Reduction of 2,5-di-tert-butylcyclopentadienone and pyridine with thulium diiodide. Structures of the complexes TmI2(THF)2[η5-But2C5H2O]TmI2(THF)3 and [TmI2(C5H5N)4]2(μ2-N2C10H10)

Reduction of 2,5-di-tert-butylcyclopentadienone with two equivalents of thulium diiodide in tetrahydrofuran afforded the binuclear thulium(iii) complex with the cyclopentadienyl oxide ligand, viz., TmI₂(THF)₂[⁵-Bu^t ₂C₅H₂O]TmI₂(THF)₃ (1). Shielding of the carbonyl carbon atom with two tert-butyl substituents prevents pinacolization of the ketyl radical anions that formed upon one-electron reduction of cyclopentadienone. The reaction of thulium diiodide with an excess of pyridine in tetrahydrofuran gave a product of reductive coupling of two pyridine radical anions, viz., [TmI₂(C₅H₅N)₄]₂(₂-N₂C₁₀H₁₀) (2). The structures of complexes 1 and 2 were established by single-crystal X-ray diffraction analysis.     

Reactions of neodymium(ii), dysprosium(ii), and thulium(ii) diiodides with cyclopentadiene. Molecular structures of complexes CpTmI2(THF)3 and [NdI2(THF)5]+[NdI4(THF)2]–

The reactions of LnI₂ (Ln = Nd (1) or Dy (2)) with cyclopentadiene (CpH) in THF at 0 °C afforded the CpLnI₂(THF)₃ complexes in 65—67% yields. The reaction of thulium diiodide (3) with an excess of CpH at 60 °C produced CpTmI₂(THF)₃, Cp₂TmI(THF)₂, and TmI₃(THF)₃ in 21, 58, and 63% yields, respectively. The reactions of 1 and 2 with pentamethylcyclopentadiene (Cp*H) in THF were accompanied by disproportionation giving rise to the Cp*₂LnI(THF)₂ and LnI₃(THF) _x complexes. Neodymium triiodide was isolated in the ionic form [NdI₂(THF)₅]⁺[NdI₄(THF)₂]^–. Its structure and the structure of CpTmI₂(THF)₃ were established by X-ray diffraction analysis.     

Potassium and sodium 2,6-di-tert-butylphenoxides and their properties

The crucial factor of the reaction of 2,6-di-tert-butylphenol with alkali hydroxides is temperature, depending on which two types of potassium or sodium 2,6-di-tert-butylphenoxides are formed. These types exhibit different catalytic activity in the alkylation of 2,6-di-tert-butylphenol with methyl acrylate. More active forms of 2,6-Bu^t ₂C₆H₃OK or 2,6-Bu^t ₂C₆H₃ONa are synthesized at temperatures higher than 160 °C and are predominantly the monomers, which dimerize on cooling. The data of ¹H NMR, electronic, and IR spectra for the corresponding forms of 2,6-Bu^t ₂C₆H₃OK and 2,6-Bu^t ₂C₆H₃ONa isolated in the individual state are in agreement with cyclohexadienone structure. In DMSO or DMF, the dimeric forms of 2,6-di-tert-butylphenoxides react with methyl acrylate to form methyl 3-(4-hydroxy-3,5-di-tert-butylphenyl)propionate in 64–92% yield. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 12, pp. 2138–2143, December, 2006.     

Lanthanide(II) Complexes of the Dihydrotriazinido Ligand [N{C(Ph)=N}2C(tBu)Ph]−

The potassium dihydrotriazinide K(L^Ph,tBu) ( 1 ) was obtained by a metal exchange route from [Li(L^Ph,tBu)(THF)₃] and KOtBu (L^Ph,tBu = [N{C(Ph)=N}₂C(tBu)Ph]). Reaction of 1 with 1 or 0.5 equivalents of SmI₂(thf)₂ yielded the monosubstituted Sm^II complex [Sm(L^Ph,tBu)I(THF)₄] ( 2 ) or the disubstituted [Sm(L^Ph,tBu)₂(THF)₂] ( 3 ), respectively. Attempted synthesis of a heteroleptic Sm^II amido‐alkyl complex by the reaction of 2 with KCH₂Ph produced compound 3 due to ligand redistribution. The Yb^II bis(dihydrotriazinide) [Yb(L^Ph,tBu)₂(THF)₂] ( 4 ) was isolated from the 1:1 reaction of YbI₂(THF)₂ and 1 . Molecular structures of the crystalline compounds 2 , 3· 2C₆H₆ and 4· PhMe were determined by X‐ray crystallography.     

