Probing organometallic structure and reactivity by transition metal NMR spectroscopy†

Transition metal NMR chemical shifts are readily measured by modern 1D and 2D pulse techniques and serve as a probe into electronic and steric effects of ligands and substituents in metal complexes. Quantitative correlations of metal chemical shifts with reaction rates and catalytic activities, both experimental and as a result of quantum chemical calculations, give new mechanistic insights and permit reactivity predictions and a screening of homogeneous catalysts. A variety of such examples involving the spin-1/2 nuclei 57Fe, 103Rh, and 187Os as well as the quadrupolar nuclei 51V, 53Cr, 55Mn, 59Co, and 91Zr are discussed.