Jaqueline L Kiplinger

Jaqueline L Kiplinger
Los Alamos National Laboratory | LANL · Chemistry Division - Inorganic, Isotope and Actinide Chemistry Group (IIAC)

PhD

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117
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Publications

Publications (117)
Article
We report two low-spin diphosphametallocenates [K(2.2.2-crypt)][M(PC 4 Me 4 ) 2 ] (M = Cr, Fe) and propose structural features that allow spin-control in 3d metallocenates.
Article
Full-text available
Aromaticity and antiaromaticity, as defined by Hückel’s rule, are key ideas in organic chemistry, and are both exemplified in biphenylene1,2,3—a molecule that consists of two benzene rings joined by a four-membered ring at its core. Biphenylene analogues in which one of the benzene rings has been replaced by a different (4n + 2) π-electron system h...
Article
Three new uranium species (C5Me5)2U(=N-2,6-iPr2-C6H3)(=S), (C5Me5)2U(=N-2,6-iPr2-C6H3)(η2-S2), and (C5Me5)2U(=N-2,6-iPr2-C6H3)(S=PMe3) were synthesized and fully characterized by a combination of NMR, IR, and UV/vis–NIR spectroscopies, elemental analysis, cyclic voltammetry, and single crystal X-ray diffraction. The compound (C5Me5)2U(=N-2,6-iPr2-C...
Article
Two new uranium metallacyclopropenes, (C5Me4R)2U(η²-Ph2PC[dbnd]CPPh2) (R = Me, Et) were prepared by reducing the corresponding (C5Me4R)2UCl2 complexes with KC8 in the presence of 1,2-bis(diphenylphosphino)acetylene (Ph2P–C[tbnd]C–PPh2). Both compounds were fully characterized by a combination of elemental analysis and multinuclear NMR, UV–visible–N...
Article
Invited for the cover of this issue are JaquelineàL. Kiplinger and co‐workers from Los Alamos National Laboratory, New Mexico, USA. The cover image shows the versatility of trimethyltin fluoride (Me3SnF) as a reagent for the conversion of actinide halides to actinide fluorides. This chemistry is a “pot‐of‐gold”, which allowed us to reach the long‐s...
Article
The Front Cover shows the versatility of trimethyltin fluoride (Me3SnF) as a reagent for the conversion of actinide halides to actinide fluorides. Me3SnF is used with a suite of organometallic actinide chloride, bromide, and iodide complexes towards the synthesis of actinide fluorides. This route is not limited by metal (thorium vs. uranium), oxida...
Article
The sterically encumbered NacNac ligand, [HC(MeCNAr)2]⁻ (Ar = 2,6-i-Pr2C6H3), was investigated as a platform for supporting Lu-halide complexes, sought for their potential capability of being further converted into hydrocarbyl derivatives via metathetical chemistries with alkali metal alkyls. These substituted analogs were targeted as potentially v...
Article
Trimethyltin fluoride (Me₃SnF) is a mild and selective reagent for the installation of actinide fluoride bonds as demonstrated by the room temperature synthesis of a variety of organometallic and inorganic thorium(IV), uranium(IV), and uranium(V) fluoride complexes ((1,2,4-tBu₃C₅H₂)₂ThF₂, (C₅Me₅)₂U(F)(O-2,6-iPr₂C₆H₃), U(F)(O-2,6-tBu₂C₆H₃)₃, U(F)[N(...
Article
The terminal actinide fluoride bonds in (C5Me5)2ThF2(py) (py = pyridine) and (C5Me5)2UF2(O=PR3) (R = Me, Ph) react with two equivalents of Me3SiN3 in toluene to form the polymeric thorium bis(azide), [(C5Me5)2Th(N3)2]∞, and a new class of monometallic uranium bis(azide) complexes, (C5Me5)2U(N3)2(O=PR3), respectively. Full characterization of the no...
