Chemistry Reference
In-Depth Information
This appears to be due to steric factors, as the remaining chloride groups on the
products remain reactive and these can be replaced by -OR groups by reactions with
potassium alkoxide (KOR).
Partially substituted products, MCl
x
y
L
y
, have been reported by the reactions of
anhydrous chlorides of various metals with alkali alkoxometallates in suitable stoi-
chiometric ratios (Eqs 3.58 - 3.62):
benzene
!
isopropanol
MCl
2
C KAl
OPr
i
4
ClMfAl
OPr
i
4
gCKCl #
3
.
58
where M D Be, Mg, Zn, Cd.
94
benzene
!
-KCl
CdCl
2
C KZr
2
OPr
i
9
1
2
[fCdfZr
2
OPr
i
9
g
-Cl
g
2
]
135
3
.
59
CdI
2
C KZr
2
OPr
i
9
! ICdfZr
2
OPr
i
9
gCKI #
136
3
.
60
benzene
!
-2KCl
PrCl
3
.
3Pr
i
OH C 2KAl
OPr
i
4
[PrfAl
OPr
i
4
g
2
Pr
i
OH
-Cl
]
2
39
3
.
61
In
addition
to
the
above
structurally
characterized
halide
isopropoxometallate
derivatives,
a
large
number
of
derivatives
of
other
metals
have
been
isolated
by similar reactions: ClCofAl
OPr
i
4
g;
137
ClCofNb
OPr
i
6
g;
137
ClCofZr
2
OPr
i
9
g;
137
ClFefAl
OPr
i
4
g;
138
ClCufAl
OPr
i
4
g;
139
ClCufTa
OPr
i
6
g;
8
ClCufZr
2
OPr
i
9
g;
8
,
126
ClCufTi
2
OPr
i
9
g;
81
ClSnfZr
2
OPr
i
9
;
141
,
142
Cl
2
YfTi
2
OPr
i
9
g;
81
Cl
2
LafZr
2
OPr
i
9
g
143
and ClLafZr
2
OPr
i
9
g
2
.
143
Thus the general
method of synthesizing chloride alkoxometallate derivatives of different metals (M)
can be easily described by the following general reaction (Eq. 3.62) with
y
<
x
:
Cl
x
SnfZr
2
OPr
i
9
g
4
x
;
140
benzene
!
y
KCl
MCl
x
C
y
KL
MCl
x
y
L
y
3
.
62
where L D Al
OPr
i
4
,Nb
OPr
i
6
,Ta
OPr
i
6
,Zr
2
OPr
i
9
,Ti
2
OPr
i
9
,etc.
A variety of heterometallic chloride alkoxides have been synthesized by a reaction
144
of the type shown in Eq. (3.63):
3LiMe C 3Bu
t
3
COH C CrCl
3
ether - THF
! [Cr
OCBu
t
3
.
LiCl
.
2thf] C 2LiCl C 3CH
4
"
3
.
63
Similarly, an interaction of LiCl with Nd
OCBu
t
3
3
in THF (Eq. 3.64) yields
145
a
derivative [
thf
Li
-Cl
Nd
OCBu
t
3
3
]. which has been characterized by X-ray crys-
tallography:
THF
! [
thf
Li
-Cl
Nd
OCBu
t
3
3
]
.
LiCl C Nd
OCBu
t
3
3
3
.
64
Chlorides of bivalent metals like Mg, Zn, Sn(
II
) are insoluble in nonpolar solvents
like
n
-heptane/benzene, but their dissolution in solutions of tetraalkoxides of Ti and Zr
in such solvents readily yields heterometallic chloride alkoxide derivatives (Eqs 3.65
and 3.66):
