参磁铁增强了有机溶剂中的H2和H2@C60中的核松
Elena Sartori1, Marco Ruzzi, Nicholas J Turro
1Department of Chemistry, Columbia University, New York, New York 10027, USA.
Journal of the American Chemical Society
|January 26, 2008
概括
与自由H2相比,偏磁性氧化物基对H2@C60内的分子质子具有5倍增强的放松效应. 在H2@C60中这种增强的自旋格子放松表明,单靠距离预测的相互作用比预测的更强.
科学领域:
- 物理化学 物理化学
- 材料科学 材料科学 材料科学
- 超分子化学 超分子化学
背景情况:
- 旋转格子放松 (R1) 对于理解溶液中的分子相互作用至关重要.
- 偏磁性氧化物基是研究放松动态的有效探针.
- 像H2@C60这样的内分体富勒伦为封装分子提供了独特的环境.
研究的目的:
- 量化H2和H2@C60在氧化物激素存在时的双分子旋转放松 (放松性).
- 为了研究烯封装对H2与外部偏磁体之间的相互作用的影响.
- 探索负责观察到的放松性变化的潜在机制.
主要方法:
- 使用核磁共振 (NMR) 光谱测量质子 (1H) 和碳-13 (13C) 缓解性 (R1).
- 使用外球模型对双分子旋转放松的放松性数据的分析.
- 计算激素和分子之间的碰撞距离 (d).
主要成果:
- 在相同条件下,与自由H2相比,H2@C60的放松度增加了5倍.
- 在C60中13C放松度明显小于预期,相对于H2@C60.0中1H放松度,显著小于预期.
- 对于H2和13C60的碰撞距离与范德瓦尔斯半径一致,但对于H2@C60.0来说要小得多.
- 在H2@C60中增强的放松性表明,这种相互作用比距离预测的更强,可能是由于超细合.
结论:
- 在C60中封装H2并不能使其免受外部的磁性相互作用;相反,它增强了它们.
- 观察到的H2@C60中增强的放松性表明与偏磁体的相互作用比通过简单的近距离预测的要强.
- 高精度合可能有助于观察到H2@C60.0的放大放松效应.
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