Diacetylenic Derivatives of Fe2(CO)6(μ-EE′): Spectroscopic Investigations of Fe2(CO)6{μ-EC(H) = C(C≡ CMe)E′} (E = E′, E ≠ E′; E, E′ = S, Se, Te)

The diacetylenic adducts, Fe₂(CO)₆{-EC(H) = C(C CMe)E} (E = E, E E; E, E = S, Se, Te) (1–8) have been obtained from the room temperature stirring of Fe₂(CO)₆(-EE) with HC CC CMe in methanol solvent containing sodium acetate. Compounds 1–8 have been characterized by IR and multinuclear NMR (¹H, ¹³C, ⁷⁷Se, and ^l25Te) spectroscopy. Trends in the chemical shifts of ⁷⁷Se and ¹²⁵Te NMR spectra of Fe₂(CO)₆{-EC(H) = C(C CMe)E} with a variation of EE are discussed.     

(Ph3P)2,Co(CO)2Cl和(dppe-P,P)2CO(CO)+的分子轨道研究

本文对(PH3P)2, Co(CO)2Cl和(dppe-P,P)2CO(CO)+(dppe=Ph2CH2CH2PPh2)五配位C2O对称性模型化合物进行了分轨道研究, 结果表明, 钴的3d轨道很少参与成键, 钴的4s, 4P与配体的S,P轨道通过形式上的二电子三中心键和二电子二中心键的相互作用构成五配位, 此外, 还解释了这两种化合物不同稳定性的原因。     

Synthesis,structure and stereochemistry of diiodide complexes (E)[(η5-t-BuC5H3)Fe(CO)2I]2 (E = Me2Si,Me2SiSiMe2, and Me2SiOSiMe2)

Reactions of diiron complexes (E)[⁵-t-BuC₅H₃)Fe(CO)]₂(-CO)₂ [E = Me₂Si (1), Me₂SiSiMe₂ (2), and Me₂SiOSiMe₂ (3)] with iodine in CHCl₃ yielded diiodide complexes (E)[⁵-t-BuC₅H³)Fe(CO)₂I]₂ [E=Me₂Si (5), Me₂SiSiMe₂ (6), and Me₂SiOSiMe₂ (7)]. Like (1–3), complexes (5–7) also exists as mixtures of cis and trans isomers even though the Fe–Fe bond in (1–3) has been cleaved. When the pure isomers (1–3) reacted with iodine respectively in CHCl₃, the cis isomers (1c–3c) yielded only the cis products (5c–7c), whereas the trans isomers (1t–3t) yielded only the trans isomers (5t–7t). This indicates that iodination of bridged diiron complexes is stereospecific. Similar treatment of trans-(Me₂Si)[{⁵-t-(heptyl)C₅H₃}Fe(CO)]₂(-CO)₂ (4t) with iodine gave only the trans product (Me_2Si)[{⁵-t-(heptyl)C₅H₃}Fe(CO)₂I]₂ (8t). The molecular structure of (5t) was determined by X-ray diffraction.     

Ir(CO)Cla(Ph2Ppy)2HgClb(HgCl2)c (a,b=1, 2, c=0, 1)的Ir-Hg相互作用和氧化还原反应性质

应用密度泛函理论(DFT)的PBE0方法, 金属原子采用SDD基组, H、C、O和N原子采用6-31G*基组, P和Cl原子采用6-311G*基组, 对单核配合物Ir(CO)Cl(Ph2Ppy)2(1), 双核配合物Ir(CO)(Cl)2(Ph2Ppy)2HgCl(2)、Ir(CO)Cl(Ph2Ppy)2HgCl2(3)和Ir(CO)(Cl)2(HgCl2)(Ph2Ppy)2HgCl(4)进行结构优化, 并在优化的基础上采用基组重叠误差(BSSE)校正计算相互作用能, 通过自然键轨道(NBO)和前线轨道分析研究Ir-Hg相互作用和氧化还原反应的实质. 通过计算发现, Ir(CO)Cl(Ph2Ppy)2与HgCl2发生氧化还原反应得到的产物2和4比非氧化还原产物3稳定. Ir-Hg相互作用强度顺序为3<4<2, 且随着Ir-Hg相互作用强度增大, HOMO轨道中Ir和Hg成分逐渐趋于接近. 配合物2和4都具有一对Ir-Hg成键与反键轨道, 其成键轨道的组成分别为0.5985sd0.06Hg+0.8012sd2.48Ir和0.5794sd0.05Hg+0.8151sd2.48Ir, 但3中Ir与Hg的相互作用较弱, 只存在弱相互作用(电荷转移作用), 表现为nIr→nHg的直接作用和σIr—P(1)→nHg、σIr—C(1)→nHg的间接作用.     

