Organolanthanide Compounds Containing Methanesulfonate and Pyrazinamide Ligand in Styrene Polymerization

The synthesis of organolanthanide compounds identified as LnCp^＊（MS）2PzA, Ln = Sm, Tb, Yb （MS = methanesulfonate, Cp^＊ = pentamethylcyclopentadienyl, and PzA = pyrazinamide）, by the reaction of coordination compounds Ln（MS）3（PzA）4 with NaCp in THF was reported. The complexes were formulated according to elemental analyses, complexometric titration with EDTA （%Ln）, and ^1H NMR. IR spectroscopy revealed that PzA coordinates with lanthanide （Ⅲ） ions and methanesulfonate coordinates via oxygen atoms in a non-equivalent manner. In preliminary catalytic studies, these compounds were active in styrene polymerization that used MAO as a cocatalyst with an activity of 12.3 kg PS molSm^-1h^-1. Differential scanning calorimetry （DSC） of polystyrene showed that the polymer was mainly atactic.

POLYMERIZATION OF ACRYLONITRILE WITH ORGANOLANTHANIDES AS SINGLE-COMPONENT CATALYSTS

Ind_(2)Y(μ-Et)_(2)AlEt_(2) and Ind_(2)LnN(i-Pr)_(2)(Ln=Y,Yb)were used as a single-component catalyst for the polymerization of acrylonitrile(AN)respectively.The regularity of polymerization of AN and stereoregularity of polyacrylonitrile(PAN)were also studied in both cases.Both catalysts can produce PAN with molecular weight from 10,000 to 30,000.In addition,the catalytic activity and molecular weights were increased by the addition of PhONa.

POLYMERIZATION OF METHYL METHACRYLATE WITH ORGANOLANTHANIDES AS SINGLE-COMPONENT CATALYSTS

It was first found that Ind(2)Y(mu -Et)(2)AlEt2 and Ind(2)LnN(i-Pr)(2) (Ln = Y, Yb) exhibit extremely high catalytic activity in the polymerization of methyl methacrylate. The reactions can be carried out over a quite broad range of polymerization temperatures from -30 to 50 degreesC. PMMA with high molecular weight (7.8 x 10(-5)) and high isotacticity (94%) can be obtained by using Ind(2)Y(mu -Et)(2)AlEt2, and narrow molecular weight distribution (M-w/M-n < 1.5) can be obtained by using Ind(2)LnN(i-Pr)(2) (Ln = Y, Yb).

Advances in Organolanthanide Chmistry in China

The article reviewed the progress in organolanthanide chemistry in China. The contents included the syntheses and molecular structures of organolanthanide complexes, such as tricyclopentadienyl,cyclopentadienyl halides, complexes containing Li-C σ bond,organohydrides, allyl-, cyclooctatetraenyl,tetraenyl-, neutral arene complexes and divalent complexes,and the application to the catalytic and organic reactions including hydrogenation,isomerization, polymerization,dehalogenation,deoxyenation and desulfuration.

Synthesis and Characterization of Chiral Binuclear Organolanthanide and Yttrium Alkoxides Containing Cyclopentudienyl Ligand

Three new chiral binuclear organolanthanide alkoxides containing cyclopentadienyl ligand have been synthesised by the reaction of Cp3Ln (Cp=C5H5; Ln=Yb, Y, Dy ) with 0.5equimolar chiral diol in THF (tetrahydrofuran) at -78℃ at room temperature. All the complexes were characterized by elemental analysis, IR and MS spectra.

Study on Divalent Organolanthanide Catalysts for Styrene Polymerization——Catalytic Activity Affected by the Substituent on the Cyclopentadienyl Ring

Divalent organosamarium and organoytterbium complexes as a kind of strong reducing agent not only can react with electron rich agents such as halides, aldehyde, ketone, unsaturated hydrocarbon and the compounds containing active hydrogen but also can catalyze hydrogenation of alkyne, ethylene polymerization and methyl methacrylate polymerization. More and more interests and attention have been given to the synthesis, structure and catalytic activity of divalent organolanthanide complexes in recent years,

Theoretical investigation on organolanthanide guanidinate complexes

Density functional theory (DFT) calculations were carried out on the compounds Cp2Ln-guan for Ln=Y, Lu, Yb, Dy and Gd, [guan=(iPrN)2CN(iPr)2]. The results were compared with the X-ray structures that were available from the literature; the calculations reproduced quite well the experimental structural features in these complexes exhibiting distorted tetrahedron geometry. The calculated evolution of the Ln-guan bond as a function of the cation showed that lanthanide-ligand distances increased with the increa...

