Unveiling Energy Transfer Mechanisms in Nanographene-Incorporated Metal–Organic Frameworks

Nanographenes are a class of extended π-conjugated
molecules
with great potential for photophysical and electrochemical properties.
However, most nanographenes show self-aggregation due to their strong
π–π interaction, resulting in structures 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 interactions between the nanographene
molecules. Here, we report a multivariate series of nanographene-incorporated
MOFs, UMOF-2-X, utilizing the graphene-like hexatopic
organic linkers, hexaphenylethynylbenzene (HPB) and hexabenzocoronene
(HBC), through a mixed-linker strategy. Remarkably, UMOF-2 inhibits
the occurrence of linker-to-metal charge transfer to Cu metal and
shows efficient energy transfer between HPB and HBC linkers.