Simple Lanthanide Amides [(Me3Si)2N]3Ln(μ-Cl)Li(THF)3 as Highly Efficient Catalysts for the Nitroaldol Reaction

This contribution is to report the application of simple lanthanide amides [(Me3Si)2N]3Ln(μ-Cl)Li(THF)3 exhibiting a high activity toward catalyzing Henry reaction of aromatic aldehydes with nitroalkanes to give β-nitroalcohols or β-nitroolefins with a very good chemoselectivity by controlling the reaction temperatures and by selecting aromatic aldehydes. It was found that this catalytic system was compatible with a wide range of substrates of aldehydes.     

[(O)MoCu_3(μ_3-S)_3(μ_3-Cl)(PPh_3)_3]·2THF的合成及其晶体结构

固体化合物(NH_4)_6Mo_7O_(24)·4H_2O和(PPh_3)_2CuCl与饱和液体NH_4HS反应获得桔红针状标题晶体。晶体空间群为P2_1/c,晶胞参数a=11.742(2),b=28.186(7),c=19.304(3),β=100.57(2)°,V=6280.4(?)~3,D_c=1.46g/cm~3,Z=4,F(000)=2816。在3≤2θ≤45°范围内收集到8414个独立衍射强度数据,其中3856个I≥1.5σ(I)强度数据参加结构计算。标题化合物分子是以{MoCu_3S_3Cl}类立方烷型簇为核心的分子,Mo—Cu的平均距离为2.716。     

Bulk polymerization of rac-lactide initiated by guanidinate alkoxide complexes of rare earth metals. The molecular structure of the cluster [{(Me3Si)2NC(NPri)2}Nd]4(μ3-OPri)8Li7(μ2-Cl)3(μ3-Cl)2(μ4-Cl)2

The complexes {(Me₃Si)₂NC(NPrⁱ)₂}₂LnOBu^t (Ln = Y (1), Lu (2)) initiate the bulk polymerization of racemic lactide (LA) at 130 °C. At the monomer: initiator molar ratio ([LA]: 1) equal to 1000: 1, the quantitative conversion of the monomer is achieved within 6 h. The resulting polymers are characterized by a rather narrow monomodal molecular weight distribution (M _w/M _n = 1.46–1.82) and molecular weights up to 33400 g mol^?1. The molecular weights of the resulting polylactides measured by gel permeation chromatography are 3–11 times lower than the values calculated from the monomer: initiator ratio on the assumption of one growing polymer chain per catalytic center. The reaction of the in-situ prepared complex [(Me₃Si)₂NC(NPrⁱ)₂]NdCl₂ with 2 equiv. of PrⁱOLi produced the 11-nuclear cluster [{(Me₃Si)₂NC(NPrⁱ)₂}Nd]₄(μ³-OPrⁱ)₈Li₇(μ²-Cl)₃(μ³-Cl)₂(μ⁴-Cl)₂ (3), which was isolated in 62% yield. The structure of compound 3 was established by X-ray diffraction. Complex 3 initiates both the bulk and solution polymerization of rac-lactide. In the bulk polymerization at the molar ratio [LA]: [Nd] = 500: 1, the 89% conversion of the monomer was achieved within one hour. The polylactide thus synthesized has the molecular weight M _n = 19720 g mol^?1 and a rather narrow polydispersity M _w/M _n = 1.54.     

Mixed-ligand guanidinate derivatives of rare-earth metals. Molecular structures of { (Me3Si)2NC(N-cyclo-Hex)2}Y[N(SiMe3)2]2, [{ (Me3Si)2NC(N-cyclo-Hex)2}YbI(THF)2]2, and [{(Me3Si)2N} Y(THF)(µ-Cl)]2 complexes