Article
The title compound, (E)-1-(2,6-diisopropylphenyl)-2-phenyldiazine (I), was synthesized and characterized using a combination of ¹H, ¹³C, and ¹⁵N NMR spectroscopy, infrared and UV/Vis spectroscopy, X-ray crystallography, and GC mass spectrometry. The solid-state structure is also reported. The unsymmetric azobenzene crystallizes in the space group P...
Article
The reaction of (C 5 Me 5 ) 2 AnCl 2 (An = Th, U) with 2.8 or 4 equivalents of LiNMe 2 , respectively, affords (C 5 Me 5 ) 2 An(NMe 2 ) 2 in high yields. In addition to improved syntheses, the solid-state structures, voltammetric...
Article
The thorium and uranium complexes (C5Me5)2AnMe2, [(C5Me5)2An(H)(µ-H)]2 (An = Th, U) and [(C5Me5)2U(H)]2 dehydrogenate dimethylamine borane (Me2NH·BH3) at room temperature. Upon mild heating at 45 °C, turnover frequencies (TOFs) of 400 h⁻¹ are obtained, which is comparable to some of the fastest Me2NH·BH3 dehydrogenation catalysts known in the liter...
Article
Calcium borohydride allows for the high-yielding synthesis of (C5Me5)2An(η³-H3BH)2 (An = Th, U) by reaction with (C5Me5)2AnCl2 (An = Th, U). While a preparative synthesis of (C5Me5)2U(η³-H3BH)2 has been previously reported in the literature using K(C5Me5) and U(BH4)4, the use of Ca(BH4)2 is higher yielding and mild. Full characterization of the nov...
Article
A new uranium metallacyclocumulene, (C5Me5)(2)U(eta(4)-1,2,3,4-PhC4Ph), was synthesized by both reaction of (C5Me5)(2)UCl2 with 1,4-diphenylbutadiyne in the presence of KC8 and by ligand exchange between (C5Me5)(2)U(eta(2)-Me3SiC2SiMe3) and 1,4-diphenylbutadiyne. Full characterization of (C5Me5)(2)U(eta(4)-1,2,3,4-PhC4Ph) is reported, including the...
Article
Two nitrogen-rich, isostructural complexes of uranium and thorium, (C5Me5)2U[η(2)-(N,N')-tetrazolate]2 (7) and (C5Me5)2Th[η(2)-(N,N')-tetrazolate]2 (8), containing 5-methyltetrazolate, have been synthesized and structurally characterized by single-crystal X-ray diffraction, electrochemical methods, UV-visible-near-IR spectroscopy, and variable-temp...
Article
This work demonstrates that the oxidation state and chemistry of uranium hydrides can be tuned with temperature and the stoichiometry of phenylsilane. The trivalent uranium hydride [(C5Me5)2U-H]x (5) was found to be comprised of an equilibrium mixture of U(III) hydrides in solution at ambient temperature. A single U(III) species can be selectively...
Article
Two organometallic 1D infinite coordination polymers and two organometallic monometallic complexes of thorium diazide have been synthesized and characterized. Steric control of these self-assembled arrays, which are dense in thorium and nitrogen, has also been demonstrated: infinite chains can be circumvented by using steric bulk either at the meta...
Article
Full-text available
The organometallic uranium species (C5Me4R)2UBr2 (R = Me, Et) were obtained by treating their chloride analogues (C5Me4R)2UCl2 (R = Me, Et) with Me3SiBr. Treatment of (C5Me4R)2UCl2 and (C5Me4R)2UBr2 (R = Me, Et) with K(O-2,6-iPr2C6H3) afforded the halide aryloxide mixed-ligand complexes (C5Me4R)2U(O-2,6-iPr2C6H3)(X) (R = Me, Et; X = Cl, Br). Comple...
