非共价复合物的电喷雾质谱分析

非共价复合物一直是质谱分析的难点,因为这些复合物大多以氢键、范德华力、疏水作用、静电作用、金属配位作用等非共价弱键形成,常规质谱相对过于剧烈的离子化条件不利于非共价复合物的检测.但由于在许多生命现象、药物筛选以及超分子化合物中都涉及到分子之间的相互作用以及相互识别过程,而且人们普遍认识到非共价复合物是这些过程形成的基础,因此许多科学工作者都致力于非共价复合物该前沿课题的开发研究,并且迫切需要发展一种分析工具来辅助解析这种现象.电喷雾离子化(ESI)技术作为一种"软"电离技术,以及它在分析极性生物大分子中得天独厚的优势,近年来被广泛的应用在非共价复合物研究上.国内由于生物质谱技术起步较晚,这个领域至今没有获得充分的发展,本论文在ESI正交离子引入飞行时间质谱上,开展了非共价复合物分析的一些初步研究.     

稀有气体化合物非共价作用研究进展

稀有气体化合物的非共价作用研究是最近发展起来的一个新兴领域,是非共价领域的重要拓展和延伸。到目前为止,本领域已经取得了一些研究成果。本文着重论述σ-hole、π-hole和稀有气体-π等3类非共价作用。这些新型非共价作用的提出,不但能够帮助研究人员更好地理解稀有气体化合物的各种非共价行为,如结晶、吸湿性等,而且为寻找有效调控其氧化性、爆炸性等性质的方法指明了方向。     

用生物质谱方法研究抗肿瘤双β-咔啉与DNA及核苷酸的非共价结合

利用电喷雾傅里叶变换离子回旋共振质谱研究一系列双β-咔啉化合物与DNA的非共价结合. 发现化合物1—5与5种不同序列的12-mer双链DNA均有明显的非共价结合, 并且有两个β-咔啉环之间连接碳链的长度对此类化合物与双链DNA的非共价结合活性有明显影响. 同时对此类化合物对于DNA非共价结合的序列选择性进行了讨论. 另外还利用电喷雾离子阱质谱研究了双β-咔啉化合物2和4与4种单核苷酸的非共价结合.     

抗抑郁化合物SIPI5358与环糊精形成的非共价复合物

用电喷雾电离质谱(ESI-MS)和串级质谱(MS/MS),并结合紫外光谱、荧光光谱等方法,研究一种芳烷醇哌嗪类抗抑郁化合物SIPI5358与α-、β-、γ-环糊精(CD)制备得到的非共价复合物.质谱分析结果显示,SIPI5358分子可以和α-CD生成配合比为1∶1的非共价复合物,而与β-、γ-CD生成不同配合比的非共价复合物.串级质谱的结果进一步验证β-CD与SIPI5358非共价复合物的组成.用紫外光谱和荧光光谱实验对液相中非共价复合物的形成进行了辅助研究,结果均再次验证了非共价复合物的生成.荧光光谱实验测得SIPI5358与β-CD反应的生成常数Kf=3.45×103 mol.L-1.     

具有非共价相互作用的金属酶模拟物

金属酶催化的高效性和选择性来源于第一配位环境金属催化中心和第二配位环境非共价相互作用力的协同作用。针对金属催化中心构效关系的研究已有大量报道,相比之下,有关非共价相互作用的研究尚不够充分。金属酶的非共价作用力,包括氢键、静电相互作用、范德华力和疏水相互作用等产生于第二配位环境中的氨基酸残基。阐述第二配位环境中氨基酸残基作用的首要障碍来自于复杂并难以界定的分子内和分子间的相互作用网络。制备包含非共价相互作用的金属酶模拟物是攻克这一难题行之有效的方法,它不但有利于理解非共价相互作用和金属离子之间的协同作用,而且有助于发展可应用于工业、医药、生物技术等领域的仿生催化剂。本文按照非共价弱相互作用的类型,对近期报道的典型案例进行综述。文中阐述了基于简单多齿配体,如联吡啶、三联吡啶、环胺、卟啉等,和基于超分子配体,如功能化的环糊精和杯芳烃等的金属酶模型物。在讨论模型物之前,本文对天然金属酶中的非共价相互作用简略探讨。     

石墨烯非共价功能化及其应用

石墨烯的湿法化学修饰,主要包括共价及非共价两种,是目前广泛采用的宏量功能化策略,亦是有效避免其团聚而充分发挥其优异纳米性能的重要修饰方法。非共价功能化因可同时保持原有及引入物质的物化性质,并可充分发挥协同作用,近年来已受到比共价修饰更多的研究关注,并已在生物科学与技术、可持续能源储存及转化、医疗和复合材料等诸多领域得到了广泛应用。本文综述了以应用为导向的石墨烯非共价功能化的构建策略,期望文中涉及的湿法组装策略能为进一步构建性能提升的新材料提供参考。     