3,5-Di-tert-butyl-o-benzoquinone complexes of lanthanides

Lanthanide semiquinolates Ln(SQ)₃ (SQ-3,5-di-tert-butyl-o-benzosemiquinone) were prepared by the reactions of Dy, Tm, Yb with 3 equiv of 3,5-di-tert-butyl-o-benzoquinone (Q). Crystallization of thulium product from DME yields structurally characterized cluster Tm₃(SQ)₄(Cat)₂(QH)(DME)₂ (1) (Cat-3,5-di-tert-butyl-catecholate, QH-o-hydroxyphenolate). The reactions of Q with excess of metal (Sm, Eu, Tm, Yb) afford catecholates Ln₂(Cat)₃. For samarium product Sm₄(Cat)₆(THF)₆ (2) X-ray diffraction study was performed. In the reaction of EuI₂ with Li₂(Cat) ate-complex EuLi₄(LiI)₂(SQ)₂(Cat)₂(THF)₆ (3) was isolated. X-ray analysis revealed that a molecule of the complex contains two semiquinone groups, two catecholate ligands, Eu²⁺ cation, four Li⁺ cations and two LiI species bonded by bridging O and I atoms. Catecholates of Eu(II), Sm(II) as well as trivalent Ce, Nd, Gd, and Tb were obtained by treatment of corresponding lanthanide silylamides Ln[N(SiMe₃)₂]_n (n = 2, 3) with the 3,5-di-tert-butyl-catechol. It was established that gadolinium product Gd₄(Cat)₆(THF)₆ (4) is isostructural to samarium complex 2. Terbium catecholate Tb₂(Cat)₃ in THF solution revealed photoluminescence typical for Tb³⁺ cation.     

New lead(II) catecholate and o-semiquinone complexes

Lead(II) catecholate complexes were prepared by reduction of 3,6-di-tert-butyl-o-benzoquinone and its derivatives with lead metal in THF. The molecular structure of the (CatPb)₄·(PbO)₂·6C₃H₆O complex (Cat is the dianion of 3,6-di-tert-butylcatechol), which was synthesized by hydrolysis of lead 3,6-di-tert-butylcatecholate in acetone, was established by X-ray diffraction. A series of lead(II) o-semiquinone complexes, which were prepared by the addition of the phenoxyl radical to lead catecholates or by oxidation of the latter with mercury(II), copper(II), or silver(I) halides, were studied by the ESR method. Lead(II) mono-o-semiquinolate complexes undergo symmetrization to form stable bis-o-semiquinolates, which were isolated and characterized in individual state. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 7, pp. 1103–1111, July, 2006.     

Complexes of lanthanum with radical anions of 2,2-bipyridyl and 3,6-di-tert-butyl-o-benzoquinone

Complexes of a rare-earth element containing only one radical-anion ligand have been synthesized and isolated in pure states for the first time. The LaI₂(bpy)(THF)₃ complex has been prepared from [LaI₂(THF)₃]₂(C₁₀H₈) and 2,2-bipyridyl in DME. The semiquinone complex LaI₂(SQ)(THF)₃ has been obtained by reaction of lanthanum iodide with 3,6-di-tert-butyl-o-benzoquinone in THF in the presence of lanthanum powder. ESR spectra of the complexes have been studied.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 11, pp. 2278–2280, November, 1995.We thank Mr. A. V. Protchenko for magnetic measurements and Dr. L. G. Abakumova for recording IR spectra and helpful discussion.This work was supported by the Russian Foundation for Basic Research (Project No. 95-03-08443a).     

