Today a new paper was published in Dalton Transactions on metathesis catalysts to rationalise the structural, electronic and spectroscopic properties of Mo and W imido olefin metathesis catalysts by using either simplified or actual ligands of the experimental complexes. A. Poater, X. Solans-Monfort, E. Clot, C. Copéret, and O. Eisenstein “DFT calculations of d0 M(NR)(CHtBu)(X)(Y) (M =