Electrocatalytic Transfer Hydrogenation of 1-Octene with [(PCP)Ir(H)(Cl)] and Water.

Electrocatalytic hydrogenation of 1-octene as non-activated model substrate with neutral water as H-donor is reported, using [(PCP)Ir(H)(Cl)] (1) as the catalyst, to form octane with high faradaic efficiency (FE) of 96 % and a k of 87 s. Cyclic voltammetry with 1 revealed that two subsequent reductions trigger the elimination of Cl and afford the highly reactive anionic Ir(I) hydride complex [(PCP)Ir(H)] (2), a previously merely proposed intermediate for which we now report first experimental data by mass spectrometry. In absence of alkene, the stoichiometric electrolysis of 1 in THF with water selectively affords the Ir(III) dihydride complex [(PCP)Ir(H)] (3) in 88 % FE from the reaction of 2 with HO.

Benzene-1,4-Di(dithiocarboxylate) Linker-Based Coordination Polymers of Mn, Zn, and Mixed-Valence Fe.

Three new coordination polymers (CPs) constructed from the linker 1,4-di(dithiocarboxylate) (BDDTC)─the sulfur-analog of 1,4-benzenedicarboxylate (BDC)─together with Mn-, Zn-, and Fe-based inorganic SBUs are reported with description of their structural and electronic properties. Single-crystal X-ray diffraction revealed structural diversity ranging from one-dimensional chains in [Mn(BDDTC)(DMF)] () to two-dimensional (2D) honeycomb sheets observed for [Zn(BDDTC)][Zn(DMF)(HO)] (). Gas adsorption experiments confirmed a 3D porous structure for the mixed-valent material [Fe(BDDTC)(OH)] ().

Nonaqueous Electrochemistry of Uranium Complexes: A Guide to Structure-Reactivity Tuning.

Uranium complexes can be stabilized in a wide range of oxidation states, ranging from U to U and a very recent example of a U complex. This review provides a comprehensive summary of electrochemistry data reported on uranium complexes in nonaqueous electrolyte, to serve as a clear point of reference for newly synthesized compounds, and to evaluate how different ligand environments influence experimentally observed electrochemical redox potentials. Data for over 200 uranium compounds are reported, together with a detailed discussion of trends observed across larger series of complexes in response to ligand field variations.

Self-adjusting binding pockets enhance H and CH adsorption in a uranium-based metal-organic framework.

A new, air-stable, permanently porous uranium(iv) metal-organic framework U(bdc) (, bdc = 1,4-benzenedicarboxylate) was synthesized and its H and CH adsorption properties were investigated. Low temperature adsorption isotherms confirm strong adsorption of both gases in the framework at low pressures. gas-dosed neutron diffraction experiments with different D loadings revealed a rare example of cooperative framework contraction (Δ = -7.

Werner-Type Complexes of Uranium(III) and (IV).

Transmetalation of the β-diketiminate salt [M][nacnac] (M = Na or K; nacnac = {PhNC(CH)}CH) with UI(THF) resulted in the formation of the homoleptic, octahedral complex [U(nacnac)] (). Green colored was fully characterized by a solid-state X-ray diffraction analysis and a combination of UV/vis/NIR, NMR, and EPR spectroscopic studies as well as solid-state SQUID magnetization studies and density functional theory calculations. Electrochemical studies of revealed this species to possess two anodic waves for the U(III/IV) and U(IV/V) redox couples, with the former being chemically accessible.

Using Diamagnetic Yttrium and Lanthanum Complexes to Explore Ligand Reduction and C-H Bond Activation in a Tris(aryloxide)mesitylene Ligand System.

[Y(N(SiMe))] reacts with (ArOH)mes to form the Y complex [((ArO)mes)Y], 1-Y. This complex reacts with potassium metal in the presence of 2.2.

The role of uranium-arene bonding in HO reduction catalysis.

The reactivity of uranium compounds towards small molecules typically occurs through stoichiometric rather than catalytic processes. Examples of uranium catalysts reacting with water are particularly scarce, because stable uranyl groups form that preclude the recovery of the uranium compound. Recently, however, an arene-anchored, electron-rich uranium complex has been shown to facilitate the electrocatalytic formation of H from HO.

