烯丙基氯化镁引发己二酸酐开环聚合

以烯丙基氯化镁引发己二酸酐开环聚合制备功能化的聚己二酸酐。考察了引发剂、温度、溶剂对聚合反应的影响.核磁端基分析表明开环聚合反应可能是通过酰氧键断裂,按“配位－插入”机理进行的。     

Potentiometric and multinuclear NMR studies on the interaction of aluminum with ascorbic acid in acidic aqueous solution

The complex-formation equilibria between aluminum(III) ion and L-(+)-ascorbic acid (AA) in 0.1 M KCl ionic medium at 25 degrees C and 0.15 M NaCl ionic medium at 37 degrees C were studied by glass electrode pH-metric measurements. The obtained experimental results were explained by the formation of the following complexation species: a weak mononuclear 1:1 species AlL(2+) together with two trinuclear mixed-hydroxo species Al(3)H(-5)L(4) and Al(3)H(-5)L(3+) in acidic aqueous solutions. Meanwhile, the formation of the complexes and structures of Al with AA were proved by multinuclear (1H, 13C, 27Al) NMR spectra in the pH range 2.0-5.0. It is supposed that Al directly coordinates with AA at O-3 moiety; also, Al can coordinate with the O-1 and O-2 moieties of ascorbate ion through the weakly binding and the intramolecular hydrogen bonding in acidic aqueous solutions.     

核磁共振技术结合模式识别对中药马兜铃酸亚急性生化效应的研究

利用核磁共振技术结合模式识别方法,研究了马兜铃酸(AristolochicAcid,AA)的亚急性生化效应.大鼠连续5日腹腔注射马兜铃酸后,不同时间段尿液¹HNMR谱显示与肾小管及肾乳头受损相关的标记物(NMRmarker)浓度有显著变化;铬酸钠、氯化汞、二溴乙胺、盐酸肼和异硫氰酸-α-萘酯,并利用主成分分析法对造成的肝肾损伤模型组、AA组和对照组的大鼠尿液¹HNMR谱解析和分类.¹HNMR谱中各种代谢物的谱峰强度变化及主成分分析结果均显示,马兜铃酸引起的肾损伤与肾小管及肾乳头损伤模型类似,且随给药量的积累,肾损伤范围扩大程度加深,引起肾脏不可逆损伤.该方法可用于中药的毒理学研究.     

Long range H,H coupling constants in cycloheptatrienes

The ¹H NMR spectra of 1,6-dicarbomethoxycyclohepta-1,3,5-triene ( 2 ) and 3,4-benzocyclohepta-1,3,5-triene ( 3 ) have been analysed in terms of chemical shifts and coupling constants. A method for the assignment of δ(AA′) and δ(BB′) in AA′BB′ systems, based on the observation of ¹³C satellites in the ¹H NMR spectrum, is described. For J(1,5) in 3 , a negative sign was established. Spin tickling experiments were used to determine the positive sign for J(2,5) in 2 and the negative sign for J(2,7) in 3. The conformation of 3 is discussed.     

轻稀土镧、铈急性生物效应的血清1H NMR谱代谢组学研究

采用现代核磁共振和模式识别技术,通过分析腹腔注射给药La(NO3)3(2，10和50 mg/kg体重)和Ce(NO3)3(2，10和50 mg/kg体重) 48 h后大鼠血清的核磁共振氢谱,由内源性代谢物浓度的变化研究了两种稀土化合物在大鼠体内的急性生物效应,利用主成分分析法对两者进行了分类比较. 在低剂量(2 mg/kg体重)组La(NO3)3和Ce(NO3)3血清中， 乳酸和肌酸酐等内源性代谢物浓度发生了微小变化； 在高剂量组(10和50 mg/kg体重)中， 含量变化较大的重要内源性代谢物包括3-羟丁酸、丙氨酸、 肌酸酐、 丙酮、 乙酸、 琥珀酸和葡萄糖等,其中3-羟丁酸和丙氨酸等在La的剂量组中变化较大,Ce的剂量组血清中丙酮、 琥珀酸和葡萄糖含量变化明显. 实验结果表明， 低剂量La和Ce的毒性较低,并对机体影响较小,高剂量则对大鼠肝脏造成损伤,且Ce的毒性大于La.     

