The Semi-selective 2D HMQC experiment is a simple modification of the 2D HSQC pulse sequence in which one of the two carbon 90 degree pulses is applied selectively on a specified region. The main purpose is to achieve better resolution in the indirect dimension and therefore is recommended when high overlapped carbon spectra precludes an easy resonance assignment. This same approach can be applied in the Semi-selective 2D HMQC experiment.

Easy implementation on any AVANCE spectrometer equipped with an inverse probehead.

A basic sequence was reported in 91MRC848 . Gradient-enhanced versions have been also published ( 95JB97 , 95MRC570 and 99JMR454-139 )

In order to achieve improved resolution, the user can also use digital filtering in the acquired proton dimension and apply linear prediction when data processing.

In analogy, other experiments like a band-selective HSQC-TOCSY experiment are designed in the same way:

The semi-selective 2D HSQC experiment can be recorded in routine/automation modes. The most important parameter to optimize is the semi-selective carbon pulse length which determines the carbon spectral width to be excited.

Tutorials: 2D inverse experiments

Tutorials: 2D gradient-based inverse experiments

The spectrum offers the same correlation map as the conventional HSQC experiment.

Related experiments:

2D Inverse experiments

2D Inverse gradient-enhanced experiments