无机含氧酸的酸性与分子拓扑指数的关系

本文提出一种新的分子拓扑指数Ｙ＝δＲ（ｍ＋ｋ０．５ｍ）ｎ－０．５。Ｙ对２５种无机含氧酸呈现唯一性表征，并与其ｐＫ１显示高度相关性。用最小二乘法拟合ｐＫ１与Ｙ的线性回归方程为：ｐＫ１＝１２．２３－１．２２Ｙ，ｒ＝－０．９７９，并在０．０１显著水平下通过Ｆ检验     

自制的红外掠角反射吸收光谱装置及其应用

自制的红外掠角反射吸收光谱装置及其应用陈铁峰，唐季安，江龙（中国科学院感光化学研究所，北京１００１０１）１引言随着傅里叶变换技术、新的实验手段和计算机应用的结合，红外光谱分析这一经典方法得到了迅速发展，并且在涉及诸如催化、电分析化学、微电子学、医学、...     

一系列氢键诱导液晶复合物的合成及表征

以２－氰基－３－（４－（２－氯－３－甲基－１－丁酰氧基）－苯基丙烯酸（Ａ）为质子给体，Ｎ－（４－吡啶基亚甲基）－４－烷氧基苯胺（ｎＳＳＺ）为质子受体，合成了一系列新的氢键复和物，经红外光谱证实了分子间氢键的存在，通过ＤＳＣ，偏光方法及Ｘ射线衍射方法对其液晶行为进行研究，结果表明复合物呈现近晶相行为。     

新型α,β—不饱和羰基桥联双二茂铁衍生物的合成及其成膜性

由３－二茂铁基－２－丁烯酸酯经三步反应制得３－二茂铁基－２－丁烯酰氯，并由它与其自身及与单取代二茂铁经酰化反应合成了４种新的α、β－不饱和羧基共轭桥联双二茂铁衍生物，以＾１ＨＮＭＲ、ＩＲ光谱及元素分析表征了这些化合物，并研究了它们形成Ｌａｎｇｍｕｉｒ膜的成膜性，结果表明：这４种新的双二茂铁衍生物皆能在空气／水果面上形成Ｌａｎｇｍｕｉｒ膜。     

新型α，β－不饱和羰基桥联双二茂铁衍生物的合成及其成膜性

由３－二茂铁基－２－丁烯酸酯经三步反应制得３－二茂铁基－２－丁烯酰氯，并由它与其自身及与单取代二茂铁经酰化反应合成了４种新的α，β－不饱和羧基共轭桥联汉二茂铁衍生物。以１ＨＮＭＲ、ＩＲ光谱及元素分析表征了这些化合物，并研究了它们形成Ｌａｎｇｍｕｉｒ膜的成膜性．结果表明：这４种新的双二茂铁衍生物皆能在空气／水界面上形成Ｌａｎｇｍｕｉｒ膜．     

非手性分子识别的一种新方法

详尽地讨论了分子的四种对称因素ｉ、σ、Ｃｎ、Ｓｎ之间的联系，把它们统一为Ｓｎ轴。阐明了Ｓｎ轴和非手性分子的１∶１对应关系。在揭示Ｓｎ轴实质的基础上，发现了非经典的Ｓ′ｎ轴，并从逻辑推理中导出了非手性分子识别的新方法，旋转镜影法。     

二氧化硫分子的成键特性

二氧化硫分子的成键特性崔瑞海，刘怡春（哈尔滨师范专科学校１５００８０）一、成键特性二氧化硫分子是角形分子，它的结构已从晶体和蒸气态中测得：键长ｄ（ｓ－ｏ）＝０．１４３ｎｍ，键角∠（ｏ－ｓ－ｏ）＝１１９．５°［１］，如图１（ａ）所示。目前，对于ＳＯ２分...     

遗传算法在分子图形显示中的应用

遗传算法在分子图形显示中的应用邵学广，蔡文生，张懋森，赵贵文（中国科学技术大学应用化学系，化学物理系，合肥２３００２６）分子图形和分子模型的研究是计算化学领域中研究的热门课题之一［１，２］，它对于结构一活性相关、有机合成路线设计、药物设计［３，４］等...     

