Highly stereoselective and stereodivergent synthesis of four types of THF cores in acetogenins using a C4-chiral building block

[reaction: see text] Four stereoisomers of the THF cores, synthetic intermediates of acetogenins, have been synthesized with high diastereoselectivity by asymmetric alkynylation and subsequent stereodivergent THF ring formation. The asymmetric alkynylation of alpha-oxyaldehyde with (S)-3-butyne-1,2-diol derivatives (C4-unit) gave good yields of syn and anti adducts with >97:3 dr and 94:6 dr, respectively. These adducts were converted into the four types of THF compounds via one-pot THF formation or via intramolecular Williamson synthesis.     

Synthesis, structure and magnetic behavior of five-coordinate bis(iminopyrrolyl) complexes of cobalt(II) containing PMe3 and THF ligands

The new bis-iminopyrrolyl five-coordinate Co(II) complexes [Co(kappa (2) N, N'-NC 4H 3C(R)N-2,6- (i)Pr 2C 6H 3) 2(PMe 3)] (R = H 3a; Me 3b) were synthesized in high yields (ca. 80-90%), using THF and diethyl ether as solvents, respectively, by (a) treatment of CoCl 2(PMe 3) 2 with the corresponding iminopyrrolyl Na salts ( Ie or If) or (b) reaction of anhydrous CoCl 2 and PMe 3 with Ie or If. A third route was tested, involving the addition of excesses of PMe 3 to the complexes [Co(kappa (2) N, N'-NC 4H 3C(R)N-2,6- (i)Pr 2C 6H 3) 2] (R = H 1e; Me 1f), which was only successful for the synthesis of 3a, in lower yields (ca. 30%). The synthesis of 3b in THF was unfruitful because of the kinetic competition of the solvent, giving rise to mixtures of 1f and its coordinated THF adduct 4b. The synthesis of the new bis-iminopyrrolyl five-coordinate Co(II) complexes [Co(kappa (2) N, N'-NC 4H 3C(R)N-2,6- (i)Pr 2C 6H 3) 2(THF)] (R = H 4a; Me 4b) were carried out in high yields (ca. 80-90%) by the reaction of CoCl 2(THF) 1.5 with the corresponding iminopyrrolyl Na salt. All the compounds have been characterized by X-ray diffraction, with 3a and 3b showing axially compressed trigonal bipyramidal geometry (with the PMe 3 ligand lying on the equatorial plane), whereas complexes 4a and 4b exhibit distorted square pyramidal geometries with the THF molecule occupying the axial position. Complex 4a shows clearly a compressed geometry, but for complex 4b, two polymorphs were characterized, exhibiting molecules with different Co-O (THF) bond lengths, one of them being compatible with an elongated form. Magnetic measurements either in the solid or in the liquid phases indicate that complexes 3a and 3b have low-spin ground states ( S = 1/2). In toluene solution, the geometry is fully confirmed by EPR data, which further indicates a d x (2) - y (2) /d xy ground state. However, compounds 4a and 4b behave unusually because they show magnetic moments that are compatible with high-spin ground states ( S = 3/2) in the solid state, but conform to low-spin ground states ( S = 1/2) when both complexes are dissolved in toluene solutions. The low-spin ground states in toluene solution are confirmed by EPR spectroscopy, which further supports, for complexes 4a and 4b, an axially elongated square pyramidal geometry and a d z (2) ground state. Thus the change in the ground-state and, consequently, in the geometry of complexes 4a and 4b from solid state to toluene solution might be a consequence of the elongation of the Co-O(THF) bond length. DFT studies performed on complexes 3 and 4 corroborate their different structure and magnetic behaviors and verify, for the latter complexes, the structural differences observed in the solid state and in toluene solution.     

