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1.
Amido Metalates of Rare Earth Elements. Syntheses and Crystal Structures of [Na(12-crown-4)2][M{N(SiMe3)2}3(OSiMe3)] (M = Sm, Yb), [Na(THF)3Sm{N(SiMe3)2}3(C≡C–Ph)], [Na(THF)6][Lu2(μ-NH2)(μ-NSiMe3){N(SiMe3)2}4], and of [NaN(SiMe3)2(THF)]2. Applications of Rare Earth Metal Complexes as Polymerization Catalysts The amido silyloxy complexes [Na(12-crown-4)2][M{N(SiMe3)2}3(OSiMe3)] with M = Sm ( 1 a ), Eu ( 1 b ), Yb ( 1 c ), and Lu ( 1 d ) were obtained from the trisamides M[N(SiMe3)3]3 and NaOSiMe3 in n-hexane in the presence of 12-crown-4; they form yellow to orange-red crystals, of which 1 a and 1 c were characterized crystallographically. The complexes crystallize isotypically with one another in the monoclinic space group I2/a with eight formula units per unit cell. The metal atoms of the complex anions are tetrahedrally coordinated by the three nitrogen atoms of the N(SiMe3)2– ligands and by the oxygen atom of the OSiMe3– ligand. With 172.4° for 1 a and 179.3° for 1 c the bond angles M–O–Si are practically linear. With ethynylbenzene in the presence of NaN(SiMe3)2 in tetrahydrofuran the trisamides M[N(SiMe3)2]3 react under formation of the complexes [Na(THF)3M{N(SiMe3)2}3 · (C≡C–Ph)] with M = Ce ( 2 a ), Sm ( 2 b ), and Eu ( 2 c ), of which 2 b was characterized crystallographically (monoclinic, space group P21/n, Z = 4). 2 b forms an ion pair in which the terminal carbon atom of the C≡C–Ph– ligand is connected with the samarium atom of the Sm[N(SiMe3)2]3 group and the sodium ion is side-on connected with the acetylido group. According to the crystal structure determination (space group P212121, Z = 4) [Na(THF)6][Lu2(μ-NH2)(μ-NSiMe3) · {N(SiMe3)2}4] ( 3 ), which is formed as a by-product, consists of [Na(THF)6]+ ions and dimeric anions, in which the lutetium atoms are connected to form a planar Lu2N2 four-membered ring via a μ-NH2 bridge with average Lu–N distances of 227.2 pm and via a μ-NSiMe3 bridge of average Lu–N distances of 218.5 pm. According to the crystal structure determination (space group P 1, Z = 1) [NaN(SiMe3)2(THF)]2 ( 4 ) forms centrosymmetric dimeric molecules with Na–N distances of the Na2N2 four-membered ring of 239.9 pm and distances Na–O of the terminally bonded THF molecules which are 226.7 pm. The vinylic polymerization of methylmethacrylate (MMA) catalyzed by 1 c resulted in high molecular weight polymethylmethacrylate (PMMA) with moderate yields. The reaction of 1 a or 2 b with MMA did not give PMMA. Insoluble polynorbornene was obtained in low yields by reaction of norbornene/methylaluminoxane (MAO) with 1 a , 1 c , or 2 b . The ring opening polymerization of ϵ-caprolacton or δ-valerolacton catalyzed by 2 b resulted in corresponding polylactones in quantitative yields.  相似文献   

2.
Crystal Structures of the Samarium Amido Complexes [Sm(l-X){N(SiMe3)2}2(THF)]2 with X = Cl, Br The crystal structures of the title compounds have been determined by X-ray methods. [Sm(μ-Cl) · {N(SiMe3)2}2(THF)]2 ( 1 ): Space group P21/n, Z = 2, lattice dimensions at 223 K: a = 1429.5(2), b = 1302.3(3), c = 1658.6(3) pm, β = 114.212(10)°, R = 0.0561. [Sm(μ-Br) · {N(SiMe3)2}2(THF)]2 ( 2 ): Space group Pbca, Z = 4, lattice dimensions at 223 K: a = 1850.0(7), b = 1611.0(9), c = 1888.1(6) pm, R = 0.0497. 1 and 2 form centrosymmetric dimeric complexes via μ-X-halogeno bridges. The samarium atoms are coordinated in a distorted trigonal-bipyramidal surrounding, the THF molecule and one of the bridging halogen atoms being in axial positions.  相似文献   

