A water soluble macromolecular nanobox having porphyrinic walls as a large host for giant guests

Cyclic tetra{5,15‐di‐p(ω‐methoxypolyethyleneoxy)phenyl]‐10,20‐p‐oxyphenyl] methylen porphyrin}, cy‐O‐(H₂‐PTPEG₂)‐O‐CH₂‐]₄ , a water soluble macromolecule consisting of four porphyrin units each with two long ω‐methoxypolyethyleneoxy (PEG) branches bound on its peripheral positions] linked by means of four methylenoxy bridges, was prepared by an interfacial etherification reaction. Structural and spectroscopic characterization of cy‐O‐(H₂‐PTPEG₂)‐O‐CH₂‐]₄ and of its cobalt‐derivative {cy‐O‐(Co‐PTPEG₂)‐O‐CH₂‐]₄} was performed by means of MALDI‐TOF mass spectrometry, NMR, UV–vis, and circular dichroism spectroscopy. The data obtained from the cy‐O‐(Co‐PTPEG₂)‐O‐CH₂‐]₄/Gramicidin‐S mixture showed that some evident spectral changes were compatible with the formation of a supramolecular structure between the porphyrinic nanobox and the Gramicidin S (a polypeptide having a relevant pharmacological importance). These preliminary data highlight how cy‐O‐(H₂‐PTPEG₂)‐O‐CH₂‐]₄ and/or its metalled derivatives, for their both chemical composition and structural arrangement, have promising properties for applications as a drug carrier in aqueous media. © 2013 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2013