Article
The thorium and uranium dihydride dimer complexes [(C5Me5)2An(H)(μ-H)]2 (An = Th, U) have been easily prepared using phenylsilane, which is an efficient and safer alternative to hydrogen gas. The synthetic utility of this new hydriding method has been demonstrated by the preparation of a variety of organometallic complexes, including, for the first...
Article
The synthesis and full characterization, including Nuclear Magnetic Resonance (NMR) data ((1)H, (13)C{(1)H} and (119)Sn{(1)H}), for a series of Me3SnX (X = O-2,6-(t)Bu2C6H3 (), (Me3Sn)N(2,6-(i)Pr2C6H3) (), NH-2,4,6-(t)Bu3C6H2 (), N(SiMe3)2 (), NEt2, C5Me5 (), Cl, Br, I, and SnMe3) compounds in benzene-d6, toluene-d8, dichloromethane-d2, chloroform-...
Article
Thorium Iodide—Running with Scissors 1,2-Dimethoxyethane (DME) is normally a robust ligand for actinide chemistry and the isolation of well-defined oxo and alkoxide complexes resulting from actinide-mediated activation of DME is rare. In their Communication on page 16846 ff., J. L. Kiplinger et al. describe the synthesis and characterization of two...
Article
The synthetic efficacy of thorium tetrachloride bis(dimethoxyethane), ThCl4(DME)2, is improved by adding 1,2-dimethoxyethane (DME) to the reaction mixture. The syntheses of the known metallocene dichlorides (C5Me5)2ThCl2, (1,2,4-tBu3-C5H2)2ThCl2, and (C5Me4Et)2ThCl2 are used to highlight this finding.
Article
A panel of seventeen experts from academia, industry, and government laboratories share their thoughts on a variety of matters of importance to the readership of Organometallics. These include directions for the field and recent breakthroughs (illustrated with selected examples), the interface with green chemistry, the quest for reproducible experi...
Article
Pentafluorophenyl-substituted cyclopentadienide anions are useful ligands for transition metals because the C6F5 substituent is not only highly electron withdrawing but also relatively stable. This chapter presents the synthesis of the monoarylated cyclopentadiene C5H5C6F5 on a useful but manageable scale (50mmol). The sequence begins with a nucleo...
Patent
Full-text available
Method of producing anhydrous thorium(IV) tetrahalide complexes, utilizing Th(NO3)4(H2O)x, where x is at least 4, as a reagent; method of producing thorium-containing complexes utilizing ThCl4(DME)2 as a precursor; method of producing purified ThCl4(ligand)x compounds, where x is from 2 to 9; and novel compounds having the structures:
Patent
Full-text available
UI3(1,4-dioxane)1.5 and UI4(1,4-dioxane)2, were synthesized in high yield by reacting turnings of elemental uranium with iodine dissolved in 1,4-dioxane under mild conditions. These molecular compounds of uranium are thermally stable and excellent precursor materials for synthesizing other molecular compounds of uranium including alkoxide, amide, o...
Article
The coordination behavior of the bulky β-diketiminate ligands N,N′-bis(2,6-diisopropylphenyl)pentane-2,4-diiminate (LMe) and N,N′-bis(2,6-diisopropylphenyl)-2,2–6,6-tetramethylheptane-3,5-diiminate (LtBu) toward ThX4(THF)4 (X = Br, I) and UCl4 has been investigated. The reaction between K[LMe] and ThX4(THF)4 (X = Br, I) afforded the mono(β-diketimi...
Article
The thorium(iv) tetraiodide complex ThI(4)(DME)(2) () (DME = 1,2-dimethoxyethane) has been prepared in high yield by reacting the corresponding chloride complex ThCl(4)(DME)(2) with an excess of trimethylsilyl iodide (Me(3)SiI) in toluene. This new route avoids the use of thorium metal as a reagent. ThI(4)(DME)(2) () exhibits excellent thermal stab...
