酶法测定人尿中L-瓜氨酸含量

L-瓜氨酸是人体多种疾病的重要检测指标。利用鸟氨酸甲氨酰转移酶和氨甲酰激酶对L-瓜氨酸的专一性作用,建立了一种准确、简便、灵敏的L-瓜氨酸含量酶法测定方法。较为适宜的酶转化条件是:30℃~35℃,pH6~7。固定化酶有较高的稳定性,4℃保存60d后酶活回收率仍高达95%。该方法测定L-瓜氨酸的线性范围为2~10mg/L;工作曲线回归系数r=0.9987;样品回收率达99%以上。     

化学-生物法制备D-精氨酸和L-瓜氨酸

在水溶液中以水杨醛为催化剂,L-精氨酸可以快速消旋为DL-精氨酸．后以DL-精氨酸为底物,利用粪链球菌（Streptococcus faecalis）精氨酸脱亚胺酶对L-精氨酸的专一脱亚胺作用,同时制备D精氨酸和L-瓜氨酸,分别以92．3％,94．2％的产率获得光学纯的D-精氨酸和L-瓜氨酸．     

酶法转化液中L-瓜氨酸的分光光度法测定

根据L-瓜氨酸在强酸性溶液中与二乙酰一肟的专一性显色反应及反应复合物在490nm处吸光度与L-瓜氨酸浓度呈线性关系的特点,通过考察酶转化液中转化底物L-精氨酸、副产物L-鸟氨酸、增效剂、磷酸盐缓冲溶液、细胞自溶释放物以及显色剂用量、显色反应时间等条件对L-瓜氨酸测定的影响,建立了一种准确、简便、灵敏的L-精氨酸酶法转化液中L-瓜氨酸的光度分析方法。该方法的相关系数r=0．999,样品回收率达99．58％。     

D-、L-和DL-青霉胺的太赫兹时域光谱

利用太赫兹时域光谱技术(THz-TDS)对D-、L-和DL-青霉胺的研究发现, 三种样品在0.2 THz到1.8 THz波段的吸收光谱存在显著差异, 实验结果表明, THz吸收光谱能够鉴别青霉胺对映异构体, 这一特点将可以用于青霉胺药物的检测. 本文利用纯D-、L-青霉胺的THz吸收光谱, 对D-、L-青霉胺混合样品的THz吸收光谱进行拟合, 证明可以用THz光谱定量分析混合样品中D-、L-青霉胺的相对含量. 这项研究为手性药物分子检测和分析提供了新的实验方法, 也对深入了解手性药物与生物靶分子之间相互作用提供了启示.     

生理条件下稀土及钙,锌离子与L—羟脯氨酸配位作用的研究

生理条件下稀土及钙、锌离子与Ｌ－羟脯氨酸配位作用的研究＊高峰＊＊牛春吉孟淑兰倪嘉缵（中国科学院长春应用化学研究所稀土化学和物理开放实验室长春１３００２２）金天柱王瑞瑶王祥云（北京大学稀土材料化学和应用国家重点实验室北京１００８７１）关键词稀土钙锌Ｌ－...     

L-羟脯氨酸寡肽混合物的高效液相色谱分离与质谱分析

研究了三氯氧磷辅助下L-羟脯氨酸的成肽反应,建立了采用反相高效液相色谱-质谱/质谱联用技术分离鉴定羟脯氨酸寡肽混合物的方法,优化了L-羟脯氨酸寡肽混合物的色谱分离条件。实验以YWG C8柱(10 μm,250 mm×10 mm)为分离柱,以乙腈-0.06%三氟乙酸水溶液(体积比为2∶98)为流动相进行等度洗脱,在正离子模式下对洗脱物进行了电喷雾电离串联质谱鉴定。结果显示,分离出的各组分分别为L-羟脯氨酸二肽、L-羟脯氨酸环二肽和L-羟脯氨酸三肽。     

L-异亮氨酸型配体交换固定相对DL-氨基酸的拆分研究

用自制的新型L-异亮氨酸配体交换固定相在配体交换模式下对11种DL-氨基酸进行了拆分研究,详细考察了流动相中铜离子浓度、甲醇含量、流速及温度对拆分效果的影响,并探讨了可能的拆分机理。研究结果表明:流动相中高浓度的铜离子不利于DL-氨基酸的拆分;增加流动相中甲醇的含量,降低流动相流速以及提高色谱柱温度均可改善拆分效果。     

镧系水合离子的密度泛函理论研究

用密度泛函理论(DFT)方法研究了镧系水合离子[Ln(H2O9)]^3+(Ln=Ce,Pr,Nd,Pm,Ho,Er,Tm,Yb)的几何构型、电荷分布和Ln^3+与水的结合能,计算结果与实验基本符合,表明DFT方法也适用于计算镧系离子与中性配体形成的化合物,对计算结果的分析表明,Ln^3+与H2O之间主要通过Ln5d轨道与氧孤对电子相互作用成键而结合,其余轨道起的作用比较小,用镧系化合物成键模型解释了镧系离子与水的结合能从La到Lu逐渐增加的事实。     

