Synthesis and relaxivity of polyamide paramagnetic metal complexes for magnetic resonance imaging

A new class of paramagnetic macromolecular magnetic resonance imaging contrast agents has been developed. Eight new polyamide ligands were synthesized by copolymerization of ethylenediaminetetraacetic acid dianhydride or diethylenetriaminepentaacetic acid dianhydride and diamine monomers. Their gadolinium(III), manganese(II) and iron(III) complexes were also synthesized. All polyamide ligands and metal complexes were characterized by ¹H nuclear magnetic resonance, infrared spectra and elemental analyses. Relaxivity studies showed that the polyamide paramagnetic metal complexes had obviously higher relaxation effectiveness as compared to corresponding simple monomeric paramagnetic metal complexes.     

锰、铑原卟啉IX-二甲酯配合物共振拉曼光谱研究

合成了MnPPCl,RhPPCl,RhPPN3,RhPP(CO)Cl四种配合物 (PP =ProtophyrinIXDimethy1Ester) ,用元素分析、红外吸收光谱及紫外吸收光谱确定了配合物的组成 ,测定了它们的共振拉曼光谱 ,对特征谱带进行了归属。分析了拉曼谱带和电子吸收谱带变化的原因 ,提出了谱带频率的变化受金属离子外层d电子和轴配体的影响。     

Carbon dioxide supercritical fluid chromatography-Fourier transform infrared spectrometry

Summary The coupling of carbon dioxide supercritical fluid chromatography with Fourier transform infrared spectrometry (SFC-FTIR) is a powerful tool for the separation and on-line identification of non-volatile compounds. The IR transparency of carbon dioxide in the Fermi resonance bands region versus its density has been studied. Functional groups with stretching vibrations outside the transparent window of carbon dioxide are examined. SFC-FTIR separations allow Gram-Schmidt reconstruction chromatograms or IR window chemigrams with high quality spectra to be obtained. This SFC-FTIR lightpipe (flow cell, beam condensing optics, narrow band detector) has allowed detection limits of 250ng for benzonitrile and 70ng for methyl benzoate to be reached. The feasibility of very rapid SFC-FTIR separations is shown along with the subsequent peak spectra.     

月光花素甲(Ⅰ)、(Ⅱ)整体分子结构的测定

本文对月光花素甲(Calonyctin A)的整体分子结构分析加以完善并进行总结。前文报道月光花素甲是两个分子量相差28a.m.u的糖甙类同系物分子的混合物。这两个分子(简称M_1和M_2)分别称为月光花素甲(Ⅰ)与月光花素甲(Ⅱ)(Calonyctm A_1,CalonyctinA_2),分子量分别为938与910。它们分别含     

Exchange interactions in some low-dimensional metal dithiolene complexes

Low-dimensional systems are formed by planar metal dithiolene complexes which stack as columnar structures in the solid state. Stronger interactions among units within a chain leads to highly anisotropic magnetic properties. The magnetic effects are a manifestation of exchange interaction,J and can be studied through detailedepr techniques in conjunction with magnetic susceptibility and x-ray crystal structure. A brief review of such studies carried out mostly in our laboratory is presented along with the relevant background materials.     

Melamine–Barbiturate Supramolecular Assembly as a pH-Dependent Organic Radical Trap Material

In the last two decades, a large number of self-assembled materials were synthesized and they have already found their way into large-scale industry and science. Hydrogen-bond-based supramolecular adducts are found to have unique properties and to be perfect host structures for trapping target molecules or ions. Such chemical systems are believed to resemble living matter and can substitute a living cell in a number of cases. Herein, a report on an organic material based on supramolecular assembly of barbituric acid and melamine is presented. Surprisingly, the structure is found to host and stabilize radicals under mild conditions allowing its use for biological applications. The number of free radicals is found to be easily tuned by changing the pH of the environment and it increases when exposed to light up to a saturation level. We describe a preparation method as well as stability properties of melamine–barbiturate self-assembly, potentiometric titration, and hydrogen ions adsorption data and EPR spectra concerning the composite.     

Twist-grain boundary phase induced by Au nanoparticles in a chiral liquid crystal host

We report on the stabilisation of the liquid-crystalline, twist-grain boundary A (TGB_A) phase in mixtures of a chiral liquid crystal and surface-functionalised spherical Au nanoparticles (NPs) of 10 nm diameter. The results, obtained by calorimetric, optical, small-angle X-ray and plasmon resonance measurements, demonstrate that a TGB_A phase, which is metastable for the pure liquid crystal host, can be effectively stabilised for a 3 K range in the presence of NPs. Moreover, the role of NPs size on the TGB_A stabilisation is briefly discussed.     

Structure analysis of polyether-based thermoplastic polyurethane elastomers by FTIR, 1H NMR and 13C NMR

One kind of unknown structure sequence and composition ratio of thermoplastic polyurethane elastomers were characterized by nuclear magnetic resonance spectroscopy, Fourier transformed infrared spectroscopy, and gel permeation chromatography (GPC). The results showed that the polyurethane (PU) was obtained from poly(tetramethylene glycol) (PTMG) as soft segment, 1,4-butanediol (BDO) as chain extender, and 4,4′-methylenediphenyl diisocyanate (MDI) as hard segment. Furthermore, the composition ratio of MDI:PTMG:BDO was 2.07:1.22:1.00. At last, the molecular weight of PU was determined by GPC, and the number average molecular weight (M_n) and weight average molecular weight (M_w) are 63,300 and 133,800?g?mol^?1, respectively.     

基于纳米金Core-satellites等离子体耦合增强效应的汞离子光纤传感器的研究

以DNA杂交双链为联接, 构建纳米金颗粒Core-satellites结构并激发等离子体耦合增强效应,利用Hg2+可与DNA中胸腺嘧啶T形成T-Hg2+-T特异性结构,研制了用于检测水中Hg2+的局域等离子体共振(LSPR)光纤传感器.待测溶液中的Hg2+能够引起富含T的DNA单链折叠,抑制DNA杂交反应,降低等离子体耦合强度,改变LSPR谐振波长.通过检测谐振波长红移变化,实现对Hg2+浓度的定量检测.本方法检测Hg2+的线性范围为5~150 nmol/L, 检出限为3.4 nmol/L (3σ). Zn2+、Mg2+、Pb2+等重金属离子对Hg2+检测无明显干扰作用.实际水样中Hg2+加样回收率为94.2%~105.4%,相对标准偏差<4.8%.