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Four titanium complexes having β-ketoiminate chelate ligands with fluorine or alkyl groups [(Ar)NC(CH3)C(H)C(CH3)O]2TiCl2 (3a: Ar = 2.6-F2C6H3; 3b: Ar = C6F5; 3c: Ar = 2.6-Me2C6H3; 3d: Ar = 2.6-iPr2C6H3) have been synthesized and characterized by 1H NMR and EA. Complexes 3a, 3c and 3d were further characterized by X-ray diffraction analysis and demonstrated distorted octahedral coordination structure around the titanium center. The substituents in ligands greatly affect the coordination mode, resulting in three different isomeric structures. These complexes are active catalysts for polymerization of ethylene with MMAO as cocatalyst. The substituents in ligands have also great influences on catalytic activity. The complexes with alkyl groups have lower activity, while the complexes with fluorine atoms have middle or high catalytic activity.

New imido-carboranes 1-(CHNC6H3R2-2,6)-1,2-C2B10H11 (R = iPr (3a), Me (3b)) were successfully prepared by Schiff base condensation of 1-CHO-1,2-C2B10H11 with R2C6H3NH2. They were readily converted into the corresponding imido-dicarbollyl ligands 7-(CHNHC6H3R2-2,6)-7,8-C2B9H11 (R = iPr (4a), Me (4b)) by refluxing in dry MeOH. Treatment of 3a with Ti(NMe2)4 in hot toluene gave a constrained-geometry complex, [η1:η5-(iPr2C6H3NCH)C2B9H10]Ti(NMe2)2 (5a). Under the same reaction conditions, interaction of 3b with Ti(NMe2)4 produced a mixture of [η1:η5-(Me2C6H3NCH)C2B9H10]Ti(NMe2)2 (5b) and [η1:η5-(Me2N)CH(NMe2)(C2B9H10)Ti(NMe2)2 (8). Reaction of 4a with M(NMe2)4 in toluene/DME at room temperature afforded 5a and [η1:η5-(iPr2C6H3NCH)C2B9H10]M(NMe2)2(NHMe2) (M = Zr (6a), Hf (7a)), respectively. Complexes 5a, 6a, and 7a were active catalysts for the polymerization of ethylene in the presence of MMAO with activities of 3−16 kg/mol·h·atm. These new complexes were fully characterized by various spectroscopic techniqu...

A series of new organolanthanide(II) complexes with furfuryl- and tetrahydrofurfuryl-functionalized indenyl ligands were synthesized via one-electron reductive elimination reaction. Treatments of [(Me3Si)2N]3LnIII(μ-Cl)Li(THF)3 (Ln = Yb, Eu) with 2 equiv. of C4H7OCH2C9H7 (1) or C4H3OCH2C9H7 (2), respectively in toluene at moderate high temperatures produced, after workup, the corresponding organolanthanide(II) complexes with formula [η5:η1-(C4H7OCH2C9H6)]2LnII (Ln = Yb (5), Ln = Eu (6)) and [η5:η1-(C4H3OCH2C9H6)]2LnII (Ln = Yb (7), Ln = Eu (8)) in reasonable to good yields. Treatments of [(Me3Si)2N]3LnIII(μ-Cl)Li(THF)3 (Ln = Yb, Eu) with 2 equiv. of C4H7OCH2C9H6SiMe3 (3) or C4H3OCH2C9H6SiMe3 (4), respectively, in toluene at moderate high temperatures afforded, after workup, the corresponding organolanthanide(II) complexes with formula [η5:η1-(C4H7OCH2C9H5SiMe3)]2LnII (Ln = Yb (9), Ln = Eu (10)) and[η5:η1-(C4H3OCH2C9H5SiMe3)]2LnII (Ln = Yb (11), Ln = Eu (12)) in good to high yields. All the compounds were fully characterized by spectroscopic methods and elemental analyses. The structure of complex 9 was additionally determined by single-crystal X-ray analyses. Studies on the catalytic activities of complexes showed that the complexes having silyl group functionalized indenyl ligands have high catalytic activities on e-caprolactone polymerization. The temperatures, substituted groups on the indenyl ligands of the complexes, and solvents effects on the catalytic activities of the complexes were examined.

Mesomeric divalent 1,1‘-(3-oxapentamethylene)-bridged bis(indenyl)lanthanidocenes, meso-[O(CH2CH2C9H6)2]Ln·(DME) (Ln = Sm (2),Yb (3)), have been synthesized by reduction of a mixture of rac/meso-[O(CH2CH2C9H6)2]LnCl·THF (Ln = Sm, Yb) with Na or reaction of LnI2 (Ln = Sm, Yb) with [O(CH2CH2C9H6K)2] in THF followed by recrystallization in DME. The structures of these meso, ansa-lanthanidocenes were determined by X-ray diffraction analysis. The factors that dictated the rac/meso selectivity are discussed. Nonbridged divalent lanthanide complexes (CH3OCH2CH2C9H6)2LnII (Ln = Sm (4), Yb (5)) were also synthesized for comparison by the reaction of LnI2 (Ln = Sm, Yb) with (CH3OCH2CH2C9H6)2K in THF. Stereoselective polymerization of methyl methacrylate with these divalent lanthanide complexes as single-component catalysts was preliminarily investigated.