Simulating the synthesis and thermodynamic characteristics of the desolvation of lanthanide borohydride tris-Tetrahydrofuranates

Lanthanide borohydride tris-tetrahydrofuranates (Ln(BH₄) · 3THF, where THF is tetrahydrofuran and Ln is La, Nd, Sm, Gd, Er, Yb, and Lu) is synthesized via the exchange reaction of lanthanide(III) chloride and sodium borohydride in THF. It is found that synthesis proceeds according to a stepwise mechanism and the product of the reaction (lanthanide borohydride) initiates the process. The two-step character of the desolvation of Ln(BH₄)₃ · 3THF under steady-state conditions in the temperature range of 300 to 400 K is determined through X-ray phase and chemical analyses, tensiometry, and gas volumetry. It is established that one mole and then two moles of THF are removed from the initial sample at the first and second steps, respectively. Equations for barograms are obtained and the thermodynamic characteristics of desolvation of Ln(BH₄)₃ · 3THF under study are calculated. Gibbs energy values of the stages of process are determined semi-empirically. The law of its change for the entire series of Ln(BH₄)₃ · 3THF is determined with the emergence of the tetrad effect.     

Bonding along a linear B...N...B triad

The synthesis of tris(2,6-dihydroxyphenyl)amine diborate, 4, is reported. This compound contains a linear B...N...B array for which a symmetrical three-center two-electron (3c-2e) bond is possible. The X-ray crystal structure of 4 shows that 3c-2e bonding is, in fact, absent. Rather, the B-N-B array of 4 is unsymmetrical, having a 2c-2e B-N dative bond with the remaining boron pyramidalized outward and bonded to the oxygen of THF, i.e., 4 x THF. In THF solution, 4 displays temperature-dependent 13C NMR spectra from which a DeltaG++ of 11.6 kcal/mol at 262 K may be calculated. The dynamic process observed in solution corresponds to a bond-switching equilibrium in which the B-N bond oscillates between the two borons ("bell clapper"). Ab initio calculations indicate that the most likely pathway for the bond switch does not involve a 3c-2e B...N...B bond, but rather occurs by nucleophilic attack of THF on the datively bonded boron to generate 4 x (THF)2, lacking any B-N interactions, followed by loss of one THF. The B-N-B system of 4 sans the perturbing effect of solvent was also investigated computationally. The form of 4 containing a 3c-2e bond is found to be a transition state in the solvent-free bond-switch reaction of 4, lying 2.66 kcal/mol above 4. The stability of three-center bonds to in-line distortion (viz., X...Y...X --> X-Y.........X) is discussed from the point of view of the second-order Jahn-Teller effect.     

Synthesis and molecular structures of phenylamides of magnesium, calcium, strontium, and barium--from molecular to polymeric structures

Several preparative procedures for the synthesis of the THF complexes of the alkaline earth metal bis(phenylamides) of Mg (1), Ca (2), Sr (3), and Ba (4) are presented such as metalation of aniline with strontium and barium, metathesis reactions of MI2 with KN(H)Ph, and metalation of aniline with arylcalcium compounds or dialkylmagnesium. The THF content of these compounds is rather low and an increasing aggregation is observed with the size of the metal atom. Thus, tetrameric [(THF)2Ca{mu-N(H)Ph}2]4 (2) and polymeric [(THF)2Sr{mu-N(H)Ph}2]infinity and {[(THF)2Ba{mu-N(H)Ph}2]2[(THF)Ba{mu-N(H)Ph}2]2}infinity show six-coordinate metal atoms with increasing interactions to the pi systems of the phenyl groups with increasing the radius of the alkaline earth metal atom.     