Article
Trifluoromethyltrimethylsilane, (CH3)3SiCF3, in the presence of CsF serves as an excellent CF3 group-transfer reagent, and reaction with Cp2TiF2 in THF gives the titanocene trifluoromethyl fluoride complex Cp2Ti(CF3)(F) (1; Cp = C5H5) in 60% isolated yield. Reaction of complex 1 with the trimethylsilyl reagents, (CH3)3SiX (X = OTf = OSO2CF3, Cl, Br...
Article
Reaction of (C5Me5)2Lu(Me)(μ-Me)Li(THF)3 (2) with excess 12-crown-4 affords the new separated ion pair complex, [Li(12-crown-4)2][(C5Me5)2LuMe2] (3), in excellent yield. This complex reacts with 2,6-diisopropylaniline and phenylacetylene to give the methyl amide complex [Li(12-crown-4)2][(C5Me5)2Lu(Me)(NH-2,6-iPr2C6H3)] (4) and the bis(acetylide) c...
Article
Reaction of the trivalent uranium complex U(O-2,6-tBu2C6H3)3(THF) (4) with copper(I) iodide affords the corresponding uranium(IV) mixed iodide–aryloxide complex (I)U(O-2,6-tBu2C6H3)3(THF) (5). The oxidative functionalization protocol can also be extended to the synthesis of (Cl)U[N(SiMe3)2]3 (7) from the reaction of the tris(amide) uranium(III) com...
Article
Abstract The title compound (C5Me5)2Th[-N=C(Ph)(tpy)]2 (1) (Ph=C6H5, tpy=2,2′:6′,2″-terpyridine) was synthesized and characterized by NMR spectroscopy, elemental analysis, and X-ray crystallography. This system represents the first example of an actinide complex featuring ketimide ligands with both a phenyl group and a terpyridyl group. The complex...
Article
A new inverted sandwich of a μ-η(6),η(6)-toluene diuranium complex reacted with quinoxaline to form a tetranuclear macrocycle with ferrocene diamide uranium(IV) vertices and reduced quinoxaline edges.
Article
AbstractThe title compound (C5Me5)2U(OtBu)(SePh) (1) was synthesized and characterized by NMR spectroscopy, elemental analysis, and X-ray crystallography. This system represents a unique example of an actinide complex with two different group 16 elements coordinated to the metal center and the first mixed-ligand actinide alkoxide-selenide complex....
Article
Reaction of the trivalent uranium complex (C5Me5)2U(O-2,6-iPr2C6H3)(THF) (1) with copper(I) chloride affords the corresponding tetravalent mixed-ligand aryloxide–chloride complex (C5Me5)2U(O-2,6-iPr2C6H3)(Cl) (2). The oxidative functionalization protocol cannot be extended to the synthesis of (C5Me5)2U(O–tBu)(Cl) (3) since the corresponding trivale...
Article
The uranium(III) and uranium(IV) iodide complexes UI3(1,4-dioxane)1.5 and UI4(1,4-dioxane)2 have been easily prepared in high yield by reacting uranium turnings with a 1,4-dioxane solution of iodine under mild conditions. The two complexes exhibit outstanding thermal stability and are excellent precursors to a variety of uranium(III), uranium(IV),...
Article
Full-text available
Uranium nitride [U[triple bond]N](x) is an alternative nuclear fuel that has great potential in the expanding future of nuclear power; however, very little is known about the U[triple bond]N functionality. We show, for the first time, that a terminal uranium nitride complex can be generated by photolysis of an azide (U-N=N=N) precursor. The transie...
Article
A series of uranium(IV) mixed-ligand amide–halide/pseudohalide complexes (C5Me5)2U[N(SiMe3)2](X) (X=F (1), Cl (2), Br (3), I (4), N3 (5), NCO (6)), (C5Me5)2U(NPh2)(X) (X=Cl (7), N3 (8)), and (C5Me5)2U[N(Ph)(SiMe3)](X) (X=Cl (9), N3 (10)) have been prepared by one electron oxidation of the corresponding uranium(III) amide precursors using either cop...
