Copper Benzene Tricarboxylate Metal–Organic Framework with Wide Permanent Mesopores Stabilized by Keggin Polyoxometallate Ions

Porous solids with organized multiple porosity are of
scientific
and technological importance for broadening the application range
from traditional areas of catalysis and adsorption/separation to drug
release and biomedical imaging. Synthesis of crystalline porous materials
offering a network of uniform micro- and mesopores remains a major
scientific challenge. One strategy is based on variation of synthesis
parameters of microporous networks, such as, for example, zeolites
or metal–organic frameworks (MOFs). Here, we show the rational
development of an hierarchical variant of the microporous cubic Cu3(BTC)2 (BTC = 1,3,5-benzenetricarboxylate) HKUST-1
MOF having strictly repetitive 5 nm wide mesopores separated by uniform
microporous walls in a single crystal structure. This new material
coined COK-15 (COK = Centrum voor Oppervlaktechemie en Katalyse) was
synthesized via a dual-templating approach. Stability was enhanced
by Keggin type phosphotungstate (HPW) systematically occluded in the
cavities constituting the walls between the mesopores.