Studies on Organolanthanide Complexes(L)——Syntheses and Crystal Structures of(CH_3OCH_2CH_2C_5H_4)_2 SmI and(CH_3OCH_2CH_2C_5H_4)SmI_2·2THF

Reactions of samarium triiodides with 2 equivalents of potassium 2-methoxyethyl- cyelopentadienyl or 1 equivalent of potassium 2-methoxyethylcyclopentadienyl in tetrehydrofuran afford bis- (2-methoxyethylcyclopentadienyl) samarium iodide complex Cp′_2 SmI 1 (Cp′=MeOCH_2CH_2C_5H_4),and (2- methoxyethylcyclopentadienyl) samarium diioidide complex Cp′SmI_2·2THF 2.Compound 1 crystallizes from THF/hexane in orthorhombic space group P2_12_12_1 with cell dimensions a= 11.074(4),b= 12.929(9), c=12.269(4) ,V=1756.9 ~3 and D_(cacld)=1.978 g/cm^3 for Z=4.The central metal Sm is coordinated with two Cp′ ring centroids,one iodine atom and two oxygen atoms of Cp′ forming a distorted trigonal bipyramid.The coordination number of Sm (Ⅲ) in 1 is 9.The crysal of 2 belongs to the monoclinie crystal system,space group P2_1/c with a=16.304(6),b=8.335(2),c=16.527(5) ,β=111.8 (1)°,V= 2085.3 ~3 D_(cacld)=2.138 g/cm^3 and Z=4.The central metal Sm is coordinated by one Cp′ ring centroid, two iodine atoms,one oxygen atom of Cp′ and two oxygen atoms of THF forming a distorted octahedron. The coordination number of Sm (Ⅲ) in 2 is 8.

Synthesis and Characterization of Ethylthioethylcyclopenta-dienyl Organolanthanide Complexes:Cp_2^(Th)LnCl(Ln=Gd,Dy),Cp_2LnCp^(Th)(Ln=Yb,Sm,Dy,Y) and Cp^(Th)ErCl_2·2THF

Six new ethylthioethylcyclopentadienyl-containing organolanthanide complexes CpTh 2LnCl [Ln=Gd (1), Dy (2)] and Cp2LnCpTh [Cp=C5H5, Ln=Yb (3), Sm (4), Dy (5), Y (6)] were synthesized by the reaction of ethylthioethyl-cyclopentadienyl (CpTh) sodium salt with LnCl3 or Cp2LnCl in THF. Complexes 16 were characterized by ele-mental analyses, infrared and mass spectroscopies. The molecular structures of complexes 13 were also deter-mined by the X-ray single crystal diffraction. The results show that the side-chain sulfur atom on the ethylthio-ethylcyclopentadienyl ring can form intramolecular chelating coordination to the central lanthanide ion, improving the stability of organolanthanide complexes and reducing the number of coordinated THF molecules.

Mass spectra of organolanthanide complexes

The EI mass spectra of seven 1,1'-(3-oxa-pentamethylene)-dicyclopentadienyl lanthanide and yttrium chlorides(1—7),and eleven dicyclopentadienyl lanthanide and yttrium chlorides(8—18) were investigated.Fragmentation patterns of these complexes were studied by using metastable ion measurements.The EI spectra of complexes 1—7 exhibited strong molecular ion peaks,the frag- mentation of molecular ions were more complicated.The EI mass spectra of complexes 8—18 sup- ported the dimeric structure under gaseous state.In the spectra of dimers(C_5H_5)_3Ln^+·observed were resulted from the skeletal rearrangement involving the migration of cyclopentadienyl moiety.

Synthesis and Crystal Structure of [NdCl_5(THF)]^(2-) [HO-4,6-di-~tBu-C_6H_2-2-CH_2{CH(~i PrNCHCHN)}]_2^+·THF

The title complex 1.THF has been synthesized by the reaction of [HO-4,6-di-^tBu- C6H2-2-CH2{CH（IPrNCHCHN）}]C1 with NdCl3 in a 2：1 molar ratio in THF, and characterized by single-crystal X-ray diffraction. It crystallizes in monoclinic, space group P2dc with a = 9.6501 （14）, b = 16.393（2）, c = 36.745（6） ]A, β = 97.444（4）^o, V= 5763.7（15） ]A^3, Mr= 1124.69, Z = 4, Dc= 1.296 g/cm^3, μ（MoKa） = 1.175 mm-1, F（000） = 2348, the final R = 0.0729 and wR = 0.1762 for 8735 observed reflections with 1 〉 2σ（I）. Complex 1 consists of an anion [NdC15（THF）]^2- and two cations [HO-4,6-di-tBu-C6H2-2-CH2{CH（iprNCHCHN）}]2^＋ to form a layer structure by the interconnection of anions and cations via hydrogen bonding. The central metal Nd in the anionic unit is coordinated by five C1 atoms and one oxygen atom from solvated THF molecule assuming a distorted octahedral geometry.

