超越整函数Fatou分支的某些性质

讨论了有限个超越整函数fi(i=1,2,…,m}迭代生成的函数g=f1 o f2 o…o fm 的Fatou分支的性质,给出了g(z)的Fatou分支有界的一个充分条件.并证明了在该条件下,对g的任意游荡域U,都有{gn}的一个子列在U上趋于∞.     

Two new paeciloxocins from a mangrove endophytic fungus Paecilomyces sp.

Paeciloxocins A and B (2-(1-hydroxy-3-methylbutyl)- and 2-(1-acetoxy-3-methylbutyl)- 11-hydroxy-9-methyl-1-methoxy-5H,7H-dibenzo[b,g]-1,5-dioxocin-5-ones), viz., two new metabolites, were isolated from the mangrove fungus Paecilomyces sp. collected from the Taiwan Strait. Their structures were elucidated by spectral methods. Paeciloxocin A exhibited strong cytotoxicity against the hepG2 cell line.     

Theoretical study on self-assembly in organic materials

Theoretical work related to the self-assembly of organic materials was dealt with, and the various mechanisms leading to self-assembly, such as transition metal mediated self-assembly, constraint induced self-assembly, covalent bond based self-assembly and van der Waals interaction driven self-assembly, etc., were discussed. The formation of ordered structures could be attributed to the competition between short range attractive forces and long-range repulsion, which was arising from dipole interaction or may result from a different mechanism based on a purely repulsive isotropic short-range pair potential with two characteristic length scales. Such mechanism could be exploited in the study of self-assembly process. First principles SAPT(DFT) interaction energy calculations, combined with the Williams-Stone-Misquitta method, offer the ability to improve the molecular dynamics (MD) accuracy which could in turn be used in the prediction of crystal structures and self-assembly tendency. The combination of experimental and theoretical studies could open new breakthroughs over the design, synthesis, and characterization of self-assembled materials.     

2,4-双[3-芳基-1,2,4-三唑并[3,4-b]-1,3,4-噻二唑-6-基]吡啶类衍生物的微波合成与结构表征

在微波辐射下,经三氯氧磷催化作用,1,2,4-三唑与2,4-吡啶二甲酸反应,高产率合成了10个未见文献报道的含双枝三唑并噻二唑稠环的吡啶类衍生物,以期为新药筛选提供先导化合物.所有化合物的结构均经1HNMR,IR,MS和元素分析进行了表征.     

新的氨基甲酸酯型猪去氧胆酸分子裂缝的设计与微波合成

在微波辐射条件下,以α-猪去氧胆酸甲酯为隔离基,通过氨基甲酸酯键挂接芳胺手臂到3α位上,设计合成了10个新的氨基甲酸酯型猪去氧胆酸分子裂缝.其结构均经1HNMR,IR,MS及元素分析所确证,并且考察了这类受体对D/L-氨基酸甲酯的识别性能.初步研究表明,这类分子裂缝对所考察的客体有良好对映选择性识别能力.     

A new xanthone derivative from mangrove endophytic fungus No. ZSU-H16

A new xanthone derivative, 3,5,8-trihydroxy-2,2-dimethyl-3,4,4-trihydro-2H,6H-pyrano[3,2-b]-xanthen-6one (1), together with three known compounds, 5,8-dihydroxy-2,2-dimethyl-2H,6H-pyrano[3,2-b]xanthen6-one (2), cyclo-(N-O-methyl-L-Trp-L-Ile-D-Pip-L-2-amino-8-oxo-decanoyl) (3), and cyclo-(Phe-Tyr) (4), was isolated from the mangrove endophytic fungus No. ZSU-H16 obtained from the South China Sea coast. Their structures were elucidated by spectroscopic methods, mainly 1D and 2D NMR spectroscopic techniques. Compound 1 exhibited cytotoxicity against KB and KB_V 200 cells with IC₅₀ values greater than 50 μg/mL, respectively.     

