利用对称位移脉冲改善分辨率-IMPRESS HMBC

众所周知异核二维实验在中、小分子的结构确定中非常重要. 例如¹H与¹³C/¹⁵N异核远程相关无疑是连接分子中孤立结构碎片及季碳的最有利的工具. 然而，在间接检测的异核二维实验中，间接检测域-异核维的太低分辨率一直是困扰着化学家的主要问题. 过去在有限的采样时间内提高分辨率的方法主要有线性预测、带选择脉冲和控制好的折叠3种方法. 文中介绍一种最新开发出的利用Hadamard激发雕刻的方法. 借助Varian核磁共振系统的高品质射频系统和灵活的软件工具, 用户可以方便的实施新的激发雕 刻方案，极大地改善gHMBC实验的F₁分辨率.

IMPROVED RESOLUTION WITH SYMMETRICALLY SHIFTED PULSES-IMPRESS HMBC

D heteronuclear NMR experiments are very useful tools for determining the structure of small or medium molecules. Especially, the heteronuclear long range experiments from 1H to 13 C or 15 N are the most powerful implements to allow chemist the bridging of isolated fragments molecules and allow placement of quaternary 13 C (or 15 N) atoms. However, the resolution in the dimension of the heteroatom of indirect detection experiments can not meet the requirement of resonance assignment. Linear prediction, band selection, and careful aliasing are three different strategies to achieve higher resolution. Recently a new approach has been advanced by utilizing Hadamard Excitation Sculpting. The high rf quality and flexibility of VNMR software tools allow users of Varian NMR systems to easily adopt novel excitation sculpting schemes to dramatically increase in gHMBC experiments.