Metal-Metal Bonding in Tri-Actinide Clusters: A DFT Study of [AnCl] (z=1-6) and [AnClCp] (z=-2-+3; An=Ac, Th, Pa, U, Np, Pu).

The actinide-actinide bonding in tri-actinide clusters [An₃Cl₆] (An=Ac-Pu, z=1-6) and [An₃Cl₆Cp₃] (z=-2-+3; Cp=(η-CH)) is studied using density functional theory. We find 3-centre bonding similar to the tri-thorium cluster [{Th(η⁸-C₈H₈)(μ₃-Cl)₂}₃{K(THF)₂}₂], as we previously reported (Nature 2021, 598, 72-75). The population of 3-centre molecular orbitals (3c-MOs) by zero, one or two electrons correlates with shortening of the An-An bond lengths, which also decrease with increasing actinide atomic number, consistent with the contraction of the actinide valence atomic orbitals.

Reactivity of a triamidoamine terminal uranium(VI)-nitride with 3d-transition metal metallocenes.

Reactions between [(Tren)UN] (1, Tren = {N(CHCHNSiPr)}) and [M(η-CR)] (M/R = Cr/H, Mn/H, Fe/H, Ni/H) were intractable, but M/R = Co/H or Co/Me afforded [(Tren)UN-(η:η-CH)Co(η-CH)] (2) and [(Tren)U-NH] (3), respectively. For M/R = V/H [(Tren)U-NV(η-CH)] (4), was isolated. Complexes 2-4 evidence one-/two-electron uranium reductions, nucleophilic nitrides, and partial N-atom transfer.

-Silanide f-Block Complexes: Insights into Paramagnetic Influence on NMR Chemical Shifts.

The paramagnetism of f-block ions has been exploited in chiral shift reagents and magnetic resonance imaging, but these applications tend to focus on H NMR shifts as paramagnetic broadening makes less sensitive nuclei more difficult to study. Here we report a solution and solid-state (ss) Si NMR study of an isostructural series of locally -symmetric early f-block metal(III) -hypersilanide complexes, [M{Si(SiMe)}(THF)] (; M = La, Ce, Pr, Nd, U); were also characterized by single crystal and powder X-ray diffraction, EPR, ATR-IR, and UV-vis-NIR spectroscopies, SQUID magnetometry, and elemental analysis. Only one SiMe signal was observed in the Si ssNMR spectra of , while two SiMe signals were seen in solution Si NMR spectra of and .

f-Element Zintl Chemistry: Actinide-Mediated Dehydrocoupling of HSb Affords the Trithorium and Triuranium Undeca-Antimontriide Zintl Clusters [{An(Tren)}(μ-Sb)] (An = Th, U; Tren = {N(CHCHNSiPr)}).

Reaction of the cesium antimonide complex [Cs(18C6)][SbH] (, 18C6 = 18-crown-6 ether) with the triamidoamine actinide separated ion pairs [An(Tren)(L)][BPh] (Tren = {N(CHCHNSiPr)}; An/L = Th/DME (); U/THF ()) affords the triactinide undeca-antimontriide Zintl clusters [{An(Tren)}(μ-Sb)] (An = Th (), U ()) by dehydrocoupling. Clusters and provide two new examples of the Sb Zintl trianion and are unprecedented examples of molecular Sb being coordinated to anything since all previous reports featured isolated Sb Zintl trianions in separated ion quadruple formulations with noncoordinating cations. Quantum chemical calculations describe dominant ionic An-Sb interactions in and , though the data suggest that the latter exhibits slightly more covalent An-Sb linkages than the former.

N-Heterocyclic Carbene to Actinide d-Based π-bonding Correlates with Observed Metal-Carbene Bond Length Shortening Versus Lanthanide Congeners.

Comparison of bonding and electronic structural features between trivalent lanthanide (Ln) and actinide (An) complexes across homologous series' of molecules can provide insights into subtle and overt periodic trends. Of keen interest and debate is the extent to which the valence f- and d-orbitals of trivalent Ln/An ions engage in covalent interactions with different ligand donor functionalities and, crucially, how bonding differences change as both the Ln and An series are traversed. Synthesis and characterization (SC-XRD, NMR, UV-vis-NIR, and computational modeling) of the homologous lanthanide and actinide N-heterocyclic carbene (NHC) complexes [M(CMe)(X)(I)] {X = I, M = La, Ce, Pr, Nd, U, Np, Pu; X = Cl, M = Nd; X = I/Cl, M = Nd, Am; and I = [C(NMeCMe)]} reveals consistently shorter An-C vs Ln-C distances that do not substantially converge upon reaching Am/Nd comparison.

