Isolation and characterization of a uranium(VI)–nitride triple bond

Abstract

The nature and extent of covalency in uranium bonding is still unclear compared with that of transition metals, and there is great interest in studying uranium-ligand multiple bonds. Although U=O and U=NR double bonds (where R is an alkyl group) are well-known analogues to transition-metal oxo and imido complexes, the uranium(VI)-nitride triple bond has long remained a synthetic target in actinide chemistry. Here, we report the preparation of a uranium(VI)-nitride triple bond. We highlight the importance of (1) ancillary ligand design, (2) employing mild redox reactions instead of harsh photochemical methods that decompose transiently formed uranium(VI) nitrides, (3) an electrostatically stabilizing sodium ion during nitride installation, (4) selecting the right sodium sequestering reagent, (5) inner versus outer sphere oxidation and (6) stability with respect to the uranium oxidation state. Computational analyses suggest covalent contributions to U≡N triple bonds that are surprisingly comparable to those of their group 6 transition-metal nitride counterparts.

Comparison of the Reactivity of 2‐Li‐C6H4CH2NMe2 with MCl4 (M=Th, U): Isolation of a Thorium Aryl Complex or a Uranium Benzyne Complex

“…This change in f orbital participation in going from Th to U has been observed previously, [18] and tentatively suggests that the f orbitals play a role in stabilizing the uranium-benzyne linkage. Similarly, the f orbitals have been found to play important roles in the stabilization of the first terminal actinide nitride, [19] and in the manifestation of the inverse trans influence (ITI). [20] However, a binding-energy analysis suggests that the benzyne interaction in the Th complex 2' is similar to that of 2 (Tables S6 and S7).…”

[2 + 2] cycloaddition reactions at terminal imido uranium(IV) complexes to yield isolable cycloadducts

“…As one transitions to uranium(IV) imido complexes, the U@N bonds become longer and more ionic, which should lead to enhanced reactivity. Unfortunately, known uranium(IV) imido compounds often contain cyclopentadienide, tris(pyrazolyl)borate, or other bulky amide/alkoxide co-ligands [1][2][3][4]6,[19][20][21][22][23][24][25][26][27][28]. Such species offer limited opportunity to alter the coordination environment, and thus the reactivity that occurs at the metal center.…”

The effect of density functional and dispersion interaction on structure and bonding analysis of uranium(VI) nitride complex [NU{N(CH2CH2NSiMe3)3}]: A theoretical study

“…The BLYP functional yields better geometry, while the TPSS geometry is the least accurate. The optimized U`N bond [12] and slightly better than the previously calculated value of 1.779 Å at the BP86/TZP level. As seen in Table S1 (Supplementary data), the absolute value of the orbital interaction energy for the U`N bond of the complex [N`U{N(CH 2 CH 2 NSiMe 3 ) 3 }] is the least for BLYP and the greatest for TPSS, consistent with the longest U\N bond distance for the BLYP functional and the shortest U\N bond distance for the functional TPSS.…”