Palladium(II) compounds with planar chirality. X-Ray crystal structures of (+)-(R)-[{(η5-C5H4)–CHN–CH(Me)–C10H7}Fe(η5-C5H5)] and (+)-(Rp,R)-[Pd{[(Et–CC–Et)2(η5-C5H3)–CHN–CH(Me)–C10H7]Fe(η5-C5H5)}Cl]

A wide variety of planar chiral cyclopalladated compounds of general formulae [Pd{[(η⁵-C₅H₃)–CHN–CH(Me)–C₁₀H₇]Fe(η⁵-C₅H₅)}Cl(L)] (with L=py-d₅ or PPh₃), [Pd{[(η⁵-C₅H₃)–CHN–CH(Me)–C₁₀H₇]Fe(η⁵-C₅H₅)}(acac)] or [Pd{[(R¹–CC–R²)₂(η⁵-C₅H₃)–CHN–CH(Me)–C₁₀H₇]Fe(η⁵-C₅H₅)}Cl] (with R¹=R²=Et; R¹=Me, R²=Ph; R¹=H, R²=Ph; R¹=R²=Ph; R¹=R²=CO₂Me or R¹=CO₂Et, R²=Ph) are reported. The diastereomers {(R_p,R) and (S_p,R)} of these compounds have been isolated by either column chromatography or fractional crystallization. The free ligand (R)-(+)-[{(η⁵-C₅H₄)–CHN–CH(Me)–C₁₀H₇}Fe(η⁵–C₅H₅)] (1) and compound (+)-(R_p,R)-[Pd{[(Et–CC–Et)₂(η⁵-C₅H₃)–CHN–CH(Me)–C₁₀H₇]Fe(η⁵-C₅H₅)}Cl] (7a) have also been characterized by X-ray diffraction. Electrochemical studies based on cyclic voltammetries of all the compounds are also reported.     

A Convenient Synthesis of 2,4(3H,5H)-Furandione (β-Tetronic Acid)

The chemical versatility of 2,4(3H,5H)-furandione (β-tetronic acid, 1) and its synthetic applicability are of considerable current interest^1b,2a-k. The multifunctional character of this small molecule confers an intriguing synthetic potential which has prompted us to develop synthetic schemes utilizing it as a synthon for certain heterocyclic systems.     

The Synthesis of the Arene Clusters Ru6C(CO)14(η6-Arene) (Arene = C6H5CHMe2, C6H5C4H9, C6H5C3H7, and C6H5C3H5)

On reaction with Ru₃(CO)₁₂, isopropenylbenzene and 4-phenyl-l-butene undergo hydrogenation, to yield the clusters, Ru₆C(CO)₁₄(⁶-C₆H₅CHMe₂) 1 and Ru₆C(CO)₁₄(⁶-C₆H₅C₄H₉) 2, respectively. With allylbenzene, both hydrogenation and isomerization occurs affording Ru₆C(CO)₁₄(⁶-C₆H₅C₃H₇) 3 and Ru₆C(CO)14(⁶-C₆H₅C₃H₅) 4. The structures of 1 and 2 have been established by single crystal X-ray diffraction. One of the Ru–Ru bond lengths in 2 is unusually long and extended Hückel molecular orbital calculations have been used in an attempt to rationalize this feature.     

Infrared investigations of the order–disorder ferroelectric phase transitions in imidazolium halogenobismuthates(III) and halogenoantimonates(III): (C3N2H5)5Bi2Cl11, (C3N2H5)5Bi2Br11 and (C3N2H5)5Sb2Br11

Infrared spectra of the powdered (C₃N₂H₅)₅Bi₂Cl₁₁, (C₃N₂H₅)₅Bi₂Br₁₁and (C₃N₂H₅)₅Sb₂Br₁₁ crystals in the region of internal vibrations of the imidazolium cations (3600 and 400 cm⁻¹) at the temperature intervals of 10–300 K, covering paraelectric–ferroelectric phase transitions, are presented and discussed in this paper. The research shows that the vibrational states of the imidazolium cations change markedly during the paraelectric–ferroelectric phase transition. The continuous nature of these transitions is well reflected in the infrared spectra, which is consistent with the previous X-ray and dielectric findings.     

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.     

Substitution and insertion reactions of (η5-C5H5)Cr(CO)3C2H5

The complex (η⁵-C₅H₅)Cr(CO)₃Cp42 H₅ has been made and its reactions with σ donor ligands L (L = (MeO)₃P and (EtO)₃P) and with SO₂ studied. The alkyl phosphites give compounds of the composition (η⁵-C₅H₅)Cr(CO)₂LC₂H₅, and sulfur dioxide gives the corresponding S-sulfinato (η⁵-C₅H₅)Cr(CO)₃SO₂C₂H₅.     

Complexation of N-Allyl Derivