DYNAMIC NMR STUDIES ON [Li(3D)] [La(η~3-C_3H_5)_4]

ＹＮＡＭＩＣＮＭＲＳＴＵＤＩＥＳＯＮ［Ｌｉ（３Ｄ）］［Ｌａ（η~３－Ｃ_３Ｈ_５）_４］￥ＦｅｎｇＦｕＬＩ；ＹｉｎｇＴａｉＪＩＮ；ＸｉＴｉａｎＺＨＡＮＧ；ＦｅｎｇＫｕｉＰＥＩ（ＣｈａｎｇｃｈｕｎＩｎｓｔｉｔｕｔｅｏｆＡｐｐｌｉｅｄＣｈｅｍｉｓｔｒｙ，Ｃｈ...     

DYNAMIC NMR STUDIES ON [Li(2D)][Nd(η~3-C_3H_5)_4]

The dynamic ~1H and ~(13)C-NMR studies on [Li(2D)][Nd(η~8-C_3H_5)_4](D=dioxane)were reported The four allyls coordinated to Hd~(8+) ion areequivalent and hydrogens appear as three groups in ~1H-NMR spectra with theirchemical shifts changing with temperature.C_1 and Ca are equivalent showing thecharacteristic of η~2=-allyl.The paramagnetic shifts of carbons in allylsinduced by Nd~(2+) ere separated sucessfully.C_1 and C_3 located on thezero-dipolar cone.The content of contact shift is greater than that of dipolarslift to Co.     

Uranium versus Thorium: Synthesis and Reactivity of [η5-1,2,4-(Me3C)3C5H2]2U[η2-C2Ph2]

The synthesis, electronic structure, and reactivity of a uranium metallacyclopropene were comprehensively studied. Addition of diphenylacetylene (PhC≡CPh) to the uranium phosphinidene metallocene [η⁵-1,2,4-(Me₃C)₃C₅H₂]₂U=P-2,4,6-tBu₃C₆H₂ ( 1 ) yields the stable uranium metallacyclopropene, [η⁵-1,2,4-(Me₃C)₃C₅H₂]₂U[η²-C₂Ph₂] ( 2 ). Based on density functional theory (DFT) results the 5f orbital contributions to the bonding within the metallacyclopropene U-(η²-C=C) moiety increases significantly compared to the related Th^IV compound [η⁵-1,2,4-(Me₃C)₃C₅H₂]₂Th[η²-C₂Ph₂], which also results in more covalent bonds between the [η⁵-1,2,4-(Me₃C)₃C₅H₂]₂U²⁺ and [η²-C₂Ph₂]²⁻ fragments. Although the thorium and uranium complexes are structurally closely related, different reaction patterns are therefore observed. For example, 2 reacts as a masked synthon for the low-valent uranium(II) metallocene [η⁵-1,2,4-(Me₃C)₃C₅H₂]₂U^II when reacted with Ph₂E₂ (E=S, Se), alkynes and a variety of hetero-unsaturated molecules such as imines, ketazine, bipy, nitriles, organic azides, and azo derivatives. In contrast, five-membered metallaheterocycles are accessible when 2 is treated with isothiocyanate, aldehydes, and ketones.     

Reaction of alkyne cluster Os3(μ-CO)(CO)9(μ3-η1:η1:η2-Me3SiC2Me) with HC≡CCOOMe. Molecular and crystal structures of Os3(CO)9{μ3-η1:η1:η2:η2-C(SiMe3)C(Me)C(COOMe)CH× and Os3(CO)8{μ3-η1:η1:η4:η1-C(SiMe3)C(Me)C(H)C(COOMe)CH× complexes

Reaction of the cluster Os₃(μ-CO)(CO)₉(μ₃-η¹:η¹:η²-Me₃SiC₂Me) with HC≡CCOOMe in benzene at 70 °C results in Os₃(CO)₉{μ₃-η¹:η¹:η²:η²-C(SiMe₃)C(Me)C(COOMe)CH× (5), Os₃(CO)₉{μ₃-η¹:η¹:η²:η²-C(SiMe₃)C(Me)C(H)C(COOMe)CH× (6), Os₃(CO)₉{μ-η¹:η¹:η⁴-C(SiMe₃)C(Me)C(H)C(COOMe)CH× (7), and Os₃(CO)_δ{μ₃-η¹:η¹:η⁴:η¹-C(SiMe₃)C(Me)C(H)C(COOMe)× complexes (8), containing an osmacyclopentadiene moiety. Complexes5–8 were characterized by¹H NMR and IR spectroscopy. The structure of clusters5 and8 was confirmed by X-ray analysis. Complex7 is formed from cluster5 as a result of a new intramolecular rearrangement and complex8 is obtained by decarbonylation of compound6. Complex8 adds PPh₃ to give Os₃(CO)_δ(PPh₃){μ-η¹:η¹:η⁴-C(SiMe₃)C(Me)C(H)C(COOMe)×.     