Zusammenfassung Die Absorptionsspektren von pseudo-trigonal-bipyramidal koordiniertem Nd(η 5 -C 5 H 4 CH 2 CH 2 OMe) 3 ( 1 ) und Nd(η 5 -C 5 H 4 CH 2 CH 2 PMe 2 ) 3 ( 2 ) wurden sowohl bei Raumtemperatur als auch bei tiefen Temperaturen gemessen. Den erhaltenen Spektren wurden die zugrundeliegenden partiellen Kristallfeld(KF)-Aufspaltungsmuster entnommen und durch Anpassung der Parameter eines phanomenologischen Hamilton-Operators simuliert. Bei 55 bzw. 53 Zuordnungen wurden fur die Komplexe 1 und 2 reduzierte r.m.s.-Abweichungen von 31 cm −1 bzw. 23 cm −1 erzielt. Die verwendeten Parameter gestatten die Bestimmung der jeweils von den Nd 3+ -Ionen wahrgenommenen Ligandenfeldstarken der Verbindungen 1 und 2 , die Einordnung dieser Komplexe in verkurzte empirische nephelauxetische und relativistische nephelauxetische Serien und die Aufstellung ihrer experimentorientierten nichtrelativistischen und relativistischen Molekulorbitalschemata im f-Bereich.

Six five-coordinate difluoro-substituted 2,6-bis(imino)pyridyl iron and cobalt complexes, [{2,6-(2,X-F2C6H3NCCH3)2C5H3N}MCl2] (X = 6, M = Fe (1), Co (2); X = 5, M = Fe (3), Co (4)); X = 4, M = Fe (5), Co (6)), were synthesized by reactions of the corresponding bis(imino)pyridyl ligands with FeCl2·4H2O or CoCl2 in tetrahydrofuran (THF). However, a reaction between 2,6-diacetylpyridinebis(2,6-difluoroanil) and FeCl2·4H2O in CH3CN provided the ion-pair complex [Fe{2,6-(2,6-F2C6H3NCCH3)2C5H3N}2]2+[FeCl4]2- (7) instead of a five-coordinate complex. The molecular structures of complexes 3 and 6 were determined by X-ray diffraction. The catalytic activities of complexes 1−7 for ethylene oligomerization were studied using modified methylaluminoxane (MMAO) as cocatalyst. At 60 °C and 10 atm of ethylene pressure, the iron complexes 1, 3, and 5 show very high activities: 4.07 × 107, 9.33 × 107, and 11.1 × 107 g/((mol of cat.) h), respectively. The oligomers formed consist mainly of dimer, trimer, and tetramer, with...

A series of silylene- and methylene-bridged fluorenyl cyclopentadienyl ansa -lanthanocene chlorides, hydrocarbyls, amides and tetrahydroborates with C s - or C 1 -symmetry have been synthesized successfully. X-ray structural studies have been carried out for these complexes. The hydrocarbyls and amides were applied for catalyzing the polymerization of methyl methacrylate and lactones.

The one-carbon atom bridged amide complex [Ph2C(Flu)(Cp)]LuN(TMS)2 (2) (Flu=C13H8, Cp=C5H4, TMS=SiMe3) has been synthesized by reaction of its chloride precursor with LiN(TMS)2 in toluene. An X-ray structure of the amide complex 2 exhibits apparently intramolecular βSiC agostic interaction with Lu. Polymerization of methyl methacrylate (MMA) and lactones with this complex has also been investigated.

Reaction of the dimethylsilyl-bridged flourene cyclopentadiene ligand with 1 equiv of n-butyllithium or sodium hydride smoothly afforded the corresponding monoalkali-metal salts [(FluMe2Si)Cp]M·(THF)n (Cp = C5H4, Flu = C13H9) (M = Li (1), n = 0; M = Na (2), n = 1). Complexes 1 and 2 were characterized by single-crystal X-ray structural analyses. These revealed that both of them have similar linear polymeric structural aggregate types in the solid state. In complexes 1 and 2, the fluorenyldimethylsilyl groups attached to the cyclopentadienyl rings are arranged in gaps and oriented on the same side of the multideck chain.

A series of chiral 1,1‘-(3-oxapentamethylene)-bridged bis(indenyl) ansa-lanthanidocenes have been high stereoselectively synthesized. The reaction of YbCl3 with O(CH2CH2C9H6K)2 in THF provided a rac/meso mixture of [O(CH2CH2C9H6)2]YbCl(THF); the major diastereomer formed is racemic. The rac-[O(CH2CH2C9H6)2]YbCl(THF) (1) was isolated after recrystallization of a rac/meso mixture of [O(CH2CH2C9H6)2]YbCl(THF) in THF. Direct amidation (or alkylation) of the rac/meso lanthanidocene chloride mixtures in toluene provided solely pure racemic ansa-lanthanidocene amides [O(CH2CH2C9H6)2]LnN(SiMe3)2 (Ln = Y (2), Pr (3), Nd (4), Yb (5), Lu (6)) and pure racemic ansa-lanthanidocene hydrocarbyls [O(CH2CH2C9H6)2]LnCH2SiMe3 (Ln = Dy (7), Yb (8)). The structures of 1 and 5 were determined by X-ray diffraction. The amide and hydrocarbyl complexes are efficient single-component catalysts for methyl methacrylate polymerization. The effects of solvent and reaction temperature on the polymerization were studied. Very high molec...

A series of new Cs-symmetric organolanthanocene chlorides, [R2Si(Flu)(R‘Cp)Ln(μ-Cl)]2 (Flu = C13H8, fluorenyl; Cp = C5H3) (R = Me, R‘ = H, Ln = Y (1), Lu (2), Dy (3), Er (4); R = Ph, R‘ = tBu, Ln = Y (5), Dy (6)), has been synthesized by the reaction of anhydrous lanthanide chloride with the dilithium salt of the ligand Me2Si(FluH)(CpH). Treatment of the resulting chlorides with ME(TMS)2 (M = Li or K, E = N, CH) gave the amide and hydrocarbyl derivatives Me2Si(Flu)(Cp)LnE(TMS)2 (E = N, Ln = Dy (7), Er (9); E = CH, Ln = Dy (8), Er (10)). X-ray structures of chloride compounds reveal unusual Cp−SiMe2−Cp bridging dimeric coordination. All of the amide and hydrocarbyl complexes show normal chelating structure and exhibit apparently intramolecular γ-agostic Ln−Me−Si interaction. These complexes are active for the polymerization of methyl methacrylate.