3.
[Yb3OBr4{N(SiMe3)2}3(THF)3], an Amido Complex of Ytterbium with a Clusterlike Structure The title compound has been prepared from YbBr3 and NaN(SiMe3)2 in THF suspension, forming yellow single crystals from hexane solutions which were characterized by a crystal structure determination. Space group P1 , Z = 2, lattice dimensions at ?100°C: a = 1085.4(1), b = 1410.2(1), c = 1912.0(1) pm; α = 78.62(1)°, β = 80.61(1)°, γ = 73.45(1)°, R = 0.025. In the molecular structure of [Yb3OBr4{N(SiMe3)2}3(THF)3] the three ytterbium atoms together with the μ3-oxygen atom and a μ3-bromine atom form a distorted trigonal bipyramid. In addition, three μ2-Br atoms coordinate the Yb atoms in the equatorial plane, whereas the THF molecules and the N(SiMe3)2? ligands are terminally coordinated, thus forming a distorted octahedrally surrounding of the Yb atoms.  相似文献   

4.
[Cs(toluene)3(FIn{N(SiMe3)2}3)], a Fluoroindate with Rectified Cs–F–In Axis The metalate [Cs(FIn{N(SiMe3)2}3)] has been prepared by the reaction of In[N(SiMe3)2]3 with CsF in THF: The title compound 1 can be obtained by recrystallization from toluene as colorless airsensitive needles. 1 has been characterized by NMR-, IR-, and MS-techniques as well as by an X-ray structure determination. The result of the structure analysis shows an prolated molecule with an almost linear Cs–F–In axis [174.7(1)°]. The Cs+ center is surrounded by the indate ion and three toluene molecules in a distorted tetrahedral fashion.  相似文献   

5.
Reaction of DyCl3 with two equivalents of NaN(SiMe3)2 in THF yielded {Dy(μ‐Cl)[N(SiMe3)2]2(THF)}2 ( 1 ). X‐ray crystal structure analysis revealed that 1 is a centrosymmetric dimer with asymmetrically bridging chloride ligands. The metal coordination arrangement can be best described as distorted trigonal bipyramid. The bond lengths of Ln–Cl and Ln–N showed a decreasing trend with the contraction of the size of Ln3+. Treatment of N,N‐bis(pyrrolyl‐α‐methyl)‐N‐methylamine (H2dpma) with 1 and known compound {Yb(μ‐Cl)[N(SiMe3)2]2(THF)}2, respectively, led to the formations of [Dy(μ‐Cl)(dpma)(THF)2]2 ( 2 ) and {Yb(μ‐Cl)[N(SiMe3)2]2(THF)}2 ( 3 ). Compounds 2 and 3 were fully characterized by single‐crystal X‐ray crystallography, elemental analysis, and 1H NMR spectroscopy. Structure determination indicated that 2 and 3 exhibit as centrosymmetric dimers with asymmetrically bridging chloride ligands. One pot reactions involving LnCl3 (Ln = Dy and Yb), LiN(SiMe3)2, and H2dpma were explored and desired products 2 and 3 were not yielded, which indicated that 1 and {Yb(μ‐Cl)[N(SiMe3)2]2(THF)}2 are the demanding precursors to synthesize Dysprosium and Ytterbium complexes supported by dpma2– ligand. Compounds 2 and 3 are the first reported lanthanide complexes chelated by dpma2– ligand.  相似文献   

6.
[ScCl2{N(SiMe3)2}(THF)2] – a Precursor for the Synthesis of Scandium Nitride [ScCl2{N(SiMe3)2}(THF)2] ( 1 ) has been prepared by the reaction of [ScCl3(THF)3] with the trisamide Sc[N(SiMe3)2]3 in tetrahydrofurane solution forming colourless moisture sensitive crystals, which were characterized by a crystal structure determination. Space group P 1, Z = 2, lattice dimensions at –50 °C: a = 841.4(1), b = 924.2(1), c = 1550.0(1) pm, α = 90.046(7)°, β = 95.671(9)°, γ = 106.066(6)°, R1 = 0.0329. In the molecular structure of 1 the scandium atom has a distorted trigonal‐bipyramidal coordination with the THF molecules in apical positions. At 400 °C 1 is converted into scandium nitride, ScN, by stepwise leaving of THF and ClSiMe3.  相似文献   