L-和DL-福多司坦的太赫兹光谱分析

利用太赫兹时域光谱技术(THz-TDS)在室温下对L-福多司坦和DL-福多司坦进行测量,发现L-和DL-福多司坦在THz波段都有特征吸收峰,且两者的吸收谱有明显差异.运用密度泛函理论的B3LYP方法计算了L-和DL-福多司坦在太赫兹波段的吸收谱,并对L-和DL-福多司坦的特征吸收峰进行了指认,理论计算与实验结果基本吻合.此外,还对福多司坦胶囊成品药进行了测量,发现该胶囊的吸收谱与L-福多司坦非常吻合,证明胶囊药的主要成分为L-福多司坦.这项研究对手性物质的检测以及化合物有效成分的鉴别有一定的参考作用.     

Hydrothermal Syntheses and Structural Studies of Lanthanide Coordination Polymers Involving In‐Situ Decarboxylation and their Luminescence Properties

Lanthanide coordination polymers with the formula [Ln(pydc)₂]·H₂O (Ln = La, 1 ; Nd, 2 ; pydc = 3,4‐pyridinedicarboxylate) and [Ln(pydc)(ina)(H₂O)₂] (Ln = Sm, 3 ; Eu, 4 ; Tb, 5 ; Dy, 6 ; pydc = 3,4‐pyridinedicarboxylate, ina = isonicotinate) were synthesized by treating Ln^III nitrates with 3,4‐pyridinedicarboxylic acid under hydrothermal conditions. Single‐crystal and powder X‐ray diffraction studies indicate that these lanthanide coordination polymers adopt two different structures. The lighter lanthanide compounds 1 and 2 consist of extended two‐dimensional layer structures with the thickness of ca. 1.7 nm. While the heavier lanthanide compounds 3 ‐ 6 have pydc‐bridged double chain structures with one chelating carboxylate group of ina ligand and two water molecules on each metal center. Interestingly, decarboxylation occurred and pydc was partially transformed into ina in the hydrothermal reactions of 3 ‐ 6 . The fluorescence activities of compounds 4 and 5 are reported.     

四氮杂大环与镧系金属配合物的热力学研究

The stability constants of the 1:1 complexes of H4L2 (5,12-dipheny1-7, 14-dimethyl-1,4,8,11-tetraazamasrocyclotetradecane-N', N", N"',N""-tetraacetic acid) with Ln3+ (Ln=La, Nd, Pr, Sm, Eu, Gd, Dy, Yb) were determined by potemtiometric titrations in 0.5mol•L-1 KCl at 40±0.1℃, 50±0.1℃ and 60±0.1℃ respectively. The △H, △S and △G of the coordination reactions of H4L2 with Ln3+ were given. Influences of the steric effect and temperature changes on the stability lanthanide complexes were discussed thermodynamically.     

Assembly of a Supramolecular Architecture Based on Keggin POMs and Lanthanide Coordination Cations

Two new compounds based on Keggin polyoxometalates (POMs) [SiW₁₂O₄₀]⁴⁻ (SiW₁₂), [Na(H₂O)₃(H₂L)SiW₁₂O₄₀](H₂L)₂   6H₂O (1), and [Ce(H₂O)₃(HL)₂(H₂L)]₂[SiW₁₂O₄₀]₂ 10H₂O (2) (HL = C₆H₅NO₂ = isonicotinic acid), have been conventionally synthesized and characterized by routine methods. Compound 1 possesses a 1D right-handed helical structure constructed by SiW₁₂O₄₀ ⁴⁻ {SiW₁₂} and [Na(H₂O)₃(HL)] complexes. Interestingly, these right-handed helical chains are linked together via H-bonds forming a novel chiral layer. By using the similar synthesis method to that for compound 1, except for employing Ce³⁺ cations in instead of La³⁺ cations, a 3D supramolecular compound 2 based on SiW₁₂ and Ce³⁺ coordination cations has been obtained, which contains 1D channels along a axis. Additionally, the luminescence properties of 2 were studied. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

N－乙酸基取代四氮杂大环及其镧系配合物的热力学研究

用ｐＨ电位滴定法分别在２５±０．１℃，４０±０．１℃和８０±０．１℃，０．５ｍｏｌ／ＬＫＮＯ３水溶液中测定了Ｈ_４Ｌ（５，７，１２，１４－四甲基－１，４，８，１１－四氮杂环十四烷－Ｎ＇，ｎ＂，Ｎ＂＇，Ｎ＂＂－四乙酸）的逐级质子化常数和焓值。又在４０±０．１℃和８０±０．１℃条件下测定了Ｈ４Ｌ与镧系金属离子（Ｌａ~（３＋），Ｎｄ~（３＋），ｐｒ~（３＋），Ｓｍ~（３＋），Ｅｕ~（３＋），Ｇｄ~（３＋），Ｄｙ~（３＋），Ｙｂ~（３＋））配合物的稳定常数。结果表明：配合物稳定性高。     