Arene-, Chlorido-, and Imido-Uranium Bis- and Tris(boryloxide) Complexes.

We introduce the boryloxide ligand {(HCNDipp)BO} (NBO, Dipp = 2,6-di-isopropylphenyl) to actinide chemistry. Protonolysis of [U{N(SiMe)}] with 3 equiv of NBOH produced the uranium(III) tris(boryloxide) complex [U(NBO)] (). In contrast, treatment of UCl with 3 equiv of NBOK in THF at room temperature or reflux conditions produced only [U(NBO)(Cl)(THF)] () with 1 equiv of NBOK remaining unreacted.

Correction: f-Element heavy pnictogen chemistry.

[This corrects the article DOI: 10.1039/D3SC05056D.].

Thorium(IV)-antimony complexes exhibiting single, double, and triple polar covalent metal-metal bonds.

There is continued burgeoning interest in metal-metal multiple bonding to further our understanding of chemical bonding across the periodic table. However, although polar covalent metal-metal multiple bonding is well known for the d and p blocks, it is relatively underdeveloped for actinides. Homometallic examples are found in spectroscopic or fullerene-confined species, and heterometallic variants exhibiting a polar covalent σ bond supplemented by up to two dative π bonds are more prevalent.

Carbene Complexes of Plutonium: Structure, Bonding, and Divergent Reactivity to Lanthanide Analogs.

Organoplutonium chemistry was established in 1965, yet structurally authenticated plutonium-carbon bonds remain rare being limited to π-bonded carbocycle and σ-bonded isonitrile and hydrocarbyl derivatives. Thus, plutonium-carbenes, including alkylidenes and N-heterocyclic carbenes (NHCs), are unknown. Here, we report the preparation and characterization of the diphosphoniomethanide-plutonium complex [Pu(BIPMH)(I)(μ-I)] (, BIPMH = (MeSiNPPh)CH) and the diphosphonioalkylidene-plutonium complexes [Pu(BIPM)(I)(DME)] (, BIPM = (MeSiNPPh)C) and [Pu(BIPM)(I)(I)] (, I = C(NMeCMe)), thus disclosing non-actinyl transneptunium multiple bonds and transneptunium NHC complexes.

C nuclear magnetic resonance chemical shift analysis confirms Ce[double bond, length as m-dash]C double bonding in cerium(iv)-diphosphonioalkylidene complexes.

Diphosphonioalkylidene dianions have emerged as highly effective ligands for lanthanide and actinide ions, and the resulting formal metal-carbon double bonds have challenged and developed conventional thinking about f-element bond multiplicity and covalency. However, f-element-diphosphonioalkylidene complexes can be represented by several resonance forms that render their metal-carbon double bond status unclear. Here, we report an experimentally-validated C Nuclear Magnetic Resonance computational assessment of two cerium(iv)-diphosphonioalkylidene complexes, [Ce(BIPM)(ODipp)] (1, BIPM = {C(PPhNSiMe)}; Dipp = 2,6-diisopropylphenyl) and [Ce(BIPM)] (2).

f-Element heavy pnictogen chemistry.

The coordination and organometallic chemistry of the f-elements, that is group 3, lanthanide, and actinide ions, supported by nitrogen ligands, amides, imides, and nitrides, has become well developed over many decades. In contrast, the corresponding f-element chemisty with the heavier pnictogen analogues phosphorus, arsenic, antimony, and bismuth has remained significantly underdeveloped, due largely to a lack of suitable synthetic methodologies and also the inherent hard(f-element)-soft(heavier pnictogen) acid-base mismatch, but has begun to flourish in recent years. Here, we review complexes containing chemical bonds between the f-elements and heavy pnictogens from phosphorus to bismuth that spans five decades of endeavour.

P Nuclear Magnetic Resonance Spectroscopy as a Probe of Thorium-Phosphorus Bond Covalency: Correlating Phosphorus Chemical Shift to Metal-Phosphorus Bond Order.

