描述了一种基于1',3,3',4-四氢螺环[chromene-2,2'-吲哚]环系统的新型化学传感器,该化学传感器可高特异性地检测氰化物。这些化学传感器在氰化钠与磷酸钠缓冲的乙腈溶液中用氰化物处理时,会显示出明显的颜色变化,并且此过程不受其他常见阴离子的影响。化学传感器对低浓度的氰化物表现出高灵敏度,符合欧盟水质控制标准,灵敏度低于0.05 mg L -1,并在数十秒内显示出非常快的响应。通过氰化阴离子对吲哚啉C-2原子上的酚氧原子进行亲核取代,形成稳定的吲哚腈加合物,并生成有色的4-硝基酚盐发色团,从而合理地确定了检测机理。这些化学传感器可以通过简单的方法由市售的起始原料合成。
描述了一种基于1',3,3',4-四氢螺环[chromene-2,2'-吲哚]环系统的新型化学传感器,该化学传感器可高特异性地检测氰化物。这些化学传感器在氰化钠与磷酸钠缓冲的乙腈溶液中用氰化物处理时,会显示出明显的颜色变化,并且此过程不受其他常见阴离子的影响。化学传感器对低浓度的氰化物表现出高灵敏度,符合欧盟水质控制标准,灵敏度低于0.05 mg L -1,并在数十秒内显示出非常快的响应。通过氰化阴离子对吲哚啉C-2原子上的酚氧原子进行亲核取代,形成稳定的吲哚腈加合物,并生成有色的4-硝基酚盐发色团,从而合理地确定了检测机理。这些化学传感器可以通过简单的方法由市售的起始原料合成。
1-Benzyl-3,3,5′,6′-tetramethylspiro[indoline-2,2′-[2H]pyrano[3,2-b]-pyridinium] iodide, its hydrate, and a neutral precursor of the salts: synthesis, crystal structure, photochromic transformations in solutions and in crystals
作者:E. A. Yurieva、S. M. Aldoshin、L. A. Nikonova、G. V. Shilov、V. A. Nadtochenko
DOI:10.1007/s11172-011-0210-z
日期:2011.7
ndoline-2,2′-[2H]pyrano[3,2-b]pyridinium] iodide, photochromic in the crystal state, was obtained. X-ray diffraction analysis was used for determination of crystalstructures of the salt, its hydrate, and a neutral precursor. It was found that a replacement of the substituent in the indoline fragment leads to a considerable change in the crystalstructure of both the neutral spiropyran and the salts
Transmission Spectroscopy and Kinetics in Crystalline Solids Using Aqueous Nanocrystalline Suspensions: The Spiropyran-Merocyanine Photochromic System
作者:Vanessa M. Breslin、Miguel A. Garcia-Garibay
DOI:10.1021/acs.cgd.6b01476
日期:2017.2.1
A comparison of the solution and solid state thermal decay kinetics of five photochromic spiropyrans with different N-alkyl groups (SP1–SP5) was carried out in acetonitrile and nanocrystalline suspensions at 298 K. The change in absorbance at ca. 550 nm was measured as a function of time for the merocyanine (MC) using transmission UV–vis spectroscopy. We found that the thermal decay kinetics are slower and follow a biexponential decay in the solid state compared to a faster, monoexponential decay that was measured in solution. We observed that, while the kinetic range measured in solution varies by a factor of 13, the decay kinetics in the solid state cover a range of ca. 150, indicating that crystal packing has an influence much greater than that of the effects of N-alkyl substitution. A fluorescence analysis of irradiated samples of SP1 in solution could be used to determine the formation of the MC species and its subsequent decay. By contrast, a similar analysis of nanocrystalline suspensions displayed changes as a function of time that are consistent with self-quenching.
在 298 K 的乙腈和纳米晶体悬浮液中,对具有不同 N-烷基的五种光致变色螺环丙烷(SP1-SP5)的溶液和固态热衰减动力学进行了比较。我们使用透射紫外可见光谱法测量了美拉西氨酸(MC)在 550 纳米波长处的吸光度随时间的变化。我们发现,与在溶液中测量到的较快的单指数衰减相比,固态下的热衰减动力学较慢,且遵循双指数衰减。我们观察到,在溶液中测得的动力学范围相差 13 倍,而在固态中的衰变动力学范围约为 150 倍,这表明晶体堆积的影响远远大于 N-烷基取代的影响。对溶液中经过辐照的 SP1 样品进行荧光分析,可以确定 MC 物种的形成及其随后的衰减。相比之下,对纳米晶体悬浮液的类似分析显示出与自淬相一致的随时间变化的变化。
Rhodium(I) catalyzed asymmetric hydrogenation of enamines
作者:Vitali I Tararov、Renat Kadyrov、Thomas H Riermeier、Jens Holz、Armin Börner
DOI:10.1016/s0040-4039(00)00197-0
日期:2000.4
The asymmetric hydrogenation of prochiral electron-rich enamines with rhodium(I) diphosphine and diphosphinite catalysts is described. The reaction is strongly sensitive to the ligand applied. Good results are observed with catalysts based on (R,R)-DIOP, Kβ+-OH, (R,R)-bdpch and other ligands forming seven-membered chelates with the metal. It is shown, that by conversion of a cyclic imine, which could