The Thermolysis of [Ru3(CO)12] in Cyclohexene: Synthesis and Charaterisation of the New Clusters [Ru3H2(CO)9(μ3-η1:η2:η1-C6H8)] and [Ru5(CO)12(μ4-η2-C6H8)(η4-C6H8)]

Thermolysis of [Ru₃(CO)₁₂] in cyclohexene for 24 h affords the complexes [Ru(CO)₃(η⁴-C₆H₈)] (1), [Ru₃H₂(CO)₉(μ₂-η¹:η²:η¹-C₆H₈)] (2), [Ru₄(CO)₁₂(μ₄-C₆H₈)] (3) [Ru₄(CO)₉(μ₄-C₆H₈)(η⁶-C₆H₆)] (4a and 4b, two isomers) and [Ru₅(CO)₁₂(μ₄-η²-C₆H₈)(η⁴-C₆H₈)] (5), where 1, 3, 4a and 4b have been previously characterised as products of the thermolysis of [Ru₃(CO)₁₂] with cyclohexa-1,3-diene. The molecular structures of the new clusters 2 and 5 were determined by single-crystal X-ray crystallography, showing that two conformational polymorphs of 5 exist in the solid state, differing in the orientation of the cyclohexa-1,3-diene ligand on a ruthenium vertex.     

Tetramethyl(2-methoxyethyl)cyclopentadienyl complexes of zirconium(iv). Crystal structure of [η5:η1−C5(CH3)4(CH2CH2OCH3)]ZrCl3

Several novel zirconium(iv) complexes with the chelating oxygen-containing cyclopentadienyl ligand, tetramethyl(2-methoxyethyl)cyclopentadiene, have been synthesized. [⁵:¹-Tetra-methyl(2-methyl)cyclopentadienyl]trichlorozirconium (2), bis[⁵-tetramethyl(2-methoxyethyl)cyclopentadienyl]dichlorozirconium (3), [⁵-pentamethylcyclopentadienyl][⁵-tetra-methyl(2-methoxyethyl)cyclopentadienyl]dichlorozirconium (4), and [⁵-tetra-methyl(2-methylthioethyl)cyclopentadienyl][⁵-tetramethyl(2-methoxyethyl)-cyclopentadienyl]dichlorozirconium (5) have been prepared from the corresponding lithium cyclopentadienide (l). The crystal structure of cyclopentadienyl complex2 has been established by X-ray analysis. The coordination OZr bond in compound2 exists both in the crystalline state and in solutions. No coordination of this type was observed in complexes3–5. Synthesized complexes2–5 are discussed in comparison with their sulfur-containing analogs.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 7, pp. 1828–1832, July, 1996.     

Comparison of the Bonding of Benzene and C60 to a Metal Cluster: Ru3(CO)9(μ3-η2,η 2,η2-C6H6) and Ru3(CO)9(μ3-η2,η2,η2-C60)

