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Fig. 3.2 a
Synthesis of tetrakis-1,3,5,7-(4-phosphonatophenyl)adamantine.
b
,
c
Computer-
stimulated model of titanium tetraphosphonate material. Reprinted with permission from Ref. [
13
].
Copyright 2006, Wiley-VCH
mesopores of about 3.8 nm accompanied with a surface area of approximately
550 m
2
g
−
1
. Additional XRD data suggested a paracrystalline material; an opti-
mization of possible molecular arrangements was simulated that was in agreement
with the experimental data. Furthermore, mesoporous vanadium phosphonates
could also be obtained using the same method, exhibiting a BET surface area of
118 m
2
g
−
1
and a Barrett-Joyner-Halenda (BJH) pore diameter of 3.8-3.9 nm
[
14
]. FT-IR and XPS as well as elemental analysis suggested that the phosphonate
claw molecules were most likely connected in the form of ArP(O)O
2
V
2
O
2
(O)PAr,
which was effective for the aerobic oxidation of benzylic alcohol substrates.
[Mn
2
(pdtd)
2
(H
2
O)
4
]
n
5
n
H
2
O (pdtd
=
3-(2-pyridyl)-5,6-diphenyl-1,2,4-triazine-
4,4′-disulfonic acid) could be constructed by a solvothermal method preformed
at 140 °C with methanol as the solvent [
15
]. Crystallographic analysis revealed
acentric structure in which the Mn(II) centers are linked via sulfonate groups and
chelating nitrogen atoms within the pdtd ligands to give a rare non-interpenetrating
(10,3)-d framework with permanent helical cavities. As shown in Fig.
3.3
, five
pdtd ligands are linked by MnII ions to form a ten-membered nanoscale loop
(Mn1-Mn2: 9.1 Å; Mn1-Mn1C: 25.5 Å). The loops are further connected via edge-
sharing to form a 3D framework with large channels that run parallel to the
a
axis.
Disappointedly, studies concerning mesoporous metal sulfonates through the ligand
extending way have been scarce reported to the best of our knowledge. The una-
voidable constrainment is that the weak coordination of sulfonate functional groups
makes them difficult to maintain the permanent porosity and periodic crystallite
structures.
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