Bent metal carbene geometries in amido N-heterocyclic carbene complexes

Lithium(I) and uranium(VI) amido-tethered But-substituted N-heterocyclic carbene (NHC) complexes exhibit very distorted metal–carbene bonds; the corresponding magnesium(II) and mesityl-substituted NHC uranium(VI) complexes are undistorted; the distortion does not affect the ligand binding strength, suggesting a dominance of electrostatic character in closed-shell electropositive metal–carbene bonds.