Chemistry Reference
In-Depth Information
still limited to a few examples mostly demonstrated by means of surface
science, and the predictive approach, based on molecular concepts, is rare.
The concept of surface organometallic chemistry has been developed as a
possible answer to this problem. Its main objective is the creation on a
support (which can be an oxide, a clay, a polymer etc.), of organometallic
fragments which will be well-defined and uniform along the entire surface.
These species will be characterized by all available physico-chemical meth-
ods in order to have a description of the coordination sphere around the
metal as precise as possible, as for homogeneous complexes. This strategy,
initially proposed by the group of J. M. Basset, has also been developed by
other groups (see Table 1.1 for some examples) and has been the subject of
numerous reviews and topics.
1-9
In most cases the support was silica (flame
d
n
9
r
4
n
g
|
1
Table 1.1
Some examples of grafting reactions of organometallic complexes on
various supports by use of surface organometallic chemistry.
Metal
Organometallic species/catalytic reaction
Ref.
Aluminium
Al(OiPr)
3
on mesoporous silicas
13
Calcium
Ca[N(SiMe
3
)
2
]
2
2THF on silica
14
Vanadium
V(
¼
NtBu)(CH
2
tBu)
3
on silica
15
Chromium
CrO
2
Cl
2
on silica/model of Phillips polymerization
catalyst
16
Cr(CH
2
tBu)
4
on silica
17
.
Cobalt
Co[N(SiMe
3
)
2
]
2
on mesoporous silicas
13
Nickel
Ni(MeCN)
6
(BF
4
)
2
on silica and MCM-41/propene
dimerization; ethylene oligomerization
18-20
Zinc
Zn[(S,S)-iPr-pybox](Et)
2
on silica
21
Zn[N(SiMe
3
)
2
]
2
on mesoporous silicas
13
Zirconium
Zr(CH
2
tBu)
4
on amino-modified SBA-15
10
Molybdenum
Mo(
¼
N)(NR
2
)(OR)
2
(pyr) on silica
22
Mo(
¼
CHCMe
2
Ph)(
¼
NAr)(OR)
2
on silica
23
Ruthenium
Ru(COD)(COT) on SiH groups of modified silica
(COT
¼
cyclooctatetraene)
11
Tantalum
Ta(
¼
NtBu)(CH
2
CMe
2
Ph)
3
on silica/oxo/imido
heterometathesis
24
Tungsten
WMe
6
on silica
25
(ArO)
2
W(
¼
O)(
¼
CHtBu) on silica/alkene metathesis
26
W
2
(NMe
2
)
6
on silica
27
Rhenium
CH
3
ReO
3
on silica-alumina/olefin metathesis
28
[Re(CO)
3
OH]
4
on silica
29
Iridium
Ir
4
(CO)
12
on silica
30
Platinum
Pt(COD) complexes on silica (COD
¼
cyclooctadiene)
31
Lanthanum
La(CH(PPh
2
NSiMe
3
)
2
)(N(SiHMe
2
)
2
)
2
on silica
32,33
Neodymium
Nd(BH
4
)
3
(THF)
3
on silica/MMA and butyrolactones
polymerization
34
Nd(NR
2
)
3
on silica/isoprene and butyrolactone
polymerization
35
Cerium
[Ce(OiPr)
3
N(SiMe
3
)
2
]
2
on MCM-41
36
Rare earths
(Y, La, Nd, Sm)
Ln[N(SiMe
3
)
2
]
3
on silica
37-39
Gadolinium
Gd[N(SiHMe
2
)
2
]
3
(THF)
2
on mesoporous silica
40
Search WWH ::
Custom Search