以实践应用为导向的石墨烯非共价功能化

石墨烯的湿法化学修饰,主要包括共价及非共价两种,是目前广泛采用的宏量功能化策略,亦是解决其易团聚充分发挥纳米性能的重要修饰方法。 非共价功能化因可同时保持原有及引入物质的物化性质,并可充分发挥协同作用,近年来已受到比共价修饰更多的研究关注,并已在生物科学与技术、可持续能源储存及转化、医疗和复合材料等诸多领域得到了广泛的应用。在这里,我们精心遴选了近三年的文献,综述了以应用为导向的石墨烯非共价功能化的构建策略,期望文中涉及的湿法组装策略能为进一步构建性能提升的新材料提供参考。     

抗抑郁化合物SIP15838和环糊精分子非共价复合物的研究

报道了用电喷雾电离质谱(ESI-MS),并结合紫外分光光度法及溶解度实验,研究一种新型的具有自主知识产权的抗抑郁化合物SIPI5838与α-环糊精(CD)和β-环糊精(CD)分子生成的非共价复合物.质谱测量结果表明,在溶液中,SIPI5838分子可以与环糊精分子之间生成非共价复合物,且两者之间的配比关系为1:1.这些非共价复合物的形成可以显著地提高这种抗抑郁化合物在水溶液中的溶解度,使得它作为高效的口服或注射药物成为可能.另外,还用紫外分光光度法和溶解度实验对液相中非共价复合物的形成进行了辅助研究,这些结果均显示了非共价复合物的生成.根据溶解度实验结果,计算了SIPI5838和两种环糊精分子在液相中的生成常数.它们分别为SIPI5838-β-环糊精:1.83×103 mol-1·L,SIPI5838-α-环糊精:3.15×101mol-1·L.两种非共价复合物的稳定程度为β-环糊精-SIPI5838>α-环糊精-SIPI5838.     

蛋白质非共价化合物的电喷雾质谱研究

介绍了近几年来利用电喷雾离子化质谱技术研究蛋白质的基本构象及蛋白质非共价化合物的基本化学信息的进展。许多研究表明,电喷雾质谱在研究蛋白质的复杂结构和功能方面有十分广阔的前景。文中列举了若干实例说明了电喷雾离子化质谱技术在分析蛋白质非共价化合物的应用和一般方法。     

抗抑郁化合物SIPI5838和环糊精分子非共价复合物的研究

报道了用电喷雾电离质谱(ESI-MS), 并结合紫外分光光度法及溶解度实验, 研究一种新型的具有自主知识产权的抗抑郁化合物SIPI5838与α-环糊精(CD)和β-环糊精(CD)分子生成的非共价复合物. 质谱测量结果表明, 在溶液中, SIPI5838分子可以与环糊精分子之间生成非共价复合物, 且两者之间的配比关系为1∶1. 这些非共价复合物的形成可以显著地提高这种抗抑郁化合物在水溶液中的溶解度, 使得它作为高效的口服或注射药物成为可能. 另外, 还用紫外分光光度法和溶解度实验对液相中非共价复合物的形成进行了辅助研究, 这些结果均显示了非共价复合物的生成. 根据溶解度实验结果, 计算了SIPI5838和两种环糊精分子在液相中的生成常数, 它们分别为SIPI5838-β-环糊精: 1.83×103 mol－1•L, SIPI5838-α-环糊精: 3.15×101 mol－1•L. 两种非共价复合物的稳定程度为β-环糊精-SIPI5838＞α-环糊精-SIPI5838.     

二氧化碳和丙烯直接合成甲基丙烯酸的NiPMo/TiO2催化剂的研究

用溶胶-凝胶法以磷钼酸(MPA)的镍盐溶液水解钛酸四丁酯制备了NiPMo/TiO2催化剂.使用ICP、 XRD、 TG-DTA、 IR、 TPD-MS和微反应技术研究了催化剂的化学组成、热稳定性、化学吸附性质和催化反应性能.杂多钼酸盐与TiO2通过O2-在TiO2表面发生了键合.在623 K下,杂多阴离子仍保持原有的Keggin结构.CO2在Lewis酸位Ni(Ⅱ)和Lewis碱位Ni-O-Mo的桥氧协同作用下生成CO2卧式吸附态Ni(Ⅱ)←O-(CO)←(O--Ni).丙烯有多种吸附态在催化剂上吸附.在563 K、 1 MPa和空速1500 h-1的反应条件下,丙烯的摩尔转化率为3.2%,产物MAA选择性为95%.     

α-Amino acid derived enaminones and their application in the synthesis of N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates and other heterocycles

A new and simple synthesis of novel N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates, which exist in equilibrium with their 4-oxo tautomers, has been developed in two steps starting from N-protected α-amino acids. The key intermediates are enaminones, which can also be isolated, characterized, and used for the construction of other functionalized heterocycles, before they spontaneously decompose to pyrrole products. 4-Hydroxypyrroles are prone to partial aerial oxidation but can be efficiently alkylated or reduced to stable polysubstituted pyrrolidine derivatives.     

