Tuning the morphology of self-assembled nanostructures of amphiphilic tetra(p-hydroxyphenyl)porphyrins with hydrogen bonding and metal–ligand coordination bonding

Abstract

Typical amphiphilic metal-free tetrakis(4-hydroxyphenyl)porphyrin H₂THPP (1) and tetrakis(4-hydroxyphenyl)porphyrinato copper complex CuTHPP (2) were fabricated into organic nanostructures by a phase-transfer method. Their self-assembly properties in aqueous solution have been comparatively studied with those of tetra(phenyl)porphyrin H₂TPP (3) by electronic absorption and Fourier transform infrared (FT-IR) spectroscopy, transmission electronic microscopy (TEM), scanning electronic microscopy (SEM), and X-ray diffraction (XRD) techniques. Experimental results reveal different molecular packing models in these aggregates, which in turn result in self-assembled nanostructures with different morphologies from nano-scale hollow spheres for 1, nanoribbons for 2, to nanobelts for 3. The present study, representing part of our continuous efforts towards understanding the relationship between synergistic interplay among noncovalent interactions such as the π–π interaction, metal–ligand coordination bonding, and hydrogen bonding in controlling and tuning the morphology of self-assembled nanostructures of tetrapyrrole derivatives, will provide information helpful for preparing self-assembled nanostructures with controlled molecular packing conformations and morphologies through molecular modification.