Synthesis of spherical particles by self-assembly of poly[2-(perfluorooctyl)ethyl acrylate-co-acrylic acid] in supercritical carbon dioxide

Spherical particles were prepared from poly[2-(perfluorooctyl)ethyl acrylateco-acrylic acid] random copolymers (P(POA-co-AA)) by self-assembly in supercritical carbon dioxide (scCO2). The P(POA-co-AA) copolymers with 9:1, 8:2, 7:3, and 6:4 molar ratios of the POA/AA unit completely dissolved in scCO2, however, the solubility was dependent on the POA/AA ratio. The copolymer with the higher AA content had a lower solubility. The scanning electron microscopy (SEM) observations revealed that the spherical particles were obtained in a heterogeneous state at pressures lower than the cloud point pressure. Dynamic light scattering and 1H NMR studies demonstrated that the copolymers formed random copolymer micelles consisting of the shells of the CO2-philic POA units and the cores of the CO2-phobic AA units and main chains. It was found that the formation of spherical particles could be optimized by the manipulation of the CO2 pressure and temperature for the different compositions of the copolymers.     

Study on the cationic ring‐opening polymerization of 1,3‐dioxepane in the presence of organic acids

1,3‐Dioxepane was polymerized with triflic acid as an initiator in the presence of acetic acid (AA) and hexane diacid. The structure of the poly(1,3‐dioxepane) (polyDOP) obtained was characterized by ¹H NMR spectra and gel permeation chromatography. The molecular weights (MWs) were determined by vapor pressure osmometry. The results obtained in both systems were completely different from those in which low‐MW polyols were used as chain‐transfer agents. When the molar ratio of carboxylic acid to triflic acid was low, high‐MW polyDOP with a controlled MW and narrow MW distribution was obtained. The content of the ester group in the final product depended greatly on the molar ratio of AA to triflic acid. The polymerization mechanism is discussed. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 38: 1232–1240, 2000     

硝酸镥急性毒性的体液核磁共振氢谱研究

采用现代核磁共振技术,通过分析灌胃给药0．01、0．05、0．2、2、10和100ms／kg剂量Lu(NO3)3 24h内大鼠尿液及24h后大鼠血清的核磁共振氢谱(^1HNMR),由体液中内源性代谢物浓度的变化研究了稀土化合物在动物体内急性毒性。较高剂量组体液中的氨基酸、尿囊素、柠檬酸、氮氧三甲胺和肌酸酐等重要内源性代谢物的核磁共振谱峰强度发生了明显的变化,说明动物体内的代谢物出现异常：高剂量的稀土的引入可能使动物肾脏和肝脏均受到损害,且受损程度随稀土剂量的增高而渐趋严重。     

反应型非离子表面活性剂的制备及其组成和结构

以丙烯酸(AA)与硬脂酸单甘油酯(GMS)、油酸单甘油酯(A300)或油酸单山梨糖醇酐酯(Span 80)为起始物, 对甲苯磺酸为催化剂, 对苯二酚为阻聚剂, 制备了三类含有1-烯键的反应型表面活性剂. 通过反应体系中AA 的加料量及其残留量, 计算得到丙烯酸的转化率为91%以上, 制备的反应型非离子表面活性剂的收率达到80%以上. 用红外光谱(FTIR)、核磁共振氢谱(1H NMR)和质谱对反应产物的组成和结构进行了表征, 确认获得了三类目标产物. 将这三类表面活性剂作为流滴剂与聚乙烯发生接枝反应后, 提高了聚乙烯的结晶温度, 降低了水在聚烯烃膜表面的接触角, 解决了聚乙烯农用棚膜的流滴期短的问题.     

Application of chemometrics to 1H NMR spectroscopic data to investigate a relationship between human serum metabolic profiles and hypertension

The application of chemometric methods to 1H NMR spectroscopic data has been documented for pathophysiological processes. In this study we show the application of 1H NMR-based metabonomics to investigate a relationship between serum metabolic profiles and hypertension. Although hypertension can be defined using blood pressure measurements, the underlying aetiology and metabolic effects are not so readily identified. Serum profiles for patients with low/normal systolic blood pressure (SBP < or = 130 mm Hg; n = 28), borderline SBP (131-149 mm Hg; n = 19) and high SBP (> or = 150 mm Hg; n = 17) were acquired using 1H NMR spectroscopy. Orthogonal signal correction followed by principal components analysis were applied to these NMR data in order to facilitate interpretation, and the resulting chemometric models were validated using Soft Independent Modelling of Class Analogy. Using 1H NMR-based metabonomics, it was possible to distinguish low/ normal SBP serum samples from borderline and high SBP samples. Borderline and high SBP samples, however, were indiscriminate from each other. Our preliminary results showed that there was a relationship between serum metabolic profiles and blood pressure which, in part, was due to lipoprotein particle composition differences between the samples. Furthermore, our results indicated that serum pathology associated with blood pressure is apparent at SBP values > 130 mm Hg, which the WHO and ISH currently define as the limit between normal and high-normal.     