[Nd（ONO2）6][Cu（Im）（Phen）2]2（OH）.4H2O的合成,晶体结构…

用Ｎｄ（ＮＯ３）３．６Ｈ２Ｏ、Ｉｍ（Ｃ３Ｈ４Ｎ２）、Ｐｈｅｎ（Ｃ１２Ｈ８Ｎ２）和Ｃｕ（ＮＯ３）２．３Ｈ２Ｏ为原料，两步反应合成了标题化合物，该化合物晶体属Ｐ１空间群，晶胞参数ａ＝１．０１２６（２）ｎｍ，ｂ＝１．１７９２（２）ｎｍ，ｃ＝１．３９８５ｎｍ，ａ＝１１１．３２（３）°，β＝９３．１７（３）°，γ＝９０．３３（３）°，Ｚ＝１，Ｒ＝０．０４３，测定了化合物的ＵＶ－Ｖｉｓ－ＮＩＲ及ＩＲ光谱和变温     

某些生物分子在C60—γ—环糊精／Nafion化学修饰电极上的电催化行为

研究了Ｃ６０－γ－环糊精（Ｃ６０－γ－ＣＤ）（１：１）／Ｎａｆｉｏｎ和Ｃ６０－γ－ＣＤ（１： ２）／Ｎａｆｉｏｎ化学修饰电极在水溶液中的电化学行为，发现它们都有一对一电子转移的可逆表面波，而且它们对某些生物分子有电催化作用。     

剪刀分子(2S, 8S)-双(2-萘甲酰氨基甲基)-1,5,9-三氮杂双环[4.4.0]癸-5-烯氯化物的合成和核磁共振研究

本文报道新的剪刀分子(2S, 8S)-双-(2-萘甲酰氨基甲基)-1,5,9-三氮杂双环[4.4.0]癸-5-烯氯化物的合成和核磁共振研究。新的剪刀分子和对硝基苯甲酸盐配合效应的研究表明, 它们通过氢键和芳环夹心π-π Stacking作用而自动缔合。     

Supramolecular chirogenesis in zinc porphyrins: interaction with bidentate ligands,formation of tweezer structures,and the origin of enhanced optical activity

The complexation behavior, binding properties, and spectral parameters of supramolecular chirality induction in the achiral host molecule, syn (face-to-face conformation) ethane-bridged bis(zinc porphyrin), upon interaction with chiral bidentate guests (diamines and amino alcohols) have been studied by means of UV-vis, CD, fluorescence, (1)H NMR, and ESI MS techniques. It was found that the guest structure plays a decisive role in the chirogenesis pathway. The majority of bidentate ligands (except those geometrically unsuitable) exhibit two major equilibria steps: the first guest ligation leading to formation of the 1:1 host-guest tweezer structure (K(1)) and the second guest molecule ligation (K(2)) forming the anti bis-ligated species (1:2). The second ligation is much weaker (K(1) > K(2)) due to the optimal geometry and stability of the 1:1 tweezer complex. The enhanced conformational stability of the tweezer complex ensures an efficient chirality transfer from the chiral guest to the achiral host, consequently inducing a remarkably high optical activity in the bis-porphyrin.     

