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首页> 外文期刊>Physica, B. Condensed Matter >9 GHz CW-EPR molecular dynamics study of polycrystalline 1-benzyl 4-hydroxy piperidine
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9 GHz CW-EPR molecular dynamics study of polycrystalline 1-benzyl 4-hydroxy piperidine

机译：多晶1-苄基4-羟基哌啶的9 GHz CW-EPR分子动力学研究

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This paper reports the results of a 9.4 GHz CW-EPR study of the molecular dynamics in a polycrystalline sample of 1-benzyl 4-hydroxy piperidine which was gamma-irradiated with a 150 kGy dose at 293 K. The temperature dependence of the hyperfine splitting (HFS) and spectral line width was measured in this acceptor-bridge-donor molecular structure from 123-273 K, A model evaluation procedure was used to determine the best-fit simulation of the observed spectrum. It was concluded that the ionizing radiation generates a free radical (I) by removal of one hydrogen from the CH2 group in the bridge connecting the benzene and piperidine rings and another free radical (II) by breaking the bond between the carbon and hydrogen atoms in the piperidine ring. The HFS parameters and the unpaired electron densities were determined. The line width for radical (I) a as found to be temperature dependent with an anomaly near 190 K indicative of either a solid-solid structural phase transition or conformational changes and did not saturate at microwave cavity input power levels up to 7 mW. The HFS parameter for radical (I) was also found to be temperature dependent between 123 and 273 K with an anomalous peak near 190 K in agreement with that observed for the line width. (C) 1998 Elsevier Science B,V. All rights reserved. [References: 12]
机译：本文报告了9.4 GHz CW-EPR研究1-苄基4-羟基哌啶多晶样品的分子动力学的结果，该样品在293 K下以150 kGy剂量进行了γ辐射。超细分裂的温度依赖性（HFS）和光谱线宽是在此受体桥供体分子结构中从123-273 K测量的。使用模型评估程序来确定观察光谱的最佳拟合模拟。结论是，电离辐射通过从连接苯和哌啶环的桥中的CH2基团中除去一个氢而生成自由基（I），并通过破坏碳原子与氢原子之间的键来产生另一个自由基（II）。哌啶环。确定了HFS参数和未配对的电子密度。发现自由基（I）a的线宽与温度有关，并具有接近190 K的异常，指示固-固结构相变或构象变化，并且在高达7 mW的微波腔输入功率下不会饱和。还发现自由基（I）的HFS参数在123和273 K之间与温度有关，并且在190 K附近有一个异常峰，与线宽所观察到的一致。 （C）1998年Elsevier Science B，V。版权所有。 [参考：12]

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