One-Step Synthesis of an Adaptive Nanographene MOF: Adsorbed Gas-Dependent Geometrical Diversity

A layered
metal–organic framework (MOF) comprising extra-large
nanographene sheets, HBCMOF,
was successfully synthesized using a dicarboxylic acid derivative
of hexa-peri-hexabenzocoronene (HBCLH2), and its structure was characterized by single-crystal X-ray
diffraction analysis. The crystal structure shows that 2D layers composed
of a dinuclear Zn2+ complex unit and HBCL are
located on top of each other through multiple weak interlayer bonds,
affording HBCMOF, having three
dimensionally connected nanopores with large nanographene surfaces.
The HBC-based nanographene sheets are anchored to the MOF framework
via two zinc carboxylate linkages and therefore have an axial rotational
freedom. The sorption isotherms of gaseous molecules such as carbon
dioxide and hydrocarbons (acetylene, propane, propylene, benzene,
and cyclohexane) on HBCMOF all
displayed a hysteretic profile with reversible structural changes,
as observed by in situ powder X-ray diffraction studies.