7.
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.  相似文献   

8.
The characterization of the unstable NiII bis(silylamide) Ni{N(SiMe3)2}2 ( 1 ), its THF complex Ni{N(SiMe3)2}2(THF) ( 2 ), and the stable bis(pyridine) derivative trans‐Ni{N(SiMe3)2}2(py)2 ( 3 ), is described. Both 1 and 2 decompose at ca. 25 °C to a tetrameric NiI species, [Ni{N(SiMe3)2}]4 ( 4 ), also obtainable from LiN(SiMe3)2 and NiCl2(DME). Experimental and computational data indicate that the instability of 1 is likely due to ease of reduction of NiII to NiI and the stabilization of 4 through dispersion forces.  相似文献   

9.
SmCl3 reacts with Me3SiCH2Li in THF yielding Sm(CH2SiMe3)3(THF)3 ( 1 ). The single crystal X‐ray structural analyses of 1 , Er(CH2SiMe3)3(THF)2 ( 2 ), Yb(CH2SiMe3)3(THF)2 ( 3 ), and Lu(CH2SiMe3)3(THF)2 ( 4 ) show the Sm atom in a fac‐octahedral coordination and the heavier lanthanides Er, Yb, and Lu trigonal bipyramidally coordinated with the three alkyl ligands in equatorial and two THF molecules in axial positions.  相似文献   

10.
Mn[N(SiMe3)2]2(THF) ( I ) (Me = methyl, THF = tetrahydrofuran) was obtained on large scale from “active” MnCl2 and LiN(SiMe3)2 in THE in 85–93% yield. The novel, theoretically interesting tetra-coordinated Mn[N(SiMe3)2]2L2 series was derived from I , where L = THF, pyridine and t-butyleyanide. All these species are quite stable thermally and exhibit exteme oxygen sensitivity. Preparation, properties, and reactions of unsymmetrically substituted (“hemi”) X? Mn? Y type compounds are presented also, where X = ? Cl, ? NO3 and n = butyl, and Y = ? N(SiMe3)2 and ? OR. From Cl? Mn? N(SiMe3)2, with or without coordinated THF being present, the unusual (Mn{SiMe3)2, was isolated as yellow crystals. The “hemi” Mn(II)-system exhibits only moderate thermal stability and tends to disproportionate. Many derivatives are photosensitive, especially with UV light.  相似文献   

11.
Reactions of LiNPPh3 with the Cyclooctatetraenide Complexes [Ln(C8H8)Cl(THF)2]2 of Cerium and Samarium. Crystal Structures of [LiNPPh3]6, [Ln(C8H8)Li3Cl2(NPPh3)2(THF)3] (Ln = Ce, Sm) and [Li(THF)4][Sm(C8H8)2] LiNPPh3 reacts with the cyclooctatetraenide complexes [Ln(C8H8)Cl(THF)2]2 of cerium and samarium in tetrahydrofuran solution forming the phosphorane iminato complexes [Ln(C8H8)Li3Cl2(NPPh3)2(THF)3]. According to crystal structure analyses these complexes show heterocubane structures under participation of the lanthanoid metal atom, of the three Li atoms as well as of the two Cl und the two N atoms of the NPPh3– groups. The crystal structure of LiNPPh3 shows hexameric molecules with a Li6N6 polyhedron which is peripherally shielded by the phenyl groups. The structure of [Li(THF)4][Sm(C8H8)2], which has been isolated as a by-product, contains the samarium atom in a sandwichlike coordination by the two η8-C8H82– rings as it is also known from the corresponding anions with cerium and neodymium.  相似文献   

