金纳米粒子比色测定细胞色素c构象变化

金纳米粒子(AuNPs)的颜色会随着细胞色素c(Cytc)构象变化而发生较大的变化,作者在改变原测定流程的基础上利用这种有规律的变化研究和测定了H+和L-半胱氨酸(L-Cys)对Cytc的构象变化.实验中分别加入pH=1-13的Cytc,可以使AuNPs显示青、蓝、紫、红等明显不同的颜色,从而可以利用AuNPs比色快速测定不同pH值的Cytc构象变化.在pH=7时,当附加L-Cys浓度从低浓度变化到高浓度时,AuNPs颜色逐渐从紫色变化到蓝色、青色,从而实现利用AuNPs比色测定由L-Cys所引起Cytc构象变化.圆二色(CD)光谱证实了pH=1-13和不同浓度L-Cys下的Cytc构象变化.借助紫外-可见吸收光谱和扫描电子显微镜(SEM)进一步明确了加入Cytc后AuNPs的不同聚集状态与其颜色变化的关系.     

功能化纳米金比色检测水中Cr~(3+)

采用柠檬酸钠还原法制备粒径13 nm的金纳米颗粒(AuNPs)作为比色信号报告分子,3-氨基-5-巯基-1,2,4-三唑(AMT)作为Cr~(3+)的识别分子,构建了一种水中Cr~(3+)的比色传感检测方法。将AMT修饰于AuNPs表面,形成稳定的AMT-AuNPs水溶复合物;根据AMT与Cr~(3+)之间的特异性结合,引起溶液中AMT-AuNPs聚集,进而导致溶液颜色由红色变为蓝紫色以及最大吸收峰红移的现象,实现了水中Cr~(3+)的比色检测。在优化实验条件(AMT修饰浓度为0.8μmol/L,pH 7.0)下,该方法的检测范围为6~14μmol/L,检出限可达100 nmol/L,其他重金属离子几乎不存在干扰。由于该方法具有响应快(5 min)、制备和操作简单、无需读取装置等优点,可望用于水体中Cr~(3+)的现场快速检测。     

CH3SH…HOO开壳型氢键复合物的结构及其电子密度拓扑性质

在DFT-B3LYP/6-311++G**水平下求得CH3SH…HOO复合物势能面上的稳定构型. 计算结果表明, 在HOO以其O8—H7作为质子供体与CH3SH分子中的S5原子为质子受体形成的氢键复合物1和2中, O8—H7明显被“拉长”, 且其伸缩振动频率发生显著的红移, 红移值分别为330.1和320.4 cm-1; 在CH3SH分子以其S5—H6作为质子供体与HOO的端基O9原子为质子受体形成的氢键复合物3和4中, 也存在类似的情况, 但S5—H6伸缩振动频率红移不大. 经MP2/6-311++G**水平计算的4种复合物含BSSE校正的相互作用能分别为-20.81, -20.10, -4.46和-4.52 kJ/mol. 自然键轨道理论(NBO)分析表明, 在CH3SH…HOO复合物1和2中, 引起H7—O8键长增加的因素包括两种电荷转移, 即孤对电子n1(S5)→σ*(H7—O8)和孤对电子n2(S5)→σ*(H7—O8), 其中后者为主要作用. 在复合物3和4中也有相似的电荷转移情况, 但轨道间的相互作用要弱一些. AIM理论分析结果表明, 4个复合物中的S5…H7间和O9…H6间都存在键鞍点, 且其Laplacian量▽2ρ(r)都是很小的正值, 说明这种相互作用介于共价键和离子键之间, 偏静电作用为主.     

固态导电聚合物多色电致变色器件的制备

制备了基于聚3-甲基噻吩(P3MeT)和聚苯胺(PANI)的两种结构(侧面结构和垂直结构)固态导电聚合物多色电致变色器件(ECD). 采用电化学现场紫外-可见光谱法研究了侧面结构固态ECD的电致变色特性, P3MeT-ECD显示出蓝色和红色的可逆变化, PANI-ECD显示出墨绿色和黄绿色的可逆变化, 同时采用P3MeT和PANI作变色材料的P3MeT-PANI-ECD可以实现红、蓝、墨绿和草绿多色变化. 用激光雕刻微型化P3MeT-PANI变色层组装制得的侧面结构固态P3MeT-PANI-ECD控制合适电压也可多色变化. 另外, 用CeO₂-TiO₂作为P3MeT-PANI对电极的垂直结构固态P3MeT-PANI-ECD在实现红、蓝、墨绿和草绿多色变化的同时, 也可进行四色自由搭配选择.     

高选择性氟离子受体的合成与识别性能研究

设计合成了一种新型腙类阴离子受体1。利用紫外-可见吸收光谱,荧光光谱考察了其与Ac O-,H2PO4-,Cl-,Br-,I-和F-几种阴离子之间的作用。当加入F-时,导致紫外光谱的可见光区明显变化(大约115nm红移),同时伴随着浅黄色变为蓝紫色的"裸眼"颜色变化。而加入其他离子后溶液颜色几乎没有发生颜色。据此建立了裸眼比色法检测F-的方法。     

一种测定S2–的金纳米棒非聚集比色探针

基于S2-对金纳米棒(AuNRs)纵横轴溶出速度的差异性所引起的红移量(△λ)和颜色变化,开发了AuNRs溶出比色探针.探针线性范围(10～ 10000.0 μmol/L)宽、灵敏度高(检出限为7.9 μmol/L)、选择性好,用于实际样品中S2-含量的测定和人体疾病诊断,其结果与亚甲基蓝法相吻合.此外,探讨了探针测定S2-的反应机理.     

