Ca2+-Mg2+-Zn2+体系在水溶性聚磷酸铵溶液中螯合规律的研究

近年来,水溶性聚磷酸铵在液体肥料和复合肥料的领域受到了广泛的关注,并在发达国家中得到了大面积的推广及应用。在pH值为5.5~8.0、温度为278.15 K~323.15 K的条件下,本文采用滴定法研究Ca_²⁺-Mg_²⁺-Zn_²⁺体系在聚磷酸铵溶液中的螯合规律。实验结果表明：相同质量分数的聚磷酸铵溶液对金属离子的螯合量会随着体系中Ca_²⁺、Mg_²⁺、Zn_²⁺的摩尔浓度的变化而变化;随着温度的升高而逐渐降低;随着pH的增加而逐渐增加;随着聚合度的升高而逐渐增加。采用傅里叶红外光谱对聚磷酸铵和A₁B₃C₃体系的螯合物进行表征。     

基于4-氨基-1,2,4-三唑和多金属氧酸盐为杂化配体的CuⅡ和CuⅠ配合物的水热合成及光催化性能

在水热条件下,制备了2个基于多金属氧酸盐（POM）的Cu^Ⅱ和Cu^Ⅰ新型杂化配合物材料,即[Cu₂（4-NH₂-trz）₄（Mo₈O₂₆）（H₂O）₄]·5H₂O（1）和[Cu₄（4-NH₂-trz）₄Mo₈O₂₆]（2）（4-NH₂-trz=4-氨基-1,2,4-三唑）。通过单晶X射线衍射、傅里叶变换红外光谱和粉末X射线衍射分析确定了它们的结构。在配合物1中,4-氨基-1,2,4-三唑双齿配体连接2个相邻的Cu^Ⅱ中心形成双核结构单元,这些双核结构单元进一步通过Mo₈O₂₆^4-连接形成一维（1D）的杂化配位结构。在配合物2中,4-氨基-1,2,4-三唑双齿配体连接相邻Cu^Ⅰ中心构筑了独特的[Cu₄（4-NH₂-trz）₄]_n一维螺旋链,这些左手和右手的一维螺旋链再通过（β-Mo₈O₂₆）^4-连接形成2D杂化骨架。光催化实验研究表明,样品1和样品2对于不同有机染料（亚甲基蓝（MB）、罗丹明B（RhB）和甲基橙（MO））具有很好的光催化降解能力。     

基于4-氨基-1,2,4-三唑和多金属氧酸盐为杂化配体的CuⅡ和CuⅠ配合物的水热合成及光催化性能

在水热条件下,制备了2个基于多金属氧酸盐（POM）的Cu^Ⅱ和Cu^Ⅰ新型杂化配合物材料,即[Cu₂（4-NH₂-trz）₄（Mo₈O₂₆）（H₂O）₄]·5H₂O（1）和[Cu₄（4-NH₂-trz）₄Mo₈O₂₆]（2）（4-NH₂-trz=4-氨基-1,2,4-三唑）。通过单晶X射线衍射、傅里叶变换红外光谱和粉末X射线衍射分析确定了它们的结构。在配合物1中,4-氨基-1,2,4-三唑双齿配体连接2个相邻的Cu^Ⅱ中心形成双核结构单元,这些双核结构单元进一步通过Mo₈O₂₆^4-连接形成一维（1D）的杂化配位结构。在配合物2中,4-氨基-1,2,4-三唑双齿配体连接相邻Cu^Ⅰ中心构筑了独特的[Cu₄（4-NH₂-trz）₄]_n一维螺旋链,这些左手和右手的一维螺旋链再通过（β-Mo₈O₂₆）^4-连接形成2D杂化骨架。光催化实验研究表明,样品1和样品2对于不同有机染料（亚甲基蓝（MB）、罗丹明B（RhB）和甲基橙（MO））具有很好的光催化降解能力。     

