Ligand binding energies in cationic platinum(II) complexes: A quantitative study in the gas phase

Quantitative energy-resolved reactive cross-section measurements and DFT calculations are used to investigate the binding energies of various ligands to the metal center in cationic Pt(II) diimine complexes involved in C-H activation reactions. Independent synthesis of isomeric ions establishes the structure of the adducts formed in gas-phase reactions. The order and relative magnitude of a series of ligand binding energies extracted from experimental cross-sections reproduce the trends seen in solution-phase experiments only when the proper transition state model is employed in the deconvolution of the experimental cross-sections. The choice of transition state model can be rationalized by qualitative structural arguments as well as quantum chemical calculations of the reaction coordinate for the dissociation of the range of possible ligands.