The insertion of N,N′-dicyclohexylcarbodiimide at one of the Y-N bonds of the [(Me₃Si)₂N]₃Y complex in toluene at 70 °C afforded the monoguanidinate diamide derivative { (Me₃Si)₂NC(N-cyclo-Hex)₂}Y[N(SiMe)₃]₂ (1) (cyclo-Hex is cyclohexyl) in 72% yield. The reaction of equimolar amounts of sodium N,N′-dicyclohexyl-N″-bis(trimethylsilyl)guanidinate, which was prepared in situ from {(Me₃Si)₂N}Na and N,N′-dicyclohexylcarbodiimide, and YbI₂(THF)₂ in THF gave the [{(Me₃Si)₂NC(N-cyclo-Hex)₂}YbI(THF)₂]₂ complex (2). An attempt to use this procedure for the synthesis of the yttrium compound { (Me₃Si)₂NC(NSiMe₃)₂}₂YCl containing the sterically more hindered guanidinate ligand unexpectedly led to the formation of the diamide chloride complex [{(Me₃Si)₂N}₂Y(THF)(µ-Cl)]₂ (3). The structures of complexes 1–3 were established by X-ray diffraction. Compound 1 is mononuclear. Complexes 2 and 3 are dinuclear and contain two µ²-bridging halide ligands.     

Guanidinate borohydride derivatives of lanthanides: synthesis and molecular structures of the [(Me3Si)2NC(NCy)2]Gd(BH4)2DME and [{(Me3Si)2NC(NPri)2}2Sm(BH4)2]−[Li(DME)3]+ complexes. Catalytic activity of the [(Me3Si)2NC(NCy)2]2Ln(BH4)2Li(THF)2 complexes (Ln = Nd, Sm, or Yb) in methyl methacrylate polymerization

The reaction of Gd(BH₄)₃(THF)₂ with two equivalents of sodium N,N′-dicyclohexyl-N″-bis(trimethylsilyl)guanidinate in THF followed by the treatment of the reaction product with 1,2-dimethoxyethane produced the monoguanidinate bis(borohydride) complex [(Me₃Si)₂NC(NCy)₂]Gd(BH₄)₂DME (1) (Cy is cyclohexyl). The treatment of the heterobimetallic samarium complex {(Me₃Si)₂NC(NPrⁱ)₂}₂Sm(BH₄)₂Li(THF)₂, in which the lanthanide and lithium atoms are linked by two bridging borohydride groups, with 1,2-dimethoxyethane afforded the ionic complex [{(Me₃Si)₂NC(NPrⁱ)₂}₂Sm(BH₄)₂]^?[Li(DME)₃]⁺ (2). The structures of complexes 1 and 2 were established by X-ray diffraction. The [(Me₃Si)₂NC(NCy)₂]₂Ln(BH₄)₂Li(THF)₂ complexes (Ln = Nd (3), Sm (4), or Yb (5)) were found to catalyze methyl methacrylate polymerization.     

[C5H4C(CH3)(C3H7)CH2CH=CH2]NdMg2(μ3-OH)(μ3-Cl)(μ2-Cl)3(THF)4Cl的合成和晶体结构分析

用Ｘ－射线衍射法测定了［Ｃ５Ｈ４Ｃ（ＣＨ３）（Ｃ３Ｈ７）ＣＨ２ＣＨ＝ ＣＨ２］ＮｄＭｇ２（μ３－ＯＨ）（μ３－Ｃｌ）（μ２－Ｃｌ）３（ＴＨＦ）４Ｃｌ的晶体结构。它属三斜晶系,空间群为Ｐ１－ ,ａ＝ １２．６９８（３）, ｂ＝ １３．６１６（３）, ｃ＝ １３．７１２（３）, α＝ ６８．９１（３）, β＝ ８４．３４（３）, γ＝ ６３．０７（３）°, Ｖ＝ １９６６（１）３, Ｍｒ＝ ８４９．７４, Ｄｘ＝ １．４１２ ｇ·ｃｍ － ３, μ＝ １．７２９７ ｍ ｍ － １, Ｆ（０００）＝ ８４０, Ｚ＝ ２, Ｒ＝ ０．０７３, ｗ Ｒ＝ ０．０８６（Ｉ≥３σ（Ｉ））。分子中Ｎｄ（Ⅲ）原子的配位数为八,形成一个严重扭曲的八面体结构。两个Ｍｇ 原子的配位情况相似,它们的配位数都是六,构成两个扭曲的八面体。这三个八面体通过三个共用平面联接     

有机镧系络合物[Li(THF)2]2(μ-Cl)4(η^5-C5H5)Ln.THF的合成

Manastyrskyj 等首次报道了重稀土环戊二烯二氯化物 C_5H_5L_nC(?)_2(Ln=Sm～Lu)的合成,但未得到相应的轻稀土环戊二烯基二氯化物。他们把这一结果归因于镧系收缩和配位不     