吡啶-3-甲醛缩氨基硫脲合镍(Ⅱ)、锌(Ⅱ)配合物的合成、晶体结构及生物活性

本文合成并表征了吡啶-3-甲醛缩氨基硫脲(HL)合镍(Ⅱ)、锌(Ⅱ)配合物。在配合物[NiL₂] (1)中,镍(Ⅱ)离子与来自2个脱氢配体的2个氮原子和2个硫原子配位,形成四配位的平面正方形构型。在配合物[Zn(HL)₂(C₂H₅OH)₂(H₂O)₂](NO₃)₂ (2)中,锌(Ⅱ)     

苯乙烯三嗪衍生物的合成及在重金属离子识别中的应用

合成了2,4-二(2-噻吩乙烯基)-6-(4'-N,N-二甲氨基苯乙烯基)-1,3,5-均三嗪(2)并鉴定了其结构。在乙腈-水混合介质中,化合物2在355和416nm处呈现双吸收峰,加入Cu²⁺,Hg²⁺ 和Fe³⁺ 后,均在520nm附近形成新的吸收峰。化合物2与Cu²⁺、Hg²⁺ 和Fe³⁺ 均形成1:1型配合物,其结合常数分别为1.9×10⁵L·mol^-1,6.6×10³L·mol^-1,2.7×10³L·mol^-1。对照化合物4与金属离子的光谱响应与化合物2相似,仅吸收峰的位置不同。因此,可认为化合物2和4中三嗪环中的N和噻吩环中的S与Cu²⁺、Hg²⁺ 和Fe³⁺ 共同配位形成了稳定的金属配合物。     

淋巴细胞膜上Na+/Ca2+交换操纵的Eu3+内流的荧光法研究

利用Fura-2荧光浓度指示剂法、通过检测360nm激发荧光强度的变化,研究了Eu³⁺能否利用人外周血淋巴细胞膜上的Na⁺/Ca²⁺交换进入细胞。结果表明:用ouabain预处理细胞无Na⁺介质中测试,当加入Eu³⁺时,360nm荧光强度发生猝灭,且随着胞外加入的Eu³⁺浓度的增大而猝灭增强。表明在实验条件下Eu³⁺可以进入细胞。电压依赖性Ca     

钌取代的钨锗和钨硼杂多化合物的合成与表征

本文合成了Keggin结构的［GeW₁₁O₃₉(Ru·OH₂)］^5-和［BW₁₁O₃₉(Ru·OH₂)］^6-杂多阴离子的四丁基铵盐。通过紫外-可见、红外光谱、核磁共振、顺磁共振和循环伏安法对上述化合物进行了表征。结果表明Ru(Ⅲ)处于一个八面体弱场中，Ru(Ⅲ)的顺磁性和核四级矩对 ¹⁸³W的化学位移和强度有明显的影响，其电化学还原与W(Ⅳ→Ⅴ)相关。Ru(Ⅲ)填充了缺位杂多阴离子的空位，但仍然保持Keggin结构。     

同位素质谱仪测定小麦植株各器官δ15N值的考察

建立了15N标记的小麦植株各器官中δ~(15)N值的元素分析仪-同位素比质谱仪联用技术(EA-IRMS)的测定方法.对仪器的稳定性和线性进行了条件优化,标准气N_2的同位素比值的标准偏差为0.03‰,在同位素信号值1e~(-9)~1e~(-8)A范围内,总体线性为0.009‰/n A.称取不同量的小麦粉标准物质(OAS/Isotope)测定δ~(15)N值,进样量为4 mg时标准偏差最小,为最佳称样量.对硫酸铵标准物质(IAEA-N2-6)、小麦粉标准物质和~(15)N标记小麦植株样品各器官进行测定,δ~(15)N值的标准偏差均小于5%,测定精度和准确度较好.方法为研究氮素在小麦体内运转及利用效率提供了有效的技术手段.     

