Accurate measurement of small heteronuclear coupling constants from pure-phase α/β HSQMBC cross-peaks
Accurate measurement of small heteronuclear coupling constants from pure-phase α/β HSQMBC cross-peaks
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DOI：
10.1016/j.jmr.2011.09.036
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发表时间：
2011-12-01
影响因子：
2.2
通讯作者：
Parella, Teodor
中科院分区：
文献类型：
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作者：
Gil, Sergi;Felix Espinosa, Juan;Parella, Teodor
提出了一种简单的质子选择性α/β-HSQMBC实验，用于精确测量小分子中的长程质子-碳耦合常数((N)J(CH))，而不需要个性化且耗时的后处理拟合过程。该方法获得了两个纯同相(IP)和反相(AP)多重态，完全没有由于没有J(HH)演化而导致的任何相位失真。可以直接测量准确的(N)J(CH)值，分析产生的IPAP交叉峰的相对位移。对各种实验条件下的信号强度依赖性和串扰进行了讨论。通过比较通过分析三种可用的IP、AP和IPAP多路复用模式而测量的(N)J(CH)值来评估该方法的稳健性。在激发质子不相互耦合的情况下，也可以有效地记录该方法的多频率和区域选择性版本。(C)2011 Elsevier Inc.保留所有权利。
A simple proton-selective alpha/beta-HSQMBC experiment is proposed for the accurate measurement of long-range proton-carbon coupling constants ((n)J(CH)) 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 J(HH) evolution. Accurate (n)J(CH) 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 (n)J(CH) 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. (C) 2011 Elsevier Inc. All rights reserved.