Synthesis and structures of bridged diruthenium complexes (E)[η5-C5H4)Ru(CO)]2(μ-CO)2 (E = Me2Ge,Me2SiOSiMe2, Me2SiOSiMe2OSiMe2)

A series of bridged diruthenium complexes (E)[(⁵-C₅H₄)Ru(CO)]₂(-CO)₂ (E = Me₂Ge (2); Me₂SiOSiMe₂ (3); Me₂SiOSiMe₂OSiMe₂ (4)) has been prepared by reacting Ru₃(CO)₁₂ with Cp₂E in refluxing heptane. The molecular structures of (2) and (4) have been determined by X-ray diffraction.     

The photo-induced decarbonylation of Cp′M(NO)(CO)2 (M = Cr,Mo, W) with diorgano dichalcogenides (R2E2; E = S,Se; R = Me,Ph)

The photo-induced decarbonylation of CpCr(NO)(CO)₂ (1a) in MeCN solution in the presence of R₂E₂ (E = S, Se; R = Me, Ph) leads to the formation of chalcogenolato-bridged binuclear complexes Cp₂Cr₂(NO)₂(-ER)₂ [E = S; R = Me (2a), Ph (3a); E = Se, R = Me (4a), Ph (5a)] while reactions between CpM(NO)(CO)₂ [M = Mo (1b), W (1c)] and Ph₂E₂ (E = S, Se) result in mononuclear complexes CpM(NO)(EPh)₂ [M = Mo; E = S (9b), Se (10b); M = W, E = S (11c), Se (12c)]. The corresponding reactions of (1b) with Me₂E₂ (E = S, Se) yielded both mono and binuclear complexes: CpMo(NO)(SeMe)₂ (8b), Cp₂Mo₂(NO)₂(-EMe)₂ [E = S (6b), Se (7b)]. The new complexes have been characterized by i.r., ¹H-, ¹³C-n.m.r. spectra and by electron-impact mass spectrometry.     

Reactions of dipropargyl manolate,terephthalate with Co2(CO)8, Mo2Cp2(CO)4 and RuCo2(CO)11 give the di or tetranuclear clusters. The crystal structure of [CH2(CO2CH2C2H-μ)2][Co2(CO)6]2 and [p-(HC2CH2OCO)C6H4(CO2CH2C2H-μ)][Co2(CO)6]

The reactions of dipropargyl manolate and terephthalate, respectively, with Co₂(CO)₈ in THF at room temperature gave four new compounds [R(CO₂CH₂C₂H-μ)₂][Co₂(CO)₆]₂ (R=CH₂, 1a; R=C₆H₄, 1b) and [(HC₂CH₂OCO)R(CO₂CH₂C₂H-μ)][Co₂(CO)₆] (R=CH₂, 2a; R=C₆H₄-1,4-, 2b), and compounds 2a and b reacted with RuCo₂(CO)₁₁ to form two new linked clusters [R(CO₂CH₂C₂H-μ)₂][Co₂(CO)₆][RuCo₂(CO)₉] (R=CH₂, 3a; R=C₆H₄-1,4-, 3b). The treatment of two dipropargyl esters, respectively, with RuCo₂(CO)₁₁ afforded another two new clusters [R(CO₂CH₂C₂H-μ)₂][RuCo₂(CO)₉]₂ (R=CH₂, 4a; R=C₆H₄-1,4-, 4b). The reactions of dipropargyl manolate, terephalate with Mo₂Cp₂(CO)₄ gave rise to the formation of dinuclear complexes [(HC₂CH₂OCO)R(CO₂CH₂C₂H-μ)][Mo₂Cp₂(CO)₄] (R=CH₂, 5a; R=C₆H₄-1,4-, 5b), compound 5a reacted with Co₂(CO)₈ to produce the cluster [CH₂(CO₂CH₂C₂H-μ)₂][Co₂(CO)₆][Mo₂Cp₂(CO)₄] 6a. All the new clusters have been characterized by C/H elemental analysis, IR and ¹H NMR spectroscopies. The structure of [CH₂(CO₂CH₂C₂H-μ)₂][Co₂(CO)₆]₂ 1a and [p-(HC₂CH₂OCO)C₆H₄(CO₂CH₂C₂H-μ)][Co₂(CO)₆] 2b have been determined by single crystal X-ray diffraction methods.     