Oriented free-standing ammonium vanadium oxide nanobelt membranes: highly selective absorbent materials

Highly selective, absorbent, free‐standing, paper‐like membranes made of ammonium vanadium oxide (NH₄V₄O₁₄) nanobelts have been engineered by taking advantage of the nanoscaled self‐assembly of architectures that display a mesh structure with an average periodic pore size of about 5 to 10 nm. The NH₄V₄O₁₄ nanobelts are synthesized by using a simple hydrothermal process, and exhibit the same orientation and assemble into bundles, each about 40 to 80 nm in width, 3 to 5 nm in thickness, and up to several millimeters in length. Importantly, the as‐obtained NH₄V₄O₁₄ nanobelt membranes can highly selectively absorb a variety of organic solvents, covering both polar and non‐polar solvents, for example, the absorbent capacity of glycol is 28 times as high as the initial weight of the membrane, and it can even separate organic solvents with similar polarities and absorb solid contaminants in organic solvents. These highly selective, absorbent membrane materials can be an ideal candidate for the separation and removal of pollution in industrial and environmental applications.     

Size Dependence of Nanoscale Confinement on Chiral Transformation

Molecular dynamic simulations of the chiral transition of a difluorobenzo[c]phenanthrene molecule (C₁₈H₁₂F₂, D molecule) in single‐walled boron‐nitride nanotubes (SWBNNTs) revealed remarkable effects of the nanoscale confinement. The critical temperature, above which the chiral transition occurs, increases considerably with the nanotube diameter, and the chiral transition frequency decreases almost exponentially with respect to the reciprocal of temperature. The chiral transitions correlate closely with the orientational transformations of the D molecule. Furthermore, the interaction energy barriers between the D molecule and the nanotube for different orientational states can characterize the chiral transition. This implies that the temperature threshold of a chiral transition can be controlled by a suitable nanotube. These findings provide new insights to the effect of nanoscale confinement on molecular chirality.     

单体结构对全息聚合物分散液晶光栅稳定性的影响

使用3种不同化学结构的单体材料制备了全息聚合物分散液晶光栅,并从光栅形貌、衍射能力、驱动特性、聚合物热稳定性4个方面评价了光栅的热稳定性.研究发现,含有刚性结构单体材料体系的光栅形貌、衍射能力等方面在200℃的温度下没有明显变化.表明光栅的热稳定性与单体材料的化学结构密切相关,单体材料中含有刚性结构有助于光栅热稳定性的提高.利用热重分析(TGA)对光栅中聚合物材料热分解温度进行了测定,并结合Freeman-Carroll微商法计算出了上述聚合物的分解活化能和分解反应级数.结果发现,含有刚性结构的聚合物材料的热分解温度、分解活化能和分解反应级数都高于柔性链结构材料,进一步验证了材料体系中刚性结构的添加有助于提高光栅的热稳定性.     

5,11,17,23-Tetrakis[(p-carboxyphenyl)azo]-25,26,27,28-tetra-hydroxy Calix[4]arene: Crystal Structure and pH Sensing Properties

Treatment of 5,11,17,23‐tetrakis[(p‐carboxyphenyl)azo]‐25,26,27,28‐tetrahydroxy calix[4]arene ( 2 ) with HCl in DMF or NaOH in MeOH produced 5,11,17,23‐tetrakis[(p‐carboxyphenyl)azo]‐25,26,27,28‐tetrahydroxycalix[4]‐arene·4DMF (2·4DMF) and 5,11,17,23‐tetrakis[(p‐carboxyphenylsodium)azo]‐25,26,27,28‐tetrahydroxycalix[4]‐ arene ( 3 ), respectively, which were characterized by elemental analysis, IR, UV‐vis, ¹H NMR and ¹³C NMR. An X‐ray analysis of 2·4DMF revealed that its calix[4]arene core adopts a flattened cone conformation in which opposed phenyl groups take parallel or sharply inclined positions. The intra‐ and intermolecular hydrogen‐bonding interactions and the π···π interactions form a 2D hydrogen‐bonded wavelike network. Compound 2 had a unique reversible color change in a wide pH range from 1 to 13.5 and showed interesting pH sensing properties.