Solvent induced ordered-supramolecular assembly of highly branched protoporphyrin IX derivative

Abstract

Protoporphyrin IX species bearing highly branched alkyl chains were self-assembled into well-defined nanostructures such as rod-like in CHCl3–cylcohexane (1:9, v/v) and a honeycomb-like morphology in a polar solvent dimethyl sulfoxide (DMSO). The rod-like morphologies observed in the atomic force microscopy (AFM) and transmission electron microscopy (TEM) suggest that the lamellar phase self-organises into multilamellar vesicles. The X-ray diffraction (XRD) results indicate molecular arrangements resulting from longitudinal and transverse stacking of the porphyrin head groups in the lamellar structure. The typical nanostructures were derived from a high level of cooperativity between the porphyrin cores via π–σ interactions and supported by hydrogen bonding and van der Waals interactions. The nanostructures were characterised by means of UV–vis, fluorescence, AFM, TEM and XRD analysis. Our methodology confirms the potential of protoporphyrin IX derivatives in supramolecular chemistry.