|Title:||Separation and characterization of different signals from intermolecular three-spin orders in solution NMR||Authors:||Chen, Zhong
Hwang, Dennis W.
|Keywords:||Intermolecular dipolar interactions;Multiple-quantum coherences;Three-spin order;Diffusion;Relaxation||Issue Date:||2004||Publisher:||Taipei:National Taiwan University Dept Chem Engn||Start page/Pages:||-||Source:||Journal of Magnetic Resonance (171),244–252||Abstract:||
In this paper, signals originating from a pure specific coherence of intermolecular three-spin orders were separated & characterized experimentally in highly polarized two-component spin systems. A modified CRAZED sequence with selective radio-frequency excitation was designed to separate the small signals from the strong conventional single-spin single-quantum signals. General theoretical expressions of the pulse sequence with arbitrary flip angle pulses were derived using dipolar field treatment. The expressions were used to predict the relaxation & diffusion properties & optimal experimental parameters such as flip angles. For the first time, relaxation & diffusion properties of pure intermolecular single-quantum, double-quantum, & triple-quantum coherences of three-spin orders were characterized & analyzed in one-dimensional experiments. All experimental observations are in excellent agreement with the theoretical predictions. The theoretical results show that the quantum-mechanical treatment leads to exactly the same predictions as the dipolar field treatment. The quantitative study of intermolecular multiple-quantum coherences of three-spin orders presented herein provides a better understanding of their mechanisms.
|Appears in Collections:||化學系|
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