Reaction of a naphthalene complex C10H8Yb(THF)2 with cyclopentadienyl-substituted alcohols and amines as a convenient synthetic route to the half-sandwich complexes of divalent ytterbium

The reactions of ytterbium naphthalene complex C₁₀H₈Yb(THF)₂ with 2-cyclopentadienylethanol, 1-cyclopentadienylpropan-2-ol, 3-cyclopentadienyl-1-butoxypropan-2-ol, and cyclopentadienyldimethylsilyl-tert-butylamine were studied. The bivalent ytterbium complexes with chelate bifunctional cyclopentadienyl ligands [(η⁵−C₅H₅)CH₂CH₂(η¹−O)]Yb(THF), [(η⁵−C₅H₅)CH₂CH₂(η¹−O)]Yb(DME). [(η⁵−C₅H₅)CH₂CH(Me)(η¹−O)]Yb(THF), [(η⁵−C₅H₅)CH₂CH(CH₂OC₄H₉)(η¹−O)]Yb(THF), and [(η⁵−C₅H₅)SiMe₂(η¹−N(Bu¹))]Yb(THF) were obtained and characterized. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 4, pp. 742–745, April, 2000.     

Synthesis, properties, and reactivity of the stilbene complex of ytterbium (PhCH=CHPh)Yb(THF)2. Crystal structure of (2,4,6-But 3C6H2O)2Yb(THF)3

The stilbene complex of ytterbium (PhCH=CHPh)Yb(THF)₂ (1) was prepared by the reaction of YbI₂(THF)₂ with a twofold excess of (PhCH=CHPh)⁻ Li⁺. Based on the data of IR and ESR spectroscopy and on the results of magnetic measurements, compound1 was characterized as a complex of divalent ytterbium with the stilbene dianion. The reactivity of complex1 toward different types of reagents was studied. The structure of the product of the reaction of1 with 2,4,6-tri(tert-butyl)phenol (2,4,6-Bu^t ₃C₆H₂O)₂Yb(THF)₃ was established by X-ray diffraction analysis. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 11, pp. 2345–2350, November, 1998.     

(μ‐Tri‐tert‐butoxysilanethiol­ato)­bis[(tetra­hydro­furan)lithium(I)] and catena‐poly[[bis­(μ‐tri‐tert‐butoxy­silanethiol­ato)dilithium(I)]‐μ‐dimethoxy­ethane]: solvent coordination as the structure‐forming factor

The title compounds, μ‐(tri‐tert‐butoxy­silanethiol­ato‐κ²S:S)‐bis[(tetra­hydro­furan‐κO)lithium(I)], [Li₂(C₁₂H₂₇O₃SSi)₂(C₄H₈O)₂], (I), and catena‐poly[[bis­(μ‐tri‐tert‐butoxysilanethiol­ato)‐1:2κ²S;1κS:2κS,O‐dilithium(I)]‐μ‐dimethoxy­ethane‐κ²O:O′], [Li₂(C₁₂H₂₇O₃SSi)₂(C₄H₁₀O₂)]_n, (II), were obtained by the reaction of tri‐tert‐butoxy­silanethiol with metallic lithium. The crude product, when recrystallized from tetra­hydro­furan (THF) yields (I), and when recrystallized from 1,2‐dimethoxy­ethane (DME) gives (II). Compound (I) forms centrosymmetric dimers in the solid state with an Li₂S₂ central core, whereas (II) forms infinitely long chains, in which the centrosymmetric dimeric units are linked together by the bidentate DME ligand (also residing on an inversion centre), thus forming a coordination polymer. The formation of a one‐dimensional structure in (II) is a consequence of replacement of a monodentate THF solvent mol­ecule with a bidentate DME mol­ecule.     

Synthesis and Chloride Affinity of Sterically Demanding Ditopic Lithium Bis(pyrazol‐1‐yl)borates

The synthesis and full characterization of the sterically demanding ditopic lithium bis(pyrazol‐1‐yl)borates Li₂[p‐C₆H₄(B(Ph)pz^R₂)₂] is reported (pz^R = 3‐phenylpyrazol‐1‐yl ( 3 ^Ph), 3‐t‐butylpyrazol‐1‐yl ( 3 ^tBu)). Compound 3 ^Ph crystallizes from THF as THF‐adduct 3 ^Ph(THF)₄ which features a straight conformation with a long Li···Li distance of 12.68(1) Å. Compound 3 ^tBu was found to function as efficient and selective scavenger of chloride ions. In the presence of LiCl it forms anionic complexes [ 3 ^tBuCl]⁻ with a central Li‐Cl‐Li core (Li···Li = 3.75(1) Å).     

