Reactivity of a Nickel Sulfide with Carbon Monoxide and Nitric Oxide

The reactivity of the “masked” terminal nickel sulfide complex, [K­(18-crown-6)]­[(L^tBu)­Ni^II(S)] (L^tBu = {(2,6-ⁱPr₂C₆H₃)­NC­(^tBu)}₂CH), with the biologically important small molecules CO and NO, was surveyed. [K­(18-crown-6)]­[(L^tBu)­Ni^II(S)] reacts with carbon monoxide (CO) via addition across the Ni–S bond to give a carbonyl sulfide complex, [K­(18-crown-6)]­[(L^tBu)­Ni^II(<i>S</i>,<i>C</i>:η²-COS)] (<b>1</b>). Additionally, [K­(18-crown-6)]­[(L^tBu)­Ni^II(S)] reacts with nitric oxide (NO) to yield a nickel nitrosyl, [(L^tBu)­Ni­(NO)] (<b>2</b>), and a perthionitrite anion, [K­(18-crown-6)]­[SSNO] (<b>3</b>). The isolation of <b>3</b> from this reaction confirms, for the first time, that transition metal sulfides can react with NO to form the biologically important [SSNO]⁻ anion

A Re-examination of the Synthesis of Monolayer-Protected Co_<i>x</i>(SCH₂CH₂Ph)_<i>m</i> Nanoclusters: Unexpected Formation of a Thiolate-Protected Co(II) T3 Supertetrahedron

Herein, we report a re-examination of the synthesis and characterization of monolayer-protected Co_<i>x</i>(SCH₂CH₂Ph)_<i>m</i> nanoclusters. These clusters were reportedly formed by the reaction of CoCl₂ with NaBH₄ in the presence of HSCH₂CH₂Ph and were suggested to contain between 25 and 30 Co atoms. In our hands, however, we found no experimental evidence to support the existence of these large clusters in the reaction mixture. Instead, this reaction results in the relatively clean formation of the cobalt­(II) coordination complex [Co₁₀(SCH₂CH₂Ph)₁₆Cl₄] (<b>1</b>). Complex <b>1</b> has been fully characterized using a wide variety of techniques, including single-crystal X-ray crystallography, NMR spectroscopy, mass spectrometry, and magnetometry. This complex represents the first example of a thiolate-protected Co­(II) T3 supertetrahedral cluster

Reversible Chalcogen-Atom Transfer to a Terminal Uranium Sulfide

The reaction of elemental S or Se with [K­(18-crown-6)]­[U­(S)­(NR₂)₃] (<b>1</b>) results in the formation of the new uranium­(IV) dichalcogenides [K­(18-crown-6)]­[U­(η²-S₂)­(NR₂)₃] (<b>2</b>) and [K­(18-crown-6)]­[U­(η²-SSe)­(NR₂)₃] (<b>5</b>). The further addition of elemental S to <b>2</b> results in the formation of [K­(18-crown-6)]­[U­(η³-S₃)­(NR₂)₃] (<b>3</b>). Complexes <b>2</b>, <b>3</b>, and <b>5</b> can be reconverted into <b>1</b> via the addition of R₃P (R = Et, Ph), concomitant with the formation of R₃PE (E = S, Se)

Synthesis of Uranium–Ligand Multiple Bonds by Cleavage of a Trityl Protecting Group

Addition of KSCPh₃ to [U­(NR₂)₃] (R = SiMe₃) in tetrahydrofuran, followed by addition of 18-crown-6, results in formation of the U­(IV) sulfide, [K­(18-crown-6)]­[U­(S)­(NR₂)₃] (<b>1</b>) and Gomberg’s dimer. Similarly, addition of KOCPh₃ to [U­(NR₂)₃] in tetrahydrofuran, followed by addition of 18-crown-6, results in formation of the U­(IV) oxide, [K­(18-crown-6)]­[U­(O)­(NR₂)₃] (<b>3</b>). Also observed in this transformation are the triphenylmethyl anion, [K­(18-crown-6)­(THF)₂]­[CPh₃] (<b>5</b>), and the U­(IV) alkoxide, [U­(OCPh₃)­(NR₂)₃] (<b>4</b>)

Synthesis of Uranium–Ligand Multiple Bonds by Cleavage of a Trityl Protecting Group

Addition of KSCPh₃ to [U­(NR₂)₃] (R = SiMe₃) in tetrahydrofuran, followed by addition of 18-crown-6, results in formation of the U­(IV) sulfide, [K­(18-crown-6)]­[U­(S)­(NR₂)₃] (<b>1</b>) and Gomberg’s dimer. Similarly, addition of KOCPh₃ to [U­(NR₂)₃] in tetrahydrofuran, followed by addition of 18-crown-6, results in formation of the U­(IV) oxide, [K­(18-crown-6)]­[U­(O)­(NR₂)₃] (<b>3</b>). Also observed in this transformation are the triphenylmethyl anion, [K­(18-crown-6)­(THF)₂]­[CPh₃] (<b>5</b>), and the U­(IV) alkoxide, [U­(OCPh₃)­(NR₂)₃] (<b>4</b>)