Racemic planar chiral metallocenes bis(2-methoxyethylindenyl) yttrium and lanthanum tetrahydroborates (MeOCH^2CH^2C^9H^6)^2Lnμ2-H)nBH^4-n (Lu = Y, n = 2(1); Ln = La, n = 3, (2)) have been stereoselectively isolated in high yield by reaction of the corresponding lanthanoeene chlorides with sodium borohydride in THF at room temperature. The two complexes have been fully characterized by elemental analyses, MS. ~1H NMR and IR spectra. The tetrahydroborate ion has been identified as slipped bidentate (μ^2-H)^2BH^2 and tridentate (μ^2H)^3BH ligands in I and 2, respectively. 2000 Elsevier Science Ltd. All rights reserved.

First examples of racemic bis(2-dimethylaminoethylindenyl) divalent unsolvated organolanthanide complexes (Me 2 NCH 2 CH 2 C 9 H 6 ) 2 Sm ( 1 ) and (Me 2 NCH 2 CH 2 C 9 H 6 ) 2 Yb ( 2 ) have been synthesized by the reaction of (Me 2 NCH 2 CH 2 C 9 H 6 )K with LnI 2 (Ln=Sm, Yb). The two compounds have been characterized by elemental analysis and 1 H-NMR spectrometry. The X-ray crystal structure of 2 has been determined by diffraction study. The crystals are prismatic, space group P 2 1 / a (≠14), with a =17.342(6) A, b =8.542(7) A, c =17.353(2) A, β =118.70°, V =2254(1) A 3 , Z =4, D =1.607 g cm −3 .

The tris-alkylborohydride Cp Q 2 NdHBEt 3 (Cp Q =C 5 H 4 CH 2 CH 2 OCH 3 ) obtained by reaction of NaHBEt 3 with Cp Q 2 NdCl is fairly stable in solution whereas the hydride Cp Q 2 NdH formed from Cp Q 2 NdCl and NaH or by hydrogenolysis of Cp Q 2 NdR (R=CH 2 SiMe 3 or CH(SiMe 3 ) 2 ) is a species of very short life, undergoing rearrangement to Cp Q 3 Nd. This transient hydride is not observed but can be trapped with ketones—propanone or pivalone, leading to the alkoxides Cp Q 2 NdOCHR′ 2 (R′=Me or CMe 3 ). The same alkoxides are obtained from Cp Q 2 NdHBEt 3 .

Chiral lanthanocene chlorides (CH3OCH2CH2C9H6)2LnCl (Ln=Y 1, La 2, Nd 3, Gd 4, Ho 5 and Lu 6) with an ether-functionalized indenyl ligand were synthesized by the reaction of 1-(2-methoxyethylindenyl) potassium (in situ) with corresponding anhydrous lanthanide chlorides in THF. The X-ray crystal structures of four such complexes were determined and these indicated that they were unsolvated monomeric complexes with a trans arrangement of both the sidearms and indenyl rings in the solid state. This configuration also predominated in THF solution, as evidenced by NMR spectra of the diamagnetic complexes 1, 2 and 6, although some minor species of 1 and 2 did form upon dissolution.

Organolanthanum reagents[RLaCl 2 ] generated in situ from LaCl 3 and alkyl lithium or allyl magnesium could undergo a highly regioselective 1,2-addition to N -alkyl α,β -unsaturated imines, which provided a new and useful approach to synthesize allyl amines with good yields and high regioselectivity. Furthermore, for N -chiral alkyl α,β -unsaturated imine, in the case of n -butyl lithium, the diastereoselectivity achieved highly 90%.

Several complexes [O(CH2CH2C5H3R)2LnCl] (R  1Bu, Ln  Y, Nd, Sm, Yb; R  SiMe3, Ln  La, Y, Nd, Yb) were synthesized using chelating ligands and characterized by mass-, IR-, 1H NMR-spectroscopies and elemental analyses. The spectra indicate that these complexes are unsolvated ansa-metallocene chlorides and the two bridged cyclopentadiene rings coordinate to the same metal ion with an intramolecular coordination bond between the oxygen atom of the bridge and the metal ion. These complexes are still sensitive to air and moisture, but they all have good thermal stability under inert gas and excellent solubility in hydrocarbon solvents. The reactivities of the systems of these metallocene chlorides and sodium hydride were investigated. Compared with the solubility of these complexes in a range of solvents, the influence of steric factors arising from the bulky substituents on the cyclopentadiene rings or the radial size of the metal ions are relatively slight.

The compounds O(CH2CH2C5H4)(2)Ln(THF)(2) [Ln = Sm(1), Yb(2)] were synthesized by the reduction of O(CH2CH2C5H4)(2)LnCl with sodium metal in tetrahydrofuran (THF) at room temperature. Recrystallization of 2 from dimethoxyethane (DME) produced the single-crystal O(CH2CH2C5H4)(2)Yb(DME) (3) whose structure has been determined by an X-ray diffraction study. The crystals are orthorhombic, space group Pcab, with a = 14.168(4), b = 13.541(6), c = 19.314(8) Angstrom, Z = 8, D-calc. = 1.66 g cm(-3).

Organic halides can be ubiquitous long-lived contaminants to the environment. Dehalogenation of organic halides with sodium hydride (NaH) as reductant catalyzed by two varieties of lanthanides was reported in respect of environmental remediation. The first catalyst is a dicyclopentadienyl yttrium halide, and organoyttrium hydride was thought to be the reactive species. The second catalyst is a lanthanide isopropoxide which showed higher catalytic reactivity, and an aggregate is involved in the suggested mechanism.