[Flu(Me)2CCp]2Yb(μ-Br)2Li(THF)2·THF的合成和晶体结构

为考察取代环戊二烯基或桥联环戊二烯基有机稀土化合物的性质,研究了碳桥联芴基环戊二烯基配体与卤化稀土的反应,其中,[2-(9-芴基)异丙基]环戊二烯基锂[Flu(Me)2CCpLi]与三溴化镱(YbBr3)在四氢呋喃(THF)中反应,分离得到了标题配合物[Flu(Me)2CCp]2Yb(μ-Br)2Li(THF)2·THF.X射线单晶结构测定表明配合物属单斜晶系,空间群为P2(1)/n,晶胞参数为a=1.4676(3) nm,b=1.2618(4) nm,c=2.9736(9) nm,β=98.172(18)°,Z=4,V=5.451(2) nm3,Mr=1098.84,Dc=1.339 mg·m-3,R=0.0695,wR=0.1721.中心Yb原子分别与两个环戊二烯基和两个溴原子成键,形成扭曲的四面体配位构型.Yb-Br1和Yb-Br2键长分别为0.2765(1)和 0.2738(1) nm,两个环戊二烯基平面的夹角为125.7°,中心Yb原子与两个环戊二烯基环中心的平均距离分别为0.232和0.231 nm.     

Synthesis and molecular structure of [1, 3-(Me3Si)2C5H3]2Lu(μ-Cl)2

Cp^* ₂Lu(-Cl)₂ (1) was isolated following the reaction of Cp^*Na (Cp^* = 1, 3-(Me₃Si)₂C₅H₃) with LuCl₃ in THF and subsequent treatment with toluene at 80°C. An X-ray structural investigation of1 was performed (MoK radiation, 2933 reflections,R = 0.020). The crystals are triclinic,a = 10.744(3) Å,b=11.821(2) Å, c=12.966(3) Å, a=71.54(1)°, =85.32(2)°, =74.83(1)°,Z = 2, space groupP-1. Two Lu atoms withdistorted tetrahedral coordination are linked by two chloride bridges with a mean Lu-Cl distance equal to 2.62 Å.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 3, pp. 568–570, March, 1993.     

稀土-锂双金属配合物的研究——(LaCl)DME(μ_2-Cl)_5(μ_3-Cl)(La·DME)Li(THF)_2的合成及其晶体结构

在稀土有机化学中,[Cp_2LnCl]_2和[Cp_2LnCl_2LiL_2][Cp为取代或未取代的环戊二烯基,Ln为稀土离子(III),L为Lewis碱]型化合物是重要的中间物。对含锂烷基、芳基或烯丙基稀土化合物的研究也有着重要的意义。这类分子中含有型桥键结构。由于这类化合物难于结晶及其不稳定性,故很难进行系统的研究。 Rossmanith首先发现了NdCl_3-LiCl-THF溶液的存在。李毅用这一溶液很方便地合成了几个轻稀土-锂双金属有机化合物。但是,在稀土配位化学中,对氯化稀土-氯化锂配合物的研究还很少,对LnCl_3LiCl-THF溶液的认识也有待深化。本文合成了组成为(LaCl)DME(μ_2-Cl)_5(μ_3-Cl)(La·DME)Li(THF)_2的新型桥式链状配合物,并测定了晶体结构。这种类型的稀土双金属配合物尚未见报道。     

Addition of HCl to a Cluster-Bound Vinylidene Ligand: Preparation and Structure of Ru5(μ3-SMe)(μ3-CMe)(μ-Cl)(μ-SMe)(μ-PPh2)2(CO)9·PhMe

Addition of aqueous HCl to Ru₅( ₃-C=CH₂)(-SMe)₂(-PPh₂)₂(CO)₁₀ afforded the structurally characterized carbyne complex Ru₅( ₃-SMe)( ₃-CMe)(-Cl)(-SMe)(-PPh₂)₂(CO)₉, formed by addition of H to the vinylidene ligand; a Cl atom bridges an Ru–Ru bond.     