Dynamics in host-guest complexes of molecular tweezers and clips

The dynamics in the host-guest complexes of the molecular tweezers 1 a,b and clips 2 a,b with 1,2,4,5-tetracyanobenzene (TCNB, 3) and tropylium tetrafluoroborate (4) as guest molecules were analyzed by temperature-dependent 1H NMR spectroscopy. The TCNB complexes of tweezers 1 a,b were found to be particularly stable (dissociation barrier: DeltaG(++)=16.8 and 15.7 kcal mol(-1), respectively), more stable than the TCNB complexes of clips 2 a,b and the tropylium complex of tweezer 1 b (dissociation barrier: DeltaG(++)=12.4, 11.2, and 12.3 kcal mol(-1), respectively). A detailed analysis of the kinetic and thermodynamic data (especially the negative entropies of activation found for complex dissociation) suggests that in the transition state of dissociation the guest molecule is still clipped between the aromatic tips of the host molecule. The 1H NMR analysis of the TCNB complexes 3@1 b and 3@2 a at low temperatures (T<-80 degrees C) showed that 3 undergoes fast rotation inside the cavity of tweezer 1 b or clip 2 a (rotational barrier: DeltaG( not equal)=11.7 and 8.3 kcal mol(-1), respectively). This rotation of a guest molecule inside the host cavity can be considered to be the dynamic equilibration of noncovalent conformers. In the case of clip complex 3@2 a the association and rotational barriers are smaller by DeltaDeltaG(++)=3-4 kcal mol(-1) than those in tweezer complexes 3@1 a,b. This can be explained by the more open topology of the trimethylene-bridged clips compared to the tetramethylene-bridged tweezers. Finally, the bromo substituents in the newly prepared clip 2 b have a substantial effect on the kinetics and thermodynamics of complex formation. Clip 2 b forms weaker complexes with (TCNB, 3) and tetracyanoquinodimethane (TCNQ, 12) and a more stable complex with 2,4,7-trinitrofluoren-9-ylidene (TNF, 13) than the parent clip 2 a. These results can be explained by a less negative electrostatic potential surface (EPS) inside the cavity and a larger van der Waals contact surface of 2 b compared to 2 a. In the case of the highly electron-deficient guest molecules TCNB and TCNQ the attractive electrostatic interaction is predominant and hence responsible for the thermodynamic complex stability, whereas in the case of TNF with its extended pi system, dispersion forces are more important for host-guest binding.     

Internal motions in a fulleropyrrolidine tertiary amide with axial chirality

The kinetic parameters for topomerization around the N-CO bond and enantiomerization around the C-CO bond in N-1-naphthoyl fulleropyrrolidine 1 and N-1-naphthoyl pyrrolidine 2 have been determined by dynamic NMR (line shape simulation and selective inversion transfer). The DeltaS(not =) values are negligible. The DeltaH# value for topomerization of 1 is smaller with respect to that of 2 by 4.3 kcal mol(-1) (explained by the electron-withdrawing effect of fullerene) and the value for enantiomerization is greater by 1.4 kcal mol(-1) (explained by the greater rigidity of the fulleropyrrolidine ring, as confirmed by ab initio analyses).     

A new versatile receptor platform

We prepared a molecular receptor based on the molecular tweezer concept. Our system offers versatility, an extremely short synthetic route, good yield, large quantities, and finally having binding constants that equal the best known tweezer molecules when it comes to binding various nitroaromatics such as 1,3,5-trinitrotoluene (24 M(-1)), 1,3,5-trinitrobenzene (182 M(-1)), and 2,4,7-trinitrofluorenone (490 M(-1)) as determined using 1H NMR in CDCl3. It is notable that these binding constants are achieved although the molecular framework is not locked in a fixed and rigid conformation. The rigidity has been claimed to be the governing factor when it comes to achieving a large binding constant. We propose that our molecular tweezer system may be preorganized and that this explains the high binding constants observed. Further, we investigated the crystal structures of both the neutral receptor molecule and a complex with 1,3,5-trinitrobenzene and found that the molecule forms a pocket suited to accommodate flat aromatic analytes.     

Total synthesis and absolute configuration of minalemine A, a guanidine peptide from the marine tunicate Didemnum rodriguesi

The total synthesis of the 3S,2S and 3R,2S diastereomers (1a and 1b) of minalemine A and the identification of the natural compound as the 3R,2S isomer is described. The key step in the synthesis is the preparation of the two enantiomers of the beta-amino diacid 3-(N-carboxymethyl)-aminodecanoic acid (Ncma), which were obtained by stereoselective alkylation with allyl bromide of two nonanoic acid imides bearing chiral oxazolidinones as chiral auxiliaries. Natural minalemine A shows identical 1H NMR and very similar 13C NMR spectra compared to the two synthetic diastereomers. Sufficient differences in their chromatographic behavior to allow conclusive identification were not found. However, the corresponding N-2-naphthoyl amides presented quite distinct circular dichroism spectra (CD), and these confirmed the 3R,2S configuration for the natural minalemines and the R configuration for the constituent beta-amino diacid, Ncma.     