Specific intramolecular aromatic CH insertion of diazosulfonamides

The chemoselectivity in the intramolecular CH insertion of various diazosulfonamides has been experimentally studied. The results reveal that the aliphatic 1,4-, 1,5-, or 1,6-C(sp³)?H insertions of diazosulfonamides are not accessible, while the aromatic 1,5-C(sp²)?H insertion can be realized specifically by adjusting the diazo-adjacent group. In addition, the general chemoselectivities in the intramolecular CH insertions of diazosulfonyl compounds are summarized. Generally, diazosulfones undergo both aromatic 1,5-C(sp²)?H and aliphatic 1,5- and 1,6-C(sp³)?H insertions, while diazosulfonates undergo aliphatic 1,5- and 1,6-C(sp³)?H insertions. However, diazosulfonamides only undergo aromatic 1,5-C(sp²)?H insertion.     

N-Heterocyclic carbene-palladacyclic complexes: synthesis,characterization and their applications in the C-N coupling and α-arylation of ketones using aryl chlorides

N-Heterocyclic carbene-palladacyclic complexes 3 were successfully achieved in a one-pot procedure under mild conditions. The structure of 3a was unambiguously confirmed by X-ray single crystal diffraction and it was an active catalyst in the Buchwald-Hartwig amination and α-arylation of ketones even at very low catalyst loadings (0.01?mol%).     

Toward new camptothecins. Part 6: Synthesis of crucial ketones and their use in Friedländer reaction

In the context of the preparation of camptothecin and luotonin A analogs, the synthesis of some key keto-precursors and their use in Friedländer condensation are described. This paper also focuses on the stability of these keto intermediates and emphasizes the major differences between indolizinones and pyrroloquinazolinones series. Noteworthy is also the report of some original structures isolated as by-products of some experiments.     

Iodine-mediated oxidative Pictet-Spengler reaction using terminal alkyne as the 2-oxoaldehyde surrogate for the synthesis of 1-aroyl-β-carbolines and fused-nitrogen heterocycles

An efficient iodine-mediated oxidative Pictet-Spengler reaction in dimethyl sulphoxide (DMSO) using terminal alkynes as the 2-oxoaldehyde surrogate for the synthesis of aryl (9H-pyrido[3,4-b]indol-1-yl)methanones is described. The scope of the protocol includes the total synthesis of Fascaplysin, Eudistomins Y₁ and Y₂. The methodology is extended for preparing pyrrolo[1,2-a]-quinoxaline and indolo[1,5-a]quinoxaline derivatives. The utility of 1-aroyl-β-carbolines was demonstrated by performing palladium-catalyzed β-carboline directed ortho-C(sp2)-H functionalization of the phenyl ring with thiomethyl (SMe) group using DMSO as source and for accessing 4-aryl-canthin-6-ones.     

Facile synthesis of bicyclic 1-arylpyrazol-5-ones

In this Letter, we described a facile method for constructing fused bicyclic 1-arylpyrazol-5-one ring system. We employed various methylene-containing carboxylic acids as the substrates and proved that the pyrazolone ring closure requires activated methylene group in intermediate II. Accordingly, a series of structurally diversified, fused bicyclic 1-arylpyrazol-5-ones was prepared in moderate to high yields using the requisite substrates.     

CoFe2O4自形成磁性液体场致结构化对磁化的影响

The Langevin paramagnetic theory can’t describe the relation between magnetization of ferrofluids and applied magnetic field. The structuralization of ferrofluids, which is considered the main influence factor of the magnetization, is regarded. The part of magnetization works is deposited when the structure is forming. This action influences the magnetization of ferrofluids directly or indirectly. On the base of the “compressing” model, the Langevin function that usually describes the magnetization of ferrofluid is modified, and a well-fitted curve is obtained. An equation of the relation between the equivalent volume fraction after being “compressed” and the intensity of magnetic field is discovered, which approximately describes the process of magnetization. The relation between the approximate initial susceptibility and the volume fraction can be obtained from modified formula.     

KMnO4-mediated oxidative CN bond cleavage of tertiary amines: Synthesis of amides and sulfonamides

KMnO₄-mediated oxidative CN bond cleavage of tertiary amines producing secondary amine was introduced, which was trapped by electrophiles (acyl chloride and sulfonyl chloride) to form amides and sulfonamides. The reaction could take place at mild condition, tolerating a wide range of function groups and affording products in moderate to excellent yields.     

Highly regioselective Buchwald–Hartwig amination at C-2 of 2,4-dichloropyridine enabling a novel approach to 2,4-bisanilinopyridine (BAPyd) libraries

The highly regioselective Buchwald–Hartwig amination at C-2 of the cheap and readily accessible reagent, 2,4-dichloropyridine with a range of anilines and heterocyclic amines is described. This new methodology is robust and provides a facile access to 4-chloro-N-phenylpyridin-2-amines on 0.25 mol scale. These intermediates undergo a further Buchwald–Hartwig amination at higher temperature to enable rapid exploration of the chemical space at C-4 and to provide a library of 2,4-bisaminopyridines.