Synthesis and X-ray structure of the [{Fe3(CO)9(micro3-O)}2H]3- trianion: dimerization of a metal carbonyl cluster via formation of an exceptionally short hydrogen bond

The synthesis, structure and characterization of the [{Fe3(CO)9(micro3-O)}2H]3- trianion in its [Cs(THF)0.33]+ and [NEt4]+ salt are reported. The title dimeric cluster has been obtained by protonation in water or in organic solvent of the [Fe3(CO)9(micro3-O)]2- dianion to the hydroxo [Fe3(CO)9(micro3-OH)]- derivative and crystallization. The solid state structure of [Cs(THF)0.33]3[{Fe3(CO)9(micro3-O)}2H] is based on ionic packing of [Cs(THF)0.33]+ cations and [{Fe3(CO)9(micro3-O)}2H]3- trianions. The fractional formula is due to the particular packing of Cs+ cations, which are at the vertices of fused cuboctahedral and trigonal antiprismatic polyhedrons. Each cuboctahedron encapsulates a [{Fe3(CO)9(micro3-O)}2H]3- trianion, whereas each trigonal antiprism encapsulates a THF molecule. The possibility that the structure of the [{Fe3(CO)9(micro3-O)}2H]3- trianion could be affected by its confinement in the cuboctahedral cage of Cs+ ions and the heavy disorder of the THF molecule urged a further structural determination of the trianion with a completely different cation. The corresponding [NEt4]3[{Fe3(CO)9(micro3-O)}2H] salt has been, therefore, prepared and structurally characterized. The [{Fe3(CO)9(micro3-O)}2H]3- trianion displays an identical structure and almost coincident molecular parameters in both salts. Its most notable feature is represented by the unique hydrogen atom symmetrically bridging the micro3-O atoms of two different [Fe3(CO)9(micro3-O)]2- molecules and displaying one of shortest O...H...O interaction so far reported in organic, inorganic and organometallic literature. The structure of [Cs(THF)]2[Fe4(CO)13], which has been obtained as a by-product of the synthesis of [Cs(THF)0.33]3[{Fe3(CO)9(micro3-O)}2H], is also briefly reported.     

Allyl strontium compounds: synthesis, molecular structure and properties

The synthesis and attempted isolation of neutral bis(allyl)strontium [Sr(C(3)H(5))(2)] (1) resulted in the isolation of potassium tris(allyl)strontiate K[Sr(C(3)H(5))(3)] (2). In situ generated 1 shows a pronounced Br?nsted basicity, inducing polymerisation of THF. Ate complex 2 crystallises as [K(THF)(2){Sr(C(3)H(5))(3)}(THF)](∞) (2·(THF)(3)). The salt-like solid state structure of 2·(THF)(3) comprises a two-dimensional network of (μ(2)-η(3):η(3)-C(3)H(5))(-) bridged potassium and strontium centres. Synthesis of allyl complexes 1 and 2 utilised SrI(2), [Sr(TMDS)(2)] (3) (TMDS = tetramethyldisilazanide), and [Sr(HMDS)(2)] (HMDS = hexamethyldisilazanide) as strontium precursors. The solid state structure of previously reported [Sr(TMDS)(2)] (3) was established by X-ray single crystal analysis as a dissymmetric dimer of [Sr(2)(TMDS)(4)(THF)(3)] (3·(THF)(3)) with multiple Si-HSr agostic interactions. The presence of ether ligands (THF, 18-crown-6) influenced the Si-HSr resonances in the NMR spectra of the amido complex 3.     

Synthesis and structural characterization of beta-diketiminate-lanthanide amides and their catalytic activity for the polymerization of methyl methacrylate and epsilon-caprolactone