Chalcogen Atom Transfer to Uranium(III): Synthesis and Characterization of [(R₂N)₃U]₂(μ-E) and [(R₂N)₃U]₂(μ‑η²:η²‑S₂) (R = SiMe₃; E = S, Se, Te)

Addition of 0.0625 equiv of S₈ to U­(NR₂)₃ (R = SiMe₃) in Et₂O generates [(R₂N)₃U]₂(μ-S) (<b>1</b>), which can be isolated in moderate yield by crystallization from cold Et₂O. Interestingly, if the U­(NR₂)₃ starting material is contaminated with the U­(IV) metallacycle U­(<i>C</i>H₂SiMe₂<i>N</i>SiMe₃)­(NR₂)₂, then a second product is also formed in the reaction with S₈, namely, [(R₂N)₃U]₂(μ-η²:η²-S₂) (<b>2</b>). This species can be separated from <b>1</b>, in low yield, by virtue of its insolubility in Et₂O. Finally, addition of 0.5 equiv of E (E = Se, Te) to U­(NR₂)₃ (R = SiMe₃) results in the formation of [(R₂N)₃U]₂(μ-E) (E = Se (<b>3</b>), Te (<b>4</b>)) in moderate yields. Complexes <b>1</b>–<b>4</b> were fully characterized, including analysis by X-ray crystallography

Reductive Silylation of the Uranyl Ion with Ph₃SiOTf

The reaction of 2 equiv of Ph₃SiOTf with UO₂(dbm)₂(THF) (dbm = <i>O</i>C­(Ph)­CHC­(Ph)<i>O</i>) and UO₂(^Aracnac)₂ (^Aracnac = Ar<i>N</i>C­(Ph)­CHC­(Ph)<i>O</i>; Ar = 3,5-^tBu₂C₆H₃) results in the formation of U­(OSiPh₃)₂(dbm)₂(OTf) (<b>1</b>) and [U­(OSiPh₃)₂(^Aracnac)₂]­[OTf] (<b>2</b>), respectively, in good yield

Synthesis, Electrochemistry, and Reactivity of the Actinide Trisulfides [K(18-crown-6)][An(η³‑S₃)(NR₂)₃] (An = U, Th; R = SiMe₃)

The reaction of [Th­(I)­(NR₂)₃] (R = SiMe₃) with [K­(18-crown-6)]₂[S₄] results in the formation of [K­(18-crown-6)]­[Th­(η³-S₃)­(NR₂)₃] (<b>2</b>). Oxidation of <b>2</b>, or its uranium analogue, [K­(18-crown-6)]­[U­(η³-S₃)­(NR₂)₃] (<b>1</b>), with AgOTf, in an attempt to generate an [S₃]^•– complex, results in the formation of [K­(18-crown-6)]­[An­(OTf)₂(NR₂)₃] (<b>3</b>, An = U; <b>4</b>, An = Th) as the only isolable products. These results suggest that the putative [S₃]^•– ligand is only weakly coordinating and can be easily displaced by nucleophiles

Chalcogen Atom Transfer to Uranium(III): Synthesis and Characterization of [(R₂N)₃U]₂(μ-E) and [(R₂N)₃U]₂(μ‑η²:η²‑S₂) (R = SiMe₃; E = S, Se, Te)

Addition of 0.0625 equiv of S₈ to U­(NR₂)₃ (R = SiMe₃) in Et₂O generates [(R₂N)₃U]₂(μ-S) (<b>1</b>), which can be isolated in moderate yield by crystallization from cold Et₂O. Interestingly, if the U­(NR₂)₃ starting material is contaminated with the U­(IV) metallacycle U­(<i>C</i>H₂SiMe₂<i>N</i>SiMe₃)­(NR₂)₂, then a second product is also formed in the reaction with S₈, namely, [(R₂N)₃U]₂(μ-η²:η²-S₂) (<b>2</b>). This species can be separated from <b>1</b>, in low yield, by virtue of its insolubility in Et₂O. Finally, addition of 0.5 equiv of E (E = Se, Te) to U­(NR₂)₃ (R = SiMe₃) results in the formation of [(R₂N)₃U]₂(μ-E) (E = Se (<b>3</b>), Te (<b>4</b>)) in moderate yields. Complexes <b>1</b>–<b>4</b> were fully characterized, including analysis by X-ray crystallography

Trapping of an Ni^II Sulfide by a Co^I Fulvene Complex

The reaction of [L^tBuNi^II(SCPh₃)] (L^tBu = {(2,6-ⁱPr₂C₆H₃)­NC­(^tBu)}₂CH) with Cp*₂Co yields a Ni^I cobaltocenium thiolate complex, [L^tBuNi^I(SCH₂Me₄C₅)­Co­(Cp*)] (<b>1</b>), along with HCPh₃. Formation of this complex is proposed to occur via the reaction of a transient Ni^II sulfide, [Cp*₂Co]­[L^tBuNi^II(S)], with a Co^I fulvene complex, [CoCp*­(C₅Me₄CH₂)]. The latter complex is formed in situ by reaction of [Cp*₂Co]⁺ with [CPh₃]⁻. Control experiments, as well as cyclic voltammetry measurements of <b>1</b>, are used to support the proposed mechanism