Chemical preparation and X-ray diffraction determined crystal structures of (CH{sub 3}OCH{sub 2}CH{sub 2}C{sub 5}H{sub 4}){sub 2}LnCl [Ln = La (1), Pr (2), Nd (3), Sm (4), Gd (5), Dy (6), Ho (7), Er (8), Tm (9), Yb (10), Lu (11), Y (12)] are reported. Further characterization by elemental analysis, MS, NMR, and IR spectroscopy was performed for these complexes. From these data, the molecular structures are described.

The salts M2[2,6-(CH2C5H4)2C5H3N] (i.e. Na2L, Li2L) react under mild conditions with anhydrous LnCl3 in the molar ratio 1:1 to afford complexes of the type [(LLnCl)2] (Ln = Y, Pr, Nd, Sm, Dy, Er, Yb, or Lu; 1–8). The dinuclear nature of the products 1–8 has been confirmed by mass spectrometry. Extended B/E-linked scans of metastable transitions suggest that L is chelating and not metal-bridging. Direct coordination of the pyridine-N atom to the Ln ion has been deduced from XPS measurements. Reaction of PrCl·(THF)x, and Na2L in the molar ratio 2:3 leads to the compound [L3Pr2] (9) which has been characterized by elemental analysis, 1H NMR and mass spectrometry. Some preliminary results on the catalytic activity of 1–8 during hydrogenation of 1-hexene by LiAlH4 suggest the formation of catalytically active, intermediate hydrides.

Reaction of 1/2 mole ratio of (η5-C5H5)SmCl2 ·3THF and NaCCCH2OCH2CHCH2 in THF solution resulted in the formation of (η5-C5H5)Sm·OC4H8; the complex crystallizes in monoclinic space group P21/n with unit cell constants a = 8.254(5), b = 24.63(1), c = 8.339(3) A, β = 101.33(5)° and Dc = 1.67 g/cm3 for Z = 4. Refinement has led to a final R value of 0.041 based on 2106 independent observed reflections. The THF molecule is coordinated to the samarium atom at a SmO distance of 2.522(6) A. The SmC(cyclopentadienyl) bond lengths range from 2.70(1) to 2.80(1) A and average 2.742(1) A. A comparison of some significant structural parameters along the isostructural series (η5-C5H5)3Ln·THF (LnLa, Pr, Nd, Gd, Dy, Lu and Sm) with the ionic radii of Ln3+ was made.

By the one-pot reaction of lanthanide trichloride with 2 equivalents of sodium cyclopentadienyl and 1 equivalent of sodium 2-methoxyethylcyclopentadienyl in THF, the mixed tricyclopentadienyl lanthanide complexes (C5H5)2Ln(CH3OCH2CH2C5H4) (Ln = La, Sm, Gd, Er, Yb, Y) were obtained. The compound (CH3OCH2CH2C5H4) Y(C5H5)2 (6) crystallized from THF. The central metal Y is coordinated to three cyclopentadienyl ring centroids and the ether oxygen forming a distorted tetrahedron. The average YC(η5) bond distance and YO bond distance of 6 are 2.702 and 2.414 A, respectively.

Four new title complexes, [CH3N(CH2CH2C5H4)2LnCl]2 (Ln = Y, Yb, Sm, Nd), were synthesized by using amine-linked biscyclopentadiene, CH3N(CH2CH2C5H5)2, as ancillary ligands and fully characterized by elemental analyses, MS, IR and 1H NMR. Their spectroscopies indicate that these complexes are chloride-bridged dimers and the two amine-linked cyclopentadienyl rings coordinate to one metal in a chelating fashion with intramolecular coordination from the nitrogen atom to the metal.

Bis(2-methoxyethylcyclopentadienyl) divalent solvent-free organolanthanide complexes (MeOCH 2 CH 2 C 5 H 4 ) 2 SM ( 1 ) and (MeOCH 2 CH 2 C 5 H 4 ) 2 Yb ( 2 ) have been synthesized by the interaction of (MeOCH 2 CH 2 C 5 H 4 )K with LnI 2 (Ln = Sm, Yb). Recrystallization of 2 from THF produced the solvated single crystal (MeOCH 2 CH 2 C 5 H 4 ) 2 Yb·OC 4 H 8 ( 3 ) which has the coordination number of nine, the highest yet reported for this class of compound. The two ring centroids of the 2-methoxyethylcyclopentadienyl rings, the two oxygen atoms of ether-substituted groups on the rings and the oxygen atom of the THF form a distorted trigonal bipyramid around the central ion of ytterbium.

The partial hydrolysis of CP′2ErCl (1) (Cp′ = CH3OCH2Ch2C5H4) affords [CP′2Er(μ-OH)]2, the single crystal X-ray structure of which reveals that the complex is dimeric with bridging hydroxide groups. The molecular structure shows the hydroxyl groups bridging with distances ErO = 2.258(5), 2.216(5) A, and the methoxyethyl group coordinating with distances ErO(1) = 2.542(3), ErCp1 = 2.3981(4) and ErCp2 = 2.1680(3) A. The bond angles of OErO* and OErO(1) in 2 are 71.6(2) and 73.2 (2)°, respectively.

Dicyclopentadienylyttrium chloride reacts with aromatic and aliphatic acid chlorides in tetrahydrofuran at room temperature, resulting in cleavage of the CpY π-bond to produce 1,5-diacylcyclopentadienes, and the acylative ring-opening of tetrahydrofuran. A possible reaction mechanism is proposed.

Seven new 1,1′-(3-oxa-pentamethylene0dicyclopentadienyl lanthanide and yttrium chlorides, (C 5 H 4 CH 2 CH 2 OCH 2 CH 2 C 5 H 4 )LnCl(Ln = Nd, Gd, Ho, Er, Yb, Lu and Y) were synthesized by using 1,1′-(3-oxa-pentamethylene)biscyclopentadienyl as ligand. Disproportionation of xicyclopentadienyl neodymium chloride is thus succesfully prevented, and a stable early lanthanocene chloride is obtained. All seven complexes are unsolvated monomers, containing an intramolecular coordination bond. Their structures were verified by elemental analyses, and IR, MS, XPS, 1 H NMR and 13 C NMR spectroscopy. They are readily soluble in various solvents and more stable towards air and moisture than other related complexes without an intramolecular coordination bond. The complex/NaH system hydrogenates 1-hexane catalytically in hydrogen.

