University of delhi, India
pp. 180 - 183
Keywords: hexabenzocoronene, porphyrinoid, graphene, newer material
Polycyclic aromatic hydrocarbons are important building blocks for the construction of organic semiconducting materials. Functional hexa–peri-hexabenzocoronenes are important polycyclic hydrocarbons with D6h symmetrical structure containing 13 fused benzene rings and there are more than five strategies to synthesize functional hexa–peri-hexabenzocoronenes (HBCs). The HBCs are regarded as the smallest model for graphenes. The tunable band gap and large optical absorptivity of graphenes are desirable for efficient light harvesting in polycyclic aromatic hydrocarbon conjugated porphyrins. Recently we have used sulfonated graphenes as solid acids in the synthesis of 5-aryldipyrromethanes as the important precursors for the synthesis of 5,15-diarylporphyrins and examined the non-covalent interactions with pristine graphenes. Now we wish to report the synthesis of covalently linked polycyclic aromatic hydrocarbons, structure and their electronic properties in different reaction conditions. The reaction of 5-hexaphenyldipyrromethane and 4-tert-butylbenzaldehyde with pyrrole in dichloromethane followed by oxidation with DDQ gave 5,15-dihexaphenyl-10,15-di(4-tert-butylphenyl) porphyrin, which on further oxidation with FeCl3 in DCM gave HBC-porphyrin. The structure of above porphyrin was confirmed by UV-vis, 1H NMR and other spectroscopic data. The 5,15-HBC-porphodimethenes have been synthesized and used in the anion detection in different organic solvents.