阳离子共价有机框架对水中非甾体药物的强化去除

以三醛基间苯三酚(TFP)和溴化乙锭(EB)为单体, 在溶剂热条件下合成了一种二维β-酮烯胺类阳离子型共价有机框架(COF)材料. 所得TFP-EB COF呈现出良好的结晶度、 高的比表面积和丰富的溴化乙锭单元, 故可将其应用于水中非甾体抗炎药(NSAIDs)的去除.阳离子TFP-EB COF对双氯芬酸钠(DCF-S)和对氨基水杨酸钠(PAS-S)两种非甾体抗炎药表现出高的吸附能力和快的吸附动力学, 其饱和吸附容量分别可达350.4和145.3 mg/g. 而采用TFP与4,4'-二氨基联苯(BND)在类似条件下合成的中性TFP-BND COF则表现出较差的吸附性能, 其对DCF-S和PAS-S的饱和吸附容量分别仅有59.7和13.6 mg/g. TFP-EB COF的吸附性能比TFP-BND COF更优异, 这主要归因于TFP-EB COF孔道中存在的大量阳离子EB单元与NSAIDs中的羧基间存在强烈的静电作用. 此外, 竞争离子干扰和循环再生实验表明阳离子型TFP-EB COF在NSAIDs污染物的去除方面具有良好的应用前景.     

β-酮烯胺类手性共价有机框架的合成及在毛细管气相色谱中的应用

利用2,4,6-三羟基-1,3,5-苯三甲醛(Tfp)和(S)-2,5-双(2-甲基丁氧基)对苯二甲酸二酰肼(Mth)作为单体, 通过席夫碱反应合成了新型的β-酮烯胺类手性共价有机框架(COF)材料TfpMth COF. 采用粉末X射线衍射、 红外光谱、 热重分析及氮气吸附-脱附等手段对制备的TfpMth COF粉末进行了表征, 结果表明其具有良好的结晶度、 高的孔隙率和优异的热稳定性. 基于此, 以该COF为新型固定相采用原位生长法制备了TfpMth COF键合毛细管柱, 成功分离了一系列直链与支链的烷烃和醇类, 以及苯/环己烷、 乙苯/苯乙烯混合物. 该结果为β-酮烯胺类COF在色谱分离中的应用提供了新思路, 也为研究新型气相色谱固定相提供了参考.     

共价有机框架材料催化剂

共价有机框架材料（covalent organic frameworks, COF）是功能材料领域研究的热点之一。COF具有孔道结构高度有序、孔径可调、比表面积较大、合成方法多样和易于功能化修饰等优点,是一类新兴的多相催化剂。目前,COF催化剂主要设计思路是：基于“自下而上”策略将非金属催化活性中心嵌入材料骨架来构筑本征型COF催化剂,或者以COF为载体,通过后修饰方式负载金属颗粒或离子构建多相催化剂。鉴于COF以上优势,预计COF催化剂在多相催化和手性催化领域中的应用也将取得更大的进展。本文综述了COF催化剂的合成和功能化策略,并展望了COF在多相催化领域中的应用前景。     

具有高气态碘吸附的二维介孔共价有机框架

合成了一种新型的二维介孔共价有机框架(COF)材料JUC-573. 粉末X射线衍射、 氮气吸附-脱附和热重等表征结果表明合成的COF材料具有高结晶度、 高比表面积以及良好的热稳定性. 在333 K、 常压条件下, 该材料表现出优异的碘吸附能力, 且吸附量高达4.15 g/g. 这是由于在JUC-573中规则定向的垂直一维介孔孔道能够有效地避免碘吸附后的堵塞, 从而优化了材料的吸附能力. JUC-573可多次循环用于气态碘的捕获且保持几乎不变的吸附量.     

锂离子电池正极材料LiNi1/3Co1/3Mn1/3O2的低温燃烧合成

以LiNO3、Ni(NO3)2·6H2O、Co(NO3)2·6H2O、Mn(NO3)2、CO(NH2)2为原料,通过低温燃烧法在空气中合成了锂离子正极材料LiNi1/3Mn1/3Co1/3O2.采用XRD研究了合成产物的物相与结构,用SEM研究了合成产物的形貌,考察了点火温度、回火温度,回火时间以及锂过量对合成产物电化学性能的影响.研究结果表明,合成产物与层状LiNiO2的结构相同,属α-NaFeO2型层状结构,合成产物的粒度较小且比较均匀,并具有良好的电化学性能.采用低温燃烧法在空气中合成LiNi1/3Mn1/3Co1/3O2的最佳条件为:500℃点火,850℃回火20h,锂过量为15mol%.在此条件下得到的合成产物首次放电比容量达到158.9mAh/g.     

球形氨基功能化共价有机骨架化合物的制备及对全氟化合物的吸附性能考察

全氟化合物(PFCs)是一类环境持久性污染物,对生态系统和人类健康造成了极大威胁。一般环境水体中PFCs含量很低,高性能萃取材料的制备和应用一直是近年来的研究热点。为了有效富集水中的PFCs,本研究通过“两步法”制备出氨基功能化的球形共价有机骨架(COF)材料。首先利用1,4-二醛基-2,5-二乙烯基苯及1,3,5-三(4-氨苯基)苯为构筑基元,通过调控反应条件在室温下合成出粒径均匀的球形乙烯基COF(Vinyl COF)材料;然后以4-氨基苯硫酚为氨基功能化单体,通过巯基-烯基点击反应引入功能化侧基,合成出硫醚桥连芳香胺功能化球形COF材料(COF-NH₂)。该材料具有丰富的氨基,能够与PFCs碳链上的氟基以及羧基发生多重氢键和静电作用,因此可以有效吸附PFCs。本论文探究了COF-NH₂的吸附动力学、等温吸附模型、再生性能以及不同酸度条件下的吸附性能。COF-NH₂微球直径约500 nm,具有较好的热稳定性,可以在较宽的pH范围内有效吸附PFCs;重复再生5次后,吸附效果几乎无影响。该材料在实际环境水体中具有良好的吸...     