有机化学中S_N2,S_N1,E2,E1反应的相互竞争关系

有机化学中的SN2,SN1,E2,E1反应在学习中有着重要的作用,同时也是学习中易混淆的知识点。通过总结它们的反应机理、反应影响因素和反应相互竞争关系图,并利用竞争关系图解答了一些典型考研真题,方便读者理解和掌握SN2,SN1,E2,E1反应的相互竞争关系。     

Synthesis and structures of the η5-C5H5Cl(CO)2W-η1,η5-(PPh2)C5H4(CO)2Fe-η1,η5-C5H4Mn(CO)3 and MeSi[C5H4(CO)2Fe-η1,η5-C5H4Mn(CO)2PPh3]3 complexes

The metallation of the η⁵-C₅H₅(CO)₂Fe-η¹,η⁵-C₅H₄Mn(CO)₃ complex with BuⁿLi (THF, ?78 °C) followed by the treatment of the lithium derivative with Ph₂PCl afforded the η⁵-Ph₂PC₅H₄(CO)₂Fe-η¹,η⁵-C₅H₄Mn(CO)₃ complex. The reaction of the latter with η⁵-C₅H₅(CO)₃WCl in the presence of Me₃NO produced the trinuclear complex η⁵-C₅H₅Cl(CO)₂W-η¹,η⁵-(Ph₂P)C₅H₄(CO)₂Fe-η¹,η⁵-C₅H₄Mn(CO)₃. The structure of the latter complex was established by IR, UV, and 1H and ³¹P NMR spectroscopy and X-ray diffraction. The reaction of MeSiCl₃ with three equivalents of LiC₅H₄(CO)₂Fe-η¹,η⁵-C₅H₄Mn(CO)₂PPh₃ gave the hexanuclear complex MeSi[C₅H₄(CO)₂Fe-η¹,η⁵-C₅H₄Mn(CO)₂PPh₃]₃.     

HYDROFORMYLATION OF 1-HEXENE WITH Rh_4(CO)_(12) AND [Rh(CO)_2Cl]_2

The hydroformylation of hexene-1 catalyzed by Rh_4 (CO)_12 and 〔Rh(CO)_2Cl〕_2 andthe effects of solvents (benzene, n-heptane and THF) and PPh_3 on the activity andselectivity of the catalysts were studied.The results indicated that the activity of Rh_4(CO)_(12) decreased with increasing solventpolarity and it did not change appreciably with addition of PPh_3 when the molar ratioPPh_3/Rh_4(CO)_(12)≤4. Thc activity of Rh_4(CO)_(12) was over twice as large as that of〔Rh(CO)_2Cl〕_2 when calculated according to the number of moles of rhodium clusters inbenzene without PPh_3, but the activities of both Rh_4(CO)_(12) and 〔Rh(CO)_2Cl〕_2 wereabout the same when calculated according to the number of rhodium atoms. It is suggestedthat the clusters probably dissociated into the similar active rhodium mononuclear speciesunder the reaction conditions and the species formed a cluster similar to Rh_4(CO)_(12) againwhen the conditions were reduced to the ambient temperature and pressure.     

Tetracarbonyliron adducts of Cp2Cr2(CO)4(μ-η2-P2). Syntheses and crystal structures of Cp2Cr2(CO)4P2[Fe(CO)4] m (m=1 and 2)

Cp₂Cr₂(CO)₄( - ² - P₂), 1, reacts with one molar equivalent of Fe₂(CO)₉ in THF to yield the mono- and di-iron complexes, Cp₂Cr₂(CO)₄P₂[Fe(CO)₄], 2, (16.5% yield) and Cp₂Cr₂(CO)₄P₂[Fe(CO)₄]₂, 3, (16.9% yield), as dark magenta brown and dark greenish brown crystals, respectively. Both complexes were characterized by single-crystal X-ray diffraction analysis. Crystal data –2: space group =P2₁/c,a=17.024(1) Å,b=8.180(1) Å,c=30.891(2) Å, =100.953(5)°,V=4223.4(7)ų,Z=8, 3743 observed reflections,R _F=0.033; 3: space group P1,a=10.209(2) Å,b=10.212(2) Å,c=15.989(3) Å, =106.93(1)°, =91.87(1)°, =119.50(1)°,V=1356.5(4) ų,Z=2, 3489 observed reflections,R _F=0.029.     

