Separation of the host-guest system for ferrocene derivatives in octahedral nanocages by electrochemical ionization

Abstract An octahedral nanosized M6L4 cage complex is assembled from six 90° Pd(II) compounds [Pd(phen)(NO3)2, phen=1,10-phenanthroline)] and four 120° trident ligands [2,4,6-tri(4-pyridyl)-1,3,5-triazine]. The size of the cage complex is verified by TEM image and electronic structure calculation. The cage complex can act as a host container that allows the encapsulation of suitable sized guest molecules, such as electroactive molecules (one is water-soluble, ferrocene methanol) and (the other is water-insoluble, ferrocene glycine ethyl ester). The host-guest complexes are characterized by NMR, IR, UV and electrochemical studies. Interestingly, under a 1.0 V electro-stimuli oxidation voltage, guest molecules encapsulated in the cage cavity are expelled upon oxidation (from neutral to monocations) respectively, which can evade from the cage cavity through controlling the reduction/oxidation state of small guest molecules.