We report the use of solution and solid-state P Nuclear Magnetic Resonance (NMR) spectroscopy combined with Density Functional Theory calculations to benchmark the covalency of actinide-phosphorus bonds, thus introducing P NMR spectroscopy to the investigation of molecular f-element chemical bond covalency. The P NMR data for [Th(PH)(Tren)] (, Tren = {N(CHCHNSiPr)}), [Th(PH)(Tren)][Na(12C4)] (, 12C4 = 12-crown-4 ether), [{Th(Tren)}(μ-PH)] (), and [{Th(Tren)}(μ-P)][Na(12C4)] () demonstrate a chemical shift anisotropy (CSA) ordering of (μ-P) > (═PH) > (μ-PH) > (-PH) and for the largest CSA for any bridging phosphido unit. The B3LYP functional with 50% Hartree-Fock mixing produced spin-orbit δ values that closely match the experimental data, providing experimentally benchmarked quantification of the nature and extent of covalency in the Th-P linkages in - via Natural Bond Orbital and Natural Localized Molecular Orbital analyses.

Process evaluations of health-promotion interventions in sports settings: a systematic review.

Sports settings have been identified as an ideal place to conduct complex multi-level health-promotion interventions, with the potential to engage a broad audience. Whilst the benefits of delivering health-promotion interventions in sports settings are well documented, such interventions' real-world implementation and success must be better understood. Process evaluations can be conducted to provide information related to an intervention's fidelity, replication, scaling, adoption, and the underlying mechanisms driving outcomes.

Actinide-Actinide Bonding: Electron Delocalisation and σ-Aromaticity in the Tri-Thorium Cluster [{Th(η -C H )(μ-Cl) } K ].

The tri-thorium cluster [{Th(η -C H )(μ -Cl) } {K(THF) } ] (Nature 2021, 598, 72-75) was reported to feature intriguing σ-aromatic bonding between the thorium atoms, a mode of metal-metal bonding unique in the actinide series. However, the presence of this bonding motif has since been challenged by others. Here, we computationally explore electron delocalisation in a molecular cluster fragment of [{Th(η -C H )(μ -Cl) } {K(THF) } ] and examine its responses to an applied magnetic field using a variety of methods.

Comparison of group 4 and thorium M(IV) substituted cyclopentadienyl silanide complexes.

We report the synthesis and characterisation of a series of M(IV) substituted cyclopentadienyl hypersilanide complexes of the general formula [M(Cp){Si(SiMe)}(X)] (M = Hf, Th; Cp = Cp', {CH(SiMe)} or Cp'', {CH(SiMe)-1,3}; X = Cl, CH). The separate salt metathesis reactions of [M(Cp)(Cl)] (M = Zr or Hf, Cp = Cp'; M = Hf or Th, Cp = Cp'') with equimolar K{Si(SiMe)} gave the respective mono-silanide complexes [M(Cp'){Si(SiMe)}(Cl)] (M = Zr, 1; Hf, 2), [Hf(Cp'')(Cp'){Si(SiMe)}(Cl)] (3) and [Th(Cp''){Si(SiMe)}(Cl)] (4), with only a trace amount of 3 presumably formed silatropic and sigmatropic shifts; the synthesis of 1 from [Zr(Cp')(Cl)] and Li{Si(SiMe)} has been reported previously. The salt elimination reaction of 2 with one equivalent of allylmagnesium chloride gave [Hf(Cp'){Si(SiMe)}(η-CH)] (5), whilst the corresponding reaction of 2 with equimolar benzyl potassium yielded [Hf(Cp')(CHPh)] (6) together with a mixture of other products, with elimination of both KCl and K{Si(SiMe)}.

Electronic structure comparisons of isostructural early d- and f-block metal(iii) bis(cyclopentadienyl) silanide complexes.

