沉淀聚合法合成拟除虫菊酯类分子印迹聚合物及其吸附性能研究

采用沉淀聚合法,以拟除虫菊酯的结构类似物二苯醚-联苯共晶作为替代模板,优化得到最佳的拟除虫菊酯类分子印迹聚合物合成条件:模板分子(二苯醚-联苯共晶)、功能单体(4-乙烯吡啶)、交联剂(乙二醇二甲基丙烯酸酯)的摩尔比为1∶6∶20,反应温度为70℃,引发剂用量为1%。将合成的分子印迹聚合物通过扫描电镜进行表征,并对吸附性能进行测试,其对60μg·mL~(-1)的二苯醚-联苯共晶的最大吸附量为6 041μg·g~(-1),且在7 h后达到吸附平衡。通过选择性实验得到印迹聚合物对毒死蜱、联苯菊酯、甲氰菊酯、氯菊酯、氯氰菊酯、氰戊菊酯的吸附量分别为259、316、311、271、305、298μg·g~(-1),而非印迹聚合物的吸附量则为169、188、181、183、151、142μg·g~(-1),印迹聚合物的选择性能明显高于非印迹聚合物。     

分子印迹固相萃取-液相色谱联用法测定3种新烟碱类农药的残留

以噻虫啉为模板分子制备了对吡虫啉、氯噻啉、噻虫啉具有特异性识别的分子印迹聚合物。功能单体与模板分子最佳摩尔比为:n(噻虫啉)∶n(甲基丙烯酸)∶n(苯乙烯)=1∶4∶4。动态吸附和选择性吸附表明,此印迹聚合物能够对目标物快速吸附,且有很好的选择性。Scatchard分析表明,此印迹聚合物对吡虫啉、氯噻啉、噻虫啉最大吸附量分别为31.7,36.7和45.3 mg/g。用此印迹聚合物作为固相萃取吸附剂处理加标样品,目标物的回收率为80.2%~98.8%,RSD为1.2%~4.5%(n=3)。本方法用于实际样品检测,获得了满意的结果。     

苏丹红Ⅰ分子印迹聚合物制备及吸附性能研究

以苏丹红Ⅰ为模板分子,α-甲基丙烯酸为功能单体,乙二醇二甲基丙烯酸酯为交联剂,偶氮二异丁腈为引发剂,在氯仿中采用沉淀聚合法制备了分子印迹聚合物.聚合物的平衡结合试验表明:模板分子/功能单体/交联剂的摩尔比为1:4:16时所得的印迹聚合物对苏丹红Ⅰ吸附量最大;合成时溶剂和引发剂用量对聚合物吸附量有很大影响;印迹和非印迹聚合物对苏丹红Ⅰ的平衡吸附量分别为49.17μmol·g-1和22.6μmol·g-1,选择性结合试验中印迹聚合物对苏丹红Ⅰ和苏丹红Ⅲ的吸附量分别为26.8μmol·g-1和5.26μmol·g-1,说明印迹聚合物对苏丹红Ⅰ具有特异性吸附;Scatchard分析表明该印迹聚合物具有两类结合位点.     

烯唑醇分子印迹聚合物的合成及其吸附性能研究

以烯唑醇为模板分子,MAA为功能单体,EDMA为交联剂,采用本体聚合法合成分子印迹聚合物。考察了采用不同比例的模板分子与功能单体合成的聚合物对烯唑醇的吸附量,通过静态吸附试验研究了烯唑醇分子印迹聚合物对烯唑醇吸附性能的影响,并进行Scatchard分析。由Scatchard分析可知模板分子烯唑醇与功能单体MAA形成了1类结合位点,结合位点的离解常数KD=0.117mmol/L,最大表观结合量Qmax=38.66μmol/g。     

