Heterometallic Alkoxides - Alkoxo and Aryloxo Derivatives of Metals - page 186

Zr OPr i 4 . Pr i OH, 52 Nb OPr i 5 Ta OPr i 5 75 Al OPr i 3

and with excess yield 1:2

products only on volatilization, 52 , 74 irrespective of the excess of Al OPr i 3 taken

(Eqs 3.8 and 3.9).

Pr i OH
! Pr i O 2 Al -OPr i 2 Zr OPr i 2 -OPr i 2 Al OPr i 2
3 . 8

Zr OPr i 4 . Pr i OHC2Al OPr i 3

Pr i OH
! Pr i O 2 Al -OPr i 2 M OPr i 3 -OPr i 2 Al OPr i 2
3 . 9

M OPr i 5 C 2Al OPr i 3

where M D Nb or Ta.
The hafnium analogue of zirconium has been prepared 76 in the 1:2 molar reaction
between Hf OPr i 4 . Pr i OH and Al OPr i 3 , with its structure recently elucidated by X-ray
crystallography. 77
The products, [ Pr i O 2 ZrfAl OPr i 4 g 2 ]and[ Pr i O 3 MfAl Pr i O 4 g 2 ] are volatile and
monomeric in organic solvents. However, dimeric volatile products are obtained in
the 1:1 molar reactions of Al OPr i 3 with Zr OPr i 4 . Pr i OH, Nb OPr i 5 and Ta OPr i 5
(Eqs 3.10 and 3.11):

2Zr OPr i 4 . Pr i OH C 2Al OPr i 3 Pr i OH !f OPr i 2 Al -OPr i 2 Zr OPr i 2 -OPr i g 2

3 . 10
2M OPr i 5 C 2Al OPr i 3 !f Pr i O 2 Al -OPr i 2 M OPr i 3 -OPr i g 2
3 . 11

where M D Nb or Ta.
A few more illustrative examples of the synthesis of heterometal alkoxides by the
interactions of component alkoxides are represented by Eqs (3.12) - (3.23).

M OBu t 2 C M 0 OBu t ! M OBu t 3 M 0

3 . 12

where M D Ge( II ), Sn( II ), Pb( II ); M 0 D In, Tl. 54

2Sn OBu t 2 C M OBu t 2 ! MfSn OBu t 3 g 2

3 . 13

where M D Sr, Ba. 78

2Tl OR C M OR 4 ! Tl 2 M OR 6 3 . 14

M D Sn IV ;RD Et . 55 M D Zr; R D CH CF 3 2 . 79

Al OPr i 3 C 3Ga OPr i 3 ! AlfGa OPr i 4 g 3 73 3 . 15

Ga OPr i 3 C 3Al OPr i 3 ! GafAl OPr i 4 g 3 73 3 . 16

Mg OEt 2 C 2Sb OEt 3 ! 2 Mg 2 Sb 4 OEt 16 80 3 . 17