Article
Reaction of the uranium alkyl complex (C(5)Me(5))(2)UMe(2) (1) with Et(3)N.3HF in toluene in the presence of a donor ligand (pyridine or trimethylphosphine oxide) results in gas evolution and the formation of the uranium(IV) difluoride complexes (C(5)Me(5))(2)UF(2)(L) (L = NC(5)H(5) (2), Me(3)P=O (3)). Similarly, reaction of (C(5)Me(5))(2)U[kappa(2...
Article
A comparative examination of the electronic interactions across a series of trimetallic actinide and mixed lanthanide-actinide and lanthanum-actinide complexes is presented. Using reduced, radical terpyridyl ligands as conduits in a bridging framework to promote intramolecular metal-metal communication, studies containing structural, electrochemica...
Article
Anhydrous thorium tetrachloride complexes ThCl(4)(DME)(2), ThCl(4)(1,4-dioxane)(2), and ThCl(4)(THF)(3.5) have been easily accessed from inexpensive, commercially available reagents under mild conditions and serve as excellent precursors to a variety of thorium(iv) halide, alkoxide, amide and organometallic compounds.
Article
Actinide complexes of the redox-active ligand dpp-BIAN2− (dpp-BIAN = 1,2-bis(2,6-diisopropylphenylimino)acenaphthylene), U(dpp-BIAN)2 (1), U(dpp-BIAN)2(THF) (1-THF), and Th(dpp-BIAN)2(THF) (2-THF), have been prepared. Solid-state magnetic and single-crystal X-ray data for complex 1 indicate a ground-state UIV−π*4 configuration, whereas a (dpp-BIAN)...
Article
This feature article presents a comprehensive overview of pentavalent uranium systems in non-aqueous solution with a focus on the various synthetic avenues employed to access this unusual and very important oxidation state. Selected characterization data and theoretical aspects are also included. The purpose is to provide a perspective on this rapi...
Article
A soft embrace for U: Replacement of C(5)Me(5) by the soft PNP pincer ligand is a successful strategy to promote new reactivities and support new structures for the actinide series (see picture, py-O = pyridine-N-oxide). The specific electronic and steric properties of the PNP ligand enable access to previously unreported structures not available f...
Article
A standing iceberg illustrates how the soft PNP pincer ligand challenges the metallocene dominance (ship) in actinide chemistry, as described by J. L. Kiplinger and co-workers in their Communication on page 3681 ff. Replacement of C(5)Me(5) by the PNP ligand is a successful strategy for the promotion of new reactivities and to support new actinide...
Article
Communication is important: The dimeric bis(imido) uranium complex [{U(NtBu)(2)(I)(tBu(2)bpy)}(2)] (see picture; U green, N blue, I red) has cation-cation interactions between [U(NR)(2)](+) ions. This f(1)-f(1) system also displays f orbital communication between uranium(V) centers at low temperatures, and can be oxidized to generate uranium(VI) bi...
Article
A safe gold-based oxidative functionalization protocol has been developed, which allows access to an assortment of uranium complexes bearing azido- and carbon-functional groups. Alkyl, alkynyl, and azido complexes are accessed in a single step from commercially available or easily prepared gold complexes. This methodology works for UIII UIV and UIV...
Article
Oxidation of (C(5)Me(5))(2)U([double bond, length as m-dash]N-2,6-(i)Pr(2)-C(6)H(3))(THF) with PhE-EPh yields the corresponding U(V)-chalcogenate complexes (C(5)Me(5))(2)U([double bond, length as m-dash]N-2,6-(i)Pr(2)-C(6)H(3))(EPh) (E = S, Se, Te) in excellent (>90%) isolated yields.
Article
The coordination behavior of the bis[2-(diisopropylphosphino)-4-methylphenyl]amido ligand (PNP) toward UI3(THF)4 and UCl4 has been investigated to access new uranium(III) and uranium(IV) halide complexes supported by one and two PNP ligands. The reaction between (PNP)K (6) and 1 equiv of UI3(THF)4 afforded the trivalent halide complex (PNP)UI2(4-tB...
