酞侧基聚芳醚酮的核磁共振研究(Ⅰ)──链结构及NMR谱的归属

用1D NMR方法研究酞侧基聚芳醚酮(PEK-C)链结构,用二维同核化学位移相关与二维异核化学位移相关实验方法对1D NMR谱峰进行归属,探讨了二维异核远程相关实验在缩聚高分子研究中的应用,为PEK-C修饰机理以及共混相容机理的研究提供重要信息。溶液NMR谱图数据表明,PEK-C具有较规整的链结构。     

新药普卢利沙的核磁共振研究

应用同核化学位移相关谱(1H-1H COSY)、氢检出异核多量子相关谱(HMQC)、氢检出多键异核多量子相关谱(HMBC)等二维谱核磁共振技术,参考19F-1H和19F-13C的偶合裂分情况对抗菌新药普卢利沙的1H NMR、13C NMR谱的信号进行了全归属。     

毛冬青甲素的核磁共振法分析

采用^1H、^13C、DEPT(无畸变极化转移增益法)、^1H-^1 COSY(氢-氢化学位移相关谱)、HMQC(异核多量子相关谱)、HMBC(异核多键相关谱)、NOESY(二维核欧沃豪斯效应谱)等多种NMR分析方法,对毛冬青甲素的^1H和^13C NMR谱信号进行了归属;并对生产过程常同时存在的丁二酸二钠也进行了谱线归属,提出通过^1H NMR法对产品中的丁二酸二钠进行定量测定。为其结构鉴定和生产过程中的质量控制提供了重要依据。     

三亚甲基碳酸酯和己内酯生物可降解共聚物序列结构的二维核磁分析

以辛酸亚锡[Sn(Oct)2]为催化剂、乙二醇为引发剂,通过本体开环共聚,合成了己内酯(CAP)与三亚甲基碳酸酯(TMC)的共聚物。采用1H、13C核磁共振及同核二维相关谱(gCOSY)、13C-1H异核相关谱(gHSQC)和13C-1H异核远程相关谱(gHMBC)等二维核磁共振(2D NMR)技术,对所合成的聚合物进行了序列微结构表征,找出了聚合物分子链中序列连接方式,并完成了1H和13C NMR谱带的归属。     

含二氮杂萘酮单元双官能团化合物结构的波谱表征

在成功地合成了11个用于制备聚芳酰胺类聚合物的含二氮杂萘酮单元的双官能团化合物基础上,本实验用核磁共振波谱确定了各化合物的结构。用二维同核位移相关谱(gCOSY)、异核^13C-^1H-键相关谱(gHSQC)和异核^13C-^1H远程相关谱(gHMBC)完成了全部^1H和^13C NMR谱带的归属;首次报道了该系列衍生物的氢和碳原子的化学位移值。对其系列化合物的核磁共振波谱及红外光谱的特征进行了讨论。     

二维NMR辅助归属4,5-脱氧美登醇的质子共振谱线

本文利用~1H NMR二维J谱及二维同核相关谱测定了4,5-脱氧美登醇的结构,并归属了它的全部谱线.     

二维NMR测定1,3-双烯膦酸酯的构型

本文报道用1H NMR二维J谱、二维同核相关谱及NOE技术测定了三个共轭双烯膦酸酯的双键构型,并求得各δ和J值。     

一种新的六氢嘧啶并嘧啶二酮衍生物的核磁共振分析

采用氢谱(1H NMR)、碳谱(13C NMR)、梯度场氢氢化学位移相关谱(1H-1H COSY)、梯度场质子检测异核单量子化学位移相关谱(HSQC)、梯度场质子检测异核多重键化学位移相关谱(HMBC)等多种NMR分析方法,确证了8a-对甲氧苯基-4,5-双(对氯苯基)六氢嘧啶[4,5-d]并嘧啶-2,7(1H,3H)-二酮的结构,对它的1H和13C NMR谱信号进行了归属,为其结构鉴定提供了重要依据。     

