Comparative NMR Properties of H2 and HD in Toluene-d8 and in H2/HD@C60
Comparative NMR Properties of H2 and HD in Toluene-d8 and in H2/HD@C60
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DOI：
10.1021/jp102860m
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发表时间：
2010-11-18
影响因子：
3.3
通讯作者：
Lawler, Ronald G.
中科院分区：
文献类型：
--
作者：
Chen, Judy Y-C;Marti, Angel A.;Lawler, Ronald G.
在200-340 K范围内测量了溶解在甲苯-d(8)中的H-2分子和嵌顿在C-60中的HD分子中的质子的自旋晶格弛豫时间T-1。发现在两种环境和所有温度下，HD弛豫比H-2慢。更详细的分析表明，与氢与He或Ar气相碰撞的情况相比，H-2在甲苯-d(8)溶液和C-60中，H-2旋转态的转变速度与HD相似，而HD的自旋-旋转和偶极子-偶极子耦合的值较小。H-2和HD的相对H-1化学位移、耦合常数hp和HD峰宽度在不同温度下的测量结果显示，影响很小，精度不够，无法保证更详细的解释
Spin lattice relaxation times, T-1, have been measured from 200-340 K for the protons in H-2 and HD molecules dissolved in toluene-d(8) and incarcerated in C-60 It is found that HD relaxes more slowly than H-2 in both environments and at all temperatures, as expected from the smaller values of the spin-rotation and dipole-dipole coupling in HD compared to H-2 More detailed analysis using models developed to describe relaxation in both condensed media and the gas phase indicates that transitions among the rotational states of H-2 occur at a rate similar to those of HD in both toluene-d(8) solution and in C-60 in contrast to the situation in gas phase collisions between hydrogen and He or Ar, where the lifetimes of rotational states of HD are markedly shorter than those for H-2 Measurements of the relative H-1 chemical shifts of H-2 and HD, the coupling constant hp, and the widths of the HD peaks at various temperatures revealed only small effects with insufficient accuracy to warrant more detailed interpretation