Chemistry Reference
In-Depth Information
2
NH
4
2
Ce
NO
3
6
C 13NaOBu
t
THF
! NaCe
2
OBu
t
9
C 4NH
3
C 12NaNO
3
C 4Bu
t
OH
3
.
38
The reaction of ZrCl
4
with KAl
OPr
i
4
in 1:2 molar ratio appears to proceed to the
formation of Cl
2
ZrfAl
OPr
i
4
g
2
, which on being treated with KOPr
i
(2 moles) yields
OPr
i
2
ZrfAl
OPr
i
4
g
2
(Eq. 3.39) which is also the end product of the reaction between
zirconium isopropoxide and excess of aluminium isopropoxide (Eq. 3.8).
Cl
2
Zr
OPr
i
2
C 2KAl
OPr
i
4
!
OPr
i
2
ZrfAl
OPr
i
4
g
2
C 2KCl #
3
.
39
Alkoxides of later 3d metals, Mn, Fe, Co, Ni, Cu, are generally polymeric insoluble
nonvolatile derivatives. However, a new dimension appears to have been added to the
alkoxide chemistry of these metals by the synthesis
97 - 100
of their monomeric soluble
tetraisopropoxoaluminates in reactions of the types shown in Eqs (3.40) and (3.41):
Pr
i
OH
!
C
6
H
6
MCl
2
C 2KAl
OPr
i
4
MfAl
OPr
i
4
g
2
C 2KCl #
3
.
40
where M D Mn,
101
Fe,
97
Co,
102
Ni,
42
Ga,
103
Cu,
104
Zn,
94
and
M
0
Cl
3
C 3KAl
OPr
i
4
! M
0
fAl
OPr
i
4
g
3
C 3KCl #
3
.
41
where M
0
D Cr,
105
Fe.
106
Stumpp and Hillebrand
107
also described the preparation of a number of other tetra-
alkoxoaluminates of Co, Ni and Cu, MfAl
OR
4
g
2
(R D Me, Et, Pr
i
), by a similar
procedure, and their spectroscopic properties.
Some MfAl
OBu
t
4
g
n
derivatives have been synthesized by the reactions of metal
chlorides with KAl
OBu
t
4
(prepared by treating Al
OBu
t
3
with 1 mole of KOBu
t
)
(Eq. 3.42):
MCl
2
C 2KAl
OBu
t
4
! MfAl
OBu
t
4
g
2
C 2KCl #
3
.
42
where M D Zn
,
108
Fe,
109
Co, Ni, Cu,
110
Mn.
101
Transition metal antimony ethoxides of the type M
2
Sb
4
OEt
16
(M D Mn, Ni) have
been prepared
111
,
112
from the corresponding metal chloride and NaSb
OEt
4
in 1:2
molar ratio (Eq. 3.43) and their structures have been confirmed
112
by X-ray crystal-
lography.
MCl
2
C 2NaSb
OEt
4
!
2
M
2
Sb
4
OEt
16
C 2NaCl #
3
.
43
Although X-ray structural confirmation has become available only since 1992,
39
,
53
OPr
i
Pr
i
O
Pr
i
O
the chelating behaviour of the moiety
Al
had usually been inferred from
OPr
i
chemical and other evidence for almost two decades
3
and the structural features of the
unit KAl
OPr
i
4
.
2Pr
i
OH, as elucidated
53
by X-ray crystallography in 1993, had been
correctly predicted as early as 1971.
3
,
5
In addition, the synthesis of a large number of similarly stable (as depicted by
volatility) and apparently covalent (as indicated by solubility with low conductivity
