Solid-state covariance NMR spectroscopy: An update

Covariance NMR spectroscopy allows acquisition of spin-spin correlation in a more efficient way compared to the traditional two-dimensional Fourier-transformation NMR spectroscopy, leading to reduction in the experimental time or increase in the sensitivity of the spectrum obtainable within a given experimental time. This article is an updated version of a review on solid-state covariance NMR (Annual Reports on NMR Spectroscopy 84 (2015) 77), summarizing recent works on covariance NMR with a focus on its applications to solid-state NMR spectroscopy. The latest topics dealt with in this updated version include inner-product spectroscopy and T*(2) weighted deconvolution (TIDE). The usefulness of covariance NMR spectroscopy is presented by exploring its applications to solid-state systems of chemical/biological interest. A number of recent reports to further improve its efficiency or to extend the scope of its applicability are reviewed.