酞侧基聚芳醚砜的核磁共振研究──PES－C的氢谱归属及碳谱峰的确认

用１３Ｃ－ＮＭＲ谱和二维异核化学位移相关谱（ＨＥＴＣＯＲ）归属了酞侧基聚芳醚砜（ＰＥＳ－Ｃ）的１Ｈ－ＮＭＲ谱峰，并经二维同核化学位移相关谱（ＣＯＳＹ）验证．对原１３Ｃ－ＮＭＲ谱峰归属作了部分修正．二维同核及异核相关谱为ＰＥＳ－Ｃ的碳、氢核磁谱峰归属提供了重要信息．由ＰＥＳ－Ｃ的核磁谱图可见其链结构的规整性     

一种新西地那非类似物的结构确证

采用核磁共振氢谱(1H NMR)、核磁共振碳谱(13C NMR)、梯度场氢氢相关化学位移相关谱(1H-1H COSY)、梯度场质子检测异核单量子化学位移相关谱(HSQC)、梯度场质子检测异核多重键化学位移相关谱(HMBC)等多种NMR分析方法,结合红外光谱分析和元素分析,确证了5-[2-丙氧基-5-(3,5-二甲基哌嗪-1-基磺基)苯基]-1-甲基-3-正丙基-1,6-二氢-7H-吡唑并[4,3-d]嘧啶-7-酮的分子结构,为鉴定西地那非类似物提供了重要依据。     

Structures with tunable strong ferromagnetic coupling: from unordered (1D) to ordered (Discrete)

The X-ray crystal structures, magnetic susceptibilities from 2 to 300 K, and theoretical analyses of the magnetism for 1D and trinuclear azido Cu(II) carboxylate complexes [Cu(1.5)(hnta)(N(3))(2)(H(2)O)](n) (1) and [Cu(3)(hnta)(4)(N(3))(2)(H(2)O)(3)] (2), respectively, where hnta is 6-hydroxynicotinate, are described. Although both exhibit strong ferromagnetic coupling, discrete complex 2 exhibits long-range ferromagnetic ordering, while the very similar 1D system 1 does not. Density functional calculations provided accurate J values and allowed rationalization of the ferromagnetic coupling in terms of the magnetic orbitals and spin densities.     

Using switched angle spinning to simplify NMR spectra of strongly oriented samples

This contribution describes a method that manipulates the alignment director of a liquid crystalline sample to obtain anisotropic magnetic interaction parameters, such as dipolar coupling, in an oriented liquid crystalline sample. By changing the axis of rotation with respect to the applied magnetic field in a spinning liquid crystalline sample, the dipolar couplings present in a normally complex strong coupling spectrum are scaled to a simple weak coupling spectrum. This simplified weak coupling spectrum is then correlated with the isotropic chemical shift in a switched angle spinning (SAS) two-dimensional (2D) experiment. This dipolar-isotropic 2D correlation was also observed for the case where the couplings are scaled to a degree where the spectrum approaches strong coupling. The SAS 2D correlation of C(6)F(5)Cl in the nematic liquid crystal I52 was obtained by first evolving at an angle close to the magic angle (54.7 degrees ) and then directly detecting at the magic angle. The SAS method provides a 2D correlation where the weak coupling pairs are revealed as cross-peaks in the indirect dimension separated by the isotropic chemical shifts in the direct dimension. Additionally, by using a more complex SAS method which involves three changes of the spinning axis, the solidlike spinning sideband patterns were correlated with the isotropic chemical shifts in a 2D experiment. These techniques are expected to enhance the interpretation and assignment of anisotropic magnetic interactions including dipolar couplings for molecules dissolved in oriented liquid crystalline phases.     