Reactions of the tetrafluoroborate complex [Mo2Cp2(κ(2)-F2BF2)(μ-PPh2)2(CO)]BF4 with mono- and bidentate ligands having E-H bonds (E = O, S, Se, N, P)

The title compound reacted rapidly with CN(t)Bu at room temperature by displacing the BF(4)(-) ligand and incorporating three molecules of isocyanide to yield the electron-precise complex [Mo(2)Cp(2)(μ-PPh(2))(2)(CN(t)Bu)(3)(CO)](BF(4))(2), which was obtained as a mixture of cis and trans isomers. Reaction with several HER(n) molecules (HER(n) = HSPh, HSePh, H(2)PCy) took place with formal elimination of HBF(4) and spontaneous carbonylation to give the electron-precise cations [Mo(2)Cp(2)(μ-ER(n))(μ-PPh(2))(2)(CO)(2)](+). Reactions with several bidentate ligands (L(2)H) having acidic E-H bonds (2-hydroxypyridine, 2-mercaptopyridine, cathecol, 2-aminophenol, and 2-aminothiophenol) proceeded analogously with deprotonation of these bonds with the preference E = S > O > N. The N,O-donor ligands yielded 32-electron chelate derivatives of the type [Mo(2)Cp(2)(O,N-L(2))(μ-PPh(2))(2)(CO)]BF(4) (L(2) = OC(5)H(4)N, OC(6)H(4)NH(2)), whereas the S,N-donors yielded 34-electron, S-bridged complexes [Mo(2)Cp(2)(μ-S:S,N-L(2))(μ-PPh(2))(2)(CO)]BF(4) [L(2) = SC(5)H(4)N (Mo-Mo = 2.8895(8) ?), SC(6)H(4)NH(2)]. However, reaction with catechol gave a monodentate derivative [Mo(2)Cp(2)(O-OC(6)H(4)OH)(μ-PPh(2))(2)(CO)]BF(4). In contrast, reactions of the title complex with several carboxylic acids and related species (acetic, benzoic, and thioacetic acids, acetamide, thioacetamide, and sodium diethyldithiocarbamate) were insensitive to the nature of the donor atoms and gave in all cases 32-electron chelate derivatives of type [Mo(2)Cp(2)(κ(2)-L(2))(μ-PPh(2))(2)(CO)]BF(4). All of the above cations having Mo-bound OH, NH, or NH(2) groups were easily deprotonated upon reaction with 1,8-diazabicycloundec-7-ene (DBU) or other bases to give neutral complexes which exhibited different coordination motifs depending on the donor atoms, including chelate complexes of the type [Mo(2)Cp(2)(κ(2)-L(2)')(μ-PPh(2))(2)(CO)] (L(2)' = OC(6)H(4)O, OC(6)H(4)NH), the bridged complexes [Mo(2)Cp(2)(μ-S,N:S,N-SC(6)H(4)NH)(μ-PPh(2))(2)] and [Mo(2)Cp(2){μ-S,N-N(S)CMe}(μ-PPh(2))(2)], and the terminal acetylimido complex [Mo(2)Cp(2){N-N(O)CMe}(μ-PPh(2))(2)(CO)].     

Solid-Phase Stereoselective Synthesis of (E)-1, 2-Disubstituted Ethenes from Polymer-Sopported a-Selenoaldehydes

Reaction of polymer-supported a-selenoaldehydes with Grignard reagents afforded polymer-bound B-hydroxyalkyl selenides, which treated with thionyl chloride and triethylamine leading to (E)-1, 2-disubstituted ethenes in good yield.     

Syntheses,crystal structures,and electrochemical studies of Fe2(CO)6(μ-PPh2)(μ-L) (L = OH,OPPh2, PPh2)

Reaction of Fe₃(CO)₁₂ and Ph₂PH in the presence of Et₃N in THF at 0?°C immediately forms Fe₂(CO)₆(μ-PPh₂)(μ-OH) (1), Fe₂(CO)₆(μ-PPh₂)(μ-k²O,P-OPPh₂) (2), and Fe₂(CO)₆(μ-PPh₂)₂ (3) in yields of 25, 14, and 19%, respectively. Experiments confirm that Et₃N shortens the reaction time. The absence of O₂ hinders the formation of 2. The presence of H₂O can increase the yield of 1. Their structures have been determined by X-ray crystallography and the complexes have been completely characterized by EA, IR, and ¹H, ¹³C, ³¹P NMR. Electrochemical studies reveal that they exhibit catalytic H₂-producing activities.     

