Synthesis and Structural Characterization of 1,4-Di（2-methoxyphenyl）-2,5-piperazinedione

A new derivative of 2,5-piperazinedione, 1,4-di（2-methoxyphenyl）-2,5-piperazinedione （I）, was synthesized by the cyclocondensation reaction of N-2-methoxyphenyl chloroacetamide, and its structure was characterized by elemental analysis, IR, ^1H NMR and single crystal X-ray diffraction method. The crystal belongs to monoclinic system, space group P21/c with unit cell dimensions a=0.56934（10） nm, b=1.3880（2） nm, c=1.00329（17） nm, β= 90.376（3）°, V= 0.7928（2） nm^3, Z=2, Dc = 1.367 g·cm^-3,μ = 0.98 cm^-1, R and wR being 0.0606 and 0.1564 respectively for 1549 unique reflections with 1247 observed reflections [I〉2σ（I）]. The molecule has a crystallographically imposed symmetry center. The three rings in the molecule are each coplanar with their attached groups, excluding methyl H atoms and the H atoms attached to the piperazinedione ring, while the whole molecule is not planar, with dihedral angles of 74.7（1）° between the piperazinedione and each of the two aromatic rings. The crystal structure is stabilized by van der Waals and dipole-dipole forces.     

Me[14]-N4大环四烯镍(Ⅱ)催化、BrO3-氧化丙酮酸的振荡化学反

本文报道了一种以２，３，９，１０－四甲基－１，４，８，１１－四氮杂环十四－１，３，８，１０－四烯镍（Ⅱ）配合物［Ｎｉ（ㄔＩＭ）］＾２＋为催化剂、ＮａＢｒＯ３为氧化剂、丙酮酸为有机废物、稀硫酸为介质的振荡化学反应新体系。对该体系的振荡特性进行了描述。研究了Ａｇ＾＋、Ｈｇ＾２＋、还原性物质、自由基抑制剂、四氯化碳以及温度对振荡的影响。     

N-烷基壳聚糖玻璃化转变温度的研究

采用差示扫描量热(DSC)法和热释电流(TSC)法研究了N-烷基壳聚糖的玻璃化转变行为. DSC法中采用二次扫描以消除溶剂和热历史的影响, 并利用物理老化方法来增强N-烷基壳聚糖在DSC曲线上的玻璃化转变区域的热焓吸热峰, 以克服DSC法的不灵敏性. 两种研究方法的结果一致表明, 三种N-烷基壳聚糖的玻璃化转变均发生在110～150 ℃温区内；取代的柔性烷基越大, 玻璃化转变温度(Tg)越低；但N-甲基壳聚糖例外, 其Tg略高于壳聚糖, 空间阻碍在这里起决定的作用.     

信息拓扑指数与烷烃分子热力学性质的关系

Two topological information indices were constructed based on Randic and Wiener indices, and the values of topological information indices for 85 alkanes were calculated. The thermodynamic properties such as the standard enthalpies of formation, the standard entropies and the standard free energies of formation for these alkanes were also correlated with these topological and information indices. It is found that the thermodynamic properties calculated for both gaseous and liquid states of the 85 alkanes are in excellent agreement with the experimental values through the regression analysis.     

2, 2＇─(1, 4─亚乙二氧基)—二苯甲酸与钴(Ⅱ)生成的两种配合物的结构研究

硝酸钴与２，２＇－（１，４－亚乙二氧基）－二苯甲酸（Ｈ２Ｌ，图１）作用分别得到红色配合物ＣｏＬ＇和蓝色配合物ＣｏＬ″。经元素分析、红外光谱、紫外可见光谱、热分析等方法进行了表征、ＣｏＬ＇配合物的分子式为［ＣｏＬ．Ｈ２Ｏ］．３Ｈ２Ｏ，近八面体构型，羧酸根以双齿形式与Ｃｏ（Ⅱ）螯合；ＣｏＬ″配合物分子式为［ＣｏＬ″］。Ｈ２Ｏ，近四面体构型，羧酸根以单齿形与Ｃｏ（Ⅱ）配位。     

基于纳米镍催化的松香加氢研究--树酯酸组成的研究

松香的主要成份是枞酸型树脂酸,其因共轭双键的存在而易被氧化,大大降低了其附加值。经氢化后的松香具有抗氧性好、脆性小、热稳定性高、颜色浅等特点,因而广泛应用于胶粘剂、合成橡胶、涂料、油黑、造纸、电子、食品等工业部门[1]。采用催化加氢的方法可使枞酸型树脂酸中的共轭双键消除[2]。以枞酸为代表的反应式为:松香催化加氢主要有熔融法[3]和溶剂法[4],所用催化剂主要是Pd和N i。熔融法制氢化松香,当反应温度低于200℃时,枞酸加氢速度较慢,反应不完全。温度升高,氢化松香中枞酸含量显著地减少,但温度高于250℃时,树脂酸脱羧严重,甚至…     

一种新型的空心镍纳米球的合成

通过以二氧化硅粒子作为模板和金纳米粒子为表面晶种的方法制备了壳厚度可控的镍空心球。采用TEM﹑XRD对二氧化硅/镍复合球和镍空心球进行了表征和研究。结果表明镍纳米壳是由似针状的面心立方的镍纳米粒子构成的，碱溶液处理过程不影响镍纳米壳的形貌。高温处理显示镍空心球具有良好的热稳定性。     

荧光共振能量转移测定杀虫单

1引言 研究了钙黄绿素（Calcein）与酚藏花红（PF）的荧光共振能量转移现象，并且将其作为探针用来测定杀虫单，扩大了荧光共振能量转移的应用领域。该方法准确、简便，灵敏度高，检出限低，同时能消除仪器噪音影响，结果令人满意。     

纳米氧化铝负载双硫腙分离富集-原子吸收法测定地质样品中的金、铂、钯的研究

金、铂、钯在地质样品中的含量甚微,国内外常采用ICP-AES,ICP-MS和ETAAS直接测定。FAAS法由于仪器便宜、操作方便,也广泛应用于预富集后的痕量贵金属的分析。目前,在测定贵金属的分析方法中,常采用固相萃取法富集分离样品,主要的固相萃取剂有:无机吸附剂,交联树脂[1],螯合树脂[     

MONTE CARLO SIMULATION ON AQUEOUS SOLUTION OF BIOLOGICAL MOLECULES——ALANINE SOLUTION

The Monte Carlo simulation is performed for a cluster consisting of a neutral alanine molecule surrounded by 56 water molecules. The average water-water and alanine-water interaction energies are found. The space surrounding the alanine molecule is divided into three regions, where the central atoms are C' atom for the earboxyl group region, N atom for the amino group region and C~β atom for the methyl group region. The water-water and water-alanine interaction energies as functions of the distance between the oxygen atom in a water molecule and the central atom in each region are calculated. In each region the orientational correlation function for the dipole moments of water molecules, the radial distribution function for the oxygen and hydrogen atoms of water molecules are evaluated. In addition, the numbers of water molecules in the first solvation shells of each region and of entire alanine molecule are also counted.