Article
Uranium(V)-imido complexes have been prepared using a combination of synthetic routes (direct oxidation, salt metathesis, protonolysis, insertion). These UV organometallic systems show reversible UV/UIV and UVI/UV redox behavior in addition to classic 5f1 spectroscopic signatures. A correlation between the oxidation potentials and C5Me5 chemical sh...
Article
Migratory insertion of diphenyldiazomethane into both metal-carbon bonds of the bis(alkyl) and bis(aryl) complexes (C(5)Me(5))(2)AnR(2) yields the first f-element bis(hydrazonato) complexes (C(5)Me(5))(2)An[eta(2)-(N,N')-R-N-N=CPh(2)](2) [An = Th, R = CH(3) (18), PhCH(2) (15), Ph (16); An = U, R = CH(3) (17), PhCH(2) (14)], which have been characte...
Article
Reaction of the trivalent uranium complexes (C5Me5)2UI(THF) (1), (C5Me5)2U[N(SiMe3)2] (3), (C5Me5)2U(NPh2)(THF) (4), and (C5Me5)2U(O-2,6-iPr2-C6H3)(THF) (5) with copper(I) iodide affords the corresponding tetravalent uranium diiodide, amide iodide, and aryloxide iodide complexes (C5Me5)2UI2 (2), (C5Me5)2U[N(SiMe3)2](I) (6), (C5Me5)2U(NPh2)(I) (7) a...
Article
Reaction of two equivalents of [(C5Me4Et)2U(CH3)(Cl)] (6) or [(C5Me5)2Th(CH3)(Br)] (7) with 1,4-dicyanobenzene leads to the formation of the novel 1,4-phenylenediketimide-bridged bimetallic organoactinide complexes [((C5Me4Et)2(Cl)U)(2)(mu-(N=C(CH3)-C6H4-(CH3)C=N))] (8) and [((C5Me5)2(Br)Th)2(mu-(N=C(CH3)-C6H4- (CH3)C==N))] (9), respectively. These...
Article
Ultrafast pump-probe spectroscopic studies have been performed on (C 5Me 5) 2U[- N=C(Ph)(CH 2Ph)] 2 and (C 5Me 5) 2Th[- N=C(Ph)(CH 2Ph)] 2 including, for the uranium complex, the first direct measurement of dynamics of electronic deactivation within a 5f-electron manifold. Evidence has been found for strong coupling between the electronic ground st...
Article
A new complex, Cp* 2Sm(tpy) ( 1, where Cp* = C 5Me 5, tpy = 2,2':6',2''-terpyridine) and its one-electron oxidized congener [Cp* 2Sm(tpy)]PF 6 ([ 1] (+)) have been synthesized and characterized with the aim of comparing their electronic and magnetic behavior to the known ytterbium analogues: Cp* 2Yb(tpy) ( 2) and [Cp* 2Yb(tpy)]OTf ([ 2] ( + )). The...
Article
Demonstrating the first application of any Cu-oxidation protocol to the UIV/UIII redox couple, both uranium(V) imide and uranium(IV) amide acetylide complexes have been prepared by chemical oxidation of the corresponding uranium(IV) imide and uranium(III) amide complexes using copper(I) phenylacetylide. These new uranium acetylide systems show reve...
Article
Hetero- and homo-trimetallic thorium and uranium complexes with mixed-valent metal centers have been prepared and studied by electrochemical (see picture; Tpy=2,2′:6′,2′′-terpyridine), spectroscopic, and magnetic analyses. Appreciable electronic interaction has been detected in this system with the UIV ion facilitating communication to the UIII cen...
