Porphyrin based molecular turnstiles.

Molecular turnstiles, based on a hinge composed of a Sn-porphyrin bearing coordinating sites at the meso positions and a handle, equipped with a tridentate coordinating pole or its Pd(ii) complex, connected to the porphyrin through Sn-O bonds, offering open (free rotation of the handle around the hinge) and close states (blockage of rotation through binding of Pd(ii)) were designed, prepared and studied both in solution and in the solid state.