​Constant time Inverse-detection Gradient Accordion Rescaled Heteronuclear Multiple Bond Correlation spectroscopy (CIGAR-HMBC) is a popular variant of gradient HMBC experiment that uses a variable HMBC delay for observation of small H-X couplings ☝🏻. For most work it is recommended to run multiple gHMBC experiments with different long range delays or at least both a gHMBC and a CIGAR 🧐. An example is in the picture. You can see some extra peaks in CIGAR. What are those we’ll discuss in the next part. #nmr_HMBC #nmr #nmrchat #nuclearmagneticresonance #chemistry #chemie #quimica

​Those extra peaks you see in CIGAR-HMBC are result of specific appearance of 1J(H-C) splitting☝🏻. Details in the picture👇🏻. It might be a real problem if one dealing with substrate with crowded 1H spectrum, because the number of 1J-related peaks is 2X compared to regular HMBC🤯.

#nmr #nuclearmagneticresonance #nmrchat #chemistry #chemie #quimica #nmr_hmbc