The synthesis and catalytic activity of lanthanide monoamido complexes supported by a beta-diketiminate ligand are described. Donor solvents, such as DME, can cleave the chloro bridges of the dinuclear beta-diketiminate ytterbium dichloride {[(DIPPh)2nacnac]YbCl(mu-Cl)3Yb[(DIPPh)2nacnac](THF)} (1) [(DIPPh)2nacnac = N,N-diisopropylphenyl-2,4-pentanediimine anion] to produce the monomeric complex [(DIPPh)2nacnac]YbCl2(DME) (2) in high isolated yield. Complex 2 is a useful precursor for the synthesis of beta-diketiminate-ytterbium monoamido derivatives. Reaction of complex 2 with 1 equiv of LiNPri2 in THF at room temperature, after crystallization in THF/toluene mixed solvent, gave the anionic beta-diketiminate-ytterbium amido complex [(DIPPh)2nacnac]Yb(NPri2)(mu-Cl)2Li(THF)2 (3), while similar reaction of complex 2 with LiNPh2 produced the neutral complex [(DIPPh)2nacnac]Yb(NPh2)Cl(THF) (4). Recrystallization of complex 3 from toluene solution at elevated temperature led to the neutral beta-diketiminate-lanthanide amido complex [{(DIPPh)2nacnac}Yb(NPri2)(mu-Cl)]2 (5). The reaction medium has a significant effect on the outcome of the reaction. Complex 2 reacted with 1 equiv of LiNPri2 and LiNC5H10 in toluene to produce directly the neutral beta-diketiminate-lanthanide amido complexes 5 and [{(DIPPh)2nacnac}Yb(NC5H10)(THF)(mu-Cl)]2 (6), respectively. These complexes were well characterized, and their crystal structures were determined. Complexes 4-6 exhibited good catalytic activity for the polymerization of methyl methacrylate and epsilon-caprolactone.     

Iron-arylimide clusters [Fe(m)()(NAr)(n)Cl(4)](2)(-) (m,n = 2, 2; 3, 4; 4, 4) from a ferric amide precursor: synthesis,characterization, and comparison to Fe-S chemistry

Tetrahedral FeCl[N(SiMe(3))(2)](2)(THF) (2), prepared from FeCl(3) and 2 equiv of Na[N(SiMe(3))(2)] in THF, is a useful ferric starting material for the synthesis of weak-field iron-imide (Fe-NR) clusters. Protonolysis of 2 with aniline yields azobenzene and [Fe(2)(mu-Cl)(3)(THF)(6)](2)[Fe(3)(mu-NPh)(4)Cl(4)] (3), a salt composed of two diferrous monocations and a trinuclear dianion with a formal 2 Fe(III)/1 Fe(IV) oxidation state. Treatment of 2 with LiCl, which gives the adduct [FeCl(2)(N(SiMe(3))(2))(2)](-) (isolated as the [Li(TMEDA)(2)](+) salt), suppresses arylamine oxidation/iron reduction chemistry during protonolysis. Thus, under appropriate conditions, the reaction of 1:1 2/LiCl with arylamine provides a practical route to the following Fe-NR clusters: [Li(2)(THF)(7)][Fe(3)(mu-NPh)(4)Cl(4)] (5a), which contains the same Fe-NR cluster found in 3; [Li(THF)(4)](2)[Fe(3)(mu-N-p-Tol)(4)Cl(4)] (5b); [Li(DME)(3)](2)[Fe(2)(mu-NPh)(2)Cl(4)] (6a); [Li(2)(THF)(7)][Fe(2)(mu-NMes)(2)Cl(4)] (6c). [Li(DME)(3)](2)[Fe(4)(mu(3)-NPh)(4)Cl(4)] (7), a trace product in the synthesis of 5a and 6a, forms readily as the sole Fe-NR complex upon reduction of these lower nuclearity clusters. Products were characterized by X-ray crystallographic analysis, by electronic absorption, (1)H NMR, and M?ssbauer spectroscopies, and by cyclic voltammetry. The structures of the Fe-NR complexes derive from tetrahedral iron centers, edge-fused by imide bridges into linear arrays (5a,b; 6a,c) or the condensed heterocubane geometry (7), and are homologous to fundamental iron-sulfur (Fe-S) cluster motifs. The analogy to Fe-S chemistry also encompasses parallels between Fe-mediated redox transformations of nitrogen and sulfur ligands and reductive core conversions of linear dinuclear and trinuclear clusters to heterocubane species and is reinforced by other recent examples of iron- and cobalt-imide cluster chemistry. The correspondence of nitrogen and sulfur chemistry at iron is intriguing in the context of speculative Fe-mediated mechanisms for biological nitrogen fixation.     