Synthesis and Crystal Structure of (1,3-~tBu_2C_5H_3)_2Sm( μ-Cl)_2Li(THF)_2

Anhydrous SmCl 3 reacts with two equal of Li(1,3 tBu 2C 5H 3) to give a complex (1,3 tBu 2C 5H 3) 2Sm( μ Cl) 2Li(THF) 2(C 34 H 58 Cl 2LiO 2Sm, M r =726.99), monoclinic, space group P2 1/n, a=10.615(2), b=21.037(4), c=17.166(3), β=93.60(3)°, V=3825\^7(13) 3, Z=4, D c =1.262Mg/m 3, μ =1.699mm -1 and F (000)=1508, final R= 0.0387 and wR =0.0741 for 5320 observed[ I2σ(I)] reflections. The average Sm-C distance is 2\^73. Sm-Cl1 and Sm-Cl2 distances are 2\^719(2) and 2.697(2), respectively. Two 1,3 tBu 2C 5H 3 ring centroids and two μ 2 bridging chloride atoms around Sm atom form a distorted tetrahedron.

Synthesis and Crystal Structure of[C_6H_5CH_2C_5H_4ErCl_2(THF)_3]·THF

C_6H_5CH_2C_5H_4ErCl_2(THF)_3]·THF, Mr=681.9, monoclinic,space group P2_1/n, with a=11. 622(5), b=10. 281(4), c=26. 040(5),β=86. 65 (4)°,V=3106 (3), Z=4, Dc=1. 46 gcm￣(-3),μ=30. 0 cm￣(-1), F (000)=1380. The final R value is 0. 040 for 1911 independent observed reflections (I>3σ(I)). The geometry around the erbium ion is described as an approximate octahedron with the centroid of the benzylcyclopentadienyl rings, the oxygens of three THF's and two chlorine atoms forming the apices of the octahedron. The average distance of Er-C(Cp'ring) is 2. 66A.

Insertion Reactions of PhEtCCO and PhNCO into Ln-S (Ln=Er, Y, Yb) Bond of [Cp_2Ln(μ-SEt)]_2

The reactivity of lanthanocene thiolates [Cp2Ln（μ-SEt）]2（Ln = Er, Y, Yb） with PhEtCCO and with PhNCO was examined. Treatment of [ Cp2Ln（μ-SEt）]2 with PhEtCCO gives the α-thiolate-substituted enolate complexes [ Cp2Ln （μ-η^1 ：η^3-OC（SEt）CPhEt）]2（Ln = Yb, Y）, while [Cp2Ln（μ-SEt）]2 react with PhNCO to give the lanthanocene amido derivatives [Cp2Ln（OC（SEt）NPh ）]2（Ln = Er, Yb）. In both cases, the insertion reaction is independent of the stoichiometric ratio and the nature of lanthanides, demonstrating that lanthanocene thiolates are high reactive toward PhEtCCO and PhNCO under the conditions involved. All complexes are characterized by elemental analysis and spectroscopic properties, of which the structures of ytterbium enolate and erbium amido are also determined by X-ray single crystal diffraction analysis, indicating that both of them are centrosymmetric binuclear structures.

Synthesis and Crystal Structure of Bis(tert-butyl-cyclopentadienyl)Erbium Ethoxide, (t-BuCp)_2ErOEt

The formation of ( t BuCp) 2ErOEt was discussed. Its single crystal structure was determined by X ray diffraction. The crystal is monoclinic, P 2(1)/ c space group, a =1.0191(2), b =1.6203(5), c =1.2118(3) nm, β =102.960(10)°, V =1.9500 (nm 3), Z =2, D c=1.566 mg·m -3 , R =0.0450, R w=0.1363. The complex is monomeric and solvent free in the solid state. The erbium ion is coordinated by two tert butyl cyclopentadienyl rings and one oxygen atom of ethoxy group to form a seven coordinated complex.

