Solution and solid-state nuclear magnetic resonance studies on interstitial atoms within transition-metal carbonyl clusters

The bonding of the interstitial atoms (C and N) within the metal skeleton in a series of transition-metal carbonyl clusters has been investigated by NMR studies of the shielding anisotropy and asymmetry in solution and in the solid state. Observed shielding anisotropies suggest that the hybridisation of the interstitial atom is dependent on the metal geometry and tends towards sp in an octahedral, sp2 in a trigonal-prismatic and sp3 in a square-antiprismatic metal skeleton.