C9‐Iridoids from Scrophularia buergeriana

Four new iridoids, buergerinins B–E ( 1 – 4 ), along with three known iridoids, were isolated from the roots of Scrophularia buergeriana. Their structures were identified on the basis of spectroscopic analysis.     

Photopolymerization induced by a benzophenone derivative photoinitiator

A benzophenone derivative photoinitiator, HBP-TDI-HQ-TDI-HBP （HTCTH）, was synthesized based on 4-hydroxy benzophenone （HBP）, toluene-2,4-diisocyanate （TDI） and hydroquinone （HQ）. HTCTH was a more effective photoinitiator which had longer wavelength absorption in the UV-vis absorption spectra than the low molecular counterpart benzophenone （BP）. It showed that both rate of polymerization （Rp） and final conversion （P） increased with increase of amine and HTCTH concentration in photopolymerization.     

纳米二氧化钛分离/富集-石墨原子吸收光谱法测定环境样品中痕量镉

以石墨炉原子吸收(GFAAS)为检测手段,研究了纳米二氧化钛(TiO2,锐钛型)对金属Cd(Ⅱ)的吸附性能,考察了吸附和解吸的主要影响因素.结果表明,在较宽的pH范围内,纳米TiO2对Cd(Ⅱ)具有良好的吸附性能,3.0 mol/L HCl能将所吸附的Cd(Ⅱ)完全洗脱.在优化的实验条件下,具有吸附容量大、吸附速度快的特点.本法的检出限(3σ)为10.6 ng/L;相对标准偏差(RSD)为1.5%,(n=7,C=2.0 μg/L),富集50倍.本法测定标准样品的测定值与参考值吻合.用于土壤类样品中Cd(Ⅱ)的测定,结果令人满意.     

Nanoporous TiO2 Coatings for Infrared Detectors

In GaAs based infrared detectors, a considerable part of the incident light will be reflected at the surface, thus it decreases the detectors sensitivity considerably. In this paper, a TiO₂ nanoporous coating was prepared successfully on the GaAs substrate by sol-gel method. The optical parameters of the coating were also controlled successfully. It was proved that the coating could greatly improve the transmittance of the incident light, which agrees with the theoretical results quite well. In the 2.5–6.0 m waveband, the maximum transmittance of GaAs substrate is 56%, while the transmittance of the GaAs substrate coated with a nanostructured TiO₂ coating is about 94%.     

离子液体中用Heck反应合成2-取代萘烯丙醇化合物

利用Heck反应, 在离子液体、金属钯或镍、碱和膦配体反应体系中, 由卤代萘与烯丙醇反应, 制得了高收率和高选择性的2-取代萘烯丙醇化合物. 该方法原料便宜易得、操作简单、反应体系可循环使用. 并讨论了醋酸镍替代醋酸钯、不同膦配体、溶剂及碱对反应转化率的影响. 通过核磁共振、红外光谱、质谱和元素分析对产物的结构进行了表征.     

[Ni(dien)_2]_2[Mn(NCS)_6]·H_2O的合成、晶体结构

硫氰酸根的结构为N≡C－S－，其两端的N原子和S原子分别有一对和三对孤对电子，因此，硫氰酸根可采用多种不同的配位模式与金属离子发生配位。硫氰酸根可作为单齿配体与一个金属离子配位，形成M－SCN或M－NCS的单核配合物，也可以作为桥联配体同时与两个、三个甚至四个金属离子配位形成多核配合物犤１～３犦；另一方面，硫氰酸根是一个具有一定共轭性的偶极子，可传递磁相作用。因此，选择硫氰酸根作为桥联配体，将多个顺磁金属离子桥联形成一维、二维或三维结构的多核金属配合物分子，并研究它们的磁性已成为分子磁学的一个研究领域…     

Chemiluminescence Determination of Benzoic Acid Using A Solid-Phase Verdigris Reactor

Benzoicacidisacommonadditiveusedwidelyasfoodpreservativeandplasticizer.Itcouldpromoteseverereactiontoallergicpopulationevenatlowconcentrationlevel1.Routinemethodsfortheassayofbenzoicacidincludeschromatographic2-6,spectrophotometry7,8,capillaryelectrophoresis9-13andelectrochemicaltitration14.Stokes15etal.monitoredairbornebenzoicacidbasedonsurface-enhancedRamanscatteringtechniques.Thereisalsoreportonamicrobialsensorusingpseudomonasforbenzoicacidandtheirderivativesinaqua16.Interestofusinglumines…     

Photochromism of viologens included in crown ether cavity

The effect of a pi-electron-donating macrocyclic molecule on the photochromic behavior of viologen derivatives was investigated in a thin polymer film. The intermolecular interactions between the viologens and the macrocyclic molecule were investigated in a solution before photoirradiation. In acetone, benzylviologens, N,N'-dibenzyl-4,4'-bipyridinium hexafluorophosphate (1) and N,N'-dibenzyl-trans-1,2-bis(4-pyridinium)ethylene hexafluorophosphate (2) each derived from 4,4'-bipiyridine and trans-1,2-bis(4-pyridyl)ethylene, respectively, form an inclusion complex with p-benzocrown ether (3) with binding constants of ca 200 M-1, which was driven by a charge transfer interaction. The peak wavelength of the charge transfer absorption band was at 453 and 421 nm for the inclusion complexes of 1 and 2 with 3, respectively. Upon photoirradiation to the polymer film containing 1, the film changed color from colorless to blue, associated with the reduction of 1 from the dication to the radical cation. The original dication was recovered after 120 min. The addition of 3 into the film containing 1 caused not only the color change from colorless to yellow, associated with the charge transfer interaction between 1 and 3 before photoirradiation, but also an acceleration in the bleaching rate of the photoreduced 1. When p-dimethoxybenzene (4) was used as an acyclic analog of 3, a negligible change in the photochromic behavior of 1 was observed. Similar effect of 3 on the photochromic behavior of 2 was observed. These results imply that the pi-electron-donating macrocyclic molecule causes a faster bleaching of photoreduced viologens by forming the inclusion complex.     

聚碳硅烷／纳米镍粉的热裂解

聚碳硅烷／纳米镍粉的热裂解王军＊宋永才冯春祥（国防科学技术大学材料工程与应用化学系长沙４１００７３）关键词聚碳硅烷，纳米材料，镍，热解，碳化硅纤维１９９６－０９－１７收稿，１９９６－１２－１３修回国家攻关计划和“８６３”高技术资助项目聚碳硅烷（ＰＣＳ...     

MOLECULAR ENGINEERING STUDIES ON NONTHROMBOGENIC BIOMATERIALS——A NOVEL CLASS OF NONTHROMBOGENIC BIOMATERIALS WITH ZWITTERIONIC STRUCTURE OF CARBOXYBETAINES

N,N-dimethyl-N-methacryloyloxyethyl-N-carboxyethyl ammonium (DMMCA) was graft-copolymerized onto the surface of segmented poly(ether urethane) (SPEU) and PE film. The carboxybetaine structure on SPEU and PE film surfaces was confirmed by ATR-FTIR, XPS and water contact angle measurements. Through the experiments with platelet adhesion and protein adhesion assay in vitro, the two materials studied, including poly-DMMCA gel, all show excellent nonthrombogenicity. This confirms once again that the zwitterionic molecular structure on the surfaces of materials is essential for improving their nonthrombogenicity and biocompatibility.