The nucleophilic addition of alpha-metallated 1,3-dioxanes to planar chiral cationic eta3-allylmolybdenum complexes. Synthesis of (2E,5S,6R,7E)-6-methyl-8-phenylocta-2,7-dienoic acid methyl ester, a key component of the Cryptophycins

Two adjacent stereogenic centres and a pendant alkene were constructed via nucleophilic addition of a 1,3-dioxan-4-ylcopper(I) reagent to a cationic eta3-allylmolybdenum complex as part of a synthesis of (2E,5S,6R,7E)-6-methyl-8-phenylocta-2,7-dienoic acid, a key component of the Cryptophycins. Oxidative addition of Mo(CO)(4)(THF)(2) to allyl benzoates provides an efficient synthesis of eta3-allylmolybdenum(dicarbonyl) complexes.     

Oligomerization and oxide formation in bismuth aryl alkoxides: synthesis and characterization of Bi4(mu 4-O)(mu-OC6F5)6(mu 3-OBi(mu-OC6F5)3)2(C6H5CH3), Bi8(mu 4-O)2(mu 3-O)2(mu-OC6F5)16, Bi6(mu 3-O)4(mu 3-OC6F5)(mu 3-OBi(OC6F5)4)3, NaBi4(mu 3-O)2(OC6F5)9(THF)2, and Na2Bi4(mu 3-O)2(OC6F5)10(THF)2

Exposing [Bi(OR)3(toluene)]2 (1, R = OC6F5) to different solvents leads to the formation of larger polymetallic bismuth oxo alkoxides via ether elimination/oligomerization reactions. Three different compounds were obtained depending upon the conditions: Bi4(mu 4-O)(mu-OR)6(mu 3-OBi(mu-OR)3)2(C6H5CH3) (2), Bi8(mu 4-O)2(mu 3-O)2(mu 2-OR)16 (3), Bi6(mu 3-O)4(mu 3-OR)(mu 3-OBi(OR)4)3 (4). Compounds 2 and 3 can also be synthesized via an alcoholysis reaction between BiPh3 and ROH in refluxing dichloromethane or chloroform. Related oxo complexes NaBi4(mu 3-O)2(OR)9(THF)2 (5) and Na2Bi4(mu 3-O)2(OR)10(THF)2 (6) were obtained from BiCl3 and NaOR in THF. The synthesis of 1 and Bi(OC6Cl5)3 via salt elimination was successful when performed in toluene as solvent. For compounds 2-6 the single-crystal X-ray structures were determined. Variable-temperature NMR spectra are reported for 2, 3, and 5.     

Stable analogs of the uranyl ion containing 1,1,3,3-tetramethylguanidine

The reaction of 1,1,3,3-tetramethylguanidine (HTMG) with [UO(2)Cl(2)(THF)2] yielded [UO(2)Cl(2)(HTMG)2] 1, the first uranyl tetralkylguanidine adduct reported, further investigation led to the synthesis of [UO(2)(DBP)2(HTMG)2] 2 and [UO(2)(DBP-4-Me)2(HTMG)2] 3 via the reaction of [UO(2){N(SiMe(3))2}2(THF)2] with HTMG and the appropriate aryl alcohol, HO-2,6-(t)Bu(2)-4-RC(6)H(2) (R = H, DBP; R = CH(3), DBP-4-Me).     

Synthesis of the AB subunit of angelmicin B through a tandem alkoxy radical fragmentation-etherification sequence

The synthesis of the tricyclic enone 2, corresponding to the AB subunit of the novel tyrosine kinase inhibitor angelmicin B, is described. The strategy centers on an intramolecular Diels-Alder (IMDA) reaction on triene 4 to provide the complex decalin 3, which is elaborated to 2. Other key steps are the formation of the THF ring in 2 through a tandem alkoxy radical fragmentation-etherification on the lactol derived from 3, and the synthesis of 4 via a ring-closing ene-yne metathesis (RCEYM).     

