Oxo–Group‐14‐Element Bond Formation in Binuclear Uranium(V) Pacman Complexes

Abstract

Simple and versatile routes to the functionalization of uranyl-derived U(V)-oxo groups are presented. The oxo-lithiated, binuclear uranium(V)-oxo complexes [{(py)3LiOUO}2(L)] and [{(py)3LiOUO}(OUOSiMe3)(L)] were prepared by the direct combination of the uranyl(VI) silylamide "ate" complex [Li(py)2][(OUO)(N")3] (N" = N(SiMe3)2) with the polypyrrolic macrocycle H4L or the mononuclear uranyl (VI) Pacman complex [UO2(py)(H2L)], respectively. These oxo-metalated complexes display distinct U-O single and multiple bonding patterns and an axial/equatorial arrangement of oxo ligands. Their ready availability allows the direct functionalization of the uranyl oxo group leading to the binuclear uranium(V) oxo-stannylated complexes [{(R3Sn)OUO}2(L)] (R = nBu, Ph), which represent rare examples of mixed uranium/tin complexes. Also, uranium-oxo-group exchange occurred in reactions with [TiCl(OiPr)3] to form U-O-C bonds [{(py)3LiOUO}(OUOiPr)(L)] and [(iPrOUO)2(L)]. Overall, these represent the first family of uranium(V) complexes that are oxo-functionalised by Group 14 elements.

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

“…5 8 4 , 2 . 6 1 5 Å ) 2 32 The U−N bonds of 2.504(6), 2.529(6), and 2.547(6) Å for the pyridine(diimine) ligands are much longer than those in 1, supporting three dative bonding interactions. 18 However, ligand reduction is apparent by examining the intraligand distances for the pyridine ring.…”

Oxo Ligand Substitution in a Cationic Uranyl Complex: Synergistic Interaction of an Electrophile and a Reductant

“…[2][3][4][5][6][7] For example, Arnold and co-workers demonstrated that sequential reaction of U VI O 2 (THF)(H 2 L) (L = polypyrrolic macrocycle) with KN(SiMe 3 ) 2 and FeI 2 resulted in formation of the U(V) silyloxide, [U V O(OSiMe 3 )(THF)Fe 2 I 2 L]. 7 Similarly, our research group has demonstrated that reaction of U VI O 2 ( Ar acnac) 2 ( Ar acnac = ArNC(Ph)CHC(Ph)O, Ar = 3,5-t Bu 2 C 6 H 3 ), 8 with a mixture of B(C 6 F 5 ) 3 and HSiR 3 (R = Ph, Et), 9,10 or with Ph 3 SiOTf alone, 11 results in formation of the reductive silylation products, U V (OSiR 3 )(OB{C 6 11 respectively. In contrast to these oxo functionalization reactions, examples of complete oxo substitution remain rare.…”

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

“…Two seminal, coincident reports of the potassium‐reduced coordination polymer {[UO 2 (py) 5 ][KI 2 (py) 2 ]} ∞ ( A ) showed that anaerobic uranyl(V) complexes are stable against disproportionation; since then, significant advances have been made in isolating uranyl(V) complexes. The reductive oxo functionalization with Group 1, Group 2, d‐block, rare‐earth, actinide, and main‐group metals as well as silicon is also possible. The linearity of the f 1 uranyl also provides a rare opportunity in f‐block chemistry to control the orientation of the magnetic vector, and uranyl(V)/transition‐metal single‐molecule magnets have been made through this oxo‐bridging strategy .…”