Oxo Group Protonation and Silylation of Pentavalent Uranyl Pacman Complexes

Abstract

New bonds for the uranyl: The controlled conversion of an uranyl oxo group ([UO2]+) into covalently bonded UOH and UOSi groups is described for pentavalent uranyl Pacman complexes. The unusual oxo–hydroxy motif is achieved by a protonation reaction and retains the normally unstable UV uranyl oxidation state. This product is readily silylated by treatment with a chlorosilane resulting in UOSi bond formation (see scheme).

Axially Symmetric U−O−Ln‐ and U−O−U‐Containing Molecules from the Control of Uranyl Reduction with Simple f‐Block Halides

“…In agreement with the formal U V oxidation state, both the terminal U−O and Ln‐bridged U−O bonds are elongated with respect to uranyl dichloride, with lengths of 1.802(6) and 1.915(6) Å, respectively, in 1‐Sm . The Sm−O and Dy−O bond lengths in 1 are consistent with a single bond (2.331(6) Å in 1‐Sm ), but longer than those in our previously reported [U V O 2 ] + endo ‐oxo Ln‐metalated complex [{UO 2 Ln(py) 2 (L)} 2 ] C (Sm–O 2.234(2) Å; L=Pacman‐shaped pyrrole macrocycle) and exo ‐oxo M‐metalated complexes [{(X n M‐O)UO(THF)}(H 2 L)] (M=Li, K, Mg, Al, Zn, U, Np) . The average U−O bond length of 1.859 Å in 1‐Sm is longer than that of 1.838 Å in the coordination polymer {[UO 2 (py) 5 ][KI 2 (py) 2 ]} ∞ ( A )…”

Synthesis, Characterization, and Stoichiometric U–O Bond Scission in Uranyl Species Supported by Pyridine(diimine) Ligand Radicals

“…7 Following this, Arnold showed controlled silylation of a uranyl using a polypyrrolic Pacman ligand system, which serves to activate one end of the uranyl unit for functionalization to occur at the other. 5,8,9 More recently, Hayton extended reductive silylation chemistry to silanes, showing U−O silylation could be achieved in the presence of a Lewis acid, which activates the Si−H bond. 10−12 Uranyl reduction is generally thought to proceed through the pentavalent uranyl ion, [UO 2 ] + .…”

Controlling uranyl oxo group interactions to group 14 elements using polypyrrolic Schiff-base macrocyclic ligands

“…2,[6][7][8] Incorporation of two uranyl units into this ligand environment results in reduction to U V and oxo group rearrangement to form the homodinuclear 'butterfly' complex (Me 3 SiOU V ) 2 {µ-(O) 2 }L Me which contains bridging oxo groups and acute OUO angles. 2,[6][7][8] Incorporation of two uranyl units into this ligand environment results in reduction to U V and oxo group rearrangement to form the homodinuclear 'butterfly' complex (Me 3 SiOU V ) 2 {µ-(O) 2 }L Me which contains bridging oxo groups and acute OUO angles.…”