Fura-2探针对希土Y3+跨PC12细胞膜行为研究

使用AR-MIC-CM阳离子测定系统,发展Fura-2荧光测定技术,将其应用于测定细胞内游离希土离子Y³⁺,并以此研究了Y³⁺跨PC12细胞(大鼠嗜铬细胞瘤细胞)膜的行为。结果表明：在模拟细胞内各离子组分,pH=7.05的溶液中,测得表观解离常数为4.5p mol·L^-1。对于PC12细胞,静息条件下Y³⁺不能跨越细胞膜进入胞内。与钙离子通道相关的KCl和去甲肾上腺素均不能刺激希土Y³⁺过膜。用Ouabain(哇巴因)使胞内Na⁺超载后,Y³⁺可过膜进入细胞内,且过膜量与胞外Y³⁺浓度和胞内Na⁺超载程度有一定的浓度依赖关系,提示Y³⁺可以经由Na⁺/Y³⁺交换机制过膜而进入细胞内。     

Yb3+/Tm3+共掺杂的钨酸镉纳米晶发光性能的研究

本文采用水热法制备了稀土离子Yb³⁺/Tm³⁺共掺杂的钨酸镉纳米晶。运用X-射线粉末衍射、场发射环境扫描电子显微镜和光谱分析对制备的样品的结构和发光性能进行了表征。根据XRD图谱可知, 钨酸镉为单斜晶系, 晶粒平均尺寸在28 nm左右。从ESEM图片可明显看出, 钨酸镉呈纳米棒结构, 直径在30 nm左右, 长径比在5~8之间。利用980 nm半导体激光器激发钨酸镉纳米晶得到样品的发射光谱, 存在一个较强的蓝光发射, 发光峰位于481 nm,对应于Tm³⁺的¹G₄→³H₆能级的跃迁, 分析了Tm³⁺/Yb³⁺离子共掺体系的发光机制。讨论了发光强度随稀土离子浓度的变化, 当Tm³⁺离子的掺杂浓度在2%, Yb³⁺/Tm³⁺物质的量浓度比为10:1时钨酸镉纳米晶的发光强度最强。根据泵浦功率与发光强度之间的关系, 可知处于481 nm的蓝光发射属于三光子过程, 由发光强度与掺杂浓度之间的双对数衰减曲线可知, 引起蓝光发射源于Tm³⁺的电偶极跃迁。     

129Xe NMR study of the localization of PdCl2 supported on carbon nanotubes

Localization of PdCl₂ clusters supported on multi-wall carbon nanotubes (MWCNT) has been investigated using ¹²⁹Xe NMR of adsorbed xenon. As-made MWCNTs with channels initially inaccessible for adsorption and ball-milled MWCNTs with the totally accessible internal surface were used as supports. The observed ¹²⁹Xe NMR spectra were determined by the dynamics of xenon exchange between the aggregate pores and nanotube channels. No considerable changes of the ¹²⁹Xe NMR spectrum with the concentration of supported PdCl₂ were observed for the as-made MWCNT, while an additional resonance appeared for the ball-milled nanotubes. The ¹²⁹Xe NMR experiments evidenced the supported species to be localized on the internal surface of the ball-milled MWCNT.     

129Xe NMR Studies of Pecan Shell-Based Biochar and Structure-Process Correlations

Pecan shell-based biochar is utilized as a filtration medium, sequestrant for metallic ions, soil conditioner, and other applications. One process for creating the biochar involves the use of phosphoric acid at high temperature in a partial oxygen atmosphere to produce a highly porous carbonaceous material. In this work, we found ¹²⁹Xe NMR to be an excellent technique to study micropores in biochar. Thus, the ¹²⁹Xe chemical shift in biochar was found to vary linearly with the xenon pressure; from the data an estimate of about 8–9 Å could be proposed for the average pore diameter in pecan shell-based biochar. Through saturation recovery and 2-D NMR exchange experiments, information on the exchange between free versus bound xenon was obtained. Furthermore, correlations of ¹²⁹Xe NMR data with the carbonization process conditions were made.     