Synthesis and Crystal Structure of [Cp_2Ln(OC(SEt)NPh )]_2

Treatment of Cp3Y with EtSH, followed by reaction with an equivalent of PhNCO, yielded the dinuclear complex [Cp2Y（μ-η^1：η^3-OC（SEt）NPh）]2. The structure was characterized by elemental analysis, IR, MS and single-crystal X-ray diffraction analysis. The title compound crystallizes in triclinic, space group P1^- with a = 8.643（3）, b = 10.752（4）, c = 11.161（4）A°, α= 117.840（5）, β = 94.086（5）, γ= 101.008（5）°, V = 884.8（6） A°^3, Z = 1, Mr = 798.66 （C38H40N2O2S2Y2）, λ（MoKα） = 0.710730 .A°, ,μ= 3.417 mm^-1, Dc = 1.499 g/cm^3, F（000） = 408, the final R = 0.0453 and wR = 0.1007 for 3067 unique reflections （Rint = 0.0317） with 2357 observed ones （I 〉 2σ（I））. X-ray analysis reveals an unusual bonding mode of the OC（SEt）NPh ligand and the OCN fragment acts as a both bridging and side-on chelating ligand. Each yttrium atom is coordinated by two η^5-cyclopentadienyl groups, one chelating η^3-OC（SEt）NPh ligand and one bridging O atom from another η^3-OC（SEt）NPh ligand.

Synthesis and Characterization of [(C_5H_4SiMe_2~tBu)_2Ln(μ-S^nBu)]_2 (Ln=Y,Er)

（C5H4SiMe2^tBu）2Ln^nBu reacted with 1 equiv, of elemental sulfur in toluene at ambient temperature to yield the corresponding lanthanocene thiolates [（C5H4SiMe2^tBu）2Ln（μ-S^nBu）]2 （Ln = Y （1）, Er （2））. Complexes 1 and 2 have been characterized by elemental analysis, IR, mass spectroscopy and X-ray single-crystal diffraction analysis. Both complexes are of monoclinic with space group P21/c, formula C52H94S2Si4Y2 1 （C52H94S2Si4Er2 2） Mr = 1073.57 （1230.27）, a = 8.495（2） （8.41（2））, b = 26.913（8） （26.67（7））, c = 13.756（4） （13.68（4）） A, α = 90（90）, β = 101.184（5） （101.57（4））, γ = 90 （90）°, V= 3085.1（15） （3007（14）） A^3, Dc = 1.156 （1.359） g·cm^-3, Z= 2 （2）, F（000） = 1144 （1260）, μ = 2.046 （2.951） cm^-1, R = 0.0687 （0.0749） and wR = 0.1306 （0.1507） for observed reflections with I 〉 2σ（I）. X-ray structures of 1 and 2 definitively prove that only one sulfur atom is inserted into the Ln-C（^nBu） bond, forming a thiolate ligand.

Synthesis and Crystal Structure of [O-4,6-di-^tBu-C6H2-2-CH2-[C{N（CHCH）NMe}]3Y

The title complex L3Y（L = [O-4,6-di-tBu-C6H2-2-CH{CH（iPr2NCHCHN） }]） has been synthesized by the reaction of LiY[N（iPr） 2]4 with H2LCl and LiBu in a 1：3：2 molar ratio at 0 ℃ in THF,and characterized by single-crystal X-ray diffraction. It crystallizes in monoclinic,space group P21 with a = 14.3612（16） ,b = 14.7524（14） ,c = 16.898（2） ,β = 105.708（3） o,V = 3446.3（6） A^3,Mr = 1203.50,Z = 2,Dc = 1.160 Mg/m^3,μ（MoKα） = 0.90 mm^-1 and F（000） = 1296. The structure was refined to R = 0.050 and wR = 0.110 for 10213 observed reflections with I 〉 2σ（I） . The Y ion is coordinated to three phenoxo groups and three NHC ligands to form a distorted octahedral geometry. The temperature effect on the reaction leads to the 1,2-benzyl migration of NHC ligand to form the title complex.

Crystal Structure of{[(μ_2-Cl)(C_5H_5)Sm(μ_2-Cl)]_2(μ_3-Cl)(μ_4-O)Sm(μ_2-Cl)·THF}_2^(2-)·[Li(DME)_2·Li(THF)_2·DME]^(2+)·DME

The crystal structure of title complex has been determined by the method of X-ray single crystal diffraction.The crystal belongs to monoclinic space group C_(2/c)with the unit parameters a=2.8907(7), b=2.0431(5),c=1.5723(3)nm;β=115.67(2)°.The unit volume V is 8.36924(348)nm^3;Z=8, Dc=1,82g·cm^(-3),μ(MoK_α)=46.4cn^(-1); F(000)=4416.The final R is 0.083,Rw 0.088.The title complex con- sists of two univalent cations and one divalent anion.The anion has a cluster structure including six Sm^(3+). Coordination numbers of all six Sm^(3+)are eight,but their surroundings are different from each other.Two of them are decahedral array,and the others are octahedral array f the centroid of each pentacyclodienyl ring is taken as one point.