Exploring the Electronic Structure of an Organic Semiconductor Based on a Compactly Fused Electron Donor–Acceptor Molecule

A Mott‐type semiconductor based on a compactly fused and partially oxidized electron donor–acceptor (D–A) molecule was recently prepared and identified to exhibit a large room‐temperature conductivity of 2 S cm^?1. In a marked contrast to the organic conductors characterized by relatively well decoupled and segregated uniform stacks of D and A moieties, the formally half‐oxidized tetrathiafulvalene donors of the actual compound are organized in columnar π stacks only, whereby the coplanar electron‐acceptor units, namely benzothiadiazole, are closely annulated along their ridges. Herein, we present a theoretical study that explores the electronic structure of this novel type of organic semiconductor. The highly symmetric‐solid state material behaves as a one‐dimensional electronic system with strong antiferromagnetic interactions (coupling constant>200 cm^?1). The unique shape and local dipole of this redox‐active fused electron D–A molecule lays the basis for further investigations of the collective electronic structure, mainly in the function of different counterions embedded in the crystalline lattice.     

Two cobalt(II) 5-aminoisophthalate complexes and their stable supramolecular microporous frameworks

Two stable supramolecular microporous cobalt(II) polymers, namely [Co(HAIP)2]n.3nH2O (1) and [Co(AIP)(H2O)]n (2), AIP = 5-aminoisophthalate, were hydrothermally synthesized and characterized by single-crystal X-ray diffraction, IR spectra, thermogravimetric analyses, and variable-temperature magnetic susceptibility measurements. The two complexes are constructed from the same Co2(CO2)2 SBU, which is extended into a 1D chain in 1 and a 2D layer in 2. As a result, 1 and 2 are 2D and 3D coordination polymers, respectively. The 3D supramolecular network of complex 1 is held up by strong hydrogen bonds formed between carboxylate groups and shows very high stability when the free H2O molecules are removed, indicating an extraordinarily stable H-bonding system. Upon water ligands being liberated, complex 2 becomes a stable microporous solid with coordination-unsaturated Co centers. The behavior of the susceptibility curve of 1 suggests the occurrence of an interesting intrachain antiferromagnetic coupling between the Co(II) ions and the presence of a significant orbital contribution, whereas the features of 2 indicate an antiferromagnetic coupling with T(N) = 3.5 K and a long-range antiferromagnetic order with a field-induced magnetic transition.     

Spectral measurement of the caesium D(2) line with a tunable heterodyne interferometer

The optical properties of a caesium atomic beam driven on a resonant hyperfine transition in the D(2) line were studied as a function of the probe laser frequency. Using a third off-resonant laser system, a heterodyne interferometer allowed simultaneous absorption and phase shift measurements of either the probe or the coupling laser. The signal features of the probe and coupling laser transmitted intensities showed strong differences in the vicinity of the hyperfine transitions excited by the probe laser. Regular absorption signals and electromagnetically induced transparency were found in either transmitted intensities. Furthermore, light induced birefringence of the probe laser was measured.     

Magnetic properties of diruthenium(II,III) carboxylate compounds with large zero-field splitting and strong antiferromagnetic coupling

The magnetic properties of mixed-valent compounds of general formula Ru2Cl(mu-O2CR)4 [R = CH2-CH3 (1), C(Me)=CHEt) (2)] have been studied in the 2-300 K temperature range. This magnetic study also includes a revision of the magnetic properties of the complex Ru2Cl(mu-O2CCMePh2)4 (3). Compounds 1-3 show a linear structure and a strong antiferromagnetic coupling between the diruthenium units through the chlorine atoms according to previous studies. Two fitting models to explain the magnetic properties of these complexes that incorporate a large zero-field splitting together with a strong antiferromagnetic coupling are described. These models consider that each diruthenium unit (S = 3/2) is magnetically coupled to the nearest diruthenium unit and ignores the longer distance magnetic coupling. The fitting models were found to be successful in fitting the magnetic data of the linear diruthenium(II,III) complexes. The zero-field splitting, D, and the antiferromagnetic coupling, zJ, vary from 37.8 to 48.0 cm-1 and from -7.43 to -13.30 cm-1, respectively, for complexes. The D values are similar to those calculated for the nonlinear diruthenium(II,III) compounds and confirm the validity of the proposed fitting models.     

