Synthesis, Structure, and Metalation of Two New Highly Porous Zirconium Metal–Organic Frameworks

Three new metal–organic frameworks [MOF-525, Zr6O4(OH)4(TCPP-H2)3; MOF-535,
Zr6O4(OH)4(XF)3; MOF-545,
Zr6O8(H2O)8(TCPP-H2)2, where porphyrin H4-TCPP-H2 = (C48H24O8N4) and cruciform
H4-XF = (C42O8H22)] based
on two new topologies, ftw and csq, have
been synthesized and structurally characterized. MOF-525 and -535
are composed of Zr6O4(OH)4 cuboctahedral
units linked by either porphyrin (MOF-525) or cruciform (MOF-535).
Another zirconium-containing unit, Zr6O8(H2O)8, is linked by porphyrin to give the MOF-545
structure. The structure of MOF-525 was obtained by analysis of powder
X-ray diffraction data. The structures of MOF-535 and -545 were resolved
from synchrotron single-crystal data. MOF-525, -535, and -545 have
Brunauer–Emmett–Teller surface areas of 2620, 1120,
and 2260 m2/g, respectively. In addition to their large
surface areas, both porphyrin-containing MOFs are exceptionally chemically
stable, maintaining their structures under aqueous and organic conditions.
MOF-525 and -545 were metalated with iron­(III) and copper­(II) to yield
the metalated analogues without losing their high surface area and
chemical stability.