The reaction of O(CH 2 CH 2 C 5 H 4 ) 2 LnCl (Ln=Y, Lu) with NaN 2 C 3 HMe 2 in tetrahydrofuran at room temperature generates the complexes O(CH 2 CH 2 C 5 H 4 ) 2 Ln(N 2 C 3 HMe 2 ) (Ln=Y (1), Lu (2)). The partial hydrolyses of 1 and 2 form the title complexes. The new compounds have been characterized by elemental analyses and IR and NMR spectra. X-structural analyses of 3 and 4

THF-solvated 1,1′-(xylylene)bis-cyclopentadienyl rare earth chlorides [C5H4CH2 C6H4CH2C5H4] LnCl · THF (Ln = La, Pr, Nd, Dy, Y, Er and Yb), were synthesized by using 1,1′-(m-xylylene)bis-cyclopentadiene and 1,1′-(p-xylylene)bis-cyclopentadiene as ligands. Disproportionation of early lanthanocene chlorides (Ln = La, Pr, Nd) is thus successfully prevented and stable early lanthanocene chlorides are obtained. Their structures were verified by elemental analyses, IR, 1H NMR, MS and XPS spectroscopy; they are possibly dimeric. The solubility of these complexes in aromatic hydrocarbons is lower than the corresponding 1,1′-(trimethylene)bis-cyclopentadienyl lanthanide chlorides.

(Cp3La) [1272-23-7] C15H15La (MW 334.21) InChI = 1S/3C5H5.La/c3*1-2-4-5-3-1;/h3*1-5H; InChIKey = FRXJDKXOOBAPRG-UHFFFAOYSA-N (NaH) [7646-69-7] HNa (MW 24.00) InChI = 1S/Na.H InChIKey = MPMYQQHEHYDOCL-UHFFFAOYSA-N (reducing agent for alkenes, organohalogen compounds, and organoheteroatom oxides; catalyst for hydrogenation and isomerization of alkenes) Physical Data: Cp3La: mp 395 °C (slight dec.). NaH: mp 800 °C (dec.). Solubility: Cp3La: sol THF; reacts with H2O and protic solvents. NaH: slightly sol THF. Form Supplied in: Cp3La: white crystalline solid. NaH used as 80% dispersion in mineral oil. Preparative Method: because Cp3La is sensitive to air and moisture, the preparative procedure and all subsequent operations on the compound must be carried out with Schlenk techniques under purified argon. The following procedure has proven efficacious: to a suspension of anhydrous Lanthanum(III) Chloride in THF was added 4–5 equiv of sodium cyclopentadienide in THF; the mixture was refluxed with stirring for 4 h; the solvent was removed under reduced pressure, and the dry residue was transferred to a sublimation apparatus; on heating at 250–260 °C/10−3–10−4 mmHg, Cp3La sublimed as a white crystalline solid. Alternatively, the residue can be recrystallized from THF to afford Cp3La(THF) as colorless crystals. Handling, Storage, and Precautions: tris(cyclopentadienyl)lanthanum and Sodium Hydride must be used as prepared or purified, and sealed in glass ampules with argon or nitrogen for storage.

The substituted cyclopentadienyl sodium salt CH3OCH2CH2C5H4Na reacts with LnCl3 (Ln = La, Nd, Gd, Ho, Er, Yb and Y) in THF at room temperature to give the new complexes [(CH3OCH2CH2C5H4)2LnCl]2 in good yield. XPS (X-ray photoelectron spectroscopy) studies show that the metals in these complexes are coordinated through the oxygen atoms.

