Synthesis and charge transport properties of new methanofullerenes†
New methanofullerene derivatives have been synthesized and characterized for their electron transport properties. Two new methanofullerenes (PC61BP & HC61NP) have been synthesized by using our reported amine assisted cycloaddition reaction (AACA) method in good yield. PC61BM is also synthesized by using the AACA method for comparison of properties. PC61BP has phenyl group and butyric acid pentyl ester substituents on the C(61) bridging carbon of the cyclopropane ring on the fullerene. HC61NP has a completely different structure where the C(61) bridging carbon is bonded to a proton and a 2-nitro cinnamyl group. Both the products have been well characterized by FTIR, UV-vis absorption spectroscopy and NMR for their structures. Their electrochemical properties have been evaluated by cyclic voltammetry. Finally, the electron mobilities of the materials have been calculated at room temperature by preparing electron-only devices. PC61BP shows the highest mobility compared to HC61NP and PC61BM and proves to be a promising acceptor material for organic solar cells.