钒钨酸盐/刚果红电致变色复合膜及器件研究

应用Layer-by-Layer自组装技术,采用聚乙烯亚胺(PEI)阳离子将无机电致变色材料[P2W15V3O62]8-(P2W15V3)阴离子与刚果红(CR)阴离子通过静电引力复合,构筑了复合膜[PEI/P2W15V3/PEI/CR]20及对比膜[PEI/P2W15V3]20.利用扫描电子显微镜、紫外-可见吸收光谱和电化学工作站研究了复合膜的形貌与电致变色性能.对比研究表明,复合膜可实现浅红色-蓝紫色-浅红色的可逆颜色调变,且保持了[P2W15V3O62]8-阴离子的电致变色性能,光反差22.55%,着色效率122.67 cm2/C.复合膜循环测试400圈后透过率(500 nm)处损耗仅为6.94%,稳定性良好;由复合膜组装的电致变色器件也实现了由浅红色到蓝紫色的颜色变化.本研究可为解决多酸电致变色材料颜色变化单一的问题提供参考.     

有机荧光分子2-氰基-3-(3, 4-二甲氧基苯基)-2-丙烯酰胺的可逆压致变色和质子刺激响应性能

设计合成了3-芳基-2-腈基丙烯酰胺类有机发光小分子2-氰基-3-(3, 4-二甲氧基苯基)-2-丙烯酰胺(CDMPA)。经研究发现, CDMPA化合物具有明显的压致变色和酸致变色现象。在外力刺激下,化合物CDMPA荧光最大发射峰发生20 nm的红移,经过加热或蒸汽处理后可恢复初始状态。对样品研磨前后粉末的X射线衍射图谱及荧光寿命衰减曲线进行测试分析得出, CDMPA压致变色现象归因于分子构型由晶态到无定形态的转化。另外,在酸刺激下CDMPA发光颜色由蓝光红移至黄光,最大发射波长红移33 nm。经过二甲基甲酰胺(DMF)处理后可恢复到初始状态。由测试得到的红外光谱及分子轨道理论计算推测,酸致变色现象是由氨基取代基的质子化影响了CDMPA前线分子轨道引起的。本研究可使人们深入了解这种类型材料的多刺激响应发光机制,且显著的颜色变化性能使CDMPA在传感器和检测装置方面具有潜在的应用前景。     

α-甘氨酸晶体的动态磁手性和磁电效应

利用变温直流磁化率测定, 在外加磁场强度为依1 T, 磁场平行于晶体b轴, 发现在301-302 K α-甘氨酸有动态磁手性相变. α-甘氨酸晶体的每个晶胞包含四个分子, 属于具有中心对称结构的P21/n群, 电荷中心对称, 不导电. 在晶体中, 两层之间的N+(3)—H(8)…O(1)和N+(3)—H(8)…O(2)氢键, 沿b轴相互交叉反向配对排列. 在303 K, 用原子力显微镜可观察到α-甘氨酸晶体表面分子层与层间有规则的交叉螺旋排列. 结合中子衍射确定相变机制为, 在相变温度及外加磁场H=±1 T时, α-甘氨酸中的N+(3)—H(8),电子自旋反转为(↑). 因为N+(3)—H(8)…O(1)和N+(3)—H(8)…O(2)两反向氢键的强度和键角不同, 由动态磁手性和磁电效应, 产生电荷中心不对称, 导致304 K附近的热电相变.     

有机荧光分子2-氰基-3-(3,4-二甲氧基苯基)-2-丙烯酰胺的可逆压致变色和质子刺激响应性能（英文）

设计合成了3-芳基-2-腈基丙烯酰胺类有机发光小分子2-氰基-3-(3,4-二甲氧基苯基)-2-丙烯酰胺(CDMPA)。经研究发现,CDMPA化合物具有明显的压致变色和酸致变色现象。在外力刺激下,化合物CDMPA荧光最大发射峰发生20 nm的红移,经过加热或蒸汽处理后可恢复初始状态。对样品研磨前后粉末的X射线衍射图谱及荧光寿命衰减曲线进行测试分析得出,CDMPA压致变色现象归因于分子构型由晶态到无定形态的转化。另外,在酸刺激下CDMPA发光颜色由蓝光红移至黄光,最大发射波长红移33 nm。经过二甲基甲酰胺(DMF)处理后可恢复到初始状态。由测试得到的红外光谱及分子轨道理论计算推测,酸致变色现象是由氨基取代基的质子化影响了CDMPA前线分子轨道引起的。本研究可使人们深入了解这种类型材料的多刺激响应发光机制,且显著的颜色变化性能使CDMPA在传感器和检测装置方面具有潜在的应用前景。     

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.