Multimetallic Uranium Nitride Cubane Clusters from Dinitrogen Cleavage

Progress in Nonaqueous Molecular Uranium Chemistry: Where to Next?

“…) and subsequent N−N cleavage to afford polynitrides by Mazzanti in 2023. 54 Collectively, these advances highlight the ability of uranium to activate N 2 , confirming the observation that uranium is a highly effective promoter for the formation of NH 3 from N 2 and H 2 , as stated in the original Haber−Bosch patent from over a century ago. 46 ■ ALKYLIDENES, CARBYNES, AND CARBIDOS Because the M = CR 2 (R = H, alkyl, silyl) motif is a fundamental structural class in transition-metal chemistry, there has long been an interest in realizing uranium alkylidenes.…”

“…135,136 The more sterically demanding [U{OC 6 H 2 [2,6-CHPh 2 ] 2 -4-Me} 3 ] (92) reported by , and CO-coupled ethynediolate derivatives. 54,134 ■ U−U BONDS Given the prevalence of Mo−Mo and W−W bonding in transition-metal chemistry, the absence of U−U bonds led to the latter being a natural target in Figure 2 in 1988. This was not for a lack of attempts to prepare U−U bonds by 1988, where one study by Cotton in 1984 130 investigating the possibility of accessing U−U bonding supported by alkoxides, given the tendency of alkoxides to support Mo−Mo and W−W bonding, stated that, "While we are not suggesting that on the basis of these two structural results all hope of observing U−U bonds is futile, we do feel that such hopes are rather dim."…”

“…Other notable achievements in this area (Figure ) include the splitting of N 2 into a bis­(nitride) in the complex [K­(DME) 4 ]­[{K­(DME)­(Et 8 -calix­[4]­tetrapyrrole)­U} 2 (μ-NK) 2 ] ( 24 ) by Gambarotta in 2002, hydrogenation to afford ammonia by [{U­(OSi­[O t Bu] 3 )} 2 (μ-N)­(μ-η 2 :η 2 -N 2 )­K 3 ] ( 25 ) by Mazzanti in 2017, and recently the formation of N 2 3– at uranium in [K­(L) n ]­[{U­(OC 6 H 2 -2,4,6- t Bu 3 ) 3 } 2 (μ-η 2 :η 2 -N 2 )] ( 26 , L = 2.2.2-cryptand, n = 1; 27 , L = THF, n = 6) and subsequent N–N cleavage to afford polynitrides by Mazzanti in 2023 . Collectively, these advances highlight the ability of uranium to activate N 2 , confirming the observation that uranium is a highly effective promoter for the formation of NH 3 from N 2 and H 2 , as stated in the original Haber–Bosch patent from over a century ago…”

“…Where aryloxides are concerned, there are still relatively few homoleptic variants (Figure ), with reports by Sattelberger in 1988 of dimeric [{U­(μ-η 1 :η 6 -ODipp)­(ODipp) 2 } 2 ] ( 89 ) and the monomers [U­(O-C 6 H 3 -2,6- t Bu 2 ) 3 ] ( 90 , suggested to be monomeric from IR data in the initial report but only structurally confirmed as such in 2011 by P. Arnold) and [U­(O-C 6 H 3 -2,6- t Bu 2 ) 4 ] ( 91 ). , The more sterically demanding [U­{OC 6 H 2 [2,6-CHPh 2 ] 2 -4-Me} 3 ] ( 92 ) reported by Meyer and Mindiola and [U­(OC 6 H 2 -2,6-Ad 2 -4-Me) 3 ] ( 93 ) disclosed by Meyer appeared in 2013 and 2016, respectively . It is worth noting that some homoleptic uranium aryloxides exist but have not been structurally authenticated; however, they have been used to make N 2 2– , N 2 3– , and CO-coupled ethynediolate derivatives. , …”

N-Aryloxide-Amidinate Thorium Complexes

“…Afterward, the Arnold group synthesized dinitrogen complexes using U III (OC 6 H 3 - t Bu 2 -2,6) 3 and U III (OC 6 H 3 - t Bu 3 -2,4,6) 3 . More recently, the Mazzanti group achieved dinitrogen cleavage by reducing complex {[U III (OC 6 H 3 - t Bu 3 -2,4,6) 3 ] 2 (μ–η 2 :η 2 -N 2 )} . The Gambarotta group obtained a terminally bonded Th IV –OH species upon reduction of Th IV (OC 6 H 3 –Ph 2 -2,6) 4 in the presence of DME .…”