共价有机框架负载贵金属铂用于电催化析氢

本工作探究了共价有机框架负载贵金属Pt的电催化析氢性能。以2, 6-二氨基蒽醌和2,4,6-三甲酰基间苯三酚为构筑单元,采用溶剂热法合成了TP-DAAQ COF。随后通过金属前驱体浸渍法制备了Pt-TP-DAAQ COF。X射线粉末衍射,傅里叶红外光谱,氮气吸附/脱附等表明成功制备了TP-DAAQ COF和Pt-TP-DAAQ COF。电化学测试结果表明Pt-TP-DAAQ COF (其中含有5.8%的Pt)展现了比20% Pt/C还优异的电催化活性。当电流密度为10 mA cm?2时,Pt-TP-DAAQ COF的过电位为45 mV,Tafel 斜率为29 mV dec?1。这高效的电催化活性源于TP-DAAQ COF与Pt之间良好的协同效应。Pt-TP-DAAQ COF具有较大的比表面积和规整的一维孔道,使催化位点更易于与电解液中的物质发生接触和相互作用,从而增强了其催化性能。     

纤维堆囊菌发酵液中埃博霉素含量的HPLC法分析

采用反馈神经网络结合遗传算法(BPANN-GA)对高效液相色谱(HPLC)法同时测定纤维堆囊菌(Sorangium cellulosum)代谢物中埃博霉素A(Epo A)和埃博霉素B(Epo B)含量的条件进行优化, 采用均匀设计(U₁₂³)方案对流动相中乙腈的体积分数、色谱柱温度和流动相的pH等3个因素进行实验设计; 以色谱函数(COF)值为优化指标, 运用双层反馈神经网络建立色谱优化函数(COF)值, 考察因素间的预测模型, 采用Levenberg-Marquardt backpropagation算法对所建立的神经网络预测模型进行训练, 以逼近度(D_a)为优化参数, 选择预测模型的最适隐含层节点数. 最优预测模型预测的COF值与实验值之间的相关系数(R)达到0.98165, 采用遗传算法在实验考察范围内进行全局寻优, 得到最优化的HPLC分析条件: 流动相中乙腈体积分数为29.2%, 色谱柱温度为34 ℃, 流动相pH为4.23. 在此最优条件下对纤维堆囊菌代谢产物进行HPLC分析, 结果表明, 该方法对两种埃博霉素色谱峰均具有较好的分离度.     

高稳定性的含氟多级孔共价有机框架材料

设计合成了一种新型含氟原子双孔共价有机框架(COF)——四(4-氨基苯)乙烯-2,3,5,6-四氟对二苯甲醛-COF(ETTA-TFA-COF),ETTA-TFA-COF是由1个D2h对称单体和1个C2对称单体连接而成的六角星形状结构,具有2. 93 nm六边形与1. 43 nm三角形的双孔结构.通过理论模拟、粉末X射线衍射(PXRD)、氮气吸附-解吸表征和傅里叶变换红外光谱(FTIR)等证实了ETTA-TFA-COF的结构.同时,通过与结构相似但不含氟原子的COF材料对比发现,ETTA-TFA-COF材料在碱性溶液中展现出优异的稳定性.     

1-(5-二茂铁基-1,3,4-噻二唑-2-基)哌啶-2-酮的合成及表征

本文报道1-(5-二茂铁基-1,3,4-噻二唑-2-基)哌啶-2-酮(1)的合成。首先,在乙酸催化下,二茂铁甲醛(2)和氨基硫脲(3)反应得到二茂铁亚胺基硫脲衍生物(4)。然后,在三氯化铁作用下,中间体4发生关环反应得到5-二茂铁基-1,3,4-噻二唑-2-胺(5)。中间体5再与5-溴戊酰氯(6)发生N-酰基化反应得到5-溴-N-(5-二茂铁基-1,3,4-噻二唑-2-基)戊酰胺(7)。最后,在碱性条件下,中间体7发生分子内关环反应得到目标化合物(1)。中间体及产物结构经¹H NMR、¹³C NMR和ESI-MS表征,产物1结构进一步通过X-单晶衍射确证。然后分别考察了中间体5及产物1收率的主要影响因素,确定中间体5合成的适宜条件为：三氯化铁的用量为n(三氯化铁)∶n(中间体4)=4∶1,反应温度80℃,反应时间为15 h,在该条件下,中间体5的收率达到61.9%;确定产物1合成的适宜条件为：反应溶剂为二氧六环,物料比为n(DIEA)∶n(6)∶(5)=3.0∶1.2∶1.0、反应温度为80℃,反应时间为4 h,在该条件下,产物1收率达到68...     

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.     

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.     

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.     

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%).     

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.     

Sulfur-directed metal-free and regiospecific methyl C(sp3)–H imidation of thioanisoles

Regiospecific and direct imidation of the methyl C(sp³)–H bond of thioanisoles is realized under mild and metal-free conditions with N-fluorobis(benzenesulfonyl)imide as an oxidant and nitrogen source. Proposed mechanism suggests that thionium ion intermediates and a Pummerer-type reaction are involved. The imidation has advantages such as high step-economy, excellent functionality tolerance, and regiospecificity, giving structurally diverse imidation products.