缓蚀剂对金属钆在水介质中腐蚀行为的影响

采用失重法、腐蚀电化学方法研究了NaOH、NH4OH、单宁酸和苯并三氮唑等缓蚀剂对金属钆在水介质中腐蚀行为的影响。在没有缓蚀剂的情况下,钆在水中发生明显的点蚀,腐蚀速度为0.152g.m-2.h-1。NaOH能有效地控制金属钆在水介质中的腐蚀,经8880h的长时间浸泡,钆表面依然呈现明显的金属光泽,没有失重与点蚀发生。当采用NaOH调节苯并三氮唑(BTA)溶液的pH值接近中性时,钆在其中长时间浸泡,同样没有失重发生,表观没有发现点蚀发生。选择合适的缓蚀剂,使得钆能够在水介质中不发生腐蚀,保证了磁制冷机的长时间正常运转。     

Preparation,Crystal Structure and Properties of a Pentametallic 3-Ferrocenyl-2-crotonic acid-Bridged Copper(II) Complex

IntroductionDimericcopper(II)carboxylatescontainingavarietyofoxygenandnitrogen donorligandshavebeenextensivelyinvestigatedandtheirpreparations ,magneticandspectralpropertieshavebeenreviewed .1 5Differentkindsofcopper(II)carboxylateadductshavebeensynthesizedandalsodinuclearcopper(II)complexeshavebeenearlystud iedasusefulmodelstoestablishmagneto structuralcorre lationsforspinexchangebetweenmetalions .Inparticu lar,theoccurrenceofdicopperionsattheactivesiteofthevariousformsoftheoxygencarrierpro…     

二氧化硅-共聚物杂化荧光纳米材料用于动物活体成像

以氧化硅(SiO_2)前驱体与三嵌段共聚物F108合成较小粒径的SiO_2-共聚物杂化纳米体系(SNP),并与高效近红外发射的疏水染料M507自组装,构建了近红外发光纳米探针M507@SNP。同时,研究了M507@SNP的光物理性能和细胞毒性。动物成像实验证明该纳米成像探针可实现活体层次高信噪比的小动物全身成像和前哨淋巴结的指示。     

The Synthesis, Reaction and Crystal Structures of Ethyltetramethylcyclopentadienylruthenium Compounds

Pentamethylcyclopentadienyl-trimethylphosphine-metal compounds play an important role in the activation studies of saturated hydrocarbons. A method to synthesize ethyltetramethylruthenium compounds was established, which started from the reaction of RuCl_3. H_2O with ethyltetramethylcyclopentadiene to give a dimer compound of 2. When 2 was reacted with different amounts of trimethylphosphine, compounds 3 [C_5Me_4EtRu(PMe_3)Cl_2] and 4 [(C_5Me_4Et)Ru(PMe_3)_2Cl] were obtained. Compound 3 is a 17-electron species which is in formula similar to Bergman's Ir compound used in hydrocarbon activation reaction, but might be more reactive because of its unsaturated electron structure. The crystal structure analysis of compounds 2, 3 and 4, showed that the ruthenium atom was coordinated in a "threeleg-piano-stool" geometry in all the three compounds. The Ru—Cl bond in 3 and 4 was lengthened, making it labile to other substitution reactions.     

两个新奇的铼的卡宾和卡拜络合物的合成和结构

铼的阳离子卡拜络合物,[π-C_5H_5(CO)_2—R_(?)CC_6H_5]BBr4(Ⅰ),在THF中低温下与邻-碳硼烷基锂反应,碳硼烷基阴离子加成到卡拜碳和羰基碳原子上生成两个新奇的铼的卡宾和卡拜络合物,π-环戊二烯基二羰基[(1-碳硼烷基)(苯基)卡宾]铼[π-C_5H_5(CO)_2ReC(C_2HB_(10)H_(10))C_6H_5](Ⅱ)和π-环戊二烯基羰基(1-碳硼烷基甲酰基)(苯基卡拜)铼[π-C_5H_5(CO)(COC_2HB_(10)H_(10))ReCC_6H_51(Ⅲ)。这表明在阳离子卡拜络合物Ⅰ中有两个亲电中心。络合物Ⅲ在溶液中室温下逐渐转变为络合物Ⅱ。Ⅱ和Ⅲ是通过元素分析和红外、核磁共振光谱及质谱分析,最后通过X射线单晶结构分析鉴定的。本文还讨论了上述反应的可能机制。     