Synthesis of Non-Aqueous Neptunium(III) Halide Solvates from NpO2

Two Np(III) halides, NpI₃(THF)₄ and NpBr₃(THF)₄, have been prepared and isolated in high yields as described in this work. Starting with neptunia (NpO₂), NpCl₄(DME)₂ was first generated in an updated, higher yielding synthesis than what was previously reported by using HCl/HF. This material was then reduced with KC₈, followed by subsequent ligand exchange, to generate NpBr₃(THF)₄ and NpI₃-(THF)₄. Full characterization by single-crystal X-ray crystallography, ¹H NMR spectroscopy and electronic absorption spectroscopy confirmed the molecular formulas and oxidation states. These trivalent materials are straightforward to synthesize and can be used as starting materials for non-aqueous Np(III) chemistry, obviating the need for rare and restricted Np metal and elemental halogens.     

Synthesis, structure, and computational studies of the tetrameric magnesium imides [2,4,6-Cl3C6H2NMg.S]4 (S=1,4-dioxane and tetrahydrofuran)

The magnesium imide complexes [(ArNMg.diox)4.3(diox)] (4) and [(ArNMg.THF)4.tol] (5) (where Ar=2,4,6-Cl3C6H2, diox=1,4-dioxane, and THF=tetrahydrofuran) were prepared by the equimolar reaction of Bu2Mg with the primary amine in suitable solvent mixtures. The successful synthesis of the halide-substituted imides is notable because similar reactions with the less acidic organo-substituted anilines cease upon monodeprotonation. Both 4 and 5 form unusual Mg4N4 cubane aggregates in the solid state. Computational studies (HF/6-31G*) indicate that a combination of sterics and metal solvation determines the aggregation state adopted.     

Phosphine-substituted Cubane Clusters with the Mo3S4Ga Core

The reaction of cationic clusters [Mo₃S₄(Dppet)₃X₃]X (I; Dppet = cis-1,2-bis(diphenylphosphino)ethylene; X = Cl, Br) with gallium metal in tetrahydrofuran (THF) affords cubane-like clusters [Mo₃S₄(GaX)(Dppet)₃X₃] (IIa, X = Cl; IIb, X = Br). In the synthesis of IIb, the crystals of the cationic cluster [Mo₃S₄(Dppet)₃Br₃](GaBr₄) (III) were isolated from the mother liquor. The structures of complexes IIa ? 1.5THF, IIb ? 1.5THF, III ? 1.625THF, and [Mo₃S₄(Dppe)₃Br₃](GaBr₄) ? 2THF (IV ? 2THF; Dppe = 1,2-bis(diphenylphosphino)ethane) were established by X-ray diffraction (CIF files CCDC № 1851341–1851344).

     

Synthese und Charakterisierung von Fluorenylgallaten und Fluorenylindaten

Synthesis and Characterization of Fluorenyl Gallates and Fluorenyl Indates GaCl₃ reacts with Fluorenyllithium (LiFl) in the ratio 1:4 in Et₂O to [Li(THF)₄][GaFl₄] ( 1 ). The addition of DME (1,2-dimethoxyethane) to solutions of 1 in THF leads to [Li(DME)₃][GaFl₄] ( 2 ) under replacement of THF molecules by DME molecules in the coordination sphere of the Li⁺ ions. Treatment of InCl with LiFl in Et₂O and recrystallization from THF gives [Li(THF)₄][ClInFl₃] ( 3 ), which is formed by an disproportionation reaction. 3 can also be obtained by the reaction of InCl with FlZnCl/LiCl in Et₂O and recrystallization from THF. 1 and 2 crystallize from THF and THF/DME as [Li(THF)₄][GaFl₄] · THF ( 1 · THF) and [Li(DME)₃][GaFl₄] · THF ( 2 · THF), respectively. Crystalline 3 is isolated from the reaction of InCl and FlZnCl/LiCl, while the reaction mixture of InCl and LiFl gives after recrystallization in THF 3 · 1,5 THF. The gallate ions in 1 and 2 differ mainly in the position of the fluorenyl ligands. The unit cells of 3 and 3 · 1,5 THF contain two crystallographic unique ion pairs of [Li(THF)₄][ClInFl₃].     