Synthesis and characterization of fluorescent copolymer containing rare earth metal complex and its interaction with DNA

A complex of Eu³⁺, acrylic acid (AA), and 1, 10‐phenanthroline (Phen) was synthesized. The structure and fluorescence of Eu(AA)₃Phen was characterized with elemental analysis, FTIR, ¹H NMR, and fluorescence spectroscopy. A novel copolymer containing rare earth complex, poly(PEGMA‐co‐NIPAm‐co‐Eu(AA)3Phen) (PPNEu), was prepared by free radical copolymerization in methanol with azodiisobutyronitrile as initiator. ¹H NMR, fluorescence spectroscopy, UV‐vis spectroscopy, and TEM were used to characterize this copolymer. The interaction of PPNEu with deoxyribonucleic acid (DNA) was studied by fluorescence spectroscopy, UV‐vis spectroscopy and agarose gel electrophoresis. The results of fluorescence, UV‐vis absorption, and agarose electrophoresis indicated that the PPNEu could interact with DNA in an electrostatic bonding mode. The TEM observation showed that the PPNEu could form spherical micelles in water solution small than 100 nm; the efficient complexation of PPNEu with DNA occurred. These results suggested the potential of the PPNEu as gene detective reagent and gene delivery carrier. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2010     

Complexation and rate of polymerization of acrylic acid and methacrylic acid in the presence of poly(4-vinylpyridine) in dilute methanol solution

A 1:1 hydrogen-bonded complex was formed between acrylic acid (AA) or methacrylic acid (MA) and the pyridine group of poly(4-vinylpyridine) (P4VP) in dilute solutions. A shift of infrared absorption of the hydrogen-bonded acid O? H to a lower energy direction and an upfield shift of acid proton in the NMR were observed when the monomers were added with pyridine. The equilibrium constants of the 1:1 complexation with P4VP measured by using a semipermeable membrane were 0.58 and 0.26 for AA and MA, respectively, at 25°C in methanol. The bromometrically measured initial rate of radical polymerization showed only a slight enhancement in the presence of P4VP, the rate being maximum at the 4VP unit:monomer mole ratio of 0.25 and 0.5 for AA and MA, respectively, in dilute methanol solution at 60°C.     

多重敏感性双亲共聚物P(DM-co-AA-co-CA)的自组装及性能

以甲基丙烯酸二甲胺乙酯（DM）、丙烯酸（AA）和香豆素丙烯酸酯化物（CA）为共聚单体,通过普通自由基溶液聚合合成了多重敏感性双亲共聚物P(DM-co-AA-co-CA),用傅里叶变换红外（FTIR）、核磁共振（1H-NMR）、凝胶渗透色谱（GPC）和差示扫描量热仪（DSC）对聚合物结构进行表征．在选择性溶剂四氢呋喃/水中对所得多重敏感性双亲共聚物P(DM-co-AA-co-CA)进行自组装,结果表明,调节组装环境的pH值可以得到荷正电或负电的两性胶束粒子．用紫外可见光分光光度计、荧光分光光度计、Zeta电位测定仪、DLS和TEM研究了多重敏感性双亲共聚物的溶液自组装及其组装体的性能,结果显示,调节pH值可以有效的控制胶束的粒径大小及其LCST,并在pH为8.54时胶束溶液的紫外吸收和荧光发射强度达到最大值,且该胶束溶液在酸碱性较强时具有良好的乳化性能．     