Synthesis, molecular structures, and properties of heterometallic cobalt tetramethylcyclobutadiene complexes (C4Me4)Co(CO)2TePh, (C4Me4)Co(CO)2TePh[W(CO)5], and Me4C4Co(μ3-S)2Cr2Cp2(μ-SC4H9)

The reaction of Cb*Co(CO)₂I (1) (Cb* is tetramethylcyclobutadiene) with sodium phenyltelluride afforded the mononuclesar complex Cb*Co(CO)₂TePh (2). The reaction of the latter with W(CO)₅(THF) produced the Cb*Co(CO)₂TePh[W(CO)₅] compound (4). The reaction of 1 with the Cp₂Cr₂(SCMe₃)₂S complex gave the heterometallic cluster Cb*Co(μ₃-S)₂Cr₂Cp2 (μ-SCMe₃) (5). Complexes 2, 4, and 5 are diamagnetic. Their structures were determined by X-ray diffraction. Complex 2 contains the Co-Te bond (2.585(1) Å); complex 4, the Co-Te (2.558(8) Å) and W-Te (2.8467(6) Å) bonds. Complex 5 has the stable triangular sulfide-and tert-butylmercaptide-bridged core Cr₂Co (Cr-Cr and Cr-Co bond lengths are 2.626(2) and 2.673(2) Å, respectively) with Cp ligands at the chromium atoms and a Cb* ligand at the cobalt atom. Complex 5 was characterized by cyclic voltammetry. The thermolysis of complex 4 was studied.     

双核钼(O)配合物[(C2H5)4N]2[Mo2(CO)8(SCH2CO2(C2H5)2]的合成, 结构, 光谱和反应性能研究

Et4NI,NaSCH2CO2C2H5和Mo(CO)6在乙腈中反应制得一种新的双核钼(0)配合物[Et4N]2-[Mo2(CO)8(SCH2CO2Et)2](1), 电化学和反应性能研究指出1在电位～-0.43V发生一有趣的双电子一步氧化, 产生[Mo2(CO)8(SCH2CO2Et)2], 若氧化反应在配位溶剂中进行, 则其部分羰基被配位溶剂分子所取代成为[Mo2(CO)6(SCH2CO2Et)2L2](L=CH3CN).在1中, Mo…Mo不存在金属键以及MoS2Mo核骨架完全不同于氧化的产物Mo(I)配合物. 这结果完全证实了双电子一步转移是由于双金属中心的金属-金属键的形成或断裂伴随桥联双金属中心结构的重排而产生的推断.     

DiastereoselectiveandEnantioselectiveSynthesisof(1S,2S)-2-Ethyl-1-aminocyclopropaneCarboxylicAcid

During the last decade, 1-aminocyclopropanecarboxylic acid and its derivatives (ACCS) have attracted increasing attention of organic and bioorganic chemists due to their outstanding biological properties, ranging from antimicrobial, insecticidal, plant growth and fruit ripening controls, etc.1. Moreover, the three-membered carbocycle provides building blocks of unprecedented synthetic potential because it undergoes selective ring opening, ring enlargement or cycloaddition reactions2. The mo…     

Rh2(CO)4(μ-Cl)2和Rh4(μ-CO)3(CO)4的简正振动分析

金属簇合物具有独特的结构和成键方式。本文对铑簇合物的简正振动分析进行了研究。通过红外光谱用石蜡油糊涂KBr和聚乙烯窗口, 在Nicolet 200SXV FT-IR光谱上测定了Rh2(CO)4(μ-Cl)2的构型, 并使用分子振动全分析程序MVTA(Basic语言), 在PC机上进行计算。     

混合金属钴钌原子簇Co3Ru(CO)11(NO)2, (RC≡CR^1)Co3Ru(CO)9(NO)的合成与表征

本文报道Co-Ru簇的合成与表征的研究。由Et4N[RuCl4(CH3CN)2]和Co2(CO)8制备了Et4N[Co3Ru(CO)12]·1/3THF, 它与等摩尔的NOBF4反应得到Co3Ru(CO)11(NO)(1)和Co2Ru(CO)11(5)。簇合物1分别与乙炔、苯基乙炔和二苯基乙炔进一步反应得到(HC≡CH)Co3Ru(CO)9(NO)(2), (PhC≡CH)Co3Ru(CO)9(NO)(3)和(PhC≡CPh)Co3Ru(CO)9(NO)(4)。在上述反应中还分离得到(HC≡CH)Co2Ru(CO)9(6), (PhC≡CH)Co2Ru(CO)9(7)和(PhC≡CPh)Co2Ru(CO)9(8)。对所得族合物1,2,3,4进行了IR, UV,^1H NMR, m.p., 元素分析和单晶X射线衍射分析等性质表征, 簇合物3的晶体属单斜晶系, pα1/n空间群, 晶胞参数为: a=1.1438(9), b=.3033(6), c=1.4345(9)nm, β=100.72(4)°, 每个晶胞中有四个分子。