2 Homometallic Alkoxides

O
M
R
M
OR
M OR
RO M
(M = Tl; R = Me;
M = Na; R = Bu
(a)
t )
R
O
RO M M OR
O
R
(M = Li; R = CBut 3;
M = Al, Sn; R = Bu
(d)
t )
RO
RO
R
O
M M
O
R
OR
OR
(M = Al, Ga; R = But )
(f)
RO
RO
H
R
O
OR
OR
M M
RO
RO
O
R
H
OR
OR
(M = Zr, Hf, Ce, Sn; R = Pr i )
(h)
R
O
M M
RO OR
M M
O
R
(M = Cu; R = But )
RO
RO
RO
RO
(b)
M
RO
(M = Al; R = Pr i )
R
O
M
O
R
Homometallic Alkoxides 53
R
O
M M
O
R
R
O
OR
M
R RO
O OR
O
R
M
RO
OR
M
RO OR
(e)
RO O
M
RO
O
M
M
O
O
O
R
R
R
O
OR
RO
OR
M
OR
RO
R
O
O
OR
R R
R
R
(M = Ti, V, W; R = Et)
(g)
R
O
O
R
R
O
M
OR
O OR
R
(M = Nb; R = Me, Pri ;
M = U; R = Pr
(i)
i )
R
O
O
R
(M = Be; Pb; R = Bu t )
(c)
RO
R
O
M
OR
RO
O
R
OR
M OR
(M = W, R = Me)
Figure 2.1 Some structural types adopted by homometallic alkoxides.
expected degrees of molecular association for alkoxides of metals and metalloids in
different oxidation states, coordination numbers, and geometries (Table 2.3).
The main factors influencing the adoption of one structural type in preference to
another 8 are: (i) the empirical formula M(OR)x, (ii) the size and formal oxidation state
of the metal atoms, (iii) the steric demand of the alkyl (R) group, and (iv) the d n
(j)