Servei de Ressonància Magnètica Nuclear, Universitat Autònoma de Barcelona, E-08193 Bellaterra, Barcelona, Spain.
J Magn Reson. 2011 Dec;213(1):145-50. doi: 10.1016/j.jmr.2011.09.036. Epub 2011 Oct 1.
A simple proton-selective α/β-HSQMBC experiment is proposed for the accurate measurement of long-range proton-carbon coupling constants (nJCH) in small molecules without need for an individualized and time-consuming post-processing fitting procedure. The method acquires two pure-phase In-phase (IP) and Anti-phase (AP) multiplets completely free of any phase distortion due to the absence of JHH evolution. Accurate nJCH values can be directly measured analyzing the relative displacement of the resulting IPAP cross-peaks. Discussion about signal intensity dependence and cross-talk is made for a range of experimental conditions. The robustness of the method is evaluated by comparing the nJCH value measured from the analysis of the three available IP, AP and IPAP multiplet patterns. Multiple-frequency and region-selective versions of the method can also be efficiently recorded provided that excited protons are not mutually coupled.
提出了一种简单的质子选择的 α/β-HSQMBC 实验方法，用于在无需个体化和耗时的后处理拟合程序的情况下，准确测量小分子中的长程质子-碳耦合常数（nJCH）。该方法获得两个完全没有任何由于 JHH 演化引起的相失真的纯相同相（IP）和反相（AP）多重峰。通过分析所得的 IPAP 交叉峰的相对位移，可以直接测量准确的 nJCH 值。针对一系列实验条件，对信号强度依赖性和串扰进行了讨论。通过比较从三种可用的 IP、AP 和 IPAP 多重峰模式的分析中测量的 nJCH 值，评估了该方法的稳健性。如果激发质子不相互耦合，则可以高效地记录多频和区域选择性版本的方法。