The electron distributions and bonding in Ru₃(CO)₉( ³- ², ², ²-C₆H₆) and Ru₃(CO)₉( ³- ², ², ²-C₆₀) are examined via electronic structure calculations in order to compare the nature of ligation of benzene and buckminsterfullerene to the common Ru₃(CO)₉ inorganic cluster. A fragment orbital approach, which is aided by the relatively high symmetry that these molecules possess, reveals important features of the electronic structures of these two systems. Reported crystal structures show that both benzene and C₆₀ are geometrically distorted when bound to the metal cluster fragment, and our ab initio calculations indicate that the energies of these distortions are similar. The experimental Ru–C_fullerene bond lengths are shorter than the corresponding Ru–C_benzene distances and the Ru–Ru bond lengths are longer in the fullerene-bound cluster than for the benzene-ligated cluster. Also, the carbonyl stretching frequencies are slightly higher for Ru₃(CO)₉( ³- ², ², ²-C₆₀) than for Ru₃(CO)₉( ³- ², ², ²-C₆H₆). As a whole, these observations suggest that electron density is being pulled away from the metal centers and CO ligands to form stronger Ru–C_fullerene than Ru–C_benzene bonds. Fenske-Hall molecular orbital calculations show that an important interaction is donation of electron density in the metal–metal bonds to empty orbitals of C₆₀ and C₆H₆. Bonds to the metal cluster that result from this interaction are the second highest occupied orbitals of both systems. A larger amount of density is donated to C₆₀ than to C₆H₆, thus accounting for the longer metal–metal bonds in the fullerene-bound cluster. The principal metal–arene bonding modes are the same in both systems, but the more band-like electronic structure of the fullerene (i.e., the greater number density of donor and acceptor orbitals in a given energy region) as compared to C₆H₆ permits a greater degree of electron flow and stronger bonding between the Ru₃(CO)₉ and C₆₀ fragments. Of significance to the reduction chemistry of M₃(CO)₉( ³- ², ², ²-C₆₀) molecules, the HOMO is largely localized on the metal–carbonyl fragment and the LUMO is largely localized on the C₆₀ portion of the molecule. The localized C₆₀ character of the LUMO is consistent with the similarity of the first two reductions of this class of molecules to the first two reductions of free C₆₀. The set of orbitals above the LUMO shows partial delocalization (in an antibonding sense) to the metal fragment, thus accounting for the relative ease of the third reduction of this class of molecules compared to the third reduction of free C₆₀.     

New polynuclear molecular ferromagnetic complex {Co3((η2-NH2)2C6H2Me2)2(μ-OOCCMe3)2(η1-OOCCMe3)2(η2-OOCCMe3)2(HOOCCMe3)2}{Co((η2-NH2)2C6H2Me2)2(η1-OOCCMe3)2}

Russian Chemical Bulletin -     

Ring and Cluster Structures of {Li[C(NtBu)2(HNtBu)]}2·(THF) and {Li2[C(NtBu)3]}2, Containing the Novel Anions [C(NtBu)2(HNtBu)]−- and [C(NtBu)3]2−

The reaction of tert.-butyl carbodiimide with one equivalent of LiNH^tBu in tetrahydrofuran at-78 °C produces {Li[C(N^tBu)₂(HN^tBu)]}₂-(THF) (1), which is an eight-membered Li₂C₂N₄ ring; the deprotonation of (1) with two equivalents of n-BuLi in tetrahydrofuran at -78 °C and recrystallisation of the product from n-pentane yielded the unsolvated dimer {Li₂[C(N^tBu)₃]}₂ (2), which adopts the structure of a distorted hexagonal prism.     

Penta- and hexaphospha ferrocenes as ligands: crystal and molecular structures of [Fe(η5-P3C2tBu2)2W(CO)5], [Fe(η5-P3C2tBu2)(η5-P2C3tBu3)W(CO)5] and the novel triruthenium carbonyl cluster complex [Fe(η5-P3C2tBu2)2Ru3(CO)10] containing two interlinked η5-P3C2tBu2 ring systems

The lone-pair electrons of one of the two directly bonded phosphorus atoms of the P₃C₂^tBu₂ ring in the penta- or hexaphosphaferrocene complexes [Fe(η⁵-P₃C₂^tBu₂)(η⁵-P₃C₂^tBu₃)] and [Fe(η⁵P₃ C₂^tBu₂)₂] can ligate to other metal centres to afford novel bi- and tetrametallic complexes, whose structures have been elucidated by NMR and single crystal X-ray crystallographic studies.     

Preparation and crystal structures of [μ-SbPh2]2[Mo(CO)2(η5-C5H5)]2·CHCl3 and SbPh[Fe(CO)2(η5-C5H5)]2

Antimony is reduced when [SbPh₂BrO]₂ is treated with Na[Mo(CO)₃(η⁵-C₅H₅)] to produce [μ-SbPh₂]₂[Mo(CO)₂(η⁵-C₅H₅)]₂. A structure determination shows diphenylstibido groups bridging between two Mo(CO)₂(η⁵-C₅H₅) moieties giving a central ‘butterfly’ shaped Sb₂Mo₂ ring. The cyclopentadiene rings are trans to each other and Mo–Sb and Sb–Sb separations are both short. An iron analogue could not be obtained from [SbPh₂BrO]₂ and Na[Fe(CO)₂(η⁵-C₅H₅)] but a mixture of SbPh[Fe(CO)₂(η⁵-C₅H₅)]₂ and SbPh₂[Fe(CO)₂(η⁵-C₅H₅)] was obtained using SbPh₂Cl. An X-ray structure for SbPh[Fe(CO)₂(η⁵-C₅H₅)]₂ shows an open stibinidine structure.     