The synthesis, structural characterization and in vitro anti-cancer activity of novel N-(3-ferrocenyl-2-naphthoyl) dipeptide ethyl esters and novel N-(6-ferrocenyl-2-naphthoyl) dipeptide ethyl esters

N-(3-ferrocenyl-2-naphthoyl) dipeptide esters (5-7) and N-(6-ferrocenyl-2-naphthoyl) dipeptide esters (8-10) were prepared by coupling either 3-ferrocenylnaphthalene-2-carboxylic acid 2 or 6-ferrocenylnaphthalene-2-carboxylic acid 4 to the dipeptide ethyl esters GlyAla(OEt) (5, 8), AlaGly(OEt) (6, 9), and AlaAla(OEt) (7, 10) using the standard N-(3-dimethylaminopropyl)-N′-ethylcarbodiimide hydrochloride (EDC), 1-hydroxybenzotriazole (HOBt) protocol. All the compounds were fully characterized using a combination of ¹H NMR, ¹³C NMR, DEPT-135 and ¹H-¹³C COSY (HMQC) spectroscopy, electrospray ionization mass spectrometry (ESI-MS) and cyclic voltammetry (CV). In vitro, the cytotoxic effects of compounds 5-10 show improvements over the corresponding N-(ferrocenyl)benzoyl derivatives, with IC₅₀ values against the H1299 lung cancer cells ranging from 1.2 μM to 8.0 μM. N-(6-ferrocenyl-2-naphthoyl)-glycine-l-alanine ethyl ester 8 was found to be the most active derivative of the naphthoyl series so far, displaying an IC₅₀ value of 1.3 ± 0.1 μM. This value is slightly lower than that found for the clinically employed anti-cancer drug cisplatin (IC₅₀ = 1.5 ± 0.1 μM against H1299).     

(+)-(1S,2S,5R)-8-联苯薄荷醇的合成

以(R)-( )-pu legone为起始原料,经1,4-加成,还原两步反应合成了手性辅助试剂( )-(1S,2S,5R)-8-联苯薄荷醇及其差向异构体(-)-(1R,2S,5R)-8-联苯薄荷醇,总产率95%。其结构经1H NMR,13C NMR,IR,MS和X-射线衍射仪表征。     

Sterically controlled recognition of macromolecular sequence information by molecular tweezers

Sequence-specific binding is demonstrated between pyrene-based tweezer molecules and soluble, high molar mass copolyimides. The binding involves complementary pi-pi stacking interactions, polymer chain-folding, and hydrogen bonding and is extremely sensitive to the steric environment around the pyromellitimide binding-site. A detailed picture of the intermolecular interactions involved has been obtained through single-crystal X-ray studies of tweezer complexes with model diimides. Ring-current magnetic shielding of polyimide protons by the pyrene "arms" of the tweezer molecule induces large complexation shifts of the corresponding 1H NMR resonances, enabling specific triplet sequences to be identified by their complexation shifts. Extended comonomer sequences (triplets of triplets in which the monomer residues differ only by the presence or absence of a methyl group) can be "read" by a mechanism which involves multiple binding of tweezer molecules to adjacent diimide residues within the copolymer chain. The adjacent-binding model for sequence recognition has been validated by two conceptually different sets of tweezer binding experiments. One approach compares sequence-recognition events for copolyimides having either restricted or unrestricted triple-triplet sequences, and the other makes use of copolymers containing both strongly binding and completely nonbinding diimide residues. In all cases the nature and relative proportions of triple-triplet sequences predicted by the adjacent-binding model are fully consistent with the observed 1H NMR data.     

膦、胂叶立德的化学与应用(ⅩⅩⅨ)──含全氟烷基胂叶立德水解合成2-吡喃酮衍生物

在无水碳酸钾存在下,以无水二氯甲烷作溶剂,室温下将溴化(2－萘甲酰基)甲基三苯基鉮(1)与2－全氟炔酸甲酯(2)反应,高产率地得到加合产物4-(2－萘甲酰基)－2－三苯基胂基－3－全氟烷基－3－丁烯酸甲酯(3)和少量4－(2－萘甲酰基)－4－三苯基胂基－3－全氟烷基－2－丁烯酸甲酯(4).加合产物3在9:1的甲醇－水溶液中在一定温度下反应,高产率地得到4-全氟烷基－6－(2－萘基)－2－吡喃酮(5).研究发现硅胶对该反应具有催化作用.提出并讨论了反应机理.