Spectral-band-selective multidimensional nuclear magnetic resonance spectroscopy using broadband dipolar recoupling schemes

Abstract

Nuclear magnetic resonance (NMR) spectroscopy is an important analytical tool for probing molecular structures and interactions. For high complexity samples, multidimensional spectroscopy is essential for improving the resolution of NMR data. However, multidimensional experiments cost significant experimental time which scales with the number of indirect points. This is particularly challenging when dealing with highly dispersed nuclei, such as ¹³C, due to the large chemical shift range, with large regions that are spectrally empty. Herein, we describe a method for limiting the spectral width of dipolar based multidimensional NMR experiments in the indirect dimension in a manner that can be easily integrated into relaxation and distance measuring schemes. We demonstrate the acquisition of narrow strips of broadband homonuclear recoupling ¹³C-¹³C correlation spectra on a range of biomolecular and cellular samples, allowing targeted acquisition of high-resolution spectra of the region of interest with a significant reduction in the acquisition time. We also demonstrate the use of the spectral-band-selective method for allowing fast acquisition of RFDR build-up experiments. The band-selective method is easy to implement in any dipolar-based multidimensional pulse sequence by an addition of one pulse per band-selected indirect dimension and a slight modification of the phase cycle.