Interaction of Scopolamine and Cholesterol with Sphingomyelin Bilayers by FT-Raman Spectroscopy

The interaction of scopolamine and cholesterol with sphingomyelin bilayers has been investigated by FT-Raman spectroscopy in head-group region (600-1000 cm^-1), the C-C stretching (1000-1200 cm^-1), CH₂ deformation (1400-1500 cm^-1) and the C-H stretching (2800-3000 cm^-1) mode regions. The results indicate that scopolamine and cholesterol do not change the conformation of O-C-C-N⁺ backbone in the choline group of sphingomyelin bilayers, the polar headgroup is still extending parallel to the bilayer surface and 0-C-C-N⁺ group is still in its gauche conformer. Scopolamine and cholesterol lower the order of the interface, the interchain, CH₂ crystal lattices and the lateral chain-chain packing, and increase their fluidity.     

Probing Membrane Surfaces and the Location of Membrane-Embedded Peptides by C MAS NMR Using Lanthanide Ions

A simple but efficient ¹³C MAS NMR method is presented for the determination of the location of embedded molecules such as peptides relative to biological membrane surfaces by exploiting the interaction with paramagnetic lanthanide ions. Using various aqueous Dy³⁺ concentrations a distance-dependent differential paramagnetic quenching of NMR lipid resonance intensities for specific carbon sites was observed, with residues at the bilayer surface quenched effectively and hydrophobic sites unaffected by Dy³⁺. Tested on the membrane-embedded 50 residue long M13 coat protein, ¹³C labeled at its Val-29 and Val-31 residues, no paramagnetic quenching was observed for the peptide resonances by Dy³⁺, suggesting that Val-29 and Val-31 are not in close proximity to the bilayer interface, but buried deeply inside the hydrophobic region of the lipid bilayer.     

FT-Raman光谱研究东莨菪碱和神经鞘磷脂的作用

本文用ＦＴ－Ｒａｍａｎ光谱研究了东莨菪碱和神经鞘磷脂的相互作用。研究结果表明，东莨菪碱对鞘磷脂极性头部的构象没有影响，降低鞘磷脂交界面，脂肪酸链，ＣＨ２晶格及脂肪酸链链间的有序性，增大其流动性。     

1H NMR Spectral Simplification with Achiral and Chiral Lanthanide Shift Reagents. Lofexidine

The ¹H NMR spectra of the potent anti-hypertensive drug, lofexidine, 1, have been studied in CDCl₃ at 60 and 300 MHz. Both the achiral shift reagentr tris (6,6,7,7,8,8,8-heptafluoro-2,2-dimethyl-3,5-octanedionatol-europium(III), 2 and the chiral reagents1 tris[3-(heptafluoropropylhydroxymethylenel-d-camphoratoleuropium(III), 3 and tris[3-(trifluoromethylhydroxymethylenel-d-camphoratoleuropium(III), 4, were employed. Substantial lanthanide induced shifts were observed with 2, 3 or 4, with the largest shifts seen for the methine at the chiral centerr followed by the signal of the NH. Enantiomeric shift differences for the CH₃ signal of 1 were seen with 3 OK 4, with 4 inducing larger values of potential analytical utility. Using a non-racemic sample of 1, the (-) enantiomer was shown to have a downfield sense of magnetic nonequivalence for the methyl resonance in the presence of added 4.     

Lanthanide Shift Reagents. Paper 22 The Influence of Mixed Silver/Praseodymium Shift Reagents on the Proton NMR Spectra of Heteroaromatics

Previous work in these laboratories¹ and elsewhere^2,3 has pointed to the value of a mixture of lanthanide fod chelates with silver fod^1,2 or with silver trifluoroacetate³ in simplifying the ¹H NMR spectra of aryl substrates which do not possess the conventional (O or N) donor groups (fod = 2,2-dimethyl-6,6,7,7,8,8,8-heptafluoro-3,5-octane dionate).     

