Terminal uranium(V)-nitride hydrogenations involving direct addition or Frustrated Lewis Pair mechanisms.

Despite their importance as mechanistic models for heterogeneous Haber Bosch ammonia synthesis from dinitrogen and dihydrogen, homogeneous molecular terminal metal-nitrides are notoriously unreactive towards dihydrogen, and only a few electron-rich, low-coordinate variants demonstrate any hydrogenolysis chemistry. Here, we report hydrogenolysis of a terminal uranium(V)-nitride under mild conditions even though it is electron-poor and not low-coordinate. Two divergent hydrogenolysis mechanisms are found; direct 1,2-dihydrogen addition across the uranium(V)-nitride then H-atom 1,1-migratory insertion to give a uranium(III)-amide, or with trimesitylborane a Frustrated Lewis Pair (FLP) route that produces a uranium(IV)-amide with sacrificial trimesitylborane radical anion.

Thermally Stable Ln(II) and Ca(II) Bis(benzhydryl) Complexes: Excellent Precatalysts for Intermolecular Hydrophosphination of C-C Multiple Bonds.

A series of Ln(II) and Ca(II) bis(alkyl) complexes with bulky benzhydryl ligands, [( p- tBu-CH)CH]M(L ) (M = Sm, L = DME, n = 2 (1); M = Sm, Yb, Ca, L = TMEDA, n = 1 (2, 3, 4), were synthesized by the salt-metathesis reaction of MI(THF) ( n = 0-2) and [( p- tBu-CH)CH]Na. In complex 1, the benzhydryl ligands are bound to the metal center in η-coordination mode. Unlike complex 1, in isomorphous complexes 3 and 4, due to the coordination unsaturation of the metal center, the both benzhydryl ligands coordinate to the metal in η-fashion.

Divalent Ytterbium Complex-Catalyzed Homo- and Cross-Coupling of Primary Arylsilanes.

Redistribution of primary silanes through C-Si and Si-H bond cleavage and reformation provides a straightforward synthesis of secondary silanes, but the poor selectivity and low efficiency severely hinders the application of this synthetic protocol. Here, we show that a newly synthesized divalent ytterbium alkyl complex exhibits unprecedentedly high catalytic activity toward the selective redistribution of primary arylsilanes to secondary arylsilanes. More significantly, this complex also effectively catalyzes the cross-coupling between electron-withdrawing substituted primary arylsilanes and electron-donating substituted primary arylsilanes to secondary arylsilanes containing two different aryls.

Cyaarside (CAs ) and 1,3-Diarsaallendiide (AsCAs ) Ligands Coordinated to Uranium and Generated via Activation of the Arsaethynolate Ligand (OCAs ).

Reaction of the trivalent uranium complex [(( ArO) N)U(DME)] with one molar equiv [Na(OCAs)(dioxane) ], in the presence of 2.2.2-crypt, yields [Na(2.

Small molecule activation with divalent samarium triflate: a synergistic effort to cleave O.

The divalent samarium triflate salt does not react with CO2 or water, but does react with traces of O2 or N2O to form a tetrameric bis-oxo samarium motif. The reaction with O2 is a 4e- reductive cleavage where the electrons are coming from four different samarium centers. This highlights a rare synergistic effect for cleaving O2, which has no precedent in divalent lanthanide complexes.

Steric control in the metal-ligand electron transfer of iminopyridine-ytterbocene complexes.

A systematic study of reactions between Cp*Yb(THF) (Cp* = η-CMe, 1) and iminopyridine ligands (IPy = 2,6-PrCHN[double bond, length as m-dash]CH(CHN-R), R = H (2a), 6-CHO (2b), 6-CHS (2c), 6-CH (2d)) featuring similar electron accepting properties but variable denticity and steric demand, has provided a new example of steric control on the redox chemistry of ytterbocenes. The reaction of the unsubstituted IPy 2a with 1, either in THF or toluene, gives rise to the paramagnetic species Cp*Yb(IPy)˙ (3a) as a result of a formal one-electron oxidation of the Yb ion along with IPy reduction to a radical-anionic state. The reactions of 1 with substituted iminopyridines 2b-d, bearing aryl or hetero-aryl dangling arms on the 6 position of the pyridine ring occur in a non-coordinating solvent (toluene) only and afford coordination compounds of a formally divalent ytterbium ion, coordinated by neutral IPy ligands Cp*Yb(IPy) (3b-d).

SO and SO reactions with [(CMe)Sm-O-Sm(CMe)]: a DFT investigation and comparison with CO reactivity.

Recently, it was shown that samarocene oxide [Cp*Sm-O-SmCp*] with Cp* = CMe could react with organic and inorganic anhydrides. The reactions of [Cp*Sm-O-SmCp*] with SO and SO are reported using DFT calculations and compared with the reactivity of CO. These reactions exhibit similar features yielding [Cp*-Sm-(μ-η:η-OSO)-SmCp*] similar to [Cp*-Sm-(μ-η:η-OCO)-SmCp*] and [Cp*-Sm-(μ-η:η-OSO)-SmCp*] complexes.