Dynamic NMR Study of the Hindered Pt−N(bipyridine) Rotation in Metal-Directed Self-Assembled Macrocycles

[reaction: see text] The activation parameters for the hindered Pt-N(bipyridyl) rotation observed for a self-assembled rectangle and triangle have been investigated by temperature-dependent and selective inversion recovery (SIR) NMR spectroscopy. The enthalpy of activation (DeltaH) and change in entropy (DeltaS) were determined to be +52.2 kJ/mol and -58.2 J/mol.K for the rectangle and +59.1 kJ/mol and -71.8 J/mol.K for the triangle, respectively, by SIR.