二氧化硅表面的GPTMS修饰

γ-(2,3-环氧丙氧基)丙基三甲氧基硅烷(GPTMS)是一种重要的硅烷偶联剂,由GPTMS修饰的纳米二氧化硅(GPTMS-SiO2)正在被广泛应用.本文对近年来GPTMS修饰二氧化硅的研究进行了简要概述:介绍了GPTMS修饰纳米二氧化硅的典型方法、修饰机理及存在的问题;归纳了FT-IR、XPS、NMR、元素分析、AFM等表征GPTMS 修饰层手段及GPTMS-SiO2表面环氧基的测定方法;探讨了不同修饰方法对所形成的GPTMS层结构及稳定性的影响;阐述了GPTMS修饰二氧化硅在色谱固定相、生化分析分离、光学材料、涂料黏合剂工业、介孔催化等领域的应用;并对其新的合成方法、分析评价体系、活性基团的测定方法及应用领域等作了展望.     

修饰碳糊电极研究进展

评述了修饰碳糊电极的材料组成、修饰方法与修饰功能及在分析化学、生物科学、环境化学等领域的应用，预测了修饰碳糊电极在化学生物传感器方面的发展趋势（引用文献54篇）。     

咖啡酸修饰电极的电化学性质及其对肾上腺素的电化学研究

研究了咖啡酸(CFA)修饰玻碳电极的制备和其电化学性质 ,测定了电极反应的动力学常数。实验结果表明 ,在 pH7.0的磷酸盐缓冲溶液中 ,肾上腺素(Ep)在该修饰电极上产生一灵敏的氧化峰 ,峰电流与Ep浓度在5.0×10 -6～1.0×10 -4mol/L范围内线性关系良好 ,检出限为7.0×10 -7mol/L。并对修饰电极反应的机理进行了初步探讨。修饰电极制备简单 ,稳定性良好     

肾上腺素在咖啡酸修饰电极上的电化学研究

研究了咖啡酸(CFA)修饰电极的性质,测定了电极反应的动力学常数.结果表明在pH 7.0的的磷酸盐缓冲溶液中,肾上腺素(Ep)在该修饰电极上产生一灵敏的氧化峰,峰电流与Ep浓度在5.0×10-6～1.0×10-4 mol/L范围内线性关系良好,检出限为7.0×10-7 mol/L.修饰电极制备简单,稳定性好.     

四硫富瓦烯四硫醇盐对纳米硫化物表面的修饰

本文报道用四硫富瓦烯四硫醇盐(TTFS₄^4-，简写TTFS₄)修饰CdS、NiS的纳米微粒的方法，通过TEM、FT-IR等手段对修饰的纳米微粒进行了表征。实验发现CdS/TTFS₄的固体荧光强度随着修饰量的增加而逐渐减弱。表面修饰后的CdS和NiS的电导率比修饰前都有提高，后者更为明显。     

Cds纳米微粒的聚四氟乙烯多孔膜法制备及其表面修饰

硫化镉;Cds纳米微粒的聚四氟乙烯多孔膜法制备及其表面修饰;纳米粒;多孔膜;表面修饰;聚四氟乙烯     

NEXAFS光谱分析聚合物修饰的单壁碳纳米管

利用C1s、O1s、N1s近边X射线吸收精细结构(Near Edge X-Ray Absorption Fine Structure,NEXAFS)光谱对聚合物修饰的碳纳米管进行了分析,研究了氧化及偶联聚合物对碳纳米管结构的影响。氧化碳纳米管及十八胺修饰的、聚合物/十八胺双修饰的碳纳米管的NEXAFS光谱均出现了碳/氧K边π*(C=O)和σ*(C-O)共振峰;而十八胺修饰的、聚合物/十八胺双修饰的碳纳米管则出现了氮K边π*(N-C=O)和σ*(N1s)共振峰。分析表明,NEXAFS光谱可有效表征聚合物修饰的碳纳米管。     

磷钼酸修饰铂电极的电化学行为及对甲醇氧化的电催化作用

通过循环伏安扫描法制备了PMo₁₂修饰Pt/Pt电极,并研究了该修饰电极在硫酸溶液中的电化学行为。研究结果表明:虽然磷钼酸具有较大的分子尺寸,但在Pt/Pt电极上仍能发生吸附作用,并且由于PMo₁₂在电极上的吸附,降低了Pt/Pt电极上氢区和氧区的荷电量,另外在0.02V左右还观察到磷钼酸的氧化-还原峰。通过稳态极化曲线和循环伏安曲线研究了PMo₁₂修饰Pt/Pt电极对甲醇氧化的电催化作用。测试结果表明:PMo₁₂修饰铂基电极不但对甲醇的电氧化具有较高的活性,而且还有一定的抗CO中毒性。该修饰电极还具有较高的稳定性。     

