Synthèse et étude cristallographique d’un nouveau composé de coordination asymétrique de l'uranium(IV) lié à deux ligands du type polytungstate [(H3SbIIIW17O59)UIV(HW5O18)]11–

Abstract

L'hétéropolytungstate [(H 3 Sb III W 17 O 59 )U IV (HW 5 O 18 )] 11a été préparé à partir de tungstate de sodium et, soit de fluorure, soit de chlorure d'uranium(IV). L'étude cristallographique montre que l'atome central d'uranium(IV) est au centre d'un antiprisme d'Archimède. Il est coordonné par quatre atomes d'oxygène à un ligand H 3 Sb III W 17 O 59 et par quatre autres atomes d'oxygène à un ligand HW 5 O 18 . La maille élémentaire est triclinique centrée :

Uranyl-silicotungstate-containing hybrid building units {α-SiW9} and {γ-SiW10} with excellent catalytic activities in the three-component synthesis of dihydropyrimidin-2(1H)-ones

“…S1 †). The bond lengths of three inner polar oxygen atoms and the corresponding U(VI) atoms (O1 for U1, O3 for U2, and O5 for U3) are in the range of 1.795 (18) to 1.811(17) Å, which are slightly longer than the typical OvUvO bonds (1.75-1.79 Å), while the outside polar oxygen atoms (O2 for U1, O4 for U2 and O6 for U3) show normal UvO bond lengths (1.736( 16) Å for O2-U1, 1.794(18) Å for O4-U2 and 1.781 (17) for O6-U3). The bond angles for OvUvO bonds are also distorted compared with a standard uranyl ion (178.048 (13)°for U1, 179.418 (10)°for U2 and 178.997 (11)°for U3).…”

“…24 The third showed an iso-heteropolytungstate hybrid structure, [(H 3 Sb III W 17 O 59 )U IV (HW 5 O 18 )] 11− , which was in situ constructed from simple materials with monovacant Lindqvist-{W 5 } and monovacant Dawson-{SbW 17 } building units. 18 Recently, Zhang's and our group have reported the fourth hybrid U-POW, K 1.5 Na 13.25 [(UO 2 ) 3 (SeO 3 ) 3 Na 5 (H 2 O) 6 (SeW 6 O 21 )(SeW 9 O 33 ) 3 ]·26H 2 O, which was in situ synthesized with one Anderson-{SeW 6 } and three Keggin-{SeW 9 } building units. 22…”

“…But it is disappointing to note that less than ten cases were in situ synthesized and dozens of U-POWs were all synthesized using lacunary POM precursors among these U-POWs. [17][18][19][20][21][22] Thus, the knowledge of the structural diversities of actinide-containing POMs still needs exploitation.…”

Recent advances in uranium-containing polyoxometalates

“…The third one is an iso-heteropolytungstate, [(H 3 SbW 17 O 59 )U IV (HW 5 O 18 )] 11− , which was constructed from a monovacant Lindqvist-{W 5 } and a monovacant Dawson-{Sb III W 17 }. 61 Significantly, this compound was synthesized from simple materials and is the first case of an in situ synthesized U-POM as far as we know.…”

Trends and new directions in the crystal chemistry of actinide oxo-clusters incorporated in polyoxometalates

“…To our knowledge, there are only two iso-heteropolytungstate hybrid systems incorporating uranium(IV) cations. 37,38 . The first one was synthesized in an aqueous solution at pH 4-4.…”