Prospects for p̄p → ȲY studies at PANDA

Strangeness and charm production provide an excellent probe of QCD in the confinement domain. With the PANDA detector at FAIR, this can be studied in e.g., hyperon production in the p?p → ?Y reactions. In PANDA, all ground state strange hyperons and single charmed Λ’s will be accessible. Simulations show that the differential cross sections and spin observables can be well reconstructed for these reaction channels.     

A Direct Assembly Approach to the Synthesis of N,N′-Bridged Calix[4]pyrroles: The Synthesis of a 1,5-Diazacyclononatriene Locked in a Saddle Conformation

Ring closure of 1,2-bis(1-pyrrolylmethyl)benzene in the acid-catalysed condensation with acetone yields the 1,5-diazacyclononatriene [ O -C₆H₄(CH₂NC₄H₃-2)₂C(CH₃)₂] as the sole identifiable product. The twisted or saddle conformation of the 1,5-diazacyclononatriene, which was confirmed by X-ray crystal structure determination, is conformationally rigid in solution. The conformation of the 1,5-diazacyclononatriene prevents the formation of the target N,N′-bridged calix[4]pyrrole by further acid-catalysed condensation with acetone, the reaction affording unidentified oligomers/polymers instead. The acid-catalysed condensation of 1,3- and 1,4-bis(1-pyrrolylmethyl)benzene with acetone also yields unidentified oligomers/polymers.     

Room Temperature Phosphorescence of 1-Bromo-4-(bromoacetyl)naphthalene Induced by Sodium Deoxycholate

Sodium deoxycholate (NaDOC) can induce 1-bromo-4-(bromoacetyl)naphthalene (BBAN) to undergo strong room temperature phosphorescence (RTP) without the removal of dissolved oxygen from the solution. RTP spectra, phosphorescence polarization and ¹³C NMR results, along with the molecular modeling calculations, supported the conclusion that BBAN molecule was combined in a sandwich with two NaDOC molecules by a “back-to-back” hydrophobic interaction arising from the apolar faces of the NaDOC molecules, which provided BBAN with a rigid enough microenvironment to produce RTP.     

Study on the Supramolecular System of TAPP and Cyclodextrins by Spectroscopy

The ability of β-cyclodextrin (β-CD), γ-CD, hydroxypropyl-β-CD (HP-β-CD), trimethyl-β-CD (TM-β-CD), sulfurbutylether-β-CD (SBE-β-CD) and carboxymethyl-β-cyclodextrin (CM-β-CD) to break the aggregate of the meso-tetrakis(4-N-trimethylaminobenzyl)porphyrin (TAPP) and to form 2:1 inclusion complexes has been studied by absorption and fluorescence spectroscopy. The formation constants are calculated, respectively, by fluorimetry, from which the inclusion capacity of different CDs is compared and the inclusion mechanism of charged-β-CD (SBE-β-CD and CM-β-CD) is quite different from that of the parent β-CD. At lower pH, the complexation between TM-β-CD and H²TAPP²⁺ (the form of the diprotonated TAPP) hampers the continuous protonation of the pyrrole nitrogen of TAPP and the hydrophobic cavity may prefer to bind an apolar neutral porphyrin molecule. ¹HNMR data support the inclusion conformation of the porphyrin–cyclodextrin supramolecular system, indicating the interaction of the meso-phenyl groups of TAPP with the cavity of CDs. For this host–guest inclusion model, cyclodextrin being regarded as the protein component, which acts as a carrier enveloping the active site of heme prosthetic group within its hydrophobic environment, provides a protective sheath for the porphyrin, creating artificial analogues of heme-containing proteins. However, for TAPP, encapsulated within this saccharide-coated barrier, its photophysical and photochemical properties changed strongly.     

Fluorophore-labeled Polyamidoamine (PAMAM) Dendritic Architectures: Synthesis and Fluorescence Sensing Properties

Novel polyamidoamine (PAMAM) dendrimers (G=0.5–2.5) with a naphthalene core unit have been prepared. They were found to display acid as well as metal ion sensitive fluorescence signal amplification, making them of potential use as chemosensing materials. PAMAM dendritic wedges as well as naphthalene-centered PAMAM dendrimers were characterized by FT-IR, ¹H and ¹³C NMR spectroscopic methods and elemental analysis.     

黄渤海近岸海域酚类内分泌干扰物分布特征及其来源解析

在黄渤海近岸海域采集了34个水体样品,利用HPLC-MS/MS分析了双酚A、辛基酚、壬基酚、2,4-二氯酚、对叔丁基苯酚和对特辛基苯酚等6种酚类内分泌干扰物的含量,并探讨了其分布特征及来源.结果表明,中国北部近岸海域6种酚类内分泌干扰物的含量范围在5.25～1351.20ng/mL之间.结合因子分析和层次聚类分析结果,说明渤海、黄海近岸海域中酚类化合物主要以辛基酚、壬基酚、2,4-二氯酚为主,局部海域伴有双酚A的高残留;从整个海域范围看,黄渤海近岸海域水体中酚类化合物污染状况具有区域特征,整体呈现出南高北低的特点,且酚类物质分布具有明显的地区特性,一定程度上具有聚集性;来源解析结果表明黄渤海近岸海域中酚类内分泌干扰物主要来源为生活污水和工业废水.     

Synthesis of Quinolines from N-Tosyl-1-azadienes

A route to aryl-substituted quinolines from N-tosyl 1-azadienes is described. The key steps are a [4 + 2] cycloaddition with benzyne followed by base treatment of the 1,4-dihydroquinoline product. The N-tosyl 1-azadienes were prepared from readily accessible cinnamaldehyde and chalcone substrates by condensation with p-TsNH₂.

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