2 Homometallic Alkoxides

190 Alkoxo and Aryloxo Derivatives of Metals
Mg2Al3⊲OPr i ⊳13 can also be prepared in good yield by the reaction of Mg and Al⊲OPr i ⊳3
in 2:3 molar ratio in isopropanol (Eq. 3.29):
2Mg C 3Al⊲OPr i ⊳3 C 4Pr i OH ! Mg2Al3⊲OPr i ⊳13 ⊲3.29⊳
Recently, the reactions of Ba and Ca with Al⊲OPr i ⊳3 in 1:3 and 2:3 reactions have
been found to yield 91 corresponding products as represented by Eqs (3.30) and (3.31).
M C 3Al⊲OPr i ⊳3 C 2Pr i OH ! MAl3⊲OPr i ⊳11 C H2 " ⊲3.30⊳
2M C 3Al⊲OPr i ⊳3 C 4Pr i OH ! M2Al3⊲OPr i ⊳13 C 2H2 " ⊲3.31⊳
2.1.3 Reactions of Metal Halides (Nitrate) with Alkali Alkoxometallates (C)
Albers et al. 30 investigated this route for the preparation of uranium(IV) tetraisopropoxoaluminate
by reacting uranium tetrachloride with a gel of sodium tetraisopropoxoaluminate
in isopropanol (Eq. 3.32):
UCl4 C 4NafAl⊲OPr i ⊳4g ! UfAl⊲OPr i ⊳4g4 C 4NaCl # ⊲3.32⊳
The greater solubility of KAl⊲OPr i ⊳4/KGa⊲OPr i ⊳4 92 in isopropanol as compared to
their sodium analogues was used to advantage by Mehrotra and co-workers for the
synthesis of a variety of heterometal isopropoxides of Al (and Ga) with lanthanons, 71,72
In, 69,73 Th, 74 Sn(IV), 93 Be, Zn, Cd, Hg(II), 94 and Sn(II) 95 (Eqs 3.33–3.35):
MCl3 C 3KAl⊲OPr i ⊳4 ! MfAl⊲OPr i ⊳4g3 C 3KCl # ⊲3.33⊳
where M D La,Pr,Nd,Sm,Gd,Ho,Er,Yb,Lu,Sc,Y,In.
ThCl4 C 4KAl⊲OPr i ⊳4 ! ThfAl⊲OPr i ⊳4g4 C 4KCl # ⊲3.34⊳
MCl2 C 2KAl⊲OPr i ⊳4 ! MfAl⊲OPr i ⊳4g2 C 2KCl # ⊲3.35⊳
where M D Be, Zn, Cd, Hg(II), Sn(II).
Although ThfAl⊲OPr i ⊳4g4 could be isolated by the 1:4 molar reaction of ThCl4
with KAl⊲OPr i ⊳4, a similar reaction between CeCl4 and KAl⊲OPr i ⊳4 was precluded
by the instability of CeCl4. It might be worth investigating the possible synthesis
of CefAl⊲OPr i ⊳4g4 by the reaction of ⊲NH4⊳2Ce⊲NO3⊳6 or ⊲C5H5NH⊳2CeCl6 with
KAl⊲OPr i ⊳4 in 1:4 molar ratio (cf. the preparation 96 of Ce⊲OBu t ⊳4 and NaCe2⊲OBu t ⊳9
by the reaction between ⊲NH4⊳2Ce⊲NO3⊳6 and NaOBu t in appropriate molar ratios
(Eqs 3.36–3.38)):
⊲NH4⊳2Ce⊲NO3⊳6 C 6NaOBu t
THF
! Ce⊲OBu t ⊳4.⊲thf⊳2 C 2NH3 C 6NaNO3 C 2Bu t OH ⊲3.36⊳
⊲NH4⊳2Ce⊲NO3⊳6 C 8NaOBu t
THF
! Na2Ce⊲OBu t ⊳6⊲thf⊳4 C 2NH3 C 6NaNO3 C 2Bu t OH ⊲3.37⊳