Noncovalent metal-ligand bond energies as studied by threshold collision-induced dissociation

This review focuses on noncovalent metal ion-ligand complexes and measurements of the bond energies of such species. The method utilized in this work is threshold collision-induced dissociation (CID), as achieved using a guided ion beam tandem mass spectrometer. Accurate determination of bond energies requires attention to many details of the experiments and data analysis. These details are discussed thoroughly and compared to other methods. A comprehensive listing of metal-ligand bond dissociation energies determined by threshold CID is provided. This list includes a variety of metals (alkalis, magnesium, aluminum, and first and second row transition metals), many different types of ligands, and variations in the number of ligands. The trends in these values are discussed, and we elucidate the importance of ion-dipole and ion-induced dipole interactions, chelation, different conformers and tautomers, steric interactions, solvation phenomena, and electronic effects such as hybridization and promotion.