Solvothermal Syntheses and Crystal Structures of Two New Nonmetal Borates:C_4H_(10)N_2·B_6O_8(OH)_2 and (NH_3CH_2CH_2NH_3)B_5O_8(OH)

Two new borate compounds,C4H10N2·B6O8(OH)2 1 and (NH3CH2CH2NH3)B5O8-(OH) 2,have been solvothermally synthesized and structurally characterized by single-crystal X-ray diffraction,IR,elemental analysis and thermal analysis. Compound 1 crystallizes in the monoclinic system,space group P21/c,with a=8.3318(17),b=6.2118(12),c=12.479(3) ,β=108.96(3)o,V=610.8(2) 3,Mr=313.02,Z=2,Dc=1.702 g/cm3,μ=0.150 mm-1,F(000)=320,R =0.0387 and wR =0.0924. Its layered structure is linked by infinite covalently coordinated neutral sheets with 3,20-membered window system,which are built up from alternative B6O8(OH)2 subunits donated by two piperzazine nitrogen donors. 2 crystallizes in monoclinic,space group Cc,with a=6.7207(13),b=11.481(2),c=12.564(3) ,β=95.25(3)o,V=965.4(3) 3,Mr=261.18,Z=4,Dc=1.797 g/cm3,μ= 0.164 mm-1,F(000)=536,R=0.0396 and wR=0.0752. Its oxoborate structure is generated from the sheets of 3,9-membered boron rings bonded diamine molecules through electrostatic and H-bonding interactions to form a two-dimensional layered network.     

一种基于二芘基苯的高效有机固态蓝色荧光化合物

利用Suzuki偶联反应,合成了一种新的二芘基苯的衍生物2,5-二甲基-1,4-双(7-特丁基-1-)芘基苯,并研究了其吸收和发光性质随着溶剂和温度等条件的变化情况.实验表明,与不含特丁基的类似化合物相比,引入特丁基可以明显减弱分子间作用并避免激基缔合物的形成,因而在保持吸收和发射光谱的谱形及峰位基本不变的同时显著地增强了荧光发光效率.该化合物的固态荧光量子效率高达0.82.     

炮制前后朝鲜淫羊藿化学成分的变化规律研究

采用电喷雾质谱技术、等离子体发射光谱技术以及紫外分光光度法分别对炮制前后朝鲜淫羊藿的化学成分进行了详细研究;结果表明,炮制后淫羊藿中与肾功能有密切关系的Ca、Mn、Fe、Mg、Zn等微量元素的含量明显增加,但黄酮类化合物的含量无明显变化,为进一步阐明淫羊藿炮制入药的科学内涵提供了实验依据。     

Photocatalysts of Cr Doped TiO2 Film Prepared by Micro Arc Oxidation

通过微弧氧化法在Na3PO4+K2Cr2O7电解液中制备了系列铬掺杂二氧化钛薄膜. X射线和扫描电镜显示薄膜的主要晶相为锐钛矿型二氧化钛,且表面为多孔结构. 在可见光照射下,薄膜对降解亚甲基蓝和分解水有着较好的光催化性能,这主要是由铬的掺杂引起的.由于铬的掺杂,一方面在二氧化钛中形成了Cr3+/Cr4+离子对,另一方面在带隙中形成了氧的空位能级. 前者降低了电子-空穴的复合几率,而后者在二氧化钛的禁带中形成了新的能级. 新能级的形成使得由二氧化钛价带跃迁至氧空位能级所需的光子能量减少. 另外探讨了微弧氧化形成掺杂二氧化钛薄膜的机制.     

基于在险价值风险度量的信度估计

在险价值度量(Value-at-Risk)是金融中的一种重要的风险度量方法,被广泛应用于金融、保险等风险管理行业.建立了在险价值的贝叶斯统计模型,利用信度理论的方法将在险价值的估计限定在经验估计的线性函数中,得到了在险价值的信度估计.进而,证明了估计相合性和渐近正态性.最后,利用数值模拟的方法在中等样本容量下验证了估计的收敛速度.     

Synthesis and Crystal Structure of 3,3,6,6-Tetramethyl-N-hydroxy-9-ethyl-1,8-dioxo-1,2,3,4,5,6,7,8,9,10-decahydroacridine

1 INTRODUCTION 1,4-Dihydropyridines (1,4-DHPs) are well-knowncompounds because of their pharmacological pro-perty as calcium channel modulators[1, . The che- 2]mical modifications, such as the introduction of dif-ferent substituents[3, or heteroatoms[5], of the DHP 4]ring have allowed the expansion of researches onthe structure-activity relationship to gain new in-sights into the molecular interactions at the receptorlevel. In fact, it is well established th…     

电喷雾串联质谱分析附子炮制中的化学成分变化

利用电喷雾质谱方法(ESI-MS)分析了附子加辅料(甘草)炮制前后水煎液中二萜类生物碱在种类和含量方面的变化,通过加入内标化合物,建立了电喷雾质谱的半定量分析方法。此方法具有快速、准确、灵敏的特点,能够更加全面地反映中药配伍炮制过程中多种化学成分的含量变化,并能根据电喷雾串联质谱的分析结果鉴定配伍后产生的新的化学成分,在共煎液中的次乌头碱、中乌头碱和乌头碱的相对含量分别是单煎液中的5.67%、4.05%和4.88%。通过研究附子与甘草的单煎液、共煎液以及药渣中化学成分的变化,揭示了甘草作为辅料,在炮制过程中对附子减毒作用机理。     

SYNTHESIS OF HYPERBRANCHED CONJUGATIVE POLY（ARYLENEETHYNYLENE）S BY ALKYNE POLYCYCLOTRIMERIZATION

A series of new hyperbranched poly(aryleneethynylene)s are synthesized by the copolycyclotrimerizations oftetraynes(Ⅰand Ⅱ)with aliphatic monoynes(A-C)catalyzed by tantalum-,niobium-,and cobalt-based catalysts.All thereactions proceed smoothly and soluble polymers of high molecular weights(M_w up to 3.8×10~4)are obtained in high yields(up to 97%).     

Synthesis and Crystal Structure of a New Zn(II) Nitronyl Nitroxide Complex [Zn(NIT4Py)(PDA)(H_2O)_3]

1 INTRODUCTION Nitronyl nitroxides, independently or in combina- tion with metal ions, have been one of the most wi- dely studied systems in molecular magnetism for understanding radical-radical or metal-radical inte- ractions as well as for synthesizing organic ferroma- gnets and metal-radical magnetic materials[1～4]. Up to now, lots of metal-radical complexes have been reported[5～8]. On the other hand, cooperative inter- molecular interactions, such as coordination bonds, hydrogen bon…