<Superscript>129</Superscript>Xe NMR spectroscopy of adsorbed xenon: Possibilites for exploration of microporous carbon materials

Despite the extensive use of ¹²⁹Xe NMR for characterization of high surface-to-volume porous solids, particularly zeolites, this method has not been widely used to explore the properties of microporous carbon materials. In this study, commercial amorphous carbons of different origin (produced from different precursors) and a series of activated carbons obtained by successive cyclic air oxidation/pyrolysis treatments of a single precursor were examined. Models of ¹²⁹Xe chemical shift as a function of local Xe density, mean pore size, and temperature are discussed. The virial coefficient arising from binary xenon collisions, σ_Xe-Xe, varied linearly with the mean pore size given by N₂ adsorption analysis; σ_Xe-Xe appeared to be a better probe of the mean pore size than the chemical shift extrapolated to zero pressure, σ_S.     

Controlling Gas Selectivity in Molecular Porous Liquids by Tuning the Cage Window Size

Control of pore window size is the standard approach for tuning gas selectivity in porous solids. Here, we present the first example where this is translated into a molecular porous liquid formed from organic cage molecules. Reduction of the cage window size by chemical synthesis switches the selectivity from Xe‐selective to CH₄‐selective, which is understood using ¹²⁹Xe, ¹H, and pulsed‐field gradient NMR spectroscopy.     

MCM-41分子筛的合成及129Xe核磁共振的研究

ＭＣＭ４１中孔分子筛是１９９２年由Ｍｏｂｉｌ公司的科学家Ｋｒｅｓｇｅ［１］等人首次合成的,并在《自然》杂志发表。这种中孔分子筛具有六角形孔径,孔径２ｎｍ～１０ｎｍ,这种分子筛的孔径可以通过水晶模板来控制［２］。已报道的合成ＭＣＭ４１,孔径一般在２．０ｎｍ～３．５ｎｍ,使用的水晶模板一般是单一或两种阳离子季铵盐表面活性剂［３,４］。本论文通过引入第二种扩孔模板,与阳离子季铵盐协同作用,合成了孔径５．２ｎｍ（ＢＥＴ法测）的ＭＣＭ４１。通过氮气的吸脱附,测定了分子筛的比表面和孔径等性质。Ｊ．Ｆｒａｉｓｓａｒｄ…     

AlMCM-41介孔分子筛的合成及表征

以拟薄水铝石为铝源、水玻璃为硅源、十六烷基三甲基溴化铵为模板剂,在110℃时水热晶化合成了含Al的MCM-41介孔分子筛.采用X射线衍射(XRD)、N2吸附-脱附、固体29Si、27Al魔角旋转核磁共振技术(MASNMR)、扫描电镜(SEM)及吡啶吸附傅里叶变换红外(FTIR)光谱技术对AlMCM-41分子筛进行了表征.结果表明:AlMCM-41分子筛具有六方排列的孔道结构,同时具有很高的相对结晶度、比表面积和孔容,且孔分布单一;AlMCM-41分子筛中Si原子在骨架内键合的程度更高,使AlMCM-41分子筛具有更好的骨架晶化程度;同时具有四配位骨架铝,使AlMCM-41介孔分子筛具有适当的酸性.     

129Xe NMR chemical shift in Xe@C60 calculated at experimental conditions: Essential role of the relativity,dynamics, and explicit solvent

The isotropic ¹²⁹Xe nuclear magnetic resonance (NMR) chemical shift (CS) in Xe@C₆₀ dissolved in liquid benzene was calculated by piecewise approximation to faithfully simulate the experimental conditions and to evaluate the role of different physical factors influencing the ¹²⁹Xe NMR CS. The ¹²⁹Xe shielding constant was obtained by averaging the ¹²⁹Xe nuclear magnetic shieldings calculated for snapshots obtained from the molecular dynamics trajectory of the Xe@C₆₀ system embedded in a periodic box of benzene molecules. Relativistic corrections were added at the Breit–Pauli perturbation theory (BPPT) level, included the solvent, and were dynamically averaged. It is demonstrated that the contribution of internal dynamics of the Xe@C₆₀ system represents about 8% of the total nonrelativistic NMR CS, whereas the effects of dynamical solvent add another 8%. The dynamically averaged relativistic effects contribute by 9% to the total calculated ¹²⁹Xe NMR CS. The final theoretical value of 172.7 ppm corresponds well to the experimental ¹²⁹Xe CS of 179.2 ppm and lies within the estimated errors of the model. The presented computational protocol serves as a prototype for calculations of ¹²⁹Xe NMR parameters in different Xe atom guest–host systems. © 2013 Wiley Periodicals, Inc.     

