Vanadium NMR of organovanadium complexes

A brief (and simplified) introduction into the background theory of NMR parameters (shielding, scalar coupling constants, and relaxation times) pertinent to the quadrupolar nucleus 51V is provided. General trends are discussed in the light of electronic and steric factors, medium effects, temperature and isotope effects influencing these parameters, in particular 51V shielding. Data are reported on vanadium complexes containing at least one vanadium-to-carbon bond, including alkyl, alkylidene and alkylidyne complexes, complexes containing η2- and η3-bonded ligands, carbonyl and isonitrile complexes, as well as η5-cyclopentadienyl and related vanadium compounds. DFT supported correlations between substituent effects and shielding, applicable to catalyst design, are included. The review focuses on solution NMR, but NMR in the crystalline solid state and in mesophases is also briefly addressed.