Cyclopalladated acetate dimers: Crystal structures and VT-NMR

The X-ray structure of two cyclopalladated acetate bridged dimers has been solved, and they are shown to exhibit an open-book type core, analogous to those that have been previously reported. Variable temperature NMR studies on these molecules demonstrates that this core persists in chloroform solution, resulting in restrictions to the movement of ancillary parts of the molecule. The barrier to rotation of a pendant phenyl ring against this core has been measured: ΔH‡ = 56 kJ mol−1, and ΔS‡ = 0.