The selective 1D HMBC experiment is the selective version of the 2D HMBC experiment. It allows to obtain a 1D ¹H spectrum only showing ¹H resonances two and three-bonds away of the selected ¹³C nucleus. This experiment is also known as SIMBA (Selective Inverse Multiple Bond Analysis) and has been proposed to measure long-range proton-carbon coupling constants from the resulting anti-phase multiplets.

Easy implementation on AVANCE spectrometers equipped with an inverse probehead and selective excitation using shaped pulses.

The selective 1D HMBC pulse sequence is easily derived from the conventional four-pulse 1D HMQC experiment in which one of the two 90º ¹³C pulses is made selective for a given ¹³C resonance, the defocusing period is optimized to 5-10 Hz, the refocusing period and 13C-decoupling during acquisition are omitted. ( 91JMR189-92 and 91MRC46 ). A low-pass filter can be inserted to remove direct correlations.

Related modified sequences have been proposed:

• Better results are obtained from the gradient-enhanced version (see selective ge-1D HMBC experiments).
• Use of chemical shift-selective filters ( 93JMRA98-101 and 93JMRB1-101 ) as a selective ¹³C excitation scheme.
• Related experiments use a selective heteronuclear echo scheme as selective ¹³C excitation ( 91JMR214-93 , and 94JMRA104-111 ).
• Analogs selective long-range-optimized 1D  reverse-INEPT ( 93JMRA97-103 , 94JMRA90-110 , 94MRC134 , and 95MRC596 ) and selective long-range-optimized 1D HSQC ( 91JMR636-92 , 92JMR411-97 , 93JMRB1-101 , 99MRC48 and 94JMRA160-108 ) experiments have been proposed for the same purpose.
• Use of a selective JANUS pulse to achieve directly antiphase-carbon magnetization ( 93JMRA234-104 ).

The selective 1D HMBC  experiment can be recorded in a fully automated way. Minor changes from a predefined parameter set are required. The most important parameter to define is the selective ¹³C pulse: the offset, the shape, the duration and the power level needed for a specific excitation profile.

For further details on practical implementation of the selective 1D HMBC  experiment on AVANCE spectrometers see Tutorial: selective 1D HMBC experiment

The selective 1D HMBC experiment affords a 1D proton spectrum in which the active long-range proton-carbon coupling constant appears in anti-phase pattern. However, a fitting procedure to extract the coupling value in complex multiplets is required, similarly as described in the 2D HMBC experiment .