Chemistry Reference
In-Depth Information
Fig. 4.8 a
Synthesis of functionalised CMPs using
i
DMF, NEt
3
, Pd(PPh
3
)
4
, CuI, 100 °C, 72 h;
b
nitrogen adsorption (closed)/desorption (open) isotherms (77 K) for CMP-1 (
black
), CMP-1-
(CH
3
)
2
(
green
), CMP-1-(OH)
2
(
orange
), CMP-1-NH
2
(
blue
) and CMP-1-COOH (
red
) each off-
set by 100 cm
3
g
−
1
for clarity;
c
surface areas and pore volumes for CMP networks. Reprinted
with permission from Ref. [
55
]. Copyright 2011, Royal Society of Chemistry
and 1 bar), despite exhibiting a higher surface area and pore volume. The dime-
thyl network, CMP-1-(CH
3
)
2
, showed the lowest uptake of CO
2
(0.94 mmol g
−
1
),
despite having higher surface area than CMP-1 (Fig.
4.8
c). In addition, the isos-
teric heat of adsorption (Qst) of gas molecules for porous materials is an important
indicator to assess the affinity of guest molecules to host materials. The carbox-
ylic acid functionalized network indicates the highest isosteric heat of sorption for
CO
2
, supporting recent computational predictions for metal-organic frameworks
that carboxylic acid group is favorable to enhance the interaction between porous
materials and CO
2
molecules. The result suggests that acid functionalized frame-
works could be widely studied in CO
2
capture and separation application.
4.4.2 Tuning the Inner Surface of POFs Using
Post-Modification Strategy
PAF-1 displays high BET surface area with a value of 5,600 m
2
g
−
1
, narrow pore
size distribution centered at 1.41 nm, high-thermal stability (decomposing temper-
ature up to 520 °C indicated by TGA, and high water stability. Therefore, PAF-1
is an excellent candidate as the starting materials for post-modification. Zhou
et al. reported two methods to tune the surface features of the PAF-1's wall. One
is the synthesis of sulfonate-grafted network (Fig.
4.9
a) and the other is the syn-
thesis of amine-grafted wall (Fig.
4.9
b) [
56
-
58
]. When the reaction occurs, the