Synthesis of a re(VI)-catecholato complex by air oxidation of oxorhenium(V)

The complex [Re(ddcat)₃] (H₂ddcat?=?3,5-di-tert-butylcatechol) was prepared by the reaction of either cis-[Re^VO₂I(PPh₃)₂] or (n-Bu₄N)[Re^VOCl₄] with H₂ddcat in toluene in air. X-ray structure determination of the product unequivocally illustrates that the bidentate chelates are in the catecholato rather than the semiquinone form and that the metal has a formal oxidation state of +VI.     

Di-tert-butylcyclopentadienyl complexes of europium and ytterbium: synthesis and crystal structures of (1,3-But 2C5H3)2 Eu·THF, (1,3-But 2C5H3)(C5Me5)Yb·THF, and\left( {1,3 - Bu^t _2 C_5 H_3 } \right)_2 Yb(\mu _2 - Cl)_2 Li(THF)_2

The (1,3-Bu^t ₂C₅H₃)₂Eu·THF complex was prepared by the reaction of 1,3-Bu^t ₂C₅H₃Na with Eul₂ in tetrahydrofuran. The mixed-ligand (1,3-Bu^t ₂C₅H₃)(C₅Me₅)Yb·THF complex was obtained by the reaction of YbI₂ with C₅Me₅Na and 1,3-Bu^t ₂C₅H₃Na. The reaction of 1,3-Bu^t ₂C₅H₃Li with YbCl₃ afforded the ( $\left( {1,3 - Bu^t _2 C_5 H_3 } \right)_2 Yb(\mu _2 - Cl)_2 Li(THF)_2 $ )ate-complex. The structures of the title compounds were established by X-ray diffraction analysis.     

Tuning Coordination in s‐Block Carbazol‐9‐yl Complexes

1,3,6,8‐Tetra‐tert‐butylcarbazol‐9‐yl and 1,8‐diaryl‐3,6‐di(tert‐butyl)carbazol‐9‐yl ligands have been utilized in the synthesis of potassium and magnesium complexes. The potassium complexes (1,3,6,8‐tBu₄carb)K(THF)₄ ( 1 ; carb=C₁₂H₄N), [(1,8‐Xyl₂‐3,6‐tBu₂carb)K(THF)]₂ ( 2 ; Xyl=3,5‐Me₂C₆H₃) and (1,8‐Mes₂‐3,6‐tBu₂carb)K(THF)₂ ( 3 ; Mes=2,4,6‐Me₃C₆H₂) were reacted with MgI₂ to give the Hauser bases 1,3,6,8‐tBu₄carbMgI(THF)₂ ( 4 ) and 1,8‐Ar₂‐3,6‐tBu₂carbMgI(THF) (Ar=Xyl 5 , Ar=Mes 6 ). Structural investigations of the potassium and magnesium derivatives highlight significant differences in the coordination motifs, which depend on the nature of the 1‐ and 8‐substituents: 1,8‐di(tert‐butyl)‐substituted ligands gave π‐type compounds ( 1 and 4 ), in which the carbazolyl ligand acts as a multi‐hapto donor, with the metal cations positioned below the coordination plane in a half‐sandwich conformation, whereas the use of 1,8‐diaryl substituted ligands gave σ‐type complexes ( 2 and 6 ). Space‐filling diagrams and percent buried volume calculations indicated that aryl‐substituted carbazolyl ligands offer a steric cleft better suited to stabilization of low‐coordinate magnesium complexes.     

Synthesis and structure of divalent thulium borohydrides, and their application in ε-caprolactone polymerisation

The new divalent thulium compound [Tm(BH(4))(2)(DME)(2)] could be prepared by reduction of [Tm(BH(4))(3)(THF)(3)] or from TmI(2) and KBH(4). It was used as a precursor to the divalent [(Tp(tBu,Me))Tm(BH(4))(THF)] by reaction with potassium tris(2-tBu-4-Me)pyrazolylborate (KTp(tBu,Me)). Both Tm(II) compounds were found active as ε-caprolactone polymerisation catalysts.     

