一种新的NMR法测定溶液中碱土金属混合物的方法原理

本文研究了碱土金属离子-锶、钡及钙可以形成在NMR标尺上是稳定配合物的条件。找到了最适合得到这样的配合物的配体-C222穴醚。研究并归属了碱土金属离子以及碱金属-钠、钾及锂配合物在氯仿中的¹³C NMR谱。检测出了可用于分析自由配体及其与碱土金属配合物的¹³C NMR信号,还研究了不同比例混合物的碱土金属及碱金属在氯仿中的¹³C NMR谱,得到了当自由配体过量时在钡、钙及锶每种金属浓度为1×10^-3M的谱中可观测到相当于自由配体及每种离子配合的配体的分立信号。这些信号的积分值的精度可以定量地表征金属离子的浓度,所得结果为首次观测到的。它可以作为用¹³C NMR波谱建立新的无机分析方法。文中并阐明了作溶液中碱土金属混合物NMR测定方法的具体条件,并讨论了将这一方法扩展到包括一系列碱金属在内的更复杂的混合物的可能性。试验在VARIAN XL-200波谱仪上进行。     

铕、铽-2-噻吩甲酸-2,2'-联吡啶配合物的合成、表征及荧光性质研究

合成了铕、铽-2-噻吩甲酸的二元配合物和铕、铽-2-噻吩甲酸-2,2'-联吡啶的三元配合物,并对它们进行了元素分析、稀土络合滴定、摩尔电导测定,确定了配合物组成分别为REL3·2H2O及REL3 L'·C2H5OH(RE=Eu,Tb;L=2-噻吩甲酸、L'=2,2'-联吡啶),测定了配体及配合物的IR谱、1H NMR谱及荧光光谱.IR谱和1H NMR谱测定表明,配体2-噻吩甲酸羧基氧、配体邻菲咯啉2个氮原子与稀土离子配位.荧光光谱实验表明,高氯酸铕和高氯酸铽分别与2,2'-联吡啶和2-噻吩甲酸反应形成的三元配合物的荧光明显强于二元配合物.     

β-烷氧羰乙撑基三氯化锡与N-芳基-2-羟基乙酰苯叉亚胺配合物的NMR谱与结构

测定了12个新合成的有机锡-Schiff碱配合物的¹H NMR谱和¹³C NMR谱,详细研究了化合物结构与NMR谱的关系,通过比较配体和配合物的NMR谱,得出配合物是通过酚羟基氧原子和锡原子的配键生成的.     

BPC6与碱金属离子相互作用的紫外光谱研究

1,3-二异丙氧基杯~([4])芳烃冠醚-6(BPC6)是一种1,3交替结构的杯芳单冠化合物,可对碱金属离子进行主客体识别并形成1∶1配合物~([1]),其配合物稳定常数与碱金属离子直径~([2])、溶剂类型~([3])、阴离子类型等因素有关。在与碱金属离子进行主客体识别过程中,BPC6的紫外光谱将发生减色效应,利用此原理,本文采用紫外光谱法研究了BPC6分子与碱金属离子主客体识别过程中的相互作用规律。结果表明,随着碱金属离子(Li~+,Na~+,K~+,Rb~+,Cs~+)直径的增大,BPC6与碱金属配合物的稳定常数也随之增大,且BPC6与Cs~+离子的稳定常数最大(LogK=6.25~6.32),可能是由于其空腔尺寸大小与Cs~+离子的离子直径更为接近,匹配度高;并且不同溶剂中配合物的稳定常数也有所不同,甲醇可与BPC6分子形成氢键阻碍其与金属离子的配合,且其溶剂化效应大于乙腈,因此配合物在乙腈中的稳定常数较甲醇中更大。     

三脚架型配体镁(Ⅱ)配合物的合成及其晶体结构

合成了一种新型的三脚架型配体的镁(Ⅱ)配合物，配合物经元素分析、^1H NMR、UV-可见分光光度及IR光谱等表征，在甲醇溶液中，配体与金属镁(Ⅱ)离子形成稳定的配合物[Mg(L)](ClO4)2，晶体结构分析表明晶体呈单斜晶系，其空间群为P2(1)/c，金属离子被6个氮原子所包围，其平均键长为0．210nm。     

氨基酸合成方法研究—(XI)N-取代亚氨酸酯与芳醛缩合产物—去氢氨基酸衍生物的构型及其NMR研究

通过~1H NMR、NOE差谱和门控去偶~(13)C NMR等的研究确定了新合成的五对α-去氢氨基酸衍生物的构型,并利用部分弛豫、APT~(13)C NMR二维碳氢相关谱及~(13)C-~(19)F偶合常数等对NMR谱线进行了归属.     

