Two types of molecular brakes based on two Zn–porphyrin units interconnected by a spacer are described. Their dynamic behaviour in solution at room temperature was studied by UV-Vis spectroscopy. In ...the absence of an external effector, the brake undergoes free rotation, whereas in the presence of an external effector, the rotational process may be hindered. The locking/unlocking processes are shown to be reversible.
A new cationic molecular turnstile based on a P(V) porphyrin backbone bearing two pyridyl interaction sites, one at the meso position of the porphyrin and the other on the handle connected to the ...porphyrin through P–O bonds, was designed and synthesized. The dynamic behavior of the turnstile 2, investigated by 1D and 2D 1H NMR techniques, showed that in the absence of an effector, the turnstile is in its open state and undergoes a free rotation of the rotor (the handle) around the stator (the porphyrin backbone). In the presence of an external effector such as Ag+ cation or H+, the turnstile is switched to its closed states 2-Ag+ and 2-H+, respectively. The locking/unlocking process is reversible and may be achieved by precipitation of AgBr upon addition of Et4NBr in the case of the silver-locked turnstile or by addition of Et3N in the case of the proton-locked turnstile.
Two types of molecular brakes based on two Zn-porphyrin units interconnected by a spacer are described. Their dynamic behaviour in solution at room temperature was studied by UV-Vis spectroscopy. In ...the absence of an external effector, the brake undergoes free rotation, whereas in the presence of an external effector, the rotational process may be hindered. The locking/unlocking processes are shown to be reversible.
The rotational movement of molecular brakes based on two Zn-porphyrin units interconnected by a spacer may be reversibly locked by addition of an external auxiliary ligand.
The combination of silver nitrate with a thiacalix4arene derivative bearing at the lower rim four benzonitrile groups leads in the crystalline phase to the formation of a 3-D coordination network in ...which the organic tectons are connected by decanuclear silver nanoclusters.
Two new p-tert-butylthiacalix4arene derivatives 2 and 3 decorated at the lower rim with four nitrile groups have been prepared and structurally characterised in the crystalline phase. The two ...ligands, differing by the length of the spacer between the calix moiety and the nitrile group, adopt the 1,3-alternate conformation in the solid state. The ligand 3 bearing four (CH(2))(3)CN fragments behaves as a tecton in the presence of silver salts (AgX, X = BF(4), PF(6) or SbF(6)) and leads to the formation of analogous 1-D linear coordination networks. The tecton 3 acts as a bischelate unit and bridges consecutive silver cations adopting a tetrahedral coordination geometry. Anions and solvent molecules occupy the free space between networks and exhibit no specific interactions with the cationic architecture.
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