12.
The reaction of [(ArN)2MoCl2] · DME (Ar = 2,6‐i‐Pr2C6H3) ( 1 ) with lithium amidinates or guanidinates resulted in molybdenum(VI) complexes [(ArN)2MoCl{N(R1)C(R2)N(R1)}] (R1 = Cy (cyclohexyl), R2 = Me ( 2 ); R1 = Cy, R2 = N(i‐Pr)2 ( 3 ); R1 = Cy, R2 = N(SiMe3)2 ( 4 ); R1 = SiMe3, R2 = C6H5 ( 5 )) with five coordinated molybdenum atoms. Methylation of these compounds was exemplified by the reactions of 2 and 3 with MeLi affording the corresponding methylates [(ArN)2MoMe{N(R1)C(R2)N(R1)}] (R1 = Cy, R2 = Me ( 6 ); R1 = Cy, R2 = N(i‐Pr)2 ( 7 )). The analogous reaction of 1 with bulky [N(SiMe3)C(C6H5)C(SiMe3)2]Li · THF did not give the corresponding metathesis product, but a Schiff base adduct [(ArN)2MoCl2] · [NH=C(C6H5)CH(SiMe3)2] ( 8 ) in low yield. The molecular structures of 7 and 8 are established by the X‐ray single crystal structural analysis.  相似文献   

13.
Bis(phenolate) ligands with benzimidazole-2-ylidene ( L1) and tetrahydropyrimidine-2-ylidene ( L2 ) linkers proved to be suitable coordination environments for the synthesis of isolable Sc3+ chloro and alkyl complexes. The treatment of Sc(CH2SiMe3)3(THF)2 with equimolar amounts of [ L1,2H3 ] Cl afforded chloro complexes L1,2ScCl ( solv ) 2 (solv=THF, Py) in 76–85 % yields. L1,2ScCl ( THF ) 2 were also prepared by the salt metathesis reactions of ScCl3 with [ L1,2 ] Na2 generated from [ L1,2H3 ] Cl and 3 equiv. of NaN(SiMe3)2 (−40 °C, THF) and isolated in somewhat lower yields (68–73 %). L2ScCl ( THF ) 2 was subjected to the alkylation reaction with LiCH2SiMe3 affording alkyl derivative [ L2Sc ( CH2SiMe3 )] 2 . This compound can be alternatively prepared by the subsequent reactions of [ L2H3 ] Cl with equimolar amount of NaN(SiMe3)2 and Sc(CH2SiMe3)3(THF)2. In the dimeric alkyl compound [ L2Sc ( CH2SiMe3 )] 2 , one of the phenoxide groups of the dianionic ligand is coordinated to one scandium center, while the second one features μ-bridging coordination with two metal centers.  相似文献   

14.
Amido Complexes of Manganese(II). Syntheses and Crystal Structures of [Mn(NPh2)2(THF)]2 and Na2[Mn(NPh2)4] · 2 C7H8 The silylated amido complex [Mn{N(SiMe3)2}2 · (THF)] reacts in toluene solution with diphenylamine under ligand exchange to form the diphenylamido complex [Mn(NPh2)2(THF)]2 ( 1 ), which forms orange-red columnar crystals. 1 reacts in THF solution with NaN(SiMe3)2 and after crystallization from toluene yellow-orange Na2[Mn(NPh2)4] · 2 C7H8 ( 2 ) is obtained. According to the crystal structure analyses the manganese atoms in 1 (space group P21/c, Z = 2) are linked via the N atoms of two of the NPh2– groups to form centrosymmetric Mn2N2 four-membered rings with Mn–N bonds of almost the same length. 2 (space group I41/a, Z = 4) forms a three-dimensional space-lattice structure, which arises from ”︁inner solvation”︁”︁ of the sodium atoms with the phenyl rings of the NPh2– group.  相似文献   