Triphospha-Ferrocenes as Ligands. Crystal Structures of [Fe(η5-C5Me5)(η5-C2 TBu2P3)M(CO)5)], (M= Cr,MO, W) and the Novel ruthenium and Nickel Complexes [Fe(η5-C5Me5) (η5-C2 TBu2P3)Ru3(CO)9] and [Fe(η5-C5Me5)(η5-C2 tBu2P3)Ni(Co)2]2

Abstract

Syntheses and structures of penta- and hexaphosphorus analogues of ferrocene have been described recently¹. Unlike their simple ferrocene analogues, these complexes have further ligating potential towards other transition metal centres by virtue of the availability of the ring phosphorus lone-pair electrons that are not involved in the η⁵-coordination. We now describe the first examples of coordination compounds of the triphospha-ferrocene [Fe(η⁵-C₅Me₅) (η⁵-C₂ ^tBu₂P₃]. In the ruthenium complex [Fe(η⁵-C₅Me₅)(η⁵-C₂ ^tBu₂P₃) Ru₃(CO)₉] ² two adjacent phosphorus atoms of the η⁵-C₂ ^tBu₂P₃ ring are interlinked by a ruthenium carbonyl cluster in which all three ruthenium atoms interact with the phosphorus atoms. The tetrametallic nickel complex [Fe(η⁵-C₅Me₅)(η⁵-C₂ ^tBu₂P₃)Ni(CO)₂]₂ ³ represents the first example of intermolecular interlinkage of two phospha-ferrocene systems by two metal centres.     

Coordination-unsaturated complexes of tris(cyclopentadienyl)samarium: Solvate (η5-C5H5)3Sm·OC4H8 and ionic salt [Li(Et2O)2][η5-C5H5)3Sm(μ-Cl)Sm(η5-C5H5)3]

X-ray structural analysis of a samarium triscyclopentadienyl complex, Cp₃Sm·OC₄H₈ (1), and a samarium ionic salt, [Li(Et₂O)₂][Cp₃Sm(-Cl)SmCp₃] (2), was carried out. In both compounds coordination saturation is achieved by coordination of the THF molecule (in1) or the Cl^– anion (in2) to the monomeric fragment Cp₃Sm. An unusual coordination of the Li⁺ cation was observed in complex2: it is bound to one of the ⁵-type cyclopentadienyl rings in addition to two ether molecules.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 6, pp. 1129–1132, June, 1993.     

[Re(η2-CS3)4]3−, a new trithiocarbonate-containing rhenium(V) dodecahedral anion

The mononuclear complex (NMe₄)₃[Re(²-CS₃)₄] has been prepared by adding CS₂ to ReS^– ₄ in a mixture of MeOH and NH₃. During the reaction, Re^VII is reduced to Re^V, the measured diamagnetism (X = –3.04 × 10^–4cm³mol^–1) of the complex showing that the two added electrons are coupled. (NMe₄)₃[Re(²-CS₃)₄] crystallizes in the space group Fddd, a = 11.985(4) Å, b = 23.001(11) Å, c = 47.463(19) Å, V = 13085(9) ų. The reaction of CS₂ results in the formation of trithiocarbonates bonded to the rhenium in a dodecahedral geometry.     

改性Pechini方法合成富锂正极材料Li[Li(1/3－x/3)CoxMn(2/3－2x/3)]O2及性能研究

通过改性Pechini方法合成不同Co含量的富锂正极材料Li[Li_(1/3－x/3)Co_xMn_(2/3－x/3)]O₂ (x＝0.4, 0.5, 0.6). XRD研究结果表明, 不同Co含量的富锂正极材料均具有良好的层状结构, 结晶度高. 电化学测试结果表明材料的初始容量随Co含量的增加而增加, 在200～220 mAh/g之间. 其中x＝0.4材料的循环性能最佳, 在0.5 C (100 mA/g)时, 循环50次后的容量保持率为75%. 容量微分曲线研究结果表明在3.5 V以下出现了Mn^4＋/Mn^3＋的还原峰, 并随循环次数的增加峰面积加大. 循环过程的XRD研究表明, 随着充放电次数的增加, 富锂正极材料的层状结构逐渐向尖晶石相转变, 且有杂质相MO_x (M＝Co, Mn)生成, 导致容量衰减.     

