Chapter 4 - Jacobs University

Chapter 6
U-peroxo-Polyoxometalate
We are currently investigating peroxo complexes with respect to their structural and
catalytic properties. 8 There is also interest in the uranium-peroxo system for uranium separation
chemistry. 9 Despite the importance of uranium-peroxide complexes, relatively little is known
about their structure and stability. In the early 1960s, Gurevich and coworkers isolated uraniumperoxide
compounds from alkaline solutions but structures have not been reported for these
materials. 10 Until recently, the only example of an inorganic uranium-peroxide reported was
Na 4 [UO 2 (O 2 ) 3 ]×9H 2 O, 11 but then Burns and coworkers reported on several interesting examples. 12
There are few well-characterized POMs containing uranium (VI) as the heteroatom. In
1999, Pope and co-workers reported the first sandwich-type uranium-POM complex
[Na 2 (UO 2 ) 2 (PW 9 O 34 ) 2 ] 12-, 13 and subsequently, several uranium containing Keggin and Wells-
Dawson polyanions were reported by Pope et al.: [Na 2 (UO 2 )(GeW 9 O 34 ) 2 ] 14- ,
[{Na(H 2 O)} 4 (UO 2 ) 4 (SiW 10 O 34 ) 4 ] 22- , [(UO 2 ) 3 (H 2 O) 6 As 3 W 30 O 104 ] 14- ,
[(UO 2 ) 3 (H 2 O) 4 As 3 W 29 O 104 ] 19− , [(UO 2 ) 12 (m 3 -O) 4 (m 2 -H 2 O) 12 (P 2 W 14 O 46 ) 4 ] 32- ,
[(UO 2 ) 2 (H 2 O) 2 (SbW 9 O 33 ) 2 ] 14- , [(UO 2 ) 2 (H 2 O) 2 (TeW 9 O 33 ) 2 ] 12- and [Na 2 As 2 W 18 U 2 O 72 ] 12- . 14
Recently, Xiaohong Wang and co-workers reported the uranium-containing tungstogermanates
[A-a-Na 2 (UO 2 ) 2 (GeW 9 O 34 ) 2 ] 14- and [A-b-Na 2 (UO 2 ) 2 (GeW 9 O 34 ) 2 ] 14-, 15 and in 2008 Alizadeh et
al. reported the uranium substituted tungstobismuthate [Na(UO 2 ) 2 (H 2 O) 4 (BiW 9 O 33 ) 2 ] 13- , 16 but
none of these uranium-substituted POM complexes contain peroxo-linkages.
Our group has been interested in the interaction of 3d and 4d transition metal ions,
lanthanides, and actinides with Tézé’s lacunary, wheel-shaped 48-tungsto-8-phosphate
[H 7 P 8 W 48 O 184 ] 33- (P 8 W 48 ) and its half unit [H 6 P 4 W 24 O 94 ] 18- (P 4 W 24 ) for some time. 17 Pope’s
group prepared the first lanthanide derivative
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