惰性稀土离子和抗衡离子对2-噻吩乙醛酸-铕配合物荧光性能的影响

研究了惰性稀土离子和抗衡离子对一系列2-噻吩乙醛酸-铕配合物荧光性能的影响。分别在2-噻吩乙醛酸-邻菲罗啉-铕和2-噻吩乙醛酸-三苯基氧化膦-铕两个体系中按不同比例掺入钇和钆,研究了它们的荧光光谱。结果表明,钇的加入对2-噻吩乙醛酸-邻菲罗啉-铕体系的荧光强度有很强的敏化作用,并且随加入量的增加,这种敏化作用逐渐增强。钇的加入对2-噻吩乙醛酸-三苯基氧化膦-铕体系则呈现出弱的敏化作用,且在一定程度上具有猝灭作用,但这两种作用都是很微小的。钆在少量加入时对2-噻吩乙醛酸-三苯基氧化膦-铕体系具有猝灭作用,当大量加入时则呈现出很强的敏化作用。不同的抗衡离子对配合物的影响是明显的。在二元配合物中,氯化物体系的固体荧光强度最大;在三元配合物中,硝酸盐体系的固体荧光强度最大。     

N.M.R. Studies of Lanthanide(III) Complexes. High Field Shifts in Complexes of 1,10-Phenanthroline

In continuation of our studies on the complexes of lanthanide(III) ions with N-donor ligands^1,2, especially those of 1,10-phenanthroline (phen)^3,4, we wish to report the proton N.M.R. spectra of several lanthanide(III) complexes of phen in aqueous (D₂O) solution at 330 K. Table 1 contains the observed chemical shifts of the four types of protons in phen relative to the methyl resonance of the internal standard 2-methyl-2-propanol. For comparison, the spectrum of an authentic sample of Nd(phen)₂Cl₃.2H₂O complex prepared by the method of Sinha⁵ was recorded and the spectrum found to be virtually indistinguishable from that obtained by mixing the individual components in the proper ratio.     

Photoacoustic and Fluorescence Spectroscopy of Metallomesogens Containing Lanthanide Ions

制备了稀土液晶配合物Ln(bta)3L2 (Ln3+：La3+,Eu3+,Ho3+;L：N-octadecyl-2-hydroxy-4-tetradec-yloxybenzaldimine;bta：benzoyltrifluoroacetonate), 所得配合物在室温下呈近晶相(SmA phase)．首次利用光声光谱对金属液晶配合物的光谱性质、弛豫过程和相变进行研究．在配体吸收处,光声强度依Eu(bta)3L2相似文献   

鞘磷脂与胆固醇相互作用的拉曼光谱研究

利用ＦＴ Ｒａｍａｎ光谱研究了不同浓度的胆固醇对鞘磷脂质脂体的作用。结果表明,胆固醇没有改变鞘磷脂的Ｏ Ｃ Ｃ Ｎ＋骨架构象,极性头仍然平行膜表面。Ｃ Ｃ骨架振动强度比Ｉ１０８６／Ｉ１０６４说明,随着胆固醇浓度上升,鞘磷酸分子内部旁式构象也逐渐增多。从Ｉ２８４７／Ｉ２８８０强度比看,胆固醇具有使鞘磷脂脂双层有序性上升,流动性降低的作用,但这种作用随胆固醇浓度上升而逐渐减弱。     

Lanthanide Shift Reagents XIII the Influence of Phenyl, 1-Adamantyl and Tert-Butyl Substituents on Equilibrium Constants

We have recently extended our Infrared studies of the binding of anilines with lanthanide shift reagents¹ to an NMR examination of hindered phenyl-carbinols² and a series of aldehydes and ketones related to benzaldehyde and acetophenone³.     

Fluorescence Properties of Frog Skeletal Muscles Treated with Lanthanide Ions

Laser-induced fluorescence from frog skeletal muscle fibers treated with lanthanides, Eu³⁺ and Tb³⁺, was recorded. The fluorescence was weak and overlapped with the Raman scattering by the Ringer solution when the muscle fibers were illuminated with an argon-ion laser. The fluorescence decay rate of the lanthanide in Ringer's solution was 2–3 times larger than that of the lanthanide bound to the muscle fiber. The number of water molecules coordinated to the lanthanide bound to the muscle fiber was determined to be about three. This suggests that lanthanide ions bind superficially to the outer membrane of the muscle fiber.     

