Division of Agriculture and Agricultural Life Sciences, The University of Tokyo, Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan.
Magn Reson Chem. 2010 Mar;48(3):179-83. doi: 10.1002/mrc.2564.
A useful pulse sequence for measuring long-range C--H coupling constants (J(C-H)) named high resolution-HMBC (HR-HMBC) has been developed. In this pulse sequence, the J-scaling pulse [(nt(1))/2-180 degrees (H/C) - (nt(1))/2] is incorporated after the spin evolution period, and then followed by an (1)H 180 degrees pulse to reverse the magnetization of J(C-H) couplings. As a result, splittings of the cross peaks due to the long-range J(C-H) are realigned with separations of nJ(C-H) along the F(1) dimension, and thus even the small long-range J(C--H) values can easily be determined. The efficiency of measuring the long-range J(C--H) using the proposed pulse sequences has been demonstrated in application to the complicated natural product, portmicin.
一种用于测量长程 C--H 耦合常数（J(C-H)）的有用的脉冲序列，名为高分辨率-HMBC（HR-HMBC）已经被开发出来。在这个脉冲序列中，J 刻度脉冲[(nt(1))/2-180 度（H/C）-(nt(1))/2]被加入到自旋演化周期之后，然后紧跟着一个 1H 180 度脉冲来反转 J(C-H)偶合的磁化。结果，由于长程 J(C-H)的交叉峰分裂与沿着 F(1)维度的 nJ(C-H)的间隔重新对准，因此即使是小的长程 J(C--H)值也可以很容易地确定。在所提出的脉冲序列在复杂天然产物 portmicin 的应用中，已经证明了测量长程 J(C--H)的效率。