三核钼簇合物(Me4N)[Mo3(μ3-O)(μ-Cl)3(μ-O2CH)3Cl3]的制备和晶体结构测定

标题簇合物系通过液相氧化低价钼(MoCl3)制得,晶体属正交晶系,空间群为D2h[16]-Pmnb,晶胞参数:α=11.403(1),b=12.345(2),c=14.292(2)A,V=2011.8(8)A[3].Z=4,Dc=2.396g.cm[-3].使用四圆衍射仪收集衍射数据,晶体结构用重原子法解出,经全矩阵最小二乘修正,R=0.050,Rw=0.056.簇阴离子结构属M1型三核钼簇构型,Mo-Mo键2.577A;Mo-O-μ3键1.982A.还讨论了桥原子、键级以及配体对Mo-Mo键的影响。     

Synthesis and properties of guanidinate derivatives of rare-earth metals. Molecular structures of the { (Me3Si)2NC(NPri)2}2Y(µ-Cl)2Li(THF)2, [{ (Me3Si)2NC(NPri)2}2SmCl]2 and {(Me3Si)2NC(NPri)2} Sm(µ3-BH4)2(DME) complexes

The reaction of anhydrous SmCl₃ with two equivalents of lithium N,N′-diisopropyl-N″-bis(trimethylsilyl)guanidinate in THF afforded the [{(Me₃Si)₂NC(NPrⁱ)₂}₂SmCl]₂ complex (1) in 82% yield. Analogous reactions with YCl₃ and GdCl₃ produced the ate-complexes { (Me₃Si)₂NC(NPrⁱ)₂}₂Ln(µ-Cl)₂Li(THF)₂ (Ln = Y (2) and Gd (3)). The structures of complexes 1 and 2 were established by X-ray diffraction. The reaction of complex 1 with NaBH₄ in hexane (20 °C) followed by treatment with dimethoxyethane yielded the unexpected product, { (Me₃Si)₂NC(NPrⁱ)₂}Sm(µ³-BH₄)₂(DME) (5). X-ray diffraction study showed that both borohydride ligands in complex 5 are tridentate.     

CRYSTAL STRUCTURE OF (C_5H_9C_5H_4)_3Er_4(μ_2-Cl)_6(μ_3-Cl)(μ_4-O)-(THF)_3

<正> The crystal of (C5H9C5H4)Er4(μ2-Cl)6(μ3-Cl)(μ4-O)(THF)3 belongs to triclinic space group P1, with a = 11. 909(4), b = 15.343(5), c=15. 619 (4)(?), α=104. 18(2), β=98. 81(3), γ= 111. 06(2)°, V = 2486(1)(?)3, Z = 2, Dc = 2. 07g/cm3, λ(MoKα) = 0.71073(?), μ= 73. 4cm-1, F(000) = 1476, Mr=1549. 25. The structure was solved by Patterson and Fourier techniques and refined by block diagonel least-squares method to final R = 0. 078 and Rw = 0. 084 for 5594 reflections with I≥1. 5σ(I). The results revealed that the complex is composed of four Er atoms bridged by seven Cl and one oxygen atoms with three of the Er atoms bonded each to a cyclopentylcyclopentadienyl group, and one Er atom, bonded to three THF. The Er atoms constitute a pseudo-tetrahedron.     

Synthesis,characterization and x-ray structure of V3(μ3-O)(μ-Cl)Cl6(μ-η1-η1-PhNHNH2)2(PhNHNH2)2(THF) · 6THF: A new binding mode for phenylhydrazine

Addition of phenylhydrazine to a mixture of VCl₃ · THF/N,N-propyl-bis (salicyladimine) and sodium hydride yielded a trinuclear vanadium complex, V₃(₃-O)(-Cl)Cl₆(-¹-¹PhNHNH₂)₂(PhNHN H₂)₂(THF), containing two bridging and two terminal phenylhydrazine ligands. The product has been crystallographically characterized (P2₁/n, a=12.949(2) Å,b=24.061(4) Å,c=22.504(4) Å, =107.22(1) deg.,V=6697(2) ų withZ=4) and was found to contain the first example of bridging monosubstituted hydrazine (phenylhydrazine) ligands.     