金属卟啉与Keggin型硅钨酸修饰电极的制备及电催化性能测定

运用自组装和电化学组装联用方法,将镍卟啉配合物THPPNi和Keggin型硅钨酸SiW₁₂修饰到玻碳电极上,制备镍卟啉修饰电极和镍卟啉/硅钨酸复合修饰电极,研究其在DMF溶液中的电化学行为,测定在碱性条件下对NO₂^-和BrO₃^-的电催化性能。循环伏安和交流阻抗研究结果表明,复合修饰电极THPPNi/SiW₁₂的电极过程属于扩散控制过程;复合修饰电极优于单一修饰金属卟啉和多酸修饰电极。     

量子点的聚合物表面修饰及其应用

量子点作为新型纳米发光材料备受关注,但由于光学稳定性和生物相容性的问题而在实际应用上受限。聚合物对量子点的修饰能够提供量子点合成的有效支撑基质,而且还可以改善量子点的稳定性和单分散性,进而可以拓展量子点应用于化学、物理以及生物学领域。基于聚合物修饰量子点的优势,本文简述了聚合物表面修饰量子点的方法、合成路线、步骤、特点以及发展现状。其中,双亲分子涂敷的量子点可以改善量子点的水溶性;多基配体包裹的量子点更具有稳定性和功能性;末端功能化聚合物表面修饰的量子点则可以合成更为先进功能的材料;胶封树枝状定域量子点具有单分散和优越发光特性。同时,还综述了各种表面修饰方法的最新研究进展,存在问题以及应用发展趋势。     

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%.     

Synthesis of 1-benzyloxypyrazin-2(1H)-one derivatives

Different approaches for the synthesis of 1-benzyloxypyrazin-2(1H)-one derivatives from simple amino acids have been investigated. A library of 33 precursors for the preparation of N-hydroxy pyrazinones was obtained in moderate to good yields.     

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.     

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.     

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.     

Chemistry of heterocyclic compounds at the A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences, over 50 years (Review)

The review contains a concise historical account and information on the most significant researches undertaken by the staff at the A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences on the Chemistry of Heterocyclic Compounds. Dedicated to Academician of the Russian Academy of Sciences B. A. Trofimov on his 70th jubilee. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1443–1502, October, 2008.     

A general and convenient synthesis of 4-(tosylmethyl)semicarbazones and their use in amidoalkylation of hydrogen,heteroatom, and carbon nucleophiles

A general synthesis of previously unknown semicarbazone-based α-amidoalkylating reagents, 4-(tosylmethyl)semicarbazones, has been developed. The synthesis involved three-component condensation of semicarbazones of aliphatic or aromatic aldehydes with the same or other aldehydes and p-toluenesulfinic acid. The scope and limitations of this reaction were investigated. The compounds obtained were demonstrated to be an efficient α-(4-semicarbazono)alkylating agents. They were reacted with H- (sodium borohydride), O- (sodium methylate), S- (sodium phenylthiolate), N- (pyrrolidine, sodium succinimide), P- (trialkyl phosphites), and C-nucleophiles (sodium diethyl malonate) to give the corresponding products of the tosyl group substitution, 4-substituted semicarbazones, including analogues of nitrofurazone. Among the prepared compounds tested in vitro for antibacterial and antifungal activity, three nitrofuryl-containing semicarbazones exhibited high biological activities with minimum inhibitory concentration (MIC) values of 8–32 μg/mL.     

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.     

Synthesis of novel chiral bidentate hydroxyalkyl-N-heterocyclic carbene ligands and their application in palladium-catalyzed Mizoroki–Heck couplings and asymmetric addition of diethylzinc to benzaldehyde

A small library of new chiral bidentate hydroxyalkyl-imidazolium salts 1 is conveniently synthesized on multi-gram scale from inexpensive and commercially available chiral pool amino acids. The corresponding carbenes, generated by deprotonation of imidazolium salts 1, in combination with palladium(II) chloride were tested in the Mizoroki–Heck coupling reaction. The most significant results in terms of yields and reactivities were achieved with low catalyst loading. The catalytic activities of these imidazolium salts were also investigated in the asymmetric addition of diethylzinc to benzaldehyde. The use of MgO nanoparticles as an additive in conjunction with these ligands played a crucial role in increasing the efficiency of these reactions.