Metallorganische Verbindungen der Lanthanoide. 88. Monomere Lanthanoid(III)-amide: Synthese und Röntgenstrukturanalyse von [Nd{N(C6H5)(SiMe3)}3(THF)], [Li(THF)2(μ-Cl)2Nd{N(C6H3Me2-2,6)(SiMe3)}2(THF)] und [ClNd{N(C6H3-iso-Pr2-2,6)(SiMe3)}2(THF)]

Organometallic Compounds of the Lanthanides. 88. Monomeric Lanthanide(III) Amides: Synthesis and X-Ray Crystal Structure of [Nd{N(C₆H₅)(SiMe₃)}₃(THF)], [Li(THF)₂(μ-Cl)₂Nd{N(C₆H₃Me₂-2,6)(SiMe₃)}₂(THF)], and [ClNd{N(C₆H₃-iso-Pr₂-2,6)(SiMe₃)} ₂(THF)] A series of lanthanide(III) amides [Ln{N(C₆H₅) · (SiMe₃)}₃(THF)_x] [Ln = Y ( 1 ), La ( 2 ), Nd ( 3 ), Sm ( 4 ), Eu ( 5 ), Tb ( 6 ), Er ( 8 ), Yb ( 9 ), Lu ( 10 )] could be prepared by the reaction of lanthanide trichlorides, LnCl₃, with LiN(C₆H₅)(SiMe₃). Treatment of NdCl₃(THF)₂ and LuCl₃(THF)₃ with the lithium salts of the bulky amides [N(C₆H₃R₂-2,6)(SiMe₃)]^? (R = Me, iso-Pr) results in the formation of the lanthanide diamides [Li(THF)₂(μ-Cl)₂Nd{N(C₆H₃Me₂-2, 6)(SiMe₃)}₂(THF)] ( 11 ) and [ClLn{N(C₆H₃-iso-Pr₂-2,6)(SiMe₃)} ₂(THF)] [Ln = Nd ( 12 ), Lu ( 13 )], respectively. The ¹H- and ¹³C-NMR and mass spectra of the new compounds as well as the X-ray crystal structures of the neodymium derivatives 3 , 11 and 12 are discussed.     

Control of Hydrolysis and Condensation Reactions of Titanium tert-butoxide by Chemical Modification with Catechol

Titanium tert-butoxide (Ti(OC(CH₃)₃)₄; Ti(O ^t Bu)₄) was chemically modified with catechol (C₆H₄(OH)₂) and hydrolysis and condensation behavior of a resultant modified alkoxide was studied. Spectroscopic results revealed that the reaction between titanium tert-butoxide and catechol resulted in the formation of catecholate groups (C₆H₄O₂ ^2–) bound to titanium and corresponding release of tert-butanol. The mass spectrometry and cryoscopy indicated that main species was a dimer [(C₆H₄O₂)₂Ti₂(O ^t Bu)₄]. The hydrolysis of the modified alkoxide in the system with Ti:tetrahydrofuran (THF):H₂O = 1:10:x (x = 0.5–10) resulted in the partial hydrolysis, and all the hydrolyzed products after the drying under reduced pressure were soluble in THF and chloroform.     

以2-(1-吡唑基甲基)吡啶类化合物为配体的羰基钼、钨衍生物的合成及结构

合成了2-[1-(3-叔丁基)吡唑基甲基]吡啶(CH2(Py)(3-ButPz)),并研究了羰基钼(钨)与该配体及其类似物2-(1-吡唑基甲基)吡啶(CH2(Py)(Pz))和2-[1-(3,5-二甲基)吡唑基甲基]吡啶(CH2(Py)(3,5-Me2Pz))的反应,合成了6个含双齿螯合的2-(1-吡唑基甲基)吡啶类配体的四羰基金属衍生物CH2(Py)(3-ButPz)M(CO)4,CH2(Py)(Pz)M(CO)4和CH2(Py)(3,5-Me2Pz)M(CO)4(M=Mo或W)。当用SnCl4处理CH2(Py)(3,5-Me2Pz)M(CO)4时,Sn-Cl键对金属中心发生氧化加成得到2个杂双核金属有机化合物CH2(Py)(3,5-Me2Pz)M(CO)3(Cl)SnCl3。所有新化合物均通过了红外和核磁的表征,CH2(Py)(3-ButPz)W(CO)4和CH2(Py)(3,5-Me2Pz)W(CO)3(Cl)SnCl3的结构还得到了X-射线单晶衍射的确证。用循环伏安法测定了四羰基金属衍生物的电化学性质。     