A new synthetic method of heterobimetallic complexes bridging with a pi,pi-phenylcyclopentadienyl ligand, tricarbonylchromium-eta(6),eta(5)-phenylcyclopentadienyl-transition metal complexes, was developed through the reactions of (eta(6)-C(6)H(5)C(5)H(5))Cr(CO)(3) or its sodium salt with transition metal complexes. The method is suitable for most transition metal elements with the advantages of easy manipulation, mild reaction conditions, and moderate to high yields. As indicated by (1)H NMR spectra, the interactions between the two pi systems of phenyl and cyclopentadienyl rings were weak. X-ray crystal structures of seven complexes were studied. Compound 23, [eta(6)-C(6)H(5)Cr(CO)(3)](2)C(10)H(10), crystallizes in orthorhombic space group Pbca with cell constants a = 29.616(8) A, b = 12.861(5) A, c = 12.397(7) A, V = 4721(6) A(3), Z = 8, R = 0.045, and R(w) = 0.045. Compound 3, (eta(6)-C(6)H(5)C(9)H(7))Cr(CO)(3), crystallizes in monoclinic space group P2(1)/c with cell constants a = 7.901(3) A, b = 14.799(2) A, c = 12.917(2) A, beta = 99.72(2) degrees, V = 1488.7(4) A(3), Z = 4, R = 0.044, and R(w) = 0.051. Compound 7, Cr(CO)(3)(eta(6),eta(5)-C(6)H(5)C(5)H(4))Ti(CO)(2)(eta(5)-C(5)H(5)), crystallizes in monoclinic space group P2(1)/c with cell constants a = 12.361(4) A, b = 12.487(6) A, c = 12.531(7) A, beta = 93.48(4) degrees, V = 1930 A(3), Z = 4, R = 0.047, and R(w) = 0.048. Compound 13, Cr(CO)(3)(eta(6),eta(5)-C(6)H(5)C(5)H(4))Mo(CO)(3)Br, crystallizes in monoclinic space group P2(1)/c with cell constants a = 14.685(2) A, b = 8.509(3) A, c = 14.960(3) A, beta = 104.46(1) degrees, V = 1810.0(7) A(3), Z = 4, R = 0.037, and R(w) = 0.037. Compound 19, Cr(CO)(3)(eta(6),eta(5)-C(6)H(5)C(9)H(6))Mn(CO)(3), crystallizes in triclinic space group P(-)(1) with cell constants a = 11.660(4) A, b = 12.578(5) A, c = 6.987(2) A, alpha = 100.03(3) degrees, beta = 104.19(2) degrees, gamma = 71.99(3) degrees, V = 939.3(6) A(3), Z = 2, R = 0.048, and R(w) = 0.065. Compound 21, Cr(CO)(3)(eta(6),eta(5)-C(6)H(5)C(5)H(4))Ru(PPh(3))(2)Cl, crystallizes with one molecule of EtOH in triclinic space group P(-)(1) with cell constants a = 14.033(4) A, b = 16.163(6) A, c = 10.411(3) A, alpha = 104.22(3) degrees, beta = 103.50(2) degrees, gamma = 90.81(3) degrees, V = 2219(1) A(3), Z = 2, R = 0.081, and R(w) = 0.096. Compound 22, Cr(CO)(3)(eta(6),eta(5)-C(6)H(5)C(5)H(4))Co(CO)(2), crystallizes in orthorhombic space group P2(1)2(1)2(1) with cell constants a = 15.083(5) A, b = 16.391(5) A, c = 6.351(4) A, V = 1570(1) A(3), Z = 4, R = 0.036, and R(w) = 0.039. The trans configurations of the two metal atoms in these molecules were found as expected; the phenyl and cyclopentadienyl or indenyl rings in the molecules were found to be not coplanar.

A new method for deoxygenation of organoheteroatom oxides using organolanthanide complex-sodium hydride systems in tetrahydrofuran is described.

A new method for deoxygenation of organoheteroatom oxides using organolanthanide complex-sodium hydride systems in tetrahydrofuran is described.

The tris(2-methoxyethylcyclopentadienyl)lanthanide complexes [Ln(C5H4CH2CH2OMe)3](Ln = La, Pr, Nd, Gd or Y) were synthesized by the reaction of sodium 2-methoxyethylcyclopentadienide with the corresponding LnCl3 and the products were characterized by elemental analyses, mass, IR and 1H NMR spectroscopy. Crystal structure determinations revealed the complexes to be unsolvated monomeric metallocenes with lanthanide centres co-ordinated by three cyclopentadienyl rings and two oxygen atoms of the three 2-methoxyethyl moieties present; the third oxygen is not co-ordinated. The distances Ln–C (η5) and Ln–O(1)(co-ordinated oxygen) decrease as the ionic radius decreases; however, Ln–O(3)(co-ordinated oxygen) increases.

The [Ln(C5H4CH2CH2OMe)2(thf)]+ cations (Ln = Sm 1 or Yb 2, thf = tetrahydrofuran) which represent the first examples of organolanthanide cationic complexes with [Co(CO)4]– as anion, have been synthesised by metathesis of [Ln(C5H4CH2CH2OMe)2I] with K[Co(CO)4] or by one-electron oxidation of divalent [Ln(C5H4CH2CH2OMe)2(thf)] with [Co2(CO)8]. The crystal structure of complex 2 has been determined: space group P21212, a= 10.700(3), b= 11.509(4), c= 10.381(4)A, Z= 2. Least-squares refinement led to convergence with R= 0.040, R′= 0.047. It exists as discrete cations and anions with no Ln–OC–Co linkage. The samarium analogue 1 is isostructural. Variable-temperature NMR studies indicated that, at low temperature, the spectra of complex 1 are in good accordance with the structure in the solid state. At high temperature the two ether chains of 2 remain co-ordinated on the metal.

Four new complexes [{Ln[[graphic omitted]CH(CH2C5H4)]Cl}2](Ln = Y, Yb, Sm or Nd) were synthesised by using furan-bridged bis(cyclopentadienes) as ancillary ligands and characterized by elemental analyses, mass, IR and 1H NMR spectroscopy. The spectra indicate that these complexes are chloride-bridged dimers and the two furan-bridged cyclopentadienyl rings co-ordinate to each metal in a chelating fashion with in transolecular co-ordination between the oxygen atom and the metal. The effects of the bridging chain and the central metal upon the reactivity of organolanthanide hydrides generated in situfrom the [Ln(C5H5)2Cl]–NaH system were investigated. The reactivity can be tuned not only by varying the ligands but also by taking advantage of the lanthanide contraction. The ligand tunability varies for different reactions. More reactive organolanthanide hydride species (in situ) can be obtained by both ‘ligand tuning’ and ‘metal tuning’, i.e. by selecting the appropriate ancillary ligands and the early lanthanide metals.

THF-solvated early lanthanocene chlorides containing ring-bridged dicyclopentadiene as a ligand [C 5 H 4 (CH 2 ) 3 C 5 H 4 ]LnCl · THF (Ln = Nd, Pr) were synthesized. The disproportionation of dicyclopentadienyl lanthanide chlorides is thus successfully prevented and the stabilization of early lanthanocene chloride achieved. In order to further demonstrate that the products obtained are tetrahydrofuran-solvated, similar complexes of Gd, Dy, Ho, Er, Yb and Lu were also synthesized and characterized. The products obtained are without exception coordinated with one molecular tetrahydrofuran. When the tetrahydrofuran coordinated lanthanocene chlorides were allowed to react with 2,2′-bipyridyl, the coordinated tetrahydrofuran was replaced by 2,2′-bipyridyl in each case to form the 2,2′-bipyridyl complex. The latter are more stable towards air and moisture than the former ones. Fifteen new complexes were synthesized and their structures were verified by elemental analyses, infrared spectra, mass spectra and 31 H NMR. Moreover, the variable temperature (77–291 K) magnetic susceptibilities were also measured.

