Coordination polymer nanocombs self-assembled at the water–chloroform interface

Abstract

We report the HgCl₂-mediated interfacial self-assembly of coordination polymer nanocombs composed of (zinc, palladium) tetrapyridylporphyrin and 4,4′-bipyridyl ligands. Scanning electron microscopic images revealed that lengths and widths of the core stems of the nanocombs were about 10 and 1 μm, respectively. Needle-like branches grew out perpendicularly from both sides of the core stems, with branch lengths of about 1–10 μm and diameters of about 0.1–15 μm. Both the X-ray photoelectron spectroscopic and energy dispersive X-ray spectroscopic measurements confirmed that the as-prepared nanocombs were composed of Hg, Cl, C and N elements. When the 4,4′-bipyridyl ligand was replaced by its derivatives, 2,2′-bipyridyl or 4,4′-trimethylenedipyridine, coordination polymer nanocombs could not be obtained. The results revealed that formation of such nanocombs was closely dependent on the structure of the bipyridyl, the mixed molar ratios of porphyrin and 4,4′-bipyridyl, as well as the interfacial reaction time.