and [W(CNMe)8] 5+ (Table ). The resulting calculated 𝑣 ̃(C≡N) vibrational frequencies of [W(CNMe)8] 4+/5+ are well in line with the experimental values while the values of the C-H vibrations show larger deviations from the calculations (Figure ). This is probably a consequence of strong hydrogen bonding to the anions in the solid state. increases). This can be explained by the decreased tendency for π -backbonding in case of higher oxidation state metal centers. Additionally, the electrostatic interaction between the lone pair of the isocyanide and the metal center further increases the C≡N bond strength. This is reflected by the fact that especially the high-valent complexes have higher 𝑣 ̃(C≡N) than free MeNC itself (IR 2166 cm -1 /Raman 2165 cm -1 ) and also slightly shortened C≡N bond lengths (1.167 Å in MeNC). this effect seems to be less pronounced for homoleptic alkyl isocyanide complexes due to their weaker π -acceptor properties. Table . Comparison of NMR shifts from cyanometalates and isonitrile complexes in ppm. C & 1 H relative to TMS in CDCl3 and N & 15 N relative to liquid NH3.