[(C~8H~8)Y(μ-OC~6H~5)(THF)]~2的合成和晶体结构

本文用(C~8H~8)Y(μ-Cl)(THF)]~2与NaOC~6H~5以1:2摩尔比在四氢呋喃中反应, 合成了新的中性配合物[(C~8H~8)Y(μ-OC~6H~5)(THF)]~2, 经过分离, 在-30℃下培养得到无色晶体, 用元素分析, 核磁共振和质谱进行了鉴定, 并以X-射线衍射测定了晶体结构。     

(η~5-C_5H_5)Ln(η~8-C_8H_8)(THF)_n(Ln=Pr,Nd,Gd)的合成及(η~5-C_5H_5)Pr(η~8-C_8H_8)(THF)_2的晶体结构

自1969年首次报道稀土环辛四烯基化合物Eu(C_8H_8)和Yb(C_8H_8)的合成以来,相继合成K[Ln(C_8H_8)_2],[Ln(C_8H_8)Cl·2THF]_2和[Ln(C_8H_8)·2THF]等,还报     

Titanium imido complexes of cyclooctatetraenyl ligands

Reaction of [Ti(NR)Cl2(py)3] (R=tBu or 2,6-iPr2C6H3) with K(2)[COT] (COT=C8H8) or Li2[COT'] (COT'=1,4-C8H6(SiMe3)2) gave the monomeric complexes [Ti(NR)(eta8-COT)] or [Ti(NR)(eta8-COT')], respectively. The pseudo-two coordinate, "pogo stick" geometry for these complexes is unique in both early transition-metal and cyclooctatetraenyl ligand chemistry. In contrast, reaction of [Ti(N-2,6-Me2C6H3)Cl2(py)3] with K2[COT] gave the mu-imido-bridged dimer [Ti2(mu-N-2,6-Me2C6H3)2(eta8-COT)2]. It appears that as the steric bulk of the imido and C8 ring substituents are decreased, dimerisation becomes more favourable. Aryl imido COT complexes were also prepared by imido ligand exchange reactions between anilines and [Ti(NtBu)(eta(8)-COT)] or [Ti(NtBu)(eta(8)-COT')]. The complexes [Ti(NtBu)(eta(8)-COT)], [Ti(N-2,6-iPr2C6H3)2(eta8-COT)] and [Ti2(mu-N-2,6-Me2C6H3)2(eta8-COT)2] have been crystallographically characterised. The electronic structures of both the monomeric and dimeric complexes have been investigated by using density functional theory (DFT) calculations and gas-phase photoelectron spectroscopy. The most striking aspect of the bonding is that binding to the imido nitrogen atom is primarily through sigma and pi interactions, whereas that to the COT or COT' ring is almost exclusively through delta symmetry orbitals. A DFT-based comparison between the bonding in [Ti(NtBu)(eta8-COT)] and the bonding in the previously reported late transition-metal "pogo stick"complexes [Os(NtBu)(eta6-C6Me6)], [Ir(NtBu)(eta5-C5Me5)] and [Ni(NO)(eta5-C5H5)] has also been undertaken.     

Electron density distribution in vanadocene (η5-C5H5)2V and mixed metallocenes (η5-C5H5)M(η5-C7H7) (M = Ti,V, or Cr) and (η5-C5H5)Ti(η8-C8H8). Effect of the nature of the cyclic ligand on the character of the M--(π-ligand) bond

The electron density distribution and atomic displacements were analyzed based on the results of precision low-temperature X-ray diffraction studies of a series of isostructural (Pnma, Z = 4) mixed metallocenes (⁵-C₅H₅)M(⁵-C₇H₇) (M = Ti, V, or Cr) and (⁵-C₅H₅)Ti(⁸-C₈H₈). The barriers to rotation of the cyclic ligands were evaluated based on rms libration amplitudes. Analysis of the deformation electron density demonstrated that the character of the M--(-ligand) chemical bond depends substantially both on the nature of the metal atom and the size of the ligand. Lowering of the local symmetry of the (⁵-C₅H₅)M(⁵-C₇H₇) complexes to C_S leads to distortion of the cylindrical symmetry of the electron density distribution observed in vanadocene (⁵-C₅H₅)₂V and titanocene (⁵-C₅H₅)Ti(⁸-C₈H₈).     

Zur Elektronenstruktur metallorganischer Komplexe der f-Elemente LXI. Welche Oxidationszahl hat Cer im tiefvioletten 1,1′,4,4′-Tetrakis(trimethylsilyl)cerocen?

Using the original and not a newly suggested synthesic route, Ce[C₈H₆(1,4-SiMe₃)₂]₂ (1) was resynthesized as an oil of deep purple color. The absorption, MCD and luminescence spectra of this compound were measured at room temperature as well as at low temperatures. Especially, the low-temperature spectra are more consistent with a Ce^III compound.     

Synthesis and Structure of Lanthanide Sandwich Complexes with Mixed Cyclooctatetraenyl and Chelating Substituted‐indenyl Ligands

Two types of sandwich complexes (η⁵‐MeOCH₂CH₂C₉H₆) Ln (η⁸‐C₈H₈) (THF)_n [Ln=La (1), Nd(2), n=0; Sm(3), Dy (4) and Er (5). n = l] and (η⁵‐C₄H₇OCH₂C₉H₆)Ln(η⁸‐C₈H₈) (THF) [Ln = La (6), Nd(7). Sm(8). Dy (9) and Er (10)] were synthesized by the reactions of LnCl₃ with equivalent mole of K₂C₈H₈, followed by treatment with corresponding potassium salt of ether‐substituted indenide. The molecular structures of 3 and 8 were determined by single crystal X‐ray diffraction. (η⁵ ‐MeOCH₂CH₂C₉H₆) Sm (η⁸‐C₈H₈) (THF) (3) monoclinic. Pt₁/c, a = 1.4793(3) nm, b = 0.8716 (2) nm, c = 1.6149 (3) nm, β = 98. 17(3), V = 2.0612(7) nm³, Z = 4, R(F)=0.0362. (η⁵‐C₄H₇OCH₂C₉H₆)Sm(η⁸‐C₈H₈)(THF) (8) orthorhombic. p2₁2₁2₁. a = 0.8754(2) nm, b = 1.1000(2) nm, c = 2.3117 (5) nm, V = 2.2260(8) nm³, Z=4, R(F) =0.0497.     

(C8H8)Sm(C8H8)Na(THF)3的晶体结构

(C_8H_8)Sm(C_8H_8)Na(THF)_3的晶体属单斜晶系,P2_1空间群.晶胞参数为α=12.140(3),b=13.794(3),c=8.944(3)(?),β=111.68(3)°,V=1391.8(7)(?)~3,Z=2,μ=21.93cm~(-1),D_c=1.43g/cm~3,F(000)=610,Mr=598.0。结构经Patterson函数和Fourier技术解出并经最小二乘修正,最终的偏离因子R为0.046.配合物具有双层夹心结构.其中Sm~(3+)和Na~+通过η~8-环辛四烯基连接。     

环辛四烯基稀土金属有机配合物

环辛四烯基稀土配合物是继茂基配合物之后的又一类非常重要的稀土金属有机配合物,本文将就这一领域的发展情况作一个简要的总结和回顾。