Unusually large ‘yaw’ angle upon coordination of a new bulky unsymmetrical 3-hydroxyadamantyl-functionalized N-heterocyclic carbene ligand to rhodium(i)

The facile synthesis of a new 3-hydroxyadamantyl-functionalized N-heterocyclic carbene (NHC) ligand and its corresponding rhodium complex [Rh(NHC)(COD)Cl] is described. This complex features an unusually large yaw distortion angle (θ=6.8°) for a monodentate NHC species, which is attributed to its unsymmetrical nature and the steric imbalance between its two wingtips. The comprehensive analysis of the yaw distortion angles in 85 related Rh species featuring various N-substituents is reported to support this hypothesis.