NMR Evidence for the Unprecedented Binding of a Naphthalene Group to Copper(I) in Solution

Variable-temperature one- and two-dimensional NMR experiments with [<BO>L</BO>Cu](PF<INF>6</INF>) (<BO>L</BO> = N-(2-(1-naphthyl)ethyl)-1-aza-4,8-dithiacyclodecane) reveal solution binding of the pendant naphthalene group, consistent with the η² binding found in the solid-state structure. The free energy for the barrier to the process that involves coordination/decoordination of the naphthalene group was estimated to be 12−13 kcal/mol.