Fixation of carbon dioxide by macrocyclic lanthanide(III) complexes under neutral conditions producing self-assembled trimeric carbonato-bridged compounds with μ3-η2:η2:η2 bonding

A series of mononuclear lanthanide(III) complexes [Ln(LH(2))(H(2)O)(3)Cl](ClO(4))(2) (Ln = La, Nd, Sm, Eu, Gd, Tb, Lu) of the tetraiminodiphenolate macrocyclic ligand (LH(2)) in 95 : 5 (v/v) methanol-water solution fix atmospheric carbon dioxide to produce the carbonato-bridged trinuclear complexes [{Ln(LH(2))(H(2)O)Cl}(3)(μ(3)-CO(3))](ClO(4))(4)·nH(2)O. Under similar conditions, the mononuclear Y(III) complex forms the dimeric compound [{Y(LH(2))(H(2)O)Cl}(μ(2)-CO(3)){Y(LH(2))(H(2)O)(2)}](ClO(4))(3)·4H(2)O. These complexes have been characterized by their IR and NMR ((1)H, (13)C) spectra. The X-ray crystal structures have been determined for the trinuclear carbonato-bridged compounds of Nd(III), Gd(III) and Tb(III) and the dinuclear compound of Y(III). In all cases, each of the metal centers are 8-coordinate involving two imine nitrogens and two phenolate oxygens of the macrocyclic ligand (LH(2)) whose two other imines are protonated and intramolecularly hydrogen-bonded with the phenolate oxygens. The oxygen atoms of the carbonate anion in the trinuclear complexes are bonded to the metal ions in tris-bidentate μ(3)-η(2):η(2):η(2) fashion, while they are in bis-bidentate μ(2)-η(2):η(2) mode in the Y(III) complex. The magnetic properties of the Gd(III) complex have been studied over the temperature range 2 to 300 K and the magnetic susceptibility data indicate a very weak antiferromagnetic exchange interaction (J = -0.042 cm(-1)) between the Gd(III) centers (S = 7/2) in the metal triangle through the carbonate bridge. The luminescence spectral behaviors of the complexes of Sm(III), Eu(III), and Tb(III) have been studied. The ligand LH(2) acts as a sensitizer for the metal ions in an acetonitrile-toluene glassy matrix (at 77 K) and luminescence intensities of the complexes decrease in the order Eu(3+) > Sm(3+) > Tb(3+).     

Oxidative dinuclear addition of a PdI-PdI moiety to arenes: generation of μ-η3:η3-arene-Pd(II)2 species

We report the oxidative dinuclear addition of a Pd(I)-Pd(I) bond to arenes. The oxidative dinuclear addition products, which have a bi-π-allyl-type arene dipalladium(II) structure, were obtained from [2.2]paracyclophane, anthracene, tetracene, and pentacene. A systematic study of the reaction of [Pd(2)(CH(3)CN)(6)][BF(4)](2) with benzene and polyacenes showed that the larger polyacenes, tetracene and pentacene, afforded the oxidative dinuclear addition products, while benzene, naphthalene, and anthracene gave the π-sandwich Pd(I)-Pd(I) complexes.     

Synthesis, structure and electrochemistry of CO incorporated diruthenium metallacyclic compounds [Ru2(CO)6{μ-η:η:η:η-1,4-Fc2C5H2O}] and [Ru2(CO)6{μ-η:η:η:η-1,5-Fc2C5H2O}]

Ferrocenyl substituted ruthenium metallacyclic compounds, [Ru₂(CO)₆{μ-η¹:η¹:η²:η²-1,4-Fc₂C₅H₂O}] (1) and [Ru₂(CO)₆{μ-η¹:η¹:η²:η²-1,5-Fc₂C₅H₂O}] (2) have been synthesized and structurally characterized. Electrochemical studies for 1 and 2 and the respective quinone derivatives 3 and 4 show weak to no electrochemical coupling at the mixed-valent intermediate state which is dependent on the complex frameworks.