Synthesis, Structure,
and Metalation of Two New Highly
Porous Zirconium Metal–Organic Frameworks
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Abstract
Three new metal–organic frameworks [MOF-525, Zr<sub>6</sub>O<sub>4</sub>(OH)<sub>4</sub>(TCPP-H<sub>2</sub>)<sub>3</sub>; MOF-535,
Zr<sub>6</sub>O<sub>4</sub>(OH)<sub>4</sub>(XF)<sub>3</sub>; MOF-545,
Zr<sub>6</sub>O<sub>8</sub>(H<sub>2</sub>O)<sub>8</sub>(TCPP-H<sub>2</sub>)<sub>2</sub>, where porphyrin H<sub>4</sub>-TCPP-H<sub>2</sub> = (C<sub>48</sub>H<sub>24</sub>O<sub>8</sub>N<sub>4</sub>) and cruciform
H<sub>4</sub>-XF = (C<sub>42</sub>O<sub>8</sub>H<sub>22</sub>)] based
on two new topologies, <b>ftw</b> and <b>csq</b>, have
been synthesized and structurally characterized. MOF-525 and -535
are composed of Zr<sub>6</sub>O<sub>4</sub>(OH)<sub>4</sub> cuboctahedral
units linked by either porphyrin (MOF-525) or cruciform (MOF-535).
Another zirconium-containing unit, Zr<sub>6</sub>O<sub>8</sub>(H<sub>2</sub>O)<sub>8</sub>, 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 m<sup>2</sup>/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