We report the synthesis of the U(iii) bis(cyclopentadienyl) hypersilanide complex [U(Cp''){Si(SiMe)}] (Cp'' = {CH(SiMe)-1,3}), together with isostructural lanthanide and group 4 M(iii) homologues, in order to meaningfully compare metal-silicon bonding between early d- and f-block metals. All complexes were characterised by a combination of NMR, EPR, UV-vis-NIR and ATR-IR spectroscopies, single crystal X-ray diffraction, SQUID magnetometry, elemental analysis and calculations. We find that for the [M(Cp''){Si(SiMe)}] (M = Ti, Zr, La, Ce, Nd, U) series the unique anisotropy axis is conserved tangential to ; this is governed by the hypersilanide ligand for the d-block complexes to give easy plane anisotropy, whereas the easy axis is fixed by the two Cp'' ligands in f-block congeners.

Synthesis and Characterization of Yttrium Methanediide Silanide Complexes.

The salt metathesis reactions of the yttrium methanediide iodide complex [Y(BIPM)(I)(THF)] (BIPM = {C(PPhNSiMe)}) with the group 1 silanide ligand-transfer reagents MSiR (M = Na, R = BuMe or Bu; M = K, R = (SiMe)) gave the yttrium methanediide silanide complexes [Y(BIPM)(SiBuMe)(THF)] (), [Y(BIPM)(SiBu)(THF)] (), and [Y(BIPM){Si(SiMe)}(THF)] (). Complexes provide rare examples of structurally authenticated rare earth metal-silicon bonds and were characterized by single-crystal X-ray diffraction, multinuclear NMR and ATR-IR spectroscopies, and elemental analysis. Density functional theory calculations were performed on to probe their electronic structures further, revealing predominantly ionic Y-Si bonding.

Actinide Pnictinidene Chemistry: A Terminal Thorium Parent-Arsinidene Complex Stabilised by a Super-Bulky Triamidoamine Ligand.

We report the direct synthesis of the terminal pnictidenes [An(Tren )(PnH)][M(2,2,2-cryptand)] (Tren ={N(CH CH NSiCy ) } ; An/Pn/M=Th/P/Na 5, Th/As/K 6, U/P/Na 7, U/As/K 8) and their conversion to the pnictides [An(Tren )(PnH )] (An/Pn=Th/P 9, Th/As 10, U/P 11, U/As 12). Use of the super-bulky Tren ligand was essential to accessing complete families, and 6 is an unprecedented example of a terminal thorium-arsinidene complex and only the second structurally authenticated parent terminal arsinidene complex of any metal. Comparison of the terminal Th=AsH unit of 6 to the bridging ThAs(H)K linkage in structurally analogous [Th(Tren ){μ-As(H)K(15-crown-5)}] (Tren ={N(CH CH NSiPr ) } ) reveals a stronger Th-As bond in the former compared to the latter, and a large response overall to the nature of the Th=AsH bonding upon removal of the electrostatically-bound K-ion; the σ-bond changes little but the π-bond is significantly perturbed.

Mesoionic Carbene Complexes of Uranium(IV) and Thorium(IV).

We report the synthesis and characterization of uranium(IV) and thorium(IV) mesoionic carbene complexes [An{N(SiMe)}(CHSiMeNSiMe){MIC}] (An = U, and Th, ; MIC = {CN(Me)C(Me)N(Me)CH}), which represent rare examples of actinide mesoionic carbene linkages and the first example of a thorium mesoionic carbene complex. Complexes and were prepared via a C-H activation intramolecular cyclometallation reaction of actinide halides, with concomitant formal 1,4-proton migration of an -heterocyclic olefin (NHO). Quantum chemical calculations suggest that the An-carbene bond comprises only a σ-component, in contrast to the uranium(III) analogue [U{N(SiMe)}(MIC)] () where computational studies suggested that the 5f uranium(III) ion engages in a weak one-electron π-backbond to the MIC.

Uranium-nitride chemistry: uranium-uranium electronic communication mediated by nitride bridges.

Treatment of [U(N)(Tren)] (1, Tren = {N(CHCHNSiPr)}) with excess Li resulted in the isolation of [{U(μ-NLi)(Tren)}] (2), which exhibits a diuranium(IV) 'diamond-core' dinitride motif. Over-reduction of 1 produces [U(Tren)] (3), and together with known [{U(μ-NLi)(Tren)}] (4) an overall reduction sequence 1 → 4 → 2 → 3 is proposed. Attempts to produce an odd-electron nitride from 2 resulted in the formation of [{U(Tren)}(μ-NH)(μ-NLi)Li] (5).