Low-Temperature Isolation of a Labile Silylated Hydrazinium-yl Radical Cation, [(Me3Si)2N−N(H)SiMe3].+

The oxidation of silylated hydrazine, (Me₃Si)₂N−N(H)SiMe₃, with silver salts led to the formation of a highly labile hydrazinium-yl radical cation, [(Me₃Si)₂N−N(H)SiMe₃]^.+, at very low temperatures (decomposition > −40 °C). EPR, NMR, DFT and Raman studies revealed the formation of a nitrogen-centered radical cation along the N−N unit of the hydrazine. In the presence of the weakly coordinating anion [Al{OCH(CF₃)₂}₄]⁻, crystallization and structural characterization in the solid state were achieved. The hydrazinium-yl radical cation has a significantly shortened N−N bond and a nearly planar N₂Si₃ framework, in contrast to the starting material. According to DFT calculations, the shortened N−N bond has a total bond order of 1.5 with a π-bond order of 0.5. The π bond can be regarded as a three-π-electron, two-center bond.     

Synthesis and properties of bis(indenyl) derivatives of ytterbium and lutetium. Molecular structures of the complexes (C9H7)2Ln(μ-Cl)2Li(Et2O)2 (Ln = Yb, Lu) and [(C9H7)2YbCl2][Li(DME)3]

The heterobimetallic bis(indenyl) chloride complexes of ytterbium and lutetium (C₉H₇)₂Ln(μ-Cl)₂Li(Et₂O)₂ (Ln = Yb or Lu) were synthesized by the metathesis reaction of LnCl₃ with two equivalents of indenyllithium in diethyl ether. In the case of ytterbium, the analogous reaction in 1,2-dimethoxyethane afforded the ionic complex [(C₉H₇)₂YbCl₂]⁻[Li(DME)₃]⁺. The reaction of YbCl₃ with indenylpotassium in a molar ratio of 1: 2 in THF is accompanied by reduction of the metal atom to give the bis(indenyl) derivative of Yb^II, (C₉H₇)₂Yb(THF)₂. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 1, pp. 39–44, January, 2008.     

Syntheses and molecular structures of organo-tellurium(IV) halides trans-[(Ph2Te)(μ-Cl)2]n,cis-[(Ph2Te)(μ-Cl)2]n, [(p-MeC6H4)2TeBr2], and [{(p-MeC6H4)2TeBr}2(μ-O)]

Abstract

Treatment of Ph₂Te with aqueous hydrogen chloride under air in refluxing THF gave trans-[(Ph₂Te)(μ-Cl)₂]_n (1), whereas interaction of Ph₂Te with ammonium chloride under similar condition afforded cis-[(Ph₂Te)(μ-Cl)₂]_n (2). Reaction of (p-MeC₆H₄)₂Te and bromine in refluxing THF resulted in formation of a discrete complex [(p-MeC₆H₄)₂TeBr₂] (3) with a step-like tetrameric structure, which further reacted with sodium hydroxide in refluxing THF to give a dinuclear tellurium oxide [{(p-Me-C₆H₄)₂TeBr}₂(μ-O)] (4) with a bridging oxygen atom. Complexes 1–4 have been spectroscopically characterized and their crystal structures have been established by X-ray crystallography.     

Reactivity of ruthenium carbonyl derivatives of lutecium. Molecular structure of (THF)[1, 3-(Me3Si)2C5H3]2Lu(μ-OH)2

The reactivity of the ruthenium carbonyl derivatives of lutecium (THF)Cp'₂LuRu(CO)₂Cp [Cp'=Cp (1) and 1, 3-(Me₃Si)₂C₅H₃ (2)] has been studied. It has been shown that the reactions of complex 1 withi.-Pr₂CO and of2 with HCl, H₂O, and HgCl₂ are accompanied by cleavage of the Lu-Ru bond. The reaction of2 with H₂O gives [1, 3-(Me₃Si)₂C₅H₃]₂Lu (-OH)₂ (3), which has been characterized by X-ray diffraction analysis (MoK radiation,R=0.0280, 2750 reflections). The crystals are monoclinic,a = 15.638(6) Å,b=15.787(2) Å,c = 12.188(1) Å, =99.06°,Z= 2, space group P2₁/n. Centrosymmetric dimer3 has two -OH ligands, and the Lu-O and Lu...Lu interatomic distances are 2.264(4) Å (mean) and 3.579(1) Å, respectively. The structure behavior of3 in a THF solution has been discussed.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 3, pp. 574–577, March, 1993.