Uranium–Carbon Multiple Bonding: Facile Access to the Pentavalent Uranium Carbene [U{C(PPh2NSiMe3)2}(Cl)2(I)] and Comparison of UVC and UIVC Bonds

Cooper, Oliver J.; Mills, David P.; McMaster, Jonathan; Moro, Fabrizio; Davies, E. Stephen; Lewis, William; Blake, Alexander J.; Liddle, Stephen T.

doi:10.1002/anie.201007675

Cited by 137 publications

(65 citation statements)

References 31 publications

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“…The magnetic moment of powdered 2 is 4.00 μ B at 300 K. This value declines smoothly until ∼50 K after which it decreases more sharply so that at 1.8 K the magnetic moment is 0.69 μ B . The SQUID magnetization trace tends to zero, which is consistent with a f 2 ( 3 H 4 ) electronic configuration that at low temperature has a magnetic singlet state (42).…”

Section: Resultssupporting

confidence: 65%

Homologation and functionalization of carbon monoxide by a recyclable uranium complex

Gardner

Stewart

Davis

et al. 2012

Proc. Natl. Acad. Sci. U.S.A.

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164

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Carbon monoxide (CO) is in principle an excellent resource from which to produce industrial hydrocarbon feedstocks as alternatives to crude oil; however, CO has proven remarkably resistant to selective homologation, and the few complexes that can effect this transformation cannot be recycled because liberation of the homologated product destroys the complexes or they are substitutionally inert. Here, we show that under mild conditions a simple triamidoamine uranium(III) complex can reductively homologate CO and be recycled for reuse. Following treatment with organosilyl halides, bis(organosiloxy)acetylenes, which readily convert to furanones, are produced, and this was confirmed by the use of isotopically 13 C-labeled CO. The precursor to the triamido uranium(III) complex is formed concomitantly. These findings establish that, under appropriate conditions, uranium(III) can mediate a complete synthetic cycle for the homologation of CO to higher derivatives. This work may prove useful in spurring wider efforts in CO homologation, and the simplicity of this system suggests that catalytic CO functionalization may soon be within reach.reduction | C-C coupling | ethyne diolate | antiferromagnetic exchange coupling T he continued growth and stability of the global economy requires the ready availability of petrochemical feedstocks, but uncertainty in cost and supply, underscored by the energy crisis in the 1970s, has driven the demand for developing alternative sources (1). CO is readily produced by steam reforming reactions and is, thus, an abundant resource that can be used in the production of bulk hydrocarbon feedstocks (2). The concept of directly homologating CO is very appealing, but the triple bond in CO is very strong with a bond energy of ∼257 kcal mol −1 , and direct dimerization of CO to O ¼ C ¼ C ¼ O is highly unfavorable with ΔG°2 98 K ≈ þ73 kcal mol −1 (3). Although direct 1,1-migratory insertion of CO into an organometallic M-R bond to give M-C(O)R is a favorable process for many metals (4) and a key step in industrially important C-C bond formation reactions, e.g., hydroformylation (5), double insertion to give M-C(O)C(O)R is usually energetically unfeasible, but it has been documented (6-8). Thus, processes involving CO can require energy intensive reaction conditions and give varied product distributions that render them economically uncompetitive overall when crude oil remains readily available; however, combining the coupling of CO with reduction results in a thermodynamically feasible process to give a family of oxocarbon dianions C n O n 2− (n ¼ 2-6), including the reductively dimerized ethyne diolate − O-C ≡ C-O − , as building blocks for more complex and value-added organic molecules (9).Molten potassium can effect reductive oligomerization of CO, but the resulting ill-defined salts are thermally unstable and shock-sensitive (10). CO can be electrochemically homologated, but an overpressure of 100-400 bar of CO is required (11). Very few transition metal complexes mediate the reductive coupling...

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Section: Resultssupporting

confidence: 65%

Homologation and functionalization of carbon monoxide by a recyclable uranium complex

Gardner

Stewart

Davis

et al. 2012

Proc. Natl. Acad. Sci. U.S.A.

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164

110

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“…The same strengthening can be observed for the negative hyperconjugation effects, which lead to even further elongated bond lengths for the P-N and especially S-O bonds with average values of 1.586(3) Å and 1.494(2) Å respectively. These observations are consistent with those reported for other mono-and dimetallated systems [14][15][16][17][18][19][20]. For example, the bond length changes in 1-Li2 are similar to those found in the corresponding thiophosphoryl compound C (Table 1), despite of the different structures formed in the solid state [26].…”

Section: Preparation Of Methanide 1-k and Methandiide 1-lisupporting

confidence: 90%

“…This is mainly due to their applicability as ligands for the preparation of carbene-type complexes by simple salt metathesis reactions [1][2][3]. Thereby, methandiides revealed to be highly efficient ligand systems stabilizing a variety of carbene complexes with main group metals [4][5][6][7], early and late transition metals [8][9][10][11][12] as well as lanthanides and actinides [13][14][15][16]. The first dilithium compound, which was employed in this chemistry, was the bis(iminophosphorano) system {Li 2 (bipm TMS )} 2 (A, bipm TMS =C(PPh 2 NSiMe 3 ) 2 ), which was simultaneously reported by the groups of Cavell and Stephan in 1999 ( Figure 1) [17,18].…”

Section: Introductionmentioning

confidence: 99%

Synthesis and Characterization of a Sulfonyl- and Iminophosphoryl-Functionalized Methanide and Methandiide

