Organic Nanostructures with Controllable Morphology Fabricated from Ferrocene-Porphyrin Derivatives: Effect of Metal-Ligand Coordination on the Morphology, Dimensions, and Semiconductor Properties of Self-Assembled Nanostructures

Two new ferrocene-porphyrin derivatives, namely 5,15-bis(ferrocenyl)-10,20-bis(4-nitrophenyl)porphyrin (1) and its nickel congener 5,15-bis(ferrocenyl)- 10,20-bis(4-nitrophenyl)porphyrinatonickel (2) have been designed, synthesized, and characterized. Their self-assembly properties have been comparatively studied by electronic absorption and FTIR spectroscopy, TEM, SEM, XRD, and X-ray photoelectron spectroscopy (XPS). Metal-free 1 self-assembles into nanospheres with diameters in the range of 30-50 nm, de-pending mainly on intermolecular pi-pi interactions. In contrast, the coordination of nickel to 1 introduces an additional Ni-O coordination bond between the nitryl group of one molecule of 2 and the nickel center of the neighboring 2 unit, which, in cooperation with the intermolecular pi-pi interaction, induces the formation of nanobelts (ca. 50-300 mu m length, 10-50 nm width) during the self-assembly process of 2.