对DEPT实验技术的一点改进

将DEPT -1 3 5实验的 1 3 5° -脉冲分成一个 90°脉冲和一个 4 5°脉冲 ,通过相位循环 ,设计了两个新的DEPT实验分别称为DEPT-90 -4 5和DEPT -90 +4 5。DEPT -90 -4 5谱中只有 -CH3的吸收峰。DEPT -90 +4 5谱中没有 >CH -的吸收峰 ,其 -CH3为正信号 ,-CH2 -为负信号。实验结果显示 ,对比DEPT -90谱 ,这两个新的DEPT谱中完全没有所选基团之外的残余干扰信号 ,而且DEPT -90 -4 5谱比DEPT-90 +4 5谱更好。

An Improvement to DEPT Experiment

Two novel DEPT experiments, referred to as DEPT-90-45 and DEPT-90+45,were designed by substituting the 135°-pulse in DEPT-135 sequence by a 90°-pulse and a 45°-pulse with different phase cycling procedures.DEPT-90-45 detects the methyl resonances only, while DEPT-90+45 measures the methyl and methylene resonances respectively as positive and negative peaks.The experimental results show that DEPT-90-45 and DEPT-90+45 spectra are completely free of the residual signals of non-selected resonance peaks,as compared to DEPT-90 interfered with substantial residual methyl and methylene signals, and that DEPT-90-45 is better than DEPT-90+45.