Chapter 4 - Jacobs University

Chapter 9
Unpublished Results
9.3.2 Synthesis of K 12 [{Zr(O 2 )(SiW 11 O 39 )} 2 ]·23H 2 O (21a)
A 0.644g (0.2 mmol) sample of K 8 [α-SiW 11 O 39 ]·14H 2 O was dissolved in 20 mL 1M KCH 3 COO
buffer solution (pH 4.8), and then 0.046g (0.2 mmol) of ZrCl 4 was added. During the reaction 5-
10 drops of 30% H 2 O 2 was introduced into the reaction mixture. The solution was heated to 80
o C for 30 min and filtered hot. Then, 6 drops of 1M NH 4 Cl were added. Slow evaporation at
room temperature led to the appearance of yellowish crystalline product within one day. The
evaporation was allowed to continue until the solution level approached the solid product which
was then collected by filtration and air dried. Yield: 0.48g (67.86%). IR: 1006 (sh), 963(s), 912
(s), 785(s), 717(sh), 522(m), 471(w) cm -1 .
55
50
45
40
35
%Transmittance
30
25
20
15
10
5
-0
1200
1100
1000
900
800
Wavenumbers (cm-1)
700
600
500
Figure 9.56 FTIR spectrum of 21a.
211