Nanographene-based Metal-Organic Frameworks for Engineering Energy Transfer Pathways

Abstract

Nanographenes are a class of extended π-conjugated molecules with great potential in photophysical and electrochemical properties. However, most nanographenes show self-aggregation due to their strong π–π interaction, resulting in struc-tures barely possessing any open π surface. We find that metal-organic frameworks (MOFs) can be an ideal platform to construct periodic arrays and pores with isolated large π-conjugated surfaces by avoiding undesired π–π interaction be-tween the nanographene molecules. Here, we report a multivariate series of nanographene-based MOFs, UMOF-2-X, utiliz-ing the graphene-like hexatopic organic linkers, hexaphenylbenzene (HPB) and hexabenzocoronene (HBC) through a mixed-linker strategy. Interestingly, UMOF-2 shows effective energy transfer between HPB and HBC linkers while sup-pressing the occurrence of linker-to-metal charge transfer from the linker to Cu metal. We successfully describe the origin of these intriguing phenomena through computational studies.