15.
Preparation, Characterization and Reaction Behaviour of Sodium and Potassium Hydridosilylamides R2(H)Si—N(M)R′ (M = Na, K) — Crystal Structure of [(Me3C)2(H)Si—N(K)SiMe3]2 · THF The alkali metal hydridosilylamides R2(H)Si—N(M)R′ 1a‐Na — 1d—Na and 1a‐K — 1d‐K ( a : R = Me, R′ = CMe3; b : R = Me, R′ = SiMe3; c : R = Me, R′ = Si(H)Me2; d : R = CMe3, R′= SiMe3) have been prepared by reaction of the corresponding hydridosilylamines 1a — 1d with alkali metal M (M = Na, K) in presence of styrene or with alkali metal hydrides MH (M = Na, K). With NaNH2 in toluene Me2(H)Si—NHCMe3 ( 1a ) reacted not under metalation but under nucleophilic substitution of the H(Si) atom to give Me2(NaNH)Si—NHCMe3 ( 5 ). In the reaction of Me2(H)Si—NHSiMe3 ( 1b ) with NaNH2 intoluene a mixture of Me2(NaNH)Si—NHSiMe3 and Me2(H)Si—N(Na)SiMe3 ( 1b‐Na ) was obtained. The hydridosilylamides have been characterized spectroscopically. The spectroscopic data of these amides and of the corresponding lithium derivatives are discussed. The 29Si‐NMR‐chemical shifts and the 29Si—1H coupling constants of homologous alkali metal hydridosilylamides R2(H)Si—N(M)R′ (M = Li, Na, K) are depending on the alkali metal. With increasing of the ionic character of the M—N bond M = K > Na > Li the 29Si‐NMR‐signals are shifted upfield and the 29Si—1H coupling constants except for compounds (Me3C)(H)Si—N(M)SiMe3 are decreased. The reaction behaviour of the amides 1a‐Na — 1c‐Na and 1a‐K — 1c‐K was investigated toward chlorotrimethylsilane in tetrahydrofuran (THF) and in n‐pentane. In THF the amides produced just like the analogous lithium amides the corresponding N‐silylation products Me2(H)Si—N(SiMe3)R′ ( 2a — 2c ) in high yields. The reaction of the sodium amides with chlorotrimethylsilane in nonpolar solvent n‐pentane produced from 1a‐Na the cyclodisilazane [Me2Si—NCMe3]2 ( 8a ), from 1b‐Na and 1‐Na mixtures of cyclodisilazane [Me2Si—NR′]2 ( 8b , 8c ) and N‐silylation product 2b , 2c . In contrast to 1b‐Na and 1c‐Na and to the analogous lithium amides the reaction of 1b‐K and 1c‐K with chlorotrimethylsilane afforded the N‐silylation products Me2(H)Si—N(SiMe3)R′ ( 2b , 2c ) in high yields. The amide [(Me3C)2(H)Si—N(K)SiMe3]2·THF ( 9 ) crystallizes in the space group C2/c with Z = 4. The central part of the molecule is a planar four‐membered K2N2 ring. One potassium atom is coordinated by two nitrogen atoms and the other one by two nitrogen atoms and one oxygen atom. Furthermore K···H(Si) and K···CH3 contacts exist in 9 . The K—N distances in the K2N2 ring differ marginally.  相似文献   

16.
(PPh4)2[(SN)ReCl3(μ‐N)(μ‐NSN)ReCl3(THF)] – a Nitrido‐Thionitrosyl‐Dinitridosulfato‐Complex of Rhenium The title compound has been prepared from PPh4[ReVIICl4(NSCl)2] with excess N(SiMe3)3 in dichloromethane solution to give red‐brown single crystals after recrystallisation from acetonitrile/THF solutions. As a by‐product PPh4[ReNCl4] is formed. (PPh4)2[(SN)ReCl3(μ‐N)(μ‐NSN)ReCl3(THF)] ( 1 ): Space group P21/n, Z = 4, lattice dimensions at –80 °C: a = 1024.1(1), b = 2350.2(1), c = 2315.4(2) pm, β = 94.09(1)°, R1 = 0.0403. In the complex anion of 1 the rhenium atoms are connected by an asymmetric Re≡N–Re bridge as well as by a (NSN)4–‐bridge to form a planar Re2N(NSN) six‐membered heterocycle. Both rhenium atoms are coordinated by three chlorine atoms, one of them by a thionitrosyl ligand, the other one by the oxygen atom of a thf molecule.  相似文献   