The absence of favorable aromatic interactions between beta-sheet peptides

This paper asks whether interactions between phenylalanine (Phe) residues of the non-hydrogen-bonded cross-strand pairs of antiparallel beta-sheets are important and finds that they are not. Peptides 1a-d [o-BuO-C6H4CO-AA1-Orn(i-PrCO-Hao)-Phe-Ile-AA5-NHMe: 1a AA1, AA5 = Phe; 1b AA1, AA5 = Cha (cyclohexylalanine); 1c AA1 = Phe, AA5 = Cha; 1d AA1 = Cha, AA5 = Phe] provide a sensitive system for probing interactions between phenylalanine residues. These peptides form beta-sheet homodimers in organic solvents. When the homodimers of different peptides are mixed, they equilibrate to form heterodimers, as well as homodimers. The position of the equilibrium reflects the propensity of the first (AA1) and fifth (AA5) amino acids to interact within the non-hydrogen-bonded cross-strand pairs of beta-sheets. Mixing peptides 1a-d in all six possible binary combinations provides a measure of the relative propensities of Phe and Cha to pair. Analysis by 1H NMR spectroscopy of the equilibrium constants in CDCl3 solution reveals no significant preference for the formation of Phe-Phe pairs. The equilibria in all six experiments are essentially statistical (K approximately 4), and no (<0.1 kcal/mol) preference is seen for any pairing combination. A survey of Phe-Phe pairs in the Interchain beta-Sheet Database (http://www.igb.uci.edu/servers/icbs/) corroborates that little significant contact occurs between the aromatic rings in the non-hydrogen-bonded cross-strand pairs of antiparallel beta-sheets at the interface between polypeptide chains. Even though contacts between aromatic rings are favorable when they are of suitable geometry, the energetic price of achieving suitable geometries appears to offset the energetic benefits of such contacts in the current model system, as well as in proteins.     

The influence of serum fatty acid binding proteins on arachidonic acid uptake by macrophages

The role of serum fatty acid binding proteins (FABPs) in arachidonic acid (AA) uptake by murine peritoneal macrophages has been studied. The kinetics of [³H]arachidonic acid uptake by the cells was investigated over a wide range of AA concentration (10⁻¹⁰–10⁻⁵ M). It was shown that these putative fatty acid transporters dramatically change the uptake processes. In the presence of FABPs, the time-course curves of AA uptake exhibited two distinct periods: one with a rapid AA uptake during the first hour with an equilibrium in 1–2.5 h and another with an equilibrium reached in 20 h, whereas in the absence of FABPs the uptake curves were smooth without kinks and with the equilibrium reached in 10 h. In addition, it was shown that the amount of incorporated AA was linearly dependent on the concentration of AA over the range of 10⁻¹⁰–10⁻⁶ M in the presence of serum FABPs and 10⁻¹⁰–10⁻⁷ M in their absence. We assume that the changes in the character of AA uptake by macrophages in the presence of FABP soccur due to the interaction of FABPs with the cell plasma membrane.     

含铕荧光两亲接枝共聚物的制备及胶束化行为

以丙烯酸(AA)、 苯甲酸(BA)和邻菲啰啉(Phen)为配体, Eu³⁺为中心离子, 制备了可聚合荧光配合物单体, 并以此单体为功能单体, 聚乙二醇单甲醚甲基丙烯酸酯(MPEGMA)和甲基丙烯酸六氟丁酯(HFMA)为共聚单体, 通过溶液聚合制备出含铕两亲荧光接枝共聚物P-[HFMA-co-Eu(AA)(BA)₂Phen]g-PEG. 利用红外光谱(FTIR)和核磁共振波谱(¹H NMR和¹⁹F NMR)对共聚物的结构进行表征; 采用表面张力法测定共聚物的临界胶束浓度(cmc)为0.20 g/L; 通过透射电子显微镜(TEM)和动态光散射仪(DLS)观察胶束的形貌及其胶束化行为, 发现该共聚物可以形成大小均一的球形胶束, 且随着共聚物浓度的提高, 胶束粒径相应增大; 在溶液浓度达到临界胶束浓度时, 溶液荧光出现强度突变.     