Five new solvated organolanthanide complexes containing Ln-C σ-bonds (η5-CH3C5H4)2ErC6H4CH3-p · THF (I), (η5-C5H5)2LnC6H4X-p · THF, Ln  Er, X  CH3 (II); Ln  Er, X  Cl (III); Ln  Yb, X = CH3 (IV); Ln  Gd, X  CH3 (V) were synthesized by the reaction of appropriate aryllithium derivatives with (η5-C5H5)2LnCl or (η5-CH3C5H4)2LnCl in THF at low temperature (−78°C). The structures of these complexes were verified by elemental analyses, infrared spectra and mass spectra. Recrystallization of these complexes from non-polar solvents such as benzene-n-hexane or toluene-n-hexane led to removal of coordinated tetrahydrofuran resulting in unsolvated products. The thermal decomposition temperature and the variable temperature (77–291 K) magnetic susceptibilities of the five unsolvated complexes were measured. The relation between the structure and oxidative and thermal stability is also discussed. Two new “mixed ligand” tri-η5-cyclopentadienyllanthanide complexes Cp2YbCp′ (VI) and Cp′2ErCp (VII) where Cp  η5-cyclopentadienyl, Cp′ = η5-methylcyclopentadienyl were also prepared. They are relatively more stable to air and moisture and more thermally stable than the complexes with LnC σ bonds. The infrared spectra of fifteen organolanthanide complexes including those aforementioned compounds and eight known compounds, i.e. Cp2GdCl, Cp′2GdCl, Cp2HoCl, Cp2ErCl, Cp′2ErCl, Cp2YbCl, Cp3Yb and Cp3Er were measured from 4000 to 200 cm−1. The absorption peak at 250 cm−1 was assigned as the characteristic absorption of the π-bonded cyclopentadienyl group to metal.

Six new 1,10-phenanthroline coordinated dicyclopentadienyl early lanthanide trifluroacetate complexes, (C5H5)2LnOC(O)CF3· n Phen (Ln = Nd, Pr, n = 1 or 2; Ln = Ce, La, n = 2; Phen = 1,10-phenanthroline) were synthesized by the reaction of CF3COONa in THF with (C5H5)2LnC1·n Phen which was in turn prepared from LnC13·n Phen and C5H5Na. The structures of these new early organolanthanide complexes were verified by elemental analysis, IR, NMR and mass spectroscopy. The stabilization by coordinated 1,10-phenanthroline and its effect on the spectra were also discussed.

Organolanthanide chloride complexes [(CH3OCH2CH2C5H4)2Ln(μ-Cl)]2 (Ln = La, Pr, Ho and Y) react with excess NaH in THF at 45°C to give the dimeric hydride complexes [(CH3OCH2CH2C5H4)2Ln(μ-H)]2, which have been characterized by IR, 1H NMR, MS and XPS spectroscopy, elemental analyses and X-ray crystallography. [(CH3OCH2CH2C5H4)2Y(μ-H)]2 crystallizes from THF/n-hexane at −30°C, in the triclinic space group P1 with a = 8.795(2) A, b = 11.040(1) A, c = 16.602(2) A, α = 93.73(1)°, β = 91.82(1)°, γ = 94.21(1)°, Dc = 1.393 gcm−3 for Z = 2 dimers. However, crystals of [(CH3OCH2CH2C5H4)2Ho(μ-OH)]2 were obtained by recrystallization of holmium hydride in THF/n-hexane at −30°C, in the orthorhombic space group Pbca with a = 11.217(2) A, b = 15.865(7) A, c = 17.608(4) A, Dc = 1.816 gcm−3 for Z = 4 dimers. In the complexes of yttrium and holmium, each Ln atom of the dimers is coordinated by two substituted cyclopentadienyl ligands, one oxygen atom and two hydrogen atoms (for the Y atom) or two hydroxyl groups (for the Ho atom) to form a distorted trigonal bipyramid if the C(η5)-bonded cyclopentadienyl is regarded as occupying a single polyhedral vertex.

Dicyclopentadienyl lanthanide chlorides (Ln = Gd, Dy, Ho, Er, Yb, Lu) react with 2,2′-bipyridyl in tetrahydrofuran at room temperature to give 2,2′-bipyridyl complexes. Elemental analyses indicate that when the molar ratios of chlorides to 2,2′-bipyridyl in the starting material vary from 1:1 to 1:0.5, 1:2 and 1:4, the molar ratio of the two components in the complexes formed remains 1:1. Both the infrared spectra and X-ray photoelectron spectra (XPS) of the products demonstrate that complexation occurs.

Four new 1,10-phenanthroline-coordinated early lanthanide complexes containing a σ-carbon-metal bond 1–4 were synthesized by the reaction of alkynylsodium or alkyllithium with (η 5 -C 5 H 5 ) 2 LnCl· n Phen in THF at 0 or −78°C. The complexes (η 5 -C 5 H 5 ) 2 LnCl· n Phen were prepared from LnCl 3 · n Phen and C 5 H 5 Na. 1,1′-Trimethylenedicyclopentadienyl(phenylacetylenylneodymium). THF 5 was also prepared. These complexes were identified by elemental analysis, IR, 1 H NMR spectroscopy and thermogravimetry. Protolysis reactions of these complexes with H 2 O. CH 3 OH and t-C 4 H 9 OH show that different protolytic reagents give the products with different cleavage extents of σ- and π-bonds. The ligands in the complexes also affect the cleavage of π-bonds. β-Hydrogen elimination of complex 3 takes place with thermal decomposition.