Feichtner

Gessner

2016

Inorganics

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The synthesis of [H 2 C(PPh 2 =NSiMe 3 )(SO 2 Ph)] (1) and its mono-and dimetalation are reported. Due to the strong anion-stabilizing abilities of the iminophosphoryl and the sulfonyl group monometalation to 1-K and dimetalation to 1-Li 2 proceed smoothly with potassium hydride and methyllithium, respectively. Both compounds could be isolated in high yields and were characterized by NMR spectroscopy as well as XRD analysis. The methanide 1-K forms a coordination polymer in the solid state, while in case of the methandiide a tetrameric structure is observed. The latter features an unusual structural motif consisting of two (SO 2 Li) 2 eight-membered rings, which are connected with each other via the methandiide carbon atoms and additional lithium atoms. With increasing metalation a contraction of the P-C-S linkage is observed, which is well in line with the increased charge at the central carbon atom and involved electrostatic interactions.Keywords: methandiides; lithium; potassium; molecular structures BackgroundIn the past 20 years, methandiides with a doubly metalated carbon atom (R 2 CM 2 with M mostly being Li) have attracted intense research interest in organometallic chemistry. This is mainly due to their applicability as ligands for the preparation of carbene-type complexes by simple salt metathesis reactions [1][2][3]. Thereby, methandiides revealed to be highly efficient ligand systems stabilizing a variety of carbene complexes with main group metals [4][5][6][7], early and late transition metals [8][9][10][11][12] as well as lanthanides and actinides [13][14][15][16]. The first dilithium compound, which was employed in this chemistry, was the bis(iminophosphorano) system {Li 2 (bipm TMS )} 2 (A, bipm TMS =C(PPh 2 NSiMe 3 ) 2 ), which was simultaneously reported by the groups of Cavell and Stephan in 1999 (Figure 1) [17,18]. Unlike all other methandiides reported before [19][20][21], A was found to be conveniently accessible by double deprotonation and isolable in high yields, thus allowing its application in carbene complex synthesis [22]. The high stability and facile synthesis of A can be explained by the strong anion-stabilizing ability of the P(V) moieties as well as the additional nitrogen donor side-arms, which efficiently coordinate lithium to form stable complexes. Analogously, the corresponding thiophosphoryl system B reported by Le Floch also proved to be a stable and powerful ligand system [23][24][25]. More recently, our group has focused on non-DPPM derived methandiides, to expand the carbene chemistry of these compounds also to ligands with other substituents. The dilithium compound C with a sulfonyl functionality turned out to be easily accessible and similarly stable than the bis(phosphonium)-substituted systems [26]. The weaker coordination ability of the sulfonyl group also gave way to the formation of transition-metal complexes with open coordination-sides [27][28][29].

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“…Uranium is one actinide that is amenable to routine study, and uranium-ligand multiple-bond complexes have attracted attention because they would be expected to contain some covalency 13-15 . Recently, in addition to the numerous uranium-oxo derivatives, for example uranyl 16 , there have been advances in the synthesis, characterization and understanding of covalent, terminal uraniumcarbene [17][18][19][20][21][22] , -imido [23][24][25][26][27][28][29][30][31][32][33][34][35][36][37] , -nitride [38][39][40] , -phosphinidene [41][42][43] and heavier-chalcogenide 44,45 multiple bonds. Nevertheless, carbon, nitrogen and oxygen donor ligands dominate, and post-first-row donor ligands remain relatively rare and sharply decrease in number as the periodic table is descended.…”

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confidence: 99%

Triamidoamine uranium(IV)–arsenic complexes containing one-, two- and threefold U–As bonding interactions

et al. 2015

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To further our fundamental understanding of the nature and extent of covalency in uranium-ligand bonding, and the benefits that this may have for the design of new ligands for nuclear waste separation, there is burgeoning interest in the nature of uranium complexes with soft- and multiple-bond-donor ligands. Despite this, there have so far been no examples of structurally authenticated molecular uranium-arsenic bonds under ambient conditions. Here, we report molecular uranium(IV)-arsenic complexes featuring formal single, double and triple U-As bonding interactions. Compound formulations are supported by a range of characterization techniques, and theoretical calculations suggest the presence of polarized covalent one-, two- and threefold bonding interactions between uranium and arsenic in parent arsenide [U-AsH2], terminal arsinidene [U=AsH] and arsenido [U≡AsK2] complexes, respectively. These studies inform our understanding of the bonding of actinides with soft donor ligands and may be of use in future ligand design in this area.

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Uranium–Carbon Multiple Bonding: Facile Access to the Pentavalent Uranium Carbene [U{C(PPh₂NSiMe₃)₂}(Cl)₂(I)] and Comparison of U^VC and U^IVC Bonds

Abstract: A straightforward oxidation strategy affords the first pentavalent uranium carbene complex, 2. Owing to the structural similarity of 1 and 2, it was possible for the first time to directly probe the differences in UC bonding on oxidation of UIV to UV.

Cited by 137 publications

References 31 publications

Homologation and functionalization of carbon monoxide by a recyclable uranium complex

Homologation and functionalization of carbon monoxide by a recyclable uranium complex

Synthesis and Characterization of a Sulfonyl- and Iminophosphoryl-Functionalized Methanide and Methandiide

Triamidoamine uranium(IV)–arsenic complexes containing one-, two- and threefold U–As bonding interactions

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