Coordination and Bond Activation in Complexes of Regioisomeric Phenylpyridines with the Nickel(II) Chloride Cation in the Gas Phase

Electrospray ionization of dilute solutions of phenylpyridines (phpy) in the presence of nickel(II) chloride leads to gaseous ions of the type [Ni(phpy)m]2+ with m = 3–5 and [NiCl(phpy)n]+ with n = 1–3, which are characterized by various gas-phase experiments in combination with calculations using density functional theory. Of the regioisomeric phpy's, 2-phpy behaves drastically different compared to 3- and 4-phpy. Ion mobility mass spectrometry allows a differentiation of the gaseous ions and an elucidation of characteristic properties of the metal complexes. For 2-phpy, C–H bond activation in the [NiCl(phpy)2]+ complex is significant, whereas this route is almost suppressed for the corresponding complexes of 3- and 4-phpy and only occurs at elevated energies.