯乙醇的光学收率达91.4%。     

Liquid chromatographic analysis of nucleosides and their mono-, di- and triphosphates using porous graphitic carbon stationary phase coupled with electrospray mass spectrometry

Analysis of nucleosides and nucleotides is desirable in many biological studies, but the task is analytically challenging due to the high polarity of the analytes. In this study, resolution of mixtures containing nucleosides and their mono-, di- and triphosphates was achieved using a porous graphitic carbon (PGC) stationary phase, Hypercarb, under conditions suitable for liquid chromatography/mass spectrometry (LC/MS). Different organic mobile phases and modifiers were evaluated and the separation of 16 nucleosides and nucleotides was optimized using gradient elution with a water/acetonitrile mobile phase containing ammonium acetate and diethylamine as modifiers. The ammonium acetate concentration proved to be critical for retention and diethylamine was found to improve the peak shapes of di- and triphosphates for mass spectrometric detection. A variety of silica-based columns designed for polar compound separation were also tested using optimized LC conditions and compared with results obtained with the Hypercarb column. Only the Hypercarb column provided separations suitable for accurate quantitation of mixed nucleosides and their phosphates.     

乙醇和甲苯组成的最低共沸混合物热力学性质的研究

The molar heat capacity of the azeotropic mixture composed of ethanol and toluene was measured by a high precision adiabatic calorimeter from 80 to 320 K. The glass transition and phase transitions of the azeotropic mixture were determined based on the heat capacity measurements. A glass transition at 103.350 K was found. A solid-solid phase transition at 127.282 K, two solid-liquid phase transitions at 153.612 and 160.584 K were observed, which correspond to the transition of metastable crystal to stable crystal of ethanol and the melting of ethanol and toluene, respectively. The thermodynamic functions and the excess ones of the mixture relative to the standard temperature 298.15 K were derived based on the relationships of the thermodynamic functions and the function of the measured heat capacity with respect to temperature.     

Titania membrane preparation with chemical stability for very hash environments applications

The high-quality tubular titania MF membranes are successfully prepared by dip-coating techniques and systematically investigated with regard to their corrosive resistances. The experiments show that dispersants PAA and anatase powder were preferably employed to prepare desired suspensions with solid loading 10–15 wt.% and that suspensions properties significantly affect the final membranes quality. The titania MF membranes with pure water permeability 742.42 l m⁻² h⁻¹ bar⁻¹ and 0.1 μm pore diameter have been obtained using the prepared suspensions. The corrosion resistance of titania membranes exhibits that the anatase layers are more stable than the alumina supports in boiling corrosive medium and that the poor quality titania MF membranes become more deteriorated due to its top layer pore blockages and fouling layer formation, which provides a wide range of practical application fields in very hash environments with reliable data supports.     

Synthesis of N—（4—Salicylideneiminoaryl）monoaza Crown Ethers and Dioxygen Affinities of Their Cobalt（Ⅱ）Complexes

The Schiff base‐containing pendant monoaza crown ether HL¹, HL², HL³ and HL⁴ have been synthesized by condensation of salicylaldehyde with N‐(4‐aminoaryl) monoaza crown ethers, which were prepared conveniently from 4‐nitro‐N, N‐di(hydroxyethyl) aniline or 4‐nitrobenzyl chloride via cyclization or condensation and reduction. The structures of HL¹—HL⁴ were verified by ¹H NMR, IR spectra, MS and elemental analysis. Moreover, the oxygenation constants (KO2) and thermodynamic parameters (δH⁰ and δS⁰) of their cobalt(II) complexes were determined in the range of ?5 °C to 25 °C, and the effect of crown ring bonded to a Schiff base on the dioxygen affinities of cobalt(II) complexes was also observed as compared to the uncrowned analogue (CoL).