Multinuclear Solid-State Magnetic Resonance Study of In+ and Ag+ in Neutral Weakly Coordinating Environments

A comprehensive multinuclear solid-state magnetic resonance study of In(I)- and Ag(I)bis(imino)pyridine systems is presented. Solid-state 115In and 109Ag NMR experiments are utilized to probe the metal cation centers, which are very weakly coordinated to the bis(imino)pyridine ligands. Along with solid-state 15N NMR data, it is shown that the metal cations interact with the N atoms within the “pocket” of the ligands. Reasonable agreement between the measured and calculated 115In NMR (electric field gradient and chemical shift) tensors is obtained. The relationship between the electric field gradient tensor and the arrangement of the metal center relative to the encumbered ligand is explored. The insights obtained aid in understanding the structure and bonding in these kinetically stable complexes of unstable metal ions and may assist in the rational design of other encumbered ligands for capturing reactive species.