Chapter 4 - Jacobs University

Chapter 9
Unpublished Results
9.3.6 Synthesis of K 8 Rb 4 [{Hf(O 2 )(SiW 11 O 39 )} 2 ]·20H 2 O(25a)
A sample of K 8 [α-SiW 11 O 39 ]·14H 2 O (0.644 g, 0.2 mmol) was dissolved in 1M KCH 3 COO buffer
solution (20 mL) at pH 4.8 then ZrCl 4 (0.0641 g, 0.2 mmol) was added. During the reaction 5-10
drops of 30% H 2 O 2 was added to the solution. Then the solution was heated to 80 °C for 30min
and filtered in hot. The resulting solution was layered with 6 drops of 1M RbCl. The filtrate was
allowed to evaporate in an open vial at room temperature. After one day, yellowish crystalline
product started to appear. After that, the evaporation was allowed to continue until the solution
level approached the solid product which was then collected by filtration and air dried. Yield:
0.46g (65.94%). IR: 1007 (sh), 962(s), 912 (s), 786(s), 728(sh), 673(sh), 521(m), 474(w) cm -1 .
65
60
55
50
%Transmittance
45
40
35
30
25
20
15
10
1200
1100
1000
900
800
Wavenumbers (cm-1)
700
600
500
Figure 9.70 FTIR spectrum of 25a.
225