Article
Reaction of (C5Me5)2U(=N-2,4,6-(t)Bu3-C6H2) or (C5Me5)2U(=N-2,6-(i)Pr2-C6H3)(THF) with 5 equiv of CuX(n) (n = 1, X = Cl, Br, I; n = 2, X = F) affords the corresponding uranium(V)-imido halide complexes, (C5Me5)2U(=N-Ar)(X) (where Ar = 2,4,6-(t)Bu3-C6H2 and X = F (3), Cl (4), Br (5), I (6); Ar = 2,6-(i)Pr2-C6H3 and X = F (7), Cl (8), Br (9), I (10))...
Article
4,4′-Di-tert-butyl-2,2′-bipyridyl (tBu2bpy) stabilizes the thermally sensitive [Lu(CH2SiMe3)3] unit, giving the isolable lutetium(III) (trimethylsilyl)methyl complex (tBu2bpy)Lu(CH2SiMe3)3 (4). This tris(alkyl) complex does not undergo alkane elimination, and it readily reacts with Ph3COH, H2N-2,6-iPr2-C6H3, H2N-2,4,6-tBu3-C6H2, and N,N′-dicyclohex...
Article
The first lanthanide complex featuring a phosphinidene functional group has been prepared and isolated. Preliminary reactivity studies demonstrate that the lutetium(III) phosphinidene complex, [{2-(iPr2P)-4-Me-C6H3}2NLu]2(μ-PMes)2, behaves as a phospha-Wittig reagent with aldehydes and ketones to give the corresponding phosphaalkenes. Attempts to u...
Article
Lutetium alkyl complexes supported by a monoanionic, tridentate ligand system formed by the dearomatization and functionalization of a 2,2′:6′,2′′-terpyridine have been reacted with 2,4,6-triphenylaniline or the fluorinated anilines 4-F-C6H4NH2 and C6F5NH2 to give both terminal mono(amide) and bis(amide) lutetium(III) complexes, which have been ful...
Article
Actinide complexes of the redox-active ligand dpp-BIAN² (dpp-BIAN = bis(2,6-diisopropylphenyl)acenaphthylene), An(dpp-BIAN)(THF){sub n} (An = Th, n = 1; An = U, n = 0, 1) have been prepared. Solid-state magnetic and single-crystal X-ray data for U(dpp-BIAN)(THF){sub n} show when n = 0, the complex exists in an f²-* configuration; whereas an intramo...
Article
Gold has had a profound impact on organic chemistry; its compounds are spectacular catalysts for many organic transformations involving the formation of C-C, C-O, C-N and CoS bonds, and have enabled unprecedented pathways for the functionalization of C-H and C-C bonds. In general, gold complexes have not been exploited as reagents in organometallic...
Article
Magnetic coupling between two or more metal centers is an important facet of d- and f-block transition metal chemistry due to its implications in chemical bonding. With respect to actinide metals, magnetic coupling between polymetallic actinide centers is less well-known. Of the few documented examples, only one bimetallic uranium(V) complex, [(MeC...
Article
Uranium(V)-imido-iodide complexes have been prepared by chemical oxidation of the corresponding uranium(IV)-imido complexes with copper(I) iodide. These U(V) organometallic systems show reversible U-V/U-IV and U-VI/U-V redox behavior in addition to classic 50 spectroscopic signatures. The generality of this Cu(I)-based oxidation protocol is demonst...
Article
The thorium alkyl complex (C5Me5)2Th(CH3)2 and 2-picoline react to give preferential sp3 C–H bond activation in the presence of a more reactive sp2 C–H bond, while the analogous uranium complex, (C5Me5)2U(CH3)2, reacts with only the ortho 2-picoline sp2 C–H bond, as originally expected. Herein, we describe this competitive sp3 versus sp2 C–H bond a...
Article
Thorium(IV) is often considered to show similar chemistry to Group IV transition metals. However, studies in our laboratory have shown that this generalization is incorrect. This report presents direct comparisons where the Th(IV) metallocene complexes (C5Me5)2ThR2 (R = CH3, Ph, CH2Ph) undergo unique chemical reactivity with pyridine, 2-picoline, p...
