Chemistry Reference
In-Depth Information
15.2.3
Introduction of Photofunctional Molecules
Three types of methods have been reported for the introduction of photofunctional
molecules into layered materials containing perfluoroalkyl groups. The first is the ion
exchange method, using the ions with both perfluoroalkyl groups and photo-functional
moiety such as C3F-azo
รพ
shown in Table 15.2. In this case the photofunctional molecules
are bonded to the layered materials by ionic bonding. The second one is the exfoliation-
restacking method. When neutral dye molecules are added to the nanosheet solution of
layered materials containing perfluoroalyl groups in organic solvents and the resulting
dispersion is cast on appropriate substrates, the exfoliated layers restack and the dye
molecules are included in the obtained film by hydrophobic interaction. When starting
from the aqueous dispersion of clay, by adding dye molecules in this dispersion, ion
exchange reaction, restacking of exfoliated layers and inclusion of dye molecules occur at
one time. The last one is the covalent attachment of dye molecules to silylated layered
materials containing perfluoroalkyl groups. The procedure is schematically illustrated in
Figure 15.4. An example of the above procedure is the covalent attachment of pyrene onto
the layers of [(C
6
F
13
C
2
H
4
Si(OH)
2
]
2.3
Si
14
O
29
shown in Table 15.2. This material contains
silanol groups originated from the hydrolysis of Si-Cl groups, which were not used for
silylation of magadiite layers. These silanol groups in this material were first silylated by
3-aminopropyltriethoxysilane, resulting in the introduction of amino groups. Then, an
active ester containing pyrene shown in Figure 15.5 (1-pyrenebutanoic acid succimidyl
ester), which selectively reacts with amino groups was added, resulting in the covalent
attachment of pyrene chromophores by amide bonding [58]. Physically adsorbed dyes onto
F
3
C
CF
2
F
3
C
F
2
C
CF
2
CF
2
H
2
N
O
F
2
C
F
2
C
F
3
C
HN
F
2
C
CF
2
H
2
N
CF
2
O
N
C
2
H
5
O
CF
2
CF
2
O
Si
C
2
H
5
O
O
F
2
C
C
2
H
5
O
Si
O
O
C
2
H
5
O
O
O
OH
Si
CF
2
C
2
H
5
O
Si
OH
F
2
C
Si
OC
2
H
5
O
CF
2
C
2
H
5
O
In N,N-dimethylformamide
Silylated layered materials
containing amino groups
Pyrene-attached silylated
layered material
HO
Si
OH
O
Toluene, reflux
Silylated layered materials
F
3
C
CF
2
F
2
C
CF
2
N
F
2
C
CF
2
C
2
H
5
O
Si
C
2
H
5
O
O
O
N
OH
Si
C
2
H
5
O
OC
2
H
5
Si
OC
2
H
5
Pyrene
-
attached silylated
layered materials
Figure 15.4 Schematic drawing for the procedures of covalent attachment of pyrene to
silylated magadiite containing perfluoalkyl groups. Adapted from Ref. 58