17.
The Reactions of Europium and Yttrium with N‐Iodinetriphenylphosphoraneimine. Crystal Structures of [EuI2(DME)3], [Eu2I(NPPh3)5(DME)] and [Y2I(NPPh3)4(THF)4]+I3– When treated with ultrasound, the reaction of europium metal with INPPh3 in 1,2‐dimethoxyethane (DME) leads to the complexes [EuI2(DME)3] ( 1 ) and [Eu2I(NPPh3)5(DME)] ( 2 ) which are separated from each other by fractional crystallization. On the other hand, the reaction of yttrium metal with INPPh3 under similar conditions in THF gives the ionic phosphoraneiminato complex [Y2I(NPPh3)4(THF)4]+I3– ( 3 ). All complexes are characterized by crystal structure determinations. 1 : Space group P21, Z = 2, lattice dimensions at 188 K: a = 848.9(1); b = 1059.4(1); c = 1227.9(1) pm; β = 93.793(6)°; R = 0.0246. In the molecular structure of 1 the europium atom is eightfold coordinated with a bond angle I–Eu–I of 158.51°. 2 · 2 DME: Space group P1, Z = 2, lattice dimensions at 193 K: a = 1405.5(1); b = 1652.2(2); c = 2203.7(2) pm; α = 89.404(11)°; β = 72.958(11)°; γ = 78.657(11)°; R = 0.0391. In 2 the europium atoms are linked by the μ‐N‐atoms of two (NPPh3–) groups to form a planar Eu2N2 four‐membered ring. One of the Eu atoms is terminally coordinated by the N atoms of two (NPPh3–) groups, thus achieving a distorted tetrahedral surrounding. The second Eu atom is coordinated by the N atom of one (NPPh3–) group, by the terminally bounded iodine atom and by the oxygen atoms of the DME chelate, thus achieving a distorted octahedral surrounding. 3 · 61/2 THF: Space group P1, Z = 2, lattice dimensions at 103 K: a = 1739.7(2); b = 1770.1(2); c = 2153.8(3) pm; α = 74.929(15)°; β = 84.223(14)°; γ = 64.612(12)°; R = 0.0638. In the cation [Y2I(NPPh3)4(THF)4]+ of 3 the yttrium atoms are linked by the μ‐N atoms of two (NPPh3–) groups as well as by the μ‐I atom. One (NPPh3–) ligand and two THF molecules complete the distorted octahedral coordination at each yttrium atom.  相似文献   

18.
Synthesis and Crystal Structures of the Zinc Amido Complexes [Zn(NPh2)2]2 and [Zn(NPh2)2(THF)2] Zinc diphenylamide is prepared from Zn[N(SiMe3)2]2 and diphenylamine by transamination reaction. The compound is characterized by a crystal structure analysis. According to it [Zn(NPh2)2]2 forms centrosymmetric dimeric molecules with Zn–N distances of 185.9 pm for the terminally bonded NPh2– ligand and Zn–N distances of 204.0 and 202.6 pm in the four-membered ring. From tetrahydrofuran solutions [Zn(NPh2)2(THF)2] crystallizes as monomeric molecular complex with Zn–N bond lengths of 192.2 pm in average.  相似文献   

19.
The reactions of a bulky amino-methoxy bis(phenolate) ligand H2L with Y(CH2SiMe3)3(THF)2 and Y[N(SiHMe2)2]3(THF)2 under mild condition leads to the selective formation of the thermally stable complexes [L]Y(CH2SiMe3)(THF) (1) and [L]Y[N(SiHMe2)2](THF) (2). The X-ray structures revealed very similar binding of the [ONOO] ligand core to the metal for both complexes, which feature an octahedral geometry involving coordination of the methoxy side-arm of the ligand and of a remaining THF molecule. 1H-NMR spectroscopy indicates that the solid state structure of 1 and 2 is retained in hydrocarbon solutions with THF coordinated to yttrium. Alkyl complex 1 showed no activity in ethylene polymerization, presumably due to the presence of coordinated THF. The amido complex 2 catalyzed sluggishly the polymerization of methyl methacrylate to give isotactic-rich PMMA but is very active for the ring-opening polymerization of ε-caprolactone.  相似文献   

20.
[{(CH3)3Si}3C–Li–C{Si(CH3)3}3][Li · 3(OC4H8)] and {(CH3)3Si}3C–Li · O=C(Si(CH3)3)2, two New Adducts of Lithium Trisylmethanide Sublimation of (Tsi–Li) · 2 THF (Tsi = –C(Si(CH3)3)3) at 180 °C and 10–4 hPa gives (Tsi–Li) · 1.5 THF in very low yield. The X‐ray structure determination shows an almost linear [Tsi–Li–Tsi]– anion connected by short agostic Li…C contacts with the threefold THF‐coordinated Li‐cation. Base‐free Tsi–Li, solved in toluene is decomposed by oxygen, forming the strawberry‐colored ketone O=C(SiMe3)2, which forms an 1 : 1 adduct with undecomposed Tsi–Li. The X‐ray structure elucidation of this compound is also discussed.  相似文献   

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