Uranium(IV) Thio‐ and Selenoether Complexes: Syntheses, Structures, and Computational Investigation of U−ER₂Interactions

Abstract

Figure 1. Uranium(III) and (IV) complexes bearing selenium-containing [N-

A Synthetic, Structural, Spectroscopic, and Computational Study of Alkali Metal–Thioether, −Selenoether, and −Telluroether Interactions

“…X-ray quality crystals of 3 ·2 toluene and 4 were obtained from toluene solutions layered with hexanes at −30 °C. Additionally, [K­(AS 2 Ph2 )­(dme)] x ( 5 ) and [K­(ASe 2 Ph2 )­(dme) 2 ] ( 6 ) were prepared by deprotonation of 1 and 2 using KCH 2 Ph, as previously reported, and X-ray quality crystals were obtained from dme solutions layered with hexanes at −30 °C.…”

“…)(dme) 2 ] (6) were prepared by deprotonation of 1 and 2 using KCH 2 Ph, as previously reported, 41 and X-ray quality crystals were obtained from dme solutions layered with hexanes at −30 °C.…”

“…) 2 UI 2 ], where an increase in uranium orbital involvement (from 9.9−14.4% in the former to 11.4−16.6% in the latter) was observed. 41 These trends are echoed in the M−E Mayer bond orders (Table 2), which are 0.26−0.27 and 0.28−0.29 in lithium compounds 3 and 4, respectively, 0.07−0.13 in potassium selenoether compounds 6 and 9*, and 0.07 or less in potassium selenoether structure 9* Constr and telluroether structures 10* and 10* Constr , suggestive of (a) increased covalency in the lithium compounds relative to the potassium compounds, and (b) marginally increased covalency in the Li−SeR 2 interactions in 4 relative to the Li−SR 2 interactions in 3. That said, the H b and δ M−E metrics do not follow the same trends, highlighting the challenges associated with probing small differences in covalency in highly ionic interactions.…”

“…24 Our group has previously employed rigid pincer ligands to prepare a range of organometallic and coordination complexes of electropositive actinide 26−33 and rare earth 34−40 elements. In addition, we recently reported the rigid thioether-and selenoether-containing ligands 4,5-bis(phenylsulfido)-2,7,9,9tetramethylacridan (H[AS 2 P h 2 ] (1)) and 4,5-bis-(phenylselenido)-2,7,9,9-tetramethylacridan (H[ASe 2Ph2 ] (2)), their deprotonation to generate the potassium salts, and subsequent reactivity with [UI 4 (1,4-dioxane) 41 The AE 2 Ph2 (E = S or Se) ligands harness the rigidity of the tricyclic acridanide ligand backbone and the positioning of the flanking chalcogenoether donors (with the direct attachment of the donor atoms to the anionic ligand backbone) to encourage κ 3 -SNS-or κ 3 -SeNSe-coordination to electropositive metal centers. Herein, we report the synthesis, solution characterization, and solid-state structures of lithium and potassium complexes of the AS ], and their potassium salts.…”

“…In addition, we recently reported the rigid thioether- and selenoether-containing ligands 4,5-bis­(phenylsulfido)-2,7,9,9-tetramethylacridan (H­[AS 2 Ph2 ] ( 1 )) and 4,5-bis­(phenylselenido)-2,7,9,9-tetramethylacridan (H­[ASe 2 Ph2 ] ( 2 )), their deprotonation to generate the potassium salts, and subsequent reactivity with [UI 4 (1,4-dioxane) 2 ] to afford [(AS 2 Ph2 ) 2 UI 2 ] and [(ASe 2 Ph2 ) 2 UI 2 ]. These uranium­(IV) complexes feature rare examples of uranium–thioether bonds and the first examples of structurally authenticated uranium–selenoether bonds, respectively …”