The synthesis, structure and ethene polymerization activity of octahedral heteroligated (salicylaldiminato)(β-enaminoketonato)titanium complexes: The X-ray crystal structure of {3-Bu-2-(O)C6H3CHN(Ph)}{(Ph)NC(Me)C(H)C(Me)O}TiCl2

Treatment of the mono(salicylaldiminato)titanium complexes {3-Bu^t-2-(O)C₆H₃CHN(Ar)}TiCl₃(THF) (Ar = C₆H₅, 2,4,6-Me₃C₆H₂ or C₆F₅) with the potassium β-enaminoketonates (C₆H₅)NC(CH₃)C(H)C(R)OK (R = CH₃, CF₃) yielded the first examples of heteroligated (salicylaldiminato) (β-enaminoketonato)titanium dichloride complexes. The complex {3-Bu^t-2-(O)C₆H₃CHN(C₆H₅)}{(C₆H₅)NC(CH₃)C(H)C(CH₃)O}TiCl₂ was structurally characterized by X-ray diffraction and has an orientation with trans-O,O,cis-Cl,Cl, cis-N,N distorted octahedral geometry. These complexes polymerize ethene when activated with MAO; the highest productivity, 5650 kg PE (mol metal)⁻¹ h⁻¹ atm⁻¹, was afforded by {3-Bu^t-2-(O)C₆H₃CHN(C₆F₅)}{(C₆H₅)NC(CH₃)C(H)C(CF₃)O}TiCl₂ at 60 °C.     

Aluminum Complexes Stabilized by Piperazidine‐Bridged Bis(phenolate) Ligands: Syntheses,Structures, and Application in the Ring‐Opening Polymerization of ε‐Caprolactone

The synthesis and characterization of aluminum alkoxide and alkyl complexes stabilized by piperazidine‐bridged bis(phenolate) ligands are described. Treatment of ligand precursors H₂[ONNO]¹ {H₂[ONNO]¹=1,4‐bis(2‐hydroxy‐3‐tert‐butyl‐5‐methylbenzyl)piperazidine} and H₂[ONNO]² {H₂[ONNO]²=1,4‐bis(2‐hydroxy‐3,5‐di‐tert‐butylbenzyl)piperazidine} with AlEt₂(OCH₂Ph) and AlEt₂(OPr‐i), which were generated in situ by the reactions of AlEt₃ with equivalent of the corresponding alcohols, in a 1:1 molar ratio in THF gave the corresponding aluminum alkoxide complexes [ONNO]¹Al(OCH₂Ph) ( 1 ) and [ONNO]²Al(OPr‐i) ( 2 ), respectively. The reaction of H₂[ONNO]¹ with AlEt₂(OCH₂Ph) in a 1:2 molar ratio in THF afforded a mixture of monometallic aluminum ethyl complex [ONNO]¹AlEt ( 3 ) and complex 1 , which can be isolated by stepwise crystallization. Similarly, H₂[ONNO]² reacted with AlEt₂(OPr‐i) in a 1:2 molar ratio in THF to give a mixture of aluminum ethyl complex [ONNO]²AlEt ( 4 ) and complex 2 . Complexes 1 and 2 were also available via treatment of complexes 3 and 4 with 1 equiv. of benzyl alcohol and isopropyl alcohol, respectively. All of these complexes were fully characterized including X‐ray structural determination. It was found that complexes 1 to 4 can initiate the ring‐opening polymerization of ε‐caprolactone, and complexes 1 and 2 showed higher catalytic activity in comparison with complexes 3 and 4 .