铕、铽-2-噻吩甲酸-2,2′-联吡啶配合物的合成、表征及荧光性质研究

合成了铕、铽-2-噻吩甲酸的二元配合物和铕、铽-2-噻吩甲酸-2,2′-联吡啶的三元配合物,并对它们进行了元素分析、稀土络合滴定、摩尔电导测定,确定了配合物组成分别为REL₃·2H₂O及REL₃ L′·C₂H₅OH(RE=Eu,Tb; L=2-噻吩甲酸、L′=2,2′-联吡啶), 测定了配体及配合物的IR谱、1H NMR谱及荧光光谱。IR谱和1H NMR谱测定表明,配体2-噻吩甲酸羧基氧、配体邻菲咯啉2个氮原子与稀土离子配位。荧光光谱实验表明,高氯酸铕和高氯酸铽分别与2,2′-联吡啶和2-噻吩甲酸反应形成的三元配合物的荧光明显强于二元配合物。     

杀菌剂环氟菌胺波谱学数据全归属

环氟菌胺是一种具有新型母核结构的优秀杀菌剂,该文采用~1H NMR、~(13)C NMR、~(19)F NMR、~1H-~(13)C HSQC、~1H-~(13)C HMBC和~1H-~(15)N HMBC等多种核磁共振(NMR)技术,并结合质谱(MS)、紫外光谱(UV)和红外光谱(IR)等方法对环氟菌胺进行了解析,同时对一维核磁共振(1D NMR)波谱数据进行全归属,讨论了UV和IR的吸收峰与该化合物各官能团的对应关系、~(19)F对其~1H和~(13)C NMR谱峰的影响,以及MS主要离子碎片的归属和化合物裂解规律.     

重稀土高氯酸盐甲基苯甲酰甲基亚砜配合物的合成及Tb3+的发光

合成了重稀土高氯酸盐甲基苯甲酰甲基亚砜配合物RE(ClO4)3·L5·C2H5OH(RE=Gd,Tb,Dy,Tm,Yb;L=C6H5COCH2SOCH3).经元素分析、稀土络合滴定、摩尔电导及热重分析确定了配合物的组成,测定了配体及配合物的IR谱、1H NMR及铽配合物的磷光光谱、荧光激发和发射光谱,根据荧光发射光谱数据计算了铽配合物的各能级值.     

含R_2NCS_2配体的Mo(W)-Cu-S簇合物的~1H NMR研究

报道了十一个含R_2NCS_2配体的Mo(W)-Cu-S簇合物的,~1H NMR研究结果,表明异金属簇合物导致配体中α-H的NMR谱线严重加宽.对谱线的位移,化合物的结构及配位键键长L_(Cu-s)之间的关系也作了讨论.     

氟喹诺酮类抗菌药物与过渡金属离子Cr3+, Mn2+和Fe3+形成配合物配位位置的研究

通过1D ¹H NMR, ¹³C NMR和1H自旋-晶格弛豫时间T₁对氟喹诺酮类抗菌药物与过渡金属离子Cr³⁺, Mn²⁺和Fe³⁺形成配合物的位置进行了研究, 合成了固体配合物对其进行了元素分析. 实验结果表明过渡金属离子Cr³⁺, Mn²⁺和Fe³⁺与氟喹诺酮类抗菌药物形成1∶2的配合物, 并确定了配位位置.     

A Comparison of Complexation of Li<Superscript>+</Superscript> Ion with Macrocyclic Ligands 15-Crown-5 and Benzo-derivatives in Binary Nitromethane–Acetonitrile Mixtures by Using Lithium-7 NMR Technique and Ab Initio Calculation

Abstract  

Lithium-7 nuclear magnetic resonance (NMR) measurements were used to investigate the stoichiometry and stability of Li⁺ complexes with 15-crown-5 (15C5), benzo-15-crown-5 (B15C5) and dibenzo-15-crown-5 (DB15C5) in a number of nitromethane (NM)–acetonitrile (AN) binary mixtures. In all cases, the exchange between the free and complexed lithium ion was fast on the NMR time scale and a single population average resonance was observed. While all crown ethers form 1:1 complexes with Li⁺ ion in the binary mixtures used, stepwise formation constants of the 1:1 (ligand/metal) complexes were evaluated from computer fitting of the NMR-mole ratio data to equations which relate the observed metal ion chemical shifts to formation constants. There is an inverse linear relationship between the logarithms of the stability constants and the mole fraction of AN in the solvent mixtures. The stability order of the 1:1 complexes was observed to be 15C5.Li⁺ > B15C5.Li⁺ > DB15C5.Li⁺. The optimized structures of the free ligands and their 1:1 complexes with the Li⁺ ion were predicted by ab initio theoretical calculations using the Gaussian 98 software. The results of calculations are discussed.     