Article
The reaction of (C5Me5)2U(CH3)2 with 2 equiv of N[triple bond]C-ArF gives the fluorinated uranium(IV) bis(ketimide) complexes (C5Me5)2U[-N=C(CH3)(ArF)]2 [where ArF=2-F-C6H4 (4), 3-F-C6H4 (5), 4-F-C6H4 (6), 2,6-F2-C6H3 (7), 3,5-F2-C6H3 (8), 2,4,6-F3-C6H2 (9), 3,4,5-F3-C6H2 (10), and C6F5 (11)]. These have been characterized by single-crystal X-ray d...
Article
Molecular materials of transition metal ions and organic acceptors of the general formula M(TCNX)2 M=V, Mn, Fe, Co, Ni; X=Q=7,7,8,8-tetracyano-p-quinodimethane, E=tetracyanoethylene, are known to exhibit magnetic ordering resulting from magnetic interactions between the 3d metal orbitals of the paramagnetic metal ion and pi* orbitals of the organic...
Article
Reaction of (C5Me5)Lu(CH2SiMe3)2(THF) with pyridine results in the activation of an ortho C−H bond to form the corresponding η2-(N,C)-pyridyl complex with elimination of SiMe4. This is a rare example of pyridine metalation at a lanthanide metal center in the absence of a bent metallocene framework. The η2-(N,C)-pyridyl coordination mode was confirm...
Article
Reaction of (C5Me5)2Th(CH3)2 with 2 equiv of NC-ArF gives the corresponding fluorinated thorium(IV) bis(ketimide) complexes (C5Me5)2Th[-N=C(CH3)(ArF)]2 (where ArF = 3-F-C6H4 (4), 4-F-C6H4 (5), 2-F-C6H4 (6), 3,5-F2-C6H3 (7), 3,4,5-F3-C6H2 (8), 2,6-F2-C6H3 (9), 2,4,6-F3-C6H2 (10), and C6F5 (11)). The complexes have been characterized by a combination...
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An eight-membered thorium(IV) tetraazamacrocycle is produced by the sequential, metal-mediated coupling of four equivalents of 4-fluorobenzonitrile; its formation is consistent with the involvement of an imido intermediate, generated from a thorium ketimide complex.
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Studies in our laboratory have shown that the thorium(IV) complexes (C5Me5)2ThPh2 and (C5Me5)2Th(CH2Ph2)2 mediate carbon–nitrogen bond cleavage and dearomatization of the pyridine ring in pyridine N-oxide. Based upon these results, we examined the analogous chemistry with a variety of pyridine compounds to determine if the electron-withdrawing oxyg...
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Lutetium(III)-bis(alkyl) and -tris(alkyl) fragments supported by either 2,2':6',2' '-terpyridine or 4,4',4' '-tri-tert-butyl-2,2':6',2' '-terpyridine are not stable and undergo facile 1,3-alkyl migration under ambient conditions resulting in dearomatization and ortho (2' or 6') functionalization of the terpyridyl ligand, clearly demonstrating that...
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(Figure Presented) Heavy metal triangles: A class of actinide metallomacrocycles has been prepared in which three (C5Me 5)2An (An = Th, U) fragments are coordinated by three 5,6-dicyano-1-methyl-3-(N-methylamino)-isoindolyl bridging ligands (N blue). The tetravalent actinide centers form a triangular array in the products obtained through an unprec...
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Novel 4f-5f complexes of U(IV) and Th(IV) with Yb have been prepared using a terpyridyl-functionalized ketimide linking group. These 4f-5f heterotrimetallic complexes (C5Me5)2An[-N=C(CH2C6H5)(tpyYb(C5Me5)2)]2 (where An = Th, U) exist in Yb(II/III) valence equilibria and exhibit rich electrochemical behavior consistent with electronic coupling betwe...