磁性胰蛋白酶分子印迹聚合物的制备及性能评价

以壳聚糖修饰的四氧化三铁为载体,利用壳聚糖表面的氨基与戊二醛结合,丙烯酰胺为功能单体和交联剂,胰蛋白酶为模板蛋白,制备了磁性胰蛋白酶分子印迹聚合物。通过静态平衡结合法研究了磁性分子印迹聚合物的吸附能力、选择性。结果表明,与磁性分子非印迹聚合物相比,磁性分子印迹聚合物对模板蛋白具有高选择性和高特异性吸附,最大吸附量为162.2mg·g-1;Scatchard分析表明,存在两类不同的吸附结合位点,其离解常数分别为96.5μg·mL-1(高结合位点)和2.41mg.mL-1(低结合位点)。     

洛克沙胂分子印迹聚合物的制备及其固相萃取研究

以阿散酸为虚拟模板分子,2-乙烯吡啶为功能单体,乙二醇二甲基丙烯酸酯为交联剂,合成了对洛克沙胂具有高选择性的分子印迹聚合物。通过考察致孔剂、单体及交联剂等因素对合成聚合物性能的影响,获得优化聚合配方为:阿散酸、2-乙烯吡啶、乙二醇二甲基丙烯酸酯、甲醇-乙腈(1∶1,V/V)及偶氮二异丁腈之比为1 mmol∶4 mmol∶20 mmol∶6 mL∶60 mg。合成印迹聚合物对洛克沙胂的最大吸附量为0.93 mg/g,作为固相萃取填料分离、富集洛克沙胂的优化萃取条件为:水和乙腈活化平衡,乙腈上样,水和甲醇依次淋洗,5%甲酸甲醇溶液洗脱。洛克沙胂在分子印迹固相萃取柱上的回收率达到95%以上,而非分子印迹固相萃取柱的回收率仅为43.1%。制备小柱应用于池塘水中洛克沙胂的净化富集,检测限可达0.05 mg/L。     

酚酞分子印迹聚合物的制备及特异吸附性能

以泻药酚酞为模板分子,4-乙烯基吡啶为功能单体制备了模板分子和功能单体不同比例的一系列酚酞分子印迹聚合物。利用扫描电镜对聚合物进行了表面形态分析,采用静态平衡实验法研究了聚合物对模板分子及其类似物的吸附行为和选择性识别能力。实验结果表明,所制备的分子印迹聚合物,吸附 3 h 后基本接近最大吸附量,其中模板分子、4-乙烯基吡啶和交联剂的摩尔比为 1∶6∶20的MIP2的印迹因子为 2.30,效果最佳。Scatchard 分析表明, 在所研究的浓度范围内,吸附过程存在两类结合位点,一类高亲和力结合位点的离解常数为Kd1= 0.63 mmol/L,最大表观结合量 Qmax1 = 25.4 umol/g,另一类低亲和力结合位点的离解常数为 Kd2 =3.5 mmol/L,最大表观结合量 Qmax2 = 61.9 umol/g,通过与酚酞类似物质在酚酞分子印迹聚合物上的吸附行为比较,表明对酚酞具有很好的选择性吸附。     

二西基锡分子印迹聚合物的合成与性能研究

以壳聚糖(CTS)为基体, 二丁基锡(DBT)为模板, 采用分子印迹技术制备了在空间结构和结合位点上与DBT匹配的分子印迹聚合物(DBT-MIPs). 研究了该分子印迹聚合物的合成条件、对DBT的吸附性能和选择识别能力, 并对其结构进行了表征. 结果表明, 所合成的DBT-MIPs对DBT具有良好的吸附和选择识别能力, 最大吸附量为178.6 μg/g.     

两步溶胀法合成奎宁印迹聚合物及性能研究

以超声合成的聚苯乙烯乳液为种子,奎宁为模板,通过两步溶胀和悬浮聚合的分子印迹技术,制备得到球形分子印迹聚合物.通过扫描电镜观察聚合物粒子形貌,测量粒径范围为50～80μm.此聚合物对模板分子具有良好的再识别能力,最大饱和净吸附量可达到61.2 μmol/g,为理论吸附量的42.5%.其对立体异构体奎宁丁也具有较好的识别作用,对结构类似物辛可宁显示一定的选择性,选择因子α分别为1.27和3.06.     