THE SYNTHESIS AND SPECTRAL CHARACTERIZATION OF NEW Cu(II), Ni(II), Co(III), AND Zn(II) COMPLEXES WITH SCHIFF BASE

ABSTRACT

Cu(II), Ni(II), Co(III) and Zn(II) complexes with Schiff base have been prepared. Ligand is derived from condensation of 1,2-bis(p>-aminophenoxy)ethane and 2- hydroxynaphthalin-1-carbaldehyde. The complexes have been characterized by elemental analyses, Λ_M, IR, UV-VIS, ¹H NMR, ¹³C NMR and magnetic measurements. The ligand is coordinated to the central metal as a tetradentade ONNO ligand. The four bonding sites are the azomethine nitrogen and aldehydic -OH groups.     

Synthesis and characterization of SWNT-heavy alkali metal intercalation compounds,effect of host SWNTs materials

Singlewall carbon nanotubes (SWNTs) produced by electric-arc and laser ablation methods were characterized by X-ray diffraction before and after the reaction with alkali metals (M=K, Rb, and Cs). Reaction with annealed SWNTs gave MC₈ composition at saturation. The alkali metal lattice showed short range order incommensurate with graphene cylinders of SWNTs. X-ray diffractogram simulations have enabled the study of the influence of SWNTs structure on that of intercalation compounds. Chemically-purified bundles, constituted of open SWNTs, can be intercalated inside and between the tubes forming disordered structures. Annealed or pristine bundles were intercalated only between the tubes leading to short or long range ordered structure depending on host crystallinity and alkali metal (K, Rb or Cs). The expansion of the 2D SWNTs lattice after intercalation is comparable to graphite intercalation compounds. Some 2D arrangements of SWNTs and K atoms are proposed and discussed to reproduce XRD results. ¹³C NMR and ESR studies of annealed doped SWNTs emphasize the fact that the intercalation compounds of SWNTs are metallic.     

Fluorine NMR Chemical Shifts in Certain Ionic Fluorides

NMR chemical shifts are known for various nuclei in numerous solid compounds. Especially detailed data were obtained for NMR of ¹⁹F. The present work cites the measurement results for fluorine NMR chemical shifts in several d¹⁰-element fluorides previously not investigated. At the same time, the fluorine chemical shift values in alkali, alkali-earth and some other metal fluorides were measured anew. (This was necessitated by the discrepancies in the shift magnitudes, cited by various authors, as well as by the inaccuracy of the mutual chemical shifts of some standards commonly used.     

Molecular structure of alkali metal 4‐nitrobenzoates

The influence of lithium, sodium, potassium, rubidium, and cesium on the electronic system of the 4‐nitrobenzoic acid molecule was studied. The vibrational (FT‐IR, FT‐Raman) and NMR (¹H and ¹³C) spectra for 4‐nitrobenzoic acid salts of alkali metals were recorded. The assignment of vibrational spectra was done. Characteristic shifts of band wavenumbers and change in band intensities along the metal series were observed. Good correlation between the wavenumbers of the vibrational bands in the IR and Raman spectra for 4‐nitrobenzoates and ionic potential, electronegativity, atomic mass, and affinity of metals were found. The chemical shifts of protons and carbons (¹H, ¹³C NMR) in the series of studied alkali metal 4‐nitrobenzoates were observed too. Optimized geometrical structures of studied compounds were calculated by HF, B3PW91, B3LYP methods using 6‐311++G** basis set. The theoretical IR, Raman, and NMR spectra were obtained. The theoretical vibrational spectra were interpreted by means of potential energy distributions (PEDs) using VEDA 3 program. The calculated parameters were compared to experimental characteristic of studied compounds. Copyright © 2007 John Wiley & Sons, Ltd.     

双-(二烷基膦)乙烷合铂配合物的~(13)C NMR研究

本文报道Cis-Pt(disphos)X_2系列化合物的~(13)C NMR研究。发现配体X、取代基R对桥环碳(C_1)化学位移有明显的影响;并证实了某些化合物象异构体的存在,还对构象特性进行了讨论。     

结晶紫内酯开环机理的￣（13）CNMR研究

报道了结晶紫内酯开环机理研究。通过测定开环前后及平衡混合物的￣（１３）ＣＮＭＲ谱，对结晶紫内酯开环形成的正碳离子结构及影响正碳离子稳定性因素进行了分析。利用开环前后及平衡体系的化学位移数据求得了平衡混合物中内酯态和正碳离子之间的平衡常数．对不同条件下结晶紫内酯开、闭环机制进行了讨论。