LuCl 3 reacts with two equivalents of sodium cyclopentadienide in THF followed by crystallization from this solvent at 5°C to afford (C 5 H 5 ) 2 LuCl · OC 4 H 8 . The product has been characterized by its proton NMR and mass spectra, elemental analysis and by single crystal X-ray diffraction studies. The complex (C 5 H 5 ) 2 LuCl · OC 4 H 8 crystallizes in the monoclinic space group P 2 1 / n with the unit cell parameters, a 8.116(2), b 12.670(2), c 14.376(1) A, β 105.61(1)°, V 1423.7 A 3 , Z = 4, D c 1.925 g cm −3 . The structure was solved by heavy-atom Patterson techniques and the least-squares refinement has led to a final R value of 0.097 based on 2253 independent observed reflections. The THF molecule is coordinated to the lutetium atom at a LuO bond length of 2.27(1) A. The LuC(η5) bond distances average 2.56 A. The compound (η 5 -C 5 H 5 ) 2 LuCl · OC 4 H 8 is a neutral monomer.

Dicyclopentadienyl lanthanide chlorides, (C 5 H 5 ) 2 LnCl, are key intermediates for the synthesis of the compounds containing LNC σ bonds, LnN and LnO bonds. However, probably due to lanthanide contraction effect, the early lanthanocene chloride complexes, particularly for La, Ce, Pr and Nd, have not yet been synthesized [1-3]. Recently, some organometallic chemists have made their efforts to study how to stabilize the dicyclopentadienyl early lanthanide chloride. Using the di(trimethylsilyl)-lanthanide chlorides. By using a bulky pentamethylcyclopentadienyl as a ligand, Evans [4] and Andersen [5] had succeeded in stabilizing dicyclopentadienyl cyclopentadienyl as a ligand, Lappert [6] succeeded in stabilizing early (f 0 –f 3 ) lanthanocene chlorides by generating an anionic complex. We now wish to report here two methods for the stabilization of early lanthanocene chlorides by using a chelate ligand. 1. By using ring-bridged dicyclopentadiene instead of two separated cyclopentadienes as a ligand we have succeeded in synthesizing the stabilized early lanthanocene chlorides tetrahydrofuran coordinated neutral complexes [7]. Because our results are different from Tsutsui's [8], we further synthesized six 1,1′-trimethylenedicyclopentadienyl lanthanide chlorides. All the products so far obtained were found to be tetrahydrofuran coordinated neutral complexes without exception. Anhydrous lanthanide chlorides reacted with disodium salt 1,3-dicyclopentadienyl-propane in THF at −50 °C to give tetrahydrofuran coordinated 1,1′-trimethylenedicyclopentadienyl lanthanide chlorides (eqn. 1). Furthermore, we found that the coordinated tetrahydrofuran could be replaced by 2,2′-bipyridyl to afford 2,2′-bipyridyl complexes which exhibit better stability to air and moisture (eqn. 2). It should be noted that even when the molar ratios of chlorides to 2,2′-bipyridyl in starting material were changed from 1:1 to 1:2, the atomic ratios of lanthanide metal to nitrogen in products remained 1:1. The infrared spectra of 2,2′-bipyridyl complexes indicate that four characteristics absorption peaks of pyridine ring at 408, 621, 994 and 1580 cm −1 all shift to higher frequencies as compared with that in [C 5 H 4 (CH 2 ) 3 C 5 H 4 ]LnCl·2,2′-bpy) 0.5 . It implies that a pair of electrons on nitrogen is coordinated to the metal to form a coordinated covalent bond. However, the dicyclopentadienyl lanthanide chlorides reacted with 2,2′-bipyridyl giving 2,2′-bipyridyl complexes, the atomic ratios of metal to nitrogen in products always were 1:2 and the coordination number is nine (eqn. 3). The infrared spectra of these complexes indicate that four characteristics absorption peaks of pyridine ring all shift to higher frequencies too, in agreement with that of [C 5 H 4 (CH 2 ) 3 C 5 H 4 ]LnCl·(2,2′-bpy) 0.5 . The X-ray photoelectron spectra of five dicyclopentadienyl lanthanide chlorides and their corresponding bipyridyl complexes (Cp 2 LnCl·2,2′-bpy) were measured. The binding energies of both Ln 4d and Cl 2p decrease as Cp 2 LnCl forms Cp 2 LnCl·2,2′-bpy complexes. This fact also demonstrated that the lone pair of electrons on nitrogen is coordinated to the metal to form a coordinated covalent bond. It was unexpectedly found that the binding energies of Cl 2p also decrease. It seems that the electron also shifts toward chlorine. The binding energies of N 1s increase at the same time. 2. The second method of stabilizing early (f 0 –f 3 ) lanthanocene chlorides we adopted is to use other types of chelate ligand, 2,2′-bipyridyl or o -phenanthroline to satisfy the coordination saturation, and thus improve the stabilization. We succeeded for the first time in synthesizing the dicyclopentadienyl early lanthanide chloride 2,2′-bipyridyl or o -phenanthroline coordination compounds (eqns. 4,5). They were allowed to react with sodium trifluoroacetate to afford the corresponding derivatives Cp 2 LnOCOCF 3 ·nB (eqn. 6). The 1 H NMR spectrum of Cp 2 LaOCOCF 3 ·2phen was determined. It indicates that the δ values of coordinated o -phenanthroline shift to lower field as compared with that in o -phenanthroline. B = 2,2′-bpy; Ln = La, Nd B = o -phen; Ln = La, Ce; N = 2; Ln = Pr, Nd; N = 1 or 2 By using ring-bridged dicyclopentadiene, 2,2′-bipyridyl or o -phenanthroline as a ligand the disproportionation of early lanthanocene chloride is thus prevented, the stabilization of early lanthanocene chlorides achieved, and the early lanthanocene chlorides can be isolated.