Synthesis,Spectroscopic and Computational Studies of Charge-Transfer Complexation Between 4-Aminoaniline and 2,3-Dichloro-5,6-dicyano-1,4-benzoquinone

A charge-transfer (CT) complex that forms from the reaction of the donor 4-amino aniline (4AA) and the π-acceptor 2,3-dichloro-5,6-dicyano-p-benzoquinone (DDQ) have been studied and characterized experimentally and as well as theoretically at room temperature. The experimental work includes the application of UV–visible spectroscopy to identify the CT band of the CT-complex. The composition of the complex has been investigated using spectrophotometric titration and Job’s method of continuous variation and found to be 1:1. Furthermore, to calculate the formation constant and molar extinction coefficient, we have used the Benesi–Hildebrand equation. Infrared, ¹H NMR, ¹³C NMR and mass spectral studies were used to characterize and confirm the formation of the CT-complex. The experimental studies were supported by quantum chemical simulations using density functional theory. The computational analysis of molecular geometry, Mulliken charges, and molecular electrostatic potential surfaces of reactants and complexes are helpful in assigning the CT route. The C=O bond length of DDQ increased upon complexation with 4AA. We have also observed that a substantial amount of charge has been transferred from 4AA to DDQ in the process of complexation. An excellent consistency has been achieved between experimental and theoretical results.     

核磁共振法研究固体表面上的吸附

应用JEOL FX-90Q NMR谱仪测定了吸附在NaY分子筛,氧化铝,二氧化硅上的四甲基硅烷和正己烷的核磁氢谱和碳谱.结果表明,在一些吸附体系的研究中,现有仪器适用于液体样品,以氢谱和碳谱比较发现碳谱在分辨率分方面较之氢谱有几个优点,顺磁杂质对谱线宽度有明显影响.在NaY分子筛上预先吸附氢以后再吸附乙烯,其吸附速率低于未吸附氢的样品.     

Diffusion and NOE NMR studies on the interactions of neutral amino-acidate arene ruthenium(II) supramolecular aggregates with ions and ion pairs

The interaction between [RuCl(AA)(cymene)]n supramolecular aggregates (1, AA = alpha-amino-acidate = alpha-aminoisobutyrate; 2, AA = N,N-dimethyl-Gly; 3, AA = Ala; 4, AA = Pro; cymene = 4-isopropyltoluene) and ionic species derived from NBu4PF6 and KPF6 is investigated through diffusion NMR measurements and 19F,1H-hetero-nuclear Overhauser effect spectroscopy experiments in CDCl3 and CD2Cl2. Aggregates containing the -NH2 functionality (1 and 3) interact strongly with NBu4PF6 as demonstrated by the observation of intense nuclear Overhauser effects between the fluorine atoms of PF6(-) and the protons of [RuCl(AA)(cymene)]n. Unexpectedly, diffusion NMR measurements indicate that the average size of the aggregates increases when a small amount of NBu4PF6 is added (Csalt/CRu < 0.1) in CD2Cl2. At higher concentration levels of NBu4PF6 or in CDCl3, NBu4PF6 exerts a destructive effect that reduces the average size of the aggregates. [RuCl(AA)(cymene)]n aggregates with NR-H (4) and NR2 (2) functionalities are little affected by the addition of NBu4PF6. KPF6 also interacts with [RuCl(AA)(cymene)]n aggregates as demonstrated by the fact that it becomes noticeably soluble in CDCl3 and CD2Cl2. Diffusion1H-NMR experiments show that the addition of KPF6 does not markedly alter the average size of [RuCl(AA)(cymene)]n supramolecular aggregates. Interestingly, the average size of PF6(-)-containing supramolecular aggregates is, in some cases, slightly higher than that of the ones that do not contain PF6(-). This was deduced by independent measurements of the hydrodynamic volume of the anion and of the ruthenium complexes by diffusion 19F- and 1H-NMR experiments, respectively.     

肝细胞癌、肝硬化患者血清中代谢物组研究

采用核磁共振方法检测肝硬化、肝细胞癌(简称肝癌)患者和健康人血清中代谢物,研究3组血清代谢物组的差异.利用偏最小二乘法-判别式分析(partial least square-discriminant analysis, PLS-DA)对NMR谱数据进行模式识别分析,探讨利用基于1H NMR代谢组学技术诊断肝癌的可行性.结果表明,与健康人相比,肝硬化、肝癌患者血清中脂质(低密度脂蛋白和极低密度脂蛋白)、胆碱、乙酰乙酸等含量减少,谷氨酰胺、丙酮酸、苯丙氨酸、酪氨酸等含量增加.PLS-DA分析结果显示肝癌患者可与健康人、肝硬化患者鉴别开来,肝癌诊断灵敏度达921%,假阳性率为5.7%,优于血清甲胎蛋白(alpha-fetoprotein, AFP)检测.研究结果表明,基于1H NMR代谢组学技术结合PLS-DA的方法具有灵敏、准确、重复性好等优点,有助于肝癌早期诊断.