Review: Lanthanide coordination chemistry: from old concepts to coordination polymers

Because of their remarkable and unmatched optical and magnetic properties, the lanthanides are under the limelight when it comes to high technology. These elements are used in strategic applications such as optical glasses and lasers, telecommunications, lighting and displays, magnetic materials, hard-disk drives, security inks and counterfeiting tags, catalysis, biosciences, and medicine, to name but a few. Long considered as minor actors in transition metal chemistry, they have now gained respect from coordination chemists who insert them into sophisticated functional and polyfunctional molecules and materials. This mini review focuses on trivalent lanthanide ions and first summarizes their basic properties. Then some classical aspects of their coordination chemistry are discussed, followed by macrocyclic chemistry, supramolecular chemistry, and self-assembly processes. The last part of this contribution deals with coordination polymers and hybrid materials including potential applications.     

A Series of Lanthanide Coordination Polymers Constructed from 4-Pyridin-4-ylbenzoate

Four lanthanide coordination polymers, LaL₃(H₂O)₂(1), LnL₂(μ₃-OH)(H₂O)[Ln=Eu(2),Tb(3)] and ErL₃·2H₂O(4) were synthesized via hydrothermal reactions of lanthanide oxide with 4-pyridin-4-ylbenzonic acid(HL), and characterized by means of elemental analyses, infrared(IR) spectrometer, powder X-ray diffraction(PXRD), thermogravimetric analyses(TGA) and single-crystal XRD. The results reveal that complex 1 possesses a linear chain structure, complexes 2 and 3 possess isostructural ladder-like chains, while complex 4 possesses a 2D layer with 4-connected sql topology. Furthermore, the luminescence properties and UV-Vis spectra of complexes 2 and 3 were investigated.     

N-二乙酸基取代四氮杂大环及其镧系配合物的热力学研究

用pH电位滴定法测定了H2L（C－meso－meso－5,12-二苯基-7,14-二甲基-1,4,8,11-四氮杂环十四烷-N,N"-二乙酸）的逐级质子化常数,并进一步计算出配位反应的热焓和熵变．在（40±0．1）℃条件下测定了H2L与调系金属离子（La3+,Nd3+,Pr3+,Sm3+,Eu3+,Gd3+,Dy3+,Yb3+）形成1：1型配合物的稳定常数．用热力学稳定性的观点讨论了大环的尺寸效应和空间位阻等因素对配位稳定性的影响．     

四甲基二硅氧基桥联双环戊二烯基稀土金属配合物的合成及结构研究

在严格的无水无氧条件下无水NdCl₃和SmCl₂与Na₂(C₅H₄SiMe₂)₂O以1:1摩尔比在四氢呋喃溶液中反应,得标题配合物[O(Me₂SiC₅H₄)₂Ln(μ-Cl)(THF)]₂[Ln=Nd(1),Sm(2)].元素分析证明配合物1和2的组成.X射线衍射分析证明1和2是通过氯原子桥联的二聚体结构.     

Studies on the Coordination Polymer of Copper Electropolyurushiol

The coordination polymer of copper electropolyurushiol(EPU-Cu~(2+)) was obtained by the reaction of copper chloride with electropolyurushiol (EPU) in an isopropyl alcohol solution. The properties of EPU-Cu~(2+) were studied by means of ESR, FTIR, XPS, DMTA and TG-DTA. The results of AES show that the content of Cu~(2+) was 8.63％. The electric resistances of EPU-Cu~(2+) and EPU were determined to be 9, 37×10~(10) Ω and 7.90×10~(10) Ω respectively. It was also ascertained that in EPU-Cu~(2+) each Cu~(2+) is coordinated with two units hydroxyl in EPU, making the EPU-Cu~(2+) cross-link further. As a result, the title polymer exhibits an insolubility in most of organic solutions, a higher glass transition temperature and thermal resistance.     

镧系元素钨钒杂多配合物的合成与表征

报道了镧系元素钨钒杂多配合物的合成方法。元素分析和热重分析确定其通式为：Ｋ７Ｈ６「Ｌｎ（ＶＷ１０ＶＯ３９）２」．ｘＨ２Ｏ（Ｌｎ＝Ｌａ＾３＋、Ｃｅ＾３＋、Ｐｒ＾３＋、Ｎｄ＾３＋、Ｓｍ＾３＋、Ｅｕ＾３＋、Ｇｄ＾３＋、ｄＹ＾３＋、Ｙｂ＾３＋）。利用红外，喇曼，电子自旋共振，紫外和Ｘ射线衍射谱对其进行了表征。配合物的热解性质研究表明，其分解温度范围为４００－４５０℃，还研究了的氧化还原性质。