Sensitivity in Supramolecular Architectures of Polyaromatic Salts Containing Two Singly‐Pimerized Bipyridines

Three novel supramolecular arrays of zigzag polyaromatic salts are reported. Both the conformation and disposition of the dications are subjected to various noncovalent interactions. Thus, the presence or absence of the π‐π interacting enclathrated molecules, the efficient packing and the involved hydrogen bonding interactions of anions, as well as the increased hydrophobic property of the dications themselves exert influence.     

某些苯二醛类双Schiff碱及其双铜(Ⅱ)配合物研究

用2-甲氧基-5-氯-1,3-苯二甲醛与含有不同取代基团X的邻氨基酚缩合,合成了一系列双Schiff碱L-X(X=OMe,diMe,Me,t-Bu,H,Cl,NO_2),它们与乙酸铜(Ⅱ)作用生成了一系列的双核配合物Cu_2L-X(OEt).用红外、紫外、磁天平、顺磁共振等手段对配合物进行了表征,并通过量化计算(CNDO/2法)探讨了配合物的成键性质。研究结果表明,该类配合物是一个较大的共轭体系,配合物中Cu(Ⅱ).Cu(Ⅱ)之间有较强的反铁磁性交换作用,其共轭程度和交换作用强弱皆随X基团的不同而呈现某种变化规律。     

含羟基的青蒿倍半萜内酯差向异构体的合成

本文报道以青蒿酸(2)为原料合成了一些含羟基的青蒿倍半萜内酯差向异构体9与10、11与12、13与14。其中9已从青蒿中分离到。     

Studies on Chemical Constituents of Polygonum Ciliinerve Ohwi

Three new apianen lactones Maomailiaoine I ( 1 ), Maomailiaoine II ( 2 ) and Maoimaliaoine III ( 3 ), together with one known apianen lactone, five known flavonoids and three other known compounds were isolated from Polgonum ciliinerve Ohwi. Their structures were deduced from spectroscopic methods and 2D NMR techniques.     

Structural features of theClostridium thermocellum cellulase Ss gene

Applied Biochemistry and Biotechnology - TheClostridium thermocellum cellulase Ss is a subunit of the extracellular cellulase complex (cellulosome). It has previously been shown that Ss hydrolyzes...     

计算机模式识别法对甲状腺机能亢进症微量元素谱的研究

据Mahlanobis距离判别法，利用计算机多元统计判别程序，对14例甲亢思者和21例健康人的血清中锌、铁、铜、锰、镁和锶等元素浓度差异进行分类判别研究。选择锌、铁、钙、锶作判别特征参量时，患者和健康人的分类准确率为100％，服碘前与服碘后的甲亢患者分类准确率为92.7％，分类研究指出，甲亢患者血清中的铁和锶浓度高于健康人，经服碘治疗后，患者血清中上述元素浓度降低与健康人相近。     

Theoretical Study on the Structures and Stability of Isomers and Complex of[Si,C,O,O] Sytem

A detailed singlet potential energy surface(PES) of [Si,C,O,O] system including a van der Waals (vdW) comples SiO……CO2,eight isomers,and twelve transiton states is investigated by MP2 and QCISD(T) (single-point)methods.At the final QCISD(T)/6-311 G(2df)//MP2/6-311G(d) level with zero-point energy included,the complex SiO……CO is found to be thermodynamically and kinetically the most stable species.Although eight ismoers are located as local energy minima,they are rather unstable toward isomerization to the dissociation fragments or comples.For the reaction of silocon atoms with carbon dioxide,two competitive reaction channels are found,and the primary pathway,which leads to the products of SiO and CO fragments,is the direct oxygen-abstraction process from carbon dioxide by silicon atom with a41.16 kJ/mol reaction barrier height.Our predications are in good agreement with previous experimental and theoretical studies.     

Briarane diterpenoids from the formosan gorgonian Coral Junceella fragilis

A new trihydroxy briarane-related diterpenoid, junceellolide I (1), along with a known metabolite, (1R,2R,5Z,7R,8S,9R,10R,12R,14R,17S)-2,14-diacetoxy-8,17-epoxy-9,12-dihydroxybriara-5,11(20)-dien-19-one (2), have been isolated from the gorgonian coral Junceella fragilis, collected off the southern Taiwan coast. The structure, including the relative configuration of the new compound 1, was elucidated by the combination of spectral data, particularly in high-resolution 1H- and 13C-NMR spectroscopy utilizing COSY, HMBC, HMQC, and NOESY experiments.