沉淀聚合法制备三聚氰胺分子印迹聚合物微球

以三聚氰胺为模板分子,以甲基丙烯酸为功能单体,乙二醇二甲基丙烯酸酯为交联剂,在乙腈-乙二醇(20∶1,V/V)混合溶剂中沉淀聚合制备了分子印迹聚合物微球.利用1H-NMR和紫外光谱方法研究了模板与功能单体相互作用情况.结果表明,三聚氰胺与甲基丙烯酸(MAA)分子通过协同氢键作用形成1∶2型氢键配合物.利用扫描电镜和红外光谱对聚合物微球的结构进行了表征.结果表明,印迹聚合物近似圆球形,粒径约为400～500 nm,且大于非印迹聚合物微球,表面存在大量的结合位点.通过静态平衡吸附实验研究了聚合物微球对模板分子的结合能力,印迹聚合物微球在4 h后逐渐达到吸附平衡,Scatchard分析表明,印迹聚合物微球主要存在两类不同的结合位点,最大表观结合量(Qmax)和平衡离解常数(Kd)分别为Qmax1=22.97μmol/g,Kd1=0.14×10-3 mol/L;Qmax2=157.65μmol/g,Kd2=2.55×10-3 mol/L,计算得出表观印迹效率和有效印迹效率分别为68%和58%.此方法合成的印迹聚合物微球对三聚氰胺有较好的结合性能,可应用于三聚氰胺的分离检测.     

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%).     

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.     

A carbanion induced synthesis of highly congested pyrazole and imidazole containing heterocycles

An efficient approach to the synthesis of highly congested di, penta and hexacyclic pyrazoles as well as imidazole fragment containing novel heterocyclic molecule has been developed through a carbanion induced transformation of suitably functionalized 2H-pyran-2-ones, benzo[h]chromene and thiochromeno[4,3-b]pyrans. Due to the presence of fluorescence, we report their prime application metal sensor as off/on switching in ferric ions.     

Synthesis of pyrrolo[1,2-a]pyrazines and pyrazino[1,2-a]indoles by Curtius reaction in Morita-Baylis-Hillman derivatives

Synthesis of substituted pyrrolo[1,2-a]pyrazines and pyrazino[1,2-a]indoles from the Morita-Baylis-Hillman derivatives of acrylates via saponification followed by Curtius reaction is described.     

正丁胺对激光染料荧光谱影响的研究

用正丁胺作为碳源,采用射频辉光放电制备碳膜,选用激光染料R6G和聚乙二醇混合液作为蒸气源,采用单源热蒸发,在蒸发室与染料同时沉积得到混合膜,用拉曼光谱和红外光谱分析了碳膜的结构和键合方式,分析表明:碳膜中存在胺基团和氢原子.混合膜的荧光谱测量结果表明,认为正丁胺对染料荧光谱的影响是因为胺基和氢原子的存在.     

Selective synthesis of 4,5-dihydroimidazo- and imidazo[1,5-a]quinoxalines via modified Pictet–Spengler reaction

An efficient tandem approach for the selective synthesis of 4,5-dihydroimidazo[1,5-a]quinoxalines 6a–g and imidazo[1,5-a]quinoxalines 7a–h by the reaction of 2-imidazolyl anilines 4a–c with aryl aldehydes 5a–k under mild reaction conditions is described. Introduction of electron releasing alkyl groups in substrates 4a–b was found to be instrumental for the success of the reaction.     

Understanding the Diels-Alder reactivity of 1,2-azaborine analogues

The Diels-Alder reactivity of 1,2-heteroborines (H₄C₄B(H)X, X?=?NH, PH, AsH; O, S, Se) has been computationally explored by means of Density Functional Theory (DFT) calculations. The influence of the HB?=?X fragment on the reactivity of the system has been quantitatively analyzed in detail by means of the so-called Activation Strain Model (ASM) of reactivity. It is found that the interaction between these species and the dienophile is significantly stronger than that computed for their all-carbon isoelectronic counterpart, benzene. In addition, the strain energy plays a key role in the observed reactivity trends. The role of the aromaticity strength of these heteroarenes on the reactivity is also assessed.