An amidinate-stabilized germatrisilacyclobutadiene ylide

The synthesis and characterization of new amidinate-stabilized germatrisilacyclobutadiene ylides [L(3)Si(3)GeL'] (L=PhC(NtBu)(2); L'=?L; ?=Ge (3), Si (7)) are described. Compound 3 was prepared by the reaction of [LSi-SiL] (1) with one equivalent of [LGe-GeL] (2) in THF. Compound 7 was synthesized by the reaction of 2 with excess 1 in THF. The bisamidinate germylene [L(2)Ge:] (4) is a by-product in both reactions. Moreover, compound 7 was prepared by the reaction of 3 with one equivalent of 1 in THF. Compounds 3 and 7 have been characterized by NMR spectroscopy, X-ray crystallography, and theoretical studies. The results show that compounds 3 and 7 are not antiaromatic. The puckered Si(3) Ge four-membered rings in 3 and 7 have a ylide structure, which is stabilized by amidinate ligands and the electron delocalization within the Si(3) Ge four-membered ring.     

Synthesis and structure of diamido ether uranium(IV) and thorium(IV) halide "ate" complexes and their conversion to salt-free bis(alkyl) complexes

The high-yield synthesis, spectroscopic and structural determination of three new uranium(IV) and thorium(IV)ate complexes supported by three different diamido ether ligands are reported. The reaction of Li2[2,6-iPr2PhN(CH2CH2)]2O (Li2[DIPPNCOCN]) with 1 equiv. of UCl4 in THF generates [DIPPNCOCN]UCl3Li(THF)2(1), while reaction in toluene/ether gives salt-free [DIPPNCOCN]UCl2.1/2C7H8(2), which was identified by paramagnetically shifted 1H NMR. Reaction of 0.5 equiv. of {[tBuNON]UCl2}2([tBuNON]=[(CH3)3CN(Si(CH3)2)]2O2-) with 3.5 equiv. LiI in toluene and a minimal amount of THF results in [tBuNON]UI3Li(THF)2(3) and is very similar in structure to 1. {[MesNON]ThCl3Li(THF)}2(4), a dimeric complex with a Th2Li2Cl6 core, is prepared by reaction of Li2[2,4,6-Me3PhN(Si(CH3)2)]2O (Li2[MesNON]) with ThCl4 in THF. The analogous reaction in toluene did not yield the salt-free complex but rather a sterically crowded diligated compound, [MesNON]2Th (5), which was also structurally characterized. Complex 5 was prepared rationally by reacting 2 equiv. Li2[MesNON] with ThCl4 in toluene. The reaction of 1 and 3 with 2 equiv. of LiCH2Si(CH3)3 generates the stable, salt-free organoactinides [DIPPNCOCN]U(CH2Si(CH3)3)2(6) and [tBuNON]U(CH2Si(CH3)3)2(7). Complex 6 was structurally characterized. These reactions illustrate the viability of ate complexes as useful synthetic precursors.     

Homoleptic 2-mercapto benzothiazolate uranium and lanthanide complexes

Treatment of [Ln(BH 4) 3(THF) 3] (Ln = Ce, Nd) with 3 and 4 mol equiv of KSBT in tetrahydrofuran (THF) led to the formation of [Ln(SBT) 3(THF)] and [K(THF)Ln(SBT) 4], respectively. The uranium(IV) compound [U(SBT) 4(THF) 2] was obtained from U(BH 4) 4 and was reversibly reduced by sodium amalgam into the corresponding anionic uranium(III) complex. The crystal structures of [Ln(SBT) 3(THF) 2] (Ln = Ce, Nd), [K(15-crown-5) 2][Nd(SBT) 4], [U(SBT) 4(THF)], and [K(15-crown-5) 2][U(SBT) 4(py)] show the bidentate coordination mode and the thionate character of the SBT ligand.