Metal versus Ligand Reduction in Ln Complexes of a Mesitylene-Anchored Tris(Aryloxide) Ligand.

The synthesis of 4f Ln complexes of the tris(aryloxide) mesitylene ligand, ((ArO)mes), with Ln = La, Ce, Pr, Sm, and Yb, and their reduction with potassium have revealed that this ligand system can be redox active with some metals. Protonolysis of [Ln(N(SiMe))] (Ln = La, Ce, Pr, Sm, Yb) with the tris(phenol) (ArOH)mes yielded the Ln complexes [((ArO)mes)Ln] (Ln = La, Ce, Pr, Sm, Yb), 1-Ln. Single electron reduction of each 4f complex, 1-Ln, using potassium yielded the reduced products, [K(2.

Electrocatalytic HO Reduction with f-Elements: Mechanistic Insight and Overpotential Tuning in a Series of Lanthanide Complexes.

Electrocatalytic energy conversion with molecular f-element catalysts is still in an early phase of its development. We here report detailed electrochemical investigations on the recently reported trivalent lanthanide coordination complexes [((ArO)mes)Ln] (1-Ln), with Ln = La, Ce, Pr, Nd, Sm, Gd, Dy, Er, and Yb, which were now found to perform as active electrocatalysts for the reduction of water to dihydrogen. Reactivity studies involving complexes 1-Ln and the Ln(II) analogues [K(2.

Comparisons of lanthanide/actinide +2 ions in a tris(aryloxide)arene coordination environment.

A new series of Ln and Ln complexes has been synthesized using the tris(aryloxide)arene ligand system, ((ArO)mes), recently used to isolate a complex of U. The triphenol precursor, (ArOH)mes, reacts with the Ln amides, Ln(NR) (R = SiMe), to form a series of [((ArO)mes)Ln] complexes, . Crystallographic characterization was achieved for Ln = Nd, Gd, Dy, and Er.

A Stable Crystalline Triarylphosphine Oxide Radical Anion.

Triarylphosphine oxides (Ar P=O) are being intensely studied as electron-accepting (n-type) materials. Despite the widespread application of these compounds as electron conductors, experimental data regarding the structural and electronic properties of their negatively charged states remain scarce owing to their propensity for follow-up chemistry. Herein, a carefully designed triarylphosphine oxide scaffold is disclosed that comprises sterically demanding spirofluorenyl moieties to shield the central phosphoryl (P=O) moiety.

Uranium-mediated electrocatalytic dihydrogen production from water.

Depleted uranium is a mildly radioactive waste product that is stockpiled worldwide. The chemical reactivity of uranium complexes is well documented, including the stoichiometric activation of small molecules of biological and industrial interest such as H2O, CO2, CO, or N2 (refs 1 - 11), but catalytic transformations with actinides remain underexplored in comparison to transition-metal catalysis. For reduction of water to H2, complexes of low-valent uranium show the highest potential, but are known to react violently and uncontrollably forming stable bridging oxo or uranyl species.

Uranium(IV) halide (F-, Cl-, Br-, and I-) monoarene complexes.

The syntheses of four nearly isostructural uranium(IV) monoarene complexes, supported by the arene anchored tris(aryloxide) chelate, [((Ad,Me)ArO)3mes](3-), are reported. Oxidation of the uranium(III) precursor [(((Ad,Me)ArO)3mes)U], 1, in the presence of tetrahydrofuran (THF) results in THF coordination and distortion of the equatorial coordination sphere to afford the uranium(IV) η(6)-arene complexes, [(((Ad,Me)ArO)3mes)U(X)(THF)], 2-X-THF, (where X = F, Cl, Br, or I) as their THF adducts. The solvate-free trigonally ligated [(((Ad,Me)ArO)3mes)U(F)], 2-F, was prepared and isolated in the absence of coordinating solvents for comparison.

Coordination and redox isomerization in the reduction of a uranium(III) monoarene complex.

Synthetic studies on the redox chemistry of trivalent uranium monoarene complexes were undertaken with a complex derived from the chelating tris(aryloxide)arene ligand ((Ad,Me) ArO)3 mes(3-) . Cyclic voltammetry of [{((Ad,Me) ArO)3 mes}U(III) ] (1) revealed a nearly reversible and chemically accessible reduction at -2.495 V vs.