三聚氰胺磷酸盐阻燃剂的合成及性能表征

以新方法合成了三聚氯胺磷酸盐自膨胀阻燃剂(MP)，其结构经元素分析、XRD，TG，DSC，IR等表征。测定了含MP阻燃材料的阻燃性能，讨论了其阻燃机理及特点。用MP对聚丙烯进行阻燃处理后其氧指数可达27．1；徐覆含MP自膨胀防火涂料的五层板在模拟火灾中的耐火极限达39min，发泡倍数为90倍-100倍。     

THE CRYSTAL STRUCTURE OF BAYLEYITE

The bayleyite crystallizes in monoclinic space group C_2~5h-P2_1/c with a=6.499(1), b=15.235(5), c=26.513(6), β= 92.92(2)°, Z=4. Intensities of 3430 independent reflections are collected with diffractometer using MoKα radiation. The crystal structure has been solved by the Patterson method and refined by block least square refinement for positional parameters and isotropic temperature factor of non-hydrogen atoms. The final R factor is 0.038.The result of crystal structure analysis shows that the structure consists of discrete [UO_2(CO_3)_3]~(4-) ions and Mg~(2 ) cations are between slab-like units, but they are not in a slablike unit. Its crystal struture is different from that of liebigite which was determined by Appleman. Complexes and cations between slab-like units and in a slab-like unit are connected by hydrogen bonds formed by water molecules.     

三聚氰胺焦磷酸盐阻燃剂的合成及性能表征

三聚氰胺焦磷酸盐自膨胀阻燃剂[1]无卤、低烟、低毒,其热解温度与被阻燃材料的降解温度的匹配,效果很好。本文合成了三聚氰胺焦磷酸盐(MPP)[2],用元素分析,XRD、TG、DSC、IR等表征,并对其阻燃性能进行了测定,讨论了阻燃机理。1　实验部分1.1　仪器与试剂三聚氰胺(化学纯,含量不少于98.5%,北京化工厂);焦磷酸钠(Na4P2O7·10H2O,分析纯,含量不少于99.0%,上海科昌精细化学品公司);浓硫酸(分析纯,成都新都金牛王化工厂);硝酸(分析纯,成都有机化学试剂厂)。岛津TG 50H热重分析仪和DSC 50H差热分析仪;PerKin Eimer240C元素分析仪;…     

十钒酸四氢钠与六次甲基四胺加合物的晶体结构

本文合成的晶体属于空间群C_i~1-Pi。晶胞参数a=9.589五,b=10.486,c=11.139,α=103.2°,β=98.20°,γ=103.16°。由Patterson函数得到诸钒原子坐标参数后,用Fourier法及差值法导出全部非氢及氢原子,最终确定晶胞中所包含的化学物种及确切成分为[Na~ ]_2[H_2V_(10)O_(28)~(4-)]·2[(CH_2)_6N_3N·H~ ]·8H_2O。经块矩阵修正所得一致性因子R=0.0279。     

基于可逆共价化学的交联聚合物加工成型研究——聚合物工程发展的新挑战

可逆共价聚合物能够通过外界刺激(包括加热、光和pH)触发可逆反应,从而实现聚合物拓扑结构的重组,同时在撤销刺激后又可以像不可逆共价聚合物一样保持结构稳定性.近年来,越来越多的研究者致力于利用该特性来解决交联聚合物加工成型的难题,这不仅打破了传统热塑性聚合物和热固性聚合物的严格界限,而且带来了新的材料研发方法和功能,使得聚合物制品种类更加多样化,其生命周期也相应得以延长.孕育着传统聚合物工程领域的新突破,具有重要价值.为及时反映这一态势,本文总结了可逆共价化学的基本原理,阐述了可逆共价聚合物的流变特性,并且综述了由此衍生的含可逆共价键交联聚合物各类成型加工技术原型和应用,如力学性能调控、塑性变形、焊接、纳米填料的分散与增强效应、模压成型与固相回收、注射成型、挤出成型、3D打印、碳纤维复合材料的可控降解与再生等,在此基础上,进一步分析了该新兴领域的挑战和发展趋势.