Enantiopure cryptophane-129Xe nuclear magnetic resonance biosensors targeting carbonic anhydrase

The (+) and ( ? ) enantiomers for a cryptophane-7-bond-linker-benzenesulfonamide biosensor (C7B) were synthesised and their chirality was confirmed by electronic circular dichroism spectroscopy. Biosensor binding to carbonic anhydrase II (CAII) was characterised for both enantiomers by hyperpolarised (HP) ¹²⁹Xe NMR spectroscopy. Our previous study of the racemic ( ± ) C7B biosensor–CAII complex [Chambers, J.M.; Hill, P.A.; Aaron, J.A.; Han, Z.H.; Christianson, D.W.; Kuzma, N.N.; Dmochowski, I.J. J. Am. Chem. Soc.2009, 131, 563–569] identified two ‘bound’ ¹²⁹Xe@C7B peaks by HP ¹²⁹Xe NMR (at 71 and 67 ppm, relative to ‘free’ biosensor at 64 ppm), which led to the initial hypothesis that (+) and ( ? ) enantiomers produce diastereomeric peaks when coordinated to Zn²⁺ at the chiral CAII active site. Unexpectedly, the single enantiomers complexed with CAII also identified two ‘bound’ ¹²⁹Xe@C7B peaks: (+) 72, 68 ppm and ( ? ) 68, 67 ppm. These results are consistent with X-ray crystallographic evidence for benzenesulfonamide inhibitors occupying a second site near the CAII surface. As illustrated by our studies of this model protein–ligand interaction, HP ¹²⁹Xe NMR spectroscopy can be useful for identifying supramolecular assemblies in solution.     

介孔分子筛MCM-48的室温合成与表面修饰

在室温条件下的碱性介质中合成了介孔分子筛MCM-48，并对其进行了有机官能团表面修饰。利用HRTEM、低温N₂吸附、XRD、TG、IR和NMR等手段对产物进行了结构和性能分析。实验结果表明，合成产物MCM-48具有规则的孔道结构、大比表面积、大孔容和窄分布的孔径。由硅烷试剂表面修饰后的MCM-48，由于有机官能团接枝在MCM-48的内表面，占据了孔道内部空间，使其比表面积、孔容和孔径都减小。     

Incorporation of heteropoly acid,tungstophosphoric acid within MCM-41 via impregnation and direct synthesis methods for the fabrication of composite membrane of DMFC

A heteropoly acid, tungstophosphoric acid (here-in-after TPA) with super acid strength was successfully encaged by two different methods, impregnation and direct synthesis. XRD and FT-IR analyses indicate that significant amount of TPA encaged by impregnation method should have been washed out upon washing treatment for TPA-MCM-41 powder. Due to significant loss of TPA upon washing, TPA was directly synthesized within MCM-41 pore channels using sodium tungstate dehydrate, disodium hydrogenphosphate dodecahydrate and hydrochloric acid. Compared to impregnation method, TPA was more effectively encaged and XRD analyses clearly show that reasonable amount of TPA in TPA-MCM-41 remains even after washing. A uniform distribution of directly synthesized TPA within MCM-41 pore channel was also confirmed by TEM images. In second part of this study, various TPA-encaged MCM-41 powders were used to fabricate composite membranes. For comparison, composite membranes fabricated with calcined MCM-41 and raw TPA, Nafion^® 115 and casting Nafion^® membrane were also prepared.