Theoretical interpretation of the line shape of the gaseous acetic acid cyclic dimer

A general quantum theoretical approach of the nu(X-H) IR line shape of cyclic dimers of weakly H-bonded species in the gas phase is proposed. In this model, the adiabatic approximation (allowing to separate the high frequency motion from the slow one of the H-bond bridge), is performed for each separate H-bond bridge of the dimer and a strong nonadiabatic correction is introduced into the model via the resonant exchange between the fast mode excited states of the two moieties. The present model reduces satisfactorily to many models in the literature dealing with more special situations. It has been applied to the cyclic dimers (CD(3)CO(2)H)(2) and (CD(3)CO(2)D)(2) in the gas phase. It correctly fits the experimental line shape of the hydrogenated compound and predict satisfactorily the evolution in the line shapes, to the deuterated one by reducing simply the angular frequency of the H-bond bridge and the anharmonic coupling parameter by the factor 1/ square root of 2.     

Synthesis of C-2 substituted vitamin D derivatives having ringed side chains and their biological evaluation, especially biological effect on bone by modification at the C-2 position

In order to obtain vitamin D derivatives, which have strong activity for enhancing bone growth, we designed vitamin D derivatives with various substitutions at the C-2 position. Novel 2 α-substituted vitamin D derivatives were synthesized starting from d-glucose as a chiral template of the A-ring with a CD-ring bromoolefin unit using the Trost coupling method. We evaluated these compounds by two in vitro assays, affinity to VDR and transactivation assays, using human osteosarcoma (Hos) cells, and demonstrated the SAR of the C-2 position of VD(3). Furthermore, by using the OVX model, we found that compound 5c, which has a hydroxypropoxy side chain at C-2 and 2,2-dimethyl cyclopentanone in the CD-ring side chain, has a strong activity for enhancing bone growth, same as the reported compound, 2α-(3-hydroxypropoxy)-1α,25-dihydroxyvitamin D(3)1d, and this derivative shows a possibility that calcemic activity is less than 1d in vivo.     

Determination of heteronuclear coupling constants from 3D HSQC-TOCSY experiment with optimized random sampling of evolution time space

An application of 3D version of HSQC-TOCSY experiment for the measurement of heteronuclear coupling constants of organic compounds yielding complex spectra is proposed. The approach presented here is based on the optimized random sampling of the evolution time space followed by Multidimensional Fourier Transform (MFT). In this study, we show that the interpretation of omega(3)-(13)C coupled (1)H-(13)C 3D HSQC-TOCSY spectra with E.COSY-type multiplets allows one to evaluate heteronuclear coupling constants of strychnine with high accuracy, whereas the employment of 2D methods is associated with signal overlap and use of conventionally recorded 3D NMR spectra cannot provide accurate results in an overnight experiment.     

Axially Chiral BODIPY DYEmers: An Apparent Exception to the Exciton Chirality Rule

The exciton chirality method (ECM) is commonly recognized as one of the best approaches to assign the absolute configuration of biaryls. This paper reports the first exception to this method for a simple biaryl system. ECD and VCD measurements in combination with DFT (B3LYP/6‐311G*), TDDFT (CAM‐B3LYP/6‐311G*), and Coupled‐Cluster (RI‐SCS‐CC2) calculations were used to determine the absolute configurations of axially chiral BODIPY DYEmers. The ECM fails to predict the sign of the intense CD couplet at 500 nm of the 1,1′‐coupled dimer. The odd behavior was rationalized by considering the strong transition magnetic dipole associated with the 500 nm transition, which leads to an unexpected dominance of the μm coupling at the expense of the μμ one in these compounds. This is the first case in which a strong μm coupling hampers the use of the ECM, but this behavior should not be restricted to the BODIPY chromophore.