Characterization of the External Surface of Silicalites Employing Electron Paramagnetic Resonance<sup>,</sup>
作者:Zhiqiang Liu、M. Francesca Ottaviani、Lloyd Abrams、Xuegong Lei、Nicholas J. Turro
DOI:10.1021/jp049275h
日期:2004.9.1
external surface have been developed using electronparamagneticresonance (EPR). The absorption of an EPR silent probe ortho-methyldibenzyl ketone (oMeDBK) (4 in Scheme 1) on the external surface of a series of monodisperse silicalite crystals was studied using an initially coadsorbed EPR active nitroxide probe. The displacement of the initially adsorbednitroxide probe by coadsorbed oMeDBK shows that
已经使用电子顺磁共振 (EPR) 开发了用于研究硅沸石外表面的灵敏且结构特定的方法。使用最初共吸附的 EPR 活性氮氧化合物探针研究了 EPR 静默探针邻甲基二苄基酮 (oMeDBK)(方案 1 中的 4)在一系列单分散硅沸石晶体的外表面上的吸收。最初吸附的氮氧化物探针被共吸附的 oMeDBK 置换表明,吸附物分子首先吸附在以探针缓慢旋转运动为特征的更强结合位点(宽 EPR 线)上,在更强的位点饱和后,置换的 EPR 探针分子吸附在以探针快速旋转运动为特征的较弱结合位点(窄 EPR 线)。从慢速到快速旋转运动的转变点提供了对硅沸石外表面积和硅沸石晶体外表面积上更强结合位点的定量测量。吸附强度取决于分子结构,极性官能团对结合强度有很大贡献。14 N 和 15 N 自旋标记的氮氧化物的顺序吸附表明强结合位点上的吸附物与溶液中或弱结合位点上的吸附物之间存在动态交换,而 14 N 和 15 N 自
Kelemen, Peter; Lugtenburg, Johan; Klumperman, Bert, Journal of Organic Chemistry, 2003, vol. 68, # 19, p. 7322 - 7328
A Time-Resolved Electron Paramagnetic Resonance Investigation of the Spin Exchange and Chemical Interactions of Reactive Free Radicals with Isotopically Symmetric (<sup>14</sup>N−X−<sup>14</sup>N) and Isotopically Asymmetric (<sup>14</sup>N−X−<sup>15</sup>N) Nitroxyl Biradicals
作者:Elena Sartori、Igor V. Khudyakov、Xuegong Lei、Nicholas J. Turro
DOI:10.1021/ja0687670
日期:2007.6.1
(14N-X-15N), were employed as probes of the spinexchange and chemical interactions between r and the nitroxylbiradicals. The interaction of r# with the asymmetric ortho-nitroxyl biradical (14N-O-15N), which exists in a condition of strong spinexchange, proved to be particularly informative. In this case, spin polarized (14N-O-15N)# (product of spinexchange with r#) and two polarized monoradicals (r14N-O-15N)#