H2O/KDEHP(75%)-HDEHP(25%)/n-HEPTANE微乳体系表面活性剂与水相互作用的谱学研究

利用傅里叶变换拉曼光谱和傅里叶变换红外光谱对H2O/KDEHP(75%)-HDEHP(25%)/n-HEPTANE微乳体系的表面活性剂疏水链和极性头基与水分子的相互作用进行了研究.结果表明:当加水量由W0＝1增加至43时,表面活性剂极性头基[PO2]-的反对称伸缩振动由1 233 cm-1移至1 207 cm-1,其对称伸缩振动由1 094 cm-1移至1 089 cm-1.表面活性剂疏水链的堆积结构也发生了变化,表现在拉曼光谱上为碳氢振动吸收峰的峰高比Ir(I2 962/I2 875),Ir(I2 937/I2 875),Ir(I2 916/I2 875)和Ir(I2 903/I2 875)随加水量增大而增大.结合二阶导数谱和傅里叶变换退卷积谱,本文还对KDEHP和HDEHP的存在状态进行了探讨,认为体系中表面活性剂分子有多种存在状态.     

1 H NMR Spectral Simplification with Achiral and Chiral Lanthanide Shift Reagents. Clenbuterol. Method for Direct Optical Purity Determination

The 60 MHz ¹H NMR spectra of clenbuterol, 1, have been studied in CDCl₃ solution with the achiral shift reagent, tris (6,6,7,7,8,8,8-hepta-fluoro-2,2-dimethyl-3,5-octanedionato)europium (III), 2, and the chiral reagent tris[3-(heptafluoropropylhydroxyn1ethyl-ene)-(+)-canphorato]europiunr(III), 3. Use of 3 resulted in observable enantiomeric shift differences, ΔΔσ, for the t-butyl, NH₂ benzylic CH and the aryl proton signals. Values of ΔΔσ as high as 135.1 Hz (2.25 ppm) and 86.5 Hz (1.44 ppn) were seen for the methine and aryl protons, respectively, with a solution 0.1035 molal in 1 and a 1:3 molar ratio of 0.551. The aryl resonance is especially well suited for direct optical purity determinations of 1.     

用核磁共振方法研究金属离子与蛋白质的相互作用

许多蛋白质含有金属离子,金属离子对蛋白质发挥生物学功能起着很大的作用. 金属离子与蛋白质的相互作用以及参与蛋白质功能调节的方式各种各样：有些金属离子高度专一性地与蛋白质紧密结合,对蛋白质发挥生物学功能起着关键性的作用;有些金属离子只是作为蛋白质发挥功能的辅助因子而瞬态地与蛋白质松散结合. 本文简要介绍目前国际上用NMR方法研究抗磁金属离子和顺磁金属离子与蛋白质相互作用的进展,并具体介绍了NMR方法在钙调蛋白、锌指蛋白、朊病毒蛋白等金属离子蛋白研究上的应用.     

丙烯酰胺-甲基丙烯酸共聚物结构的NMR研究

用¹H NMR谱,¹³C NMR谱,DEPT谱,gHMQC,gHMBC二维谱和质子弛豫时间等方法研究了在紫外光辐照条件下丙烯酰胺(AM) -甲基丙烯酸(MAA)共聚合反应,讨论了AM-MAA共聚合反应时间与转化率的关系、共聚单体的连接方式、共聚物序列结构以及不同辐照时间下形成的共聚物链运动. 结果表明在紫外光辐照条件下,AM-MAA共聚物链节中同时存在多种连接方式,当反应时间为45 min时,共聚合转化率可达100%. 从自旋-晶格弛豫时间（T₁）和自旋-自旋弛豫时间（T₂）测定中得出,在辐照1小时范围内,时间越长聚合物长链分子运动速度越快,但主链的链段运动变化不明显.     

1H NMR Spectral Simplification with Achiral and Chiral Lanthanide Shift Reagents. Meparfynol, 3-Methyl-L-Pentyn-3-Ol. Apparent Anomalous Results with a Binuclear Shift Reagent

The 60 MHz ¹H NMR spectra of racemic meparfynol, 1, have been studied in CDCl₃ solution at 28° with the achiral shift reagentt tris(6,6,7,7,8,8,8-hepta-fluoro-2,2-dimethyl-3,5-octanedionato) europium (III), 2, and the chiral reagent, tris[3-(heptafluoropropyl-hydroxymethylene)-d-camphorat01 europium(III), 3. With 3, observable enantiomeric shift differences for the 3-methyl should make possible direct optical purity determinations. Additions of increments of (6,6,7,7,8,8,8-heptafluoro-2,2-dimenthyl-3,5-octane-dionato)silver(I) 4, to a CDCl₃ solution of 1 and 3 resulted in changes in Δδ magnitudes and in some line intensities that are discussed in terms of interactions with the ethynyl and hydroxyl groups.     

镧系离子(Eu3+,Tb3+)氧氟沙星配合物的合成和光谱表征

本文报道了镧系离子Eu3 + ,Tb3 + 同喹诺酮羧酸类衍生物氧氟沙星形成配合物的合成。用元素分析法和ICP确定了配合物的组成为Ln(oflo) 3 Cl3 ·8H2 O。红外光谱表明氧氟沙星配体羧基同中心离子发生螯合 ,并可能与邻位羰基形成六元环稳定结构。荧光光谱表明 ,Eu配合物具有很宽的激发谱带 (2 0 0～ 45 0nm) ,明显区别于其他羧酸类的稀土配合物 ;中心离子Eu3 + 发射谱位于 5 79 0nm(5D0 7F0 ) ,5 92 2nm(5D0 7F1) ,6 12 2nm(5D0 7F2 ) ;而Tb3 + 配合物则同时有配体和中心离子的荧光发射     

镧系元素双1：11系列杂多蓝的红外光谱和紫外光谱研究

本文首次系统研究了镧系元素钼采双１：１１系列两子杂多蓝ＫｚＨｙ（Ｌｎ（ＸＭｏ１１Ｏ３９０２）．ｎＨ２Ｏ（Ｘ＝Ｐ，Ｌｎ＝Ｌａ，Ｃｅ，Ｐｒ，Ｎｄ，Ｓｍ，Ｇｄ；Ｘ＝Ｓｉ，Ｌｎ＝Ｃｅ，Ｐｒ，Ｓｍ，Ｔｂ，Ｄｙ）的红外光谱和紫外光谱，对特征峰进行指认，并与还原前的杂多酸盐进行比较，发现有的特征峰出现小的位移，有的峰强度稍有变化，所以得出结论，还原前后，杂多阴离子结构基本不变，但有轻微的畸变。     

GB1与金属离子相互作用的NMR研究

G群链球菌G蛋白的B1结构域——GB1蛋白,常被用作发展体外及体内基于顺磁核磁共振（NMR）的蛋白质结构测定方法的研究模型.为确保赝接触化学位移（PCS）、顺磁弛豫增强（PRE）等顺磁约束数据的准确性,了解GB1和金属离子,尤其是顺磁离子的相互作用非常必要.然而GB1和二价金属离子以及镧系金属离子的相互作用并不十分清楚.本文利用NMR波谱研究了GB1和镧系金属离子以及多种二价金属离子的相互作用.我们发现GB1和镧系金属离子之间存在弱特异性相互作用,和Mn²⁺、Cu²⁺以及Co²⁺等顺磁二价离子弱结合,但不与Ca²⁺、Mg²⁺以及Zn²⁺等抗磁二价离子结合.该研究表明在GB1上链接顺磁探针时,应使用与固有位点结合常数差异明显的顺磁标签以获取正确的PRE数据.     

2-磺酸对苯二甲酸铕配合物的发光性质及对苯甲醛的检测

水热法合成了新的配位聚合物,[Eu(2-stp)(2,2’-bipy)(H₂O)]·H₂O (2-stp=2-磺酸对苯二甲酸根,2,2’-bipy=2,2’-联吡啶）。通过X-射线单晶衍射确定了该配合物的晶体结构。该配合物为一维平行双链结构。Eu3+与2-磺酸对苯二甲酸根的六个氧原子,2,2’-联吡啶的两个氮原子和一个水分子配位。对该配合物进行了荧光性质的研究,发射光谱中出现了Eu3+的五个特征峰,分别位于581,594,619,654和698 nm,对应于Eu3+的5D₀→7F_J (J=0～4)跃迁。位于619 nm的最强发射峰是由5D₀→7F₂跃迁产生的。不同有机溶剂对该配合物荧光强度有不同程度的影响,苯甲醛对该配合物具有显著的荧光猝灭效应,故该配合物可作为苯甲醛的荧光感应探针。