The Nature of Unsupported Uranium–Ruthenium Bonds: A Combined Experimental and Theoretical Study

Abstract

Four new uranium-ruthenium complexes, [(Tren(TMS))URu(η(5)-C(5)H(5))(CO)(2)] (9), [(Tren(DMSB))URu(η(5)-C(5)H(5))(CO)(2)] (10), [(Ts(Tolyl))(THF)URu(η(5)-C(5)H(5))(CO)(2)] (11), and [(Ts(Xylyl))(THF)URu(η(5)-C(5)H(5))(CO)(2)] (12) [Tren(TMS)=N(CH(2)CH(2)NSiMe(3))(3); Tren(DMSB)=N(CH(2)CH(2)NSiMe(2)tBu)(3)]; Ts(Tolyl)=HC(SiMe(2)NC(6)H(4)-4-Me)(3); Ts(Xylyl)=HC(SiMe(2)NC(6)H(3)-3,5-Me(2))(3)], were prepared by a salt-elimination strategy. Structural, spectroscopic, and computational analyses of 9-12 shows: i) the formation of unsupported uranium-ruthenium bonds with no isocarbonyl linkages in the solid state; ii) ruthenium-carbonyl backbonding in the [Ru(η(5)-C(5)H(5))(CO)(2)](-) ions that is tempered by polarization of charge within the ruthenium fragments towards uranium; iii) closed-shell uranium-ruthenium interactions that can be classified as predominantly ionic with little covalent character. Comparison of the calculated U-Ru bond interaction energies (BIEs) of 9-12 with the BIE of [(η(5)-C(5)H(5))(3)URu(η(5)-C(5)H(5))(CO)(2)], for which an experimentally determined U-Ru bond disruption enthalpy (BDE) has been reported, suggests BDEs of approximately 150 kJ mol(-1) for 9-12.

Triamidoamine–Uranium(IV)‐Stabilized Terminal Parent Phosphide and Phosphinidene Complexes

“…The calculated MDC q charges for uranium (2.32-2.61) are typical of Tren-uranium(IV) complexes. [24] The phosphorus charges reflect the changes from mono-anionic phosphide in 2 to dianionic phosphinidenes in 3 and 4. The uranium spin densities span 2.31-2.41 and together with the charges support the notion of increased donation of electron density from the ligands in the order 4 > 3 > 2, as would be expected from the progression of terminal phosphinidene to pseudo-bridging phosphinidene to phosphide.…”

Photochemical Route to Actinide-Transition Metal Bonds: Synthesis, Characterization and Reactivity of a Series of Thorium and Uranium Heterobimetallic Complexes

“…Accordingly, only 17 structurally characterized examples have been reported, 16 establishing uranium bound to iron, ruthenium, rhenium and cobalt, in addition to the first example involving thorium. [17][18][19][20][21][22][23] Expanding the limited number of synthetic avenues to actinide metal-metal bonds provides an exciting opportunity to develop this field, with the potential to offer new insight into electronic structure and yield alternative modes of bimetallic cooperativity for novel catalytic applications.…”

f-Element-metal bond chemistry

“…The fi rst structurally characterised series of complexes containing unsupported uranium-ruthenium bonds were reported recently by Liddle (Gardner et al 2011c or, in the case of osmium, no identifi able products. This may have been due to the [Fe( η 5 -C 5 H 5 )(CO) 2 ] -ion being too strongly reducing, and this might disfavour uranium-metal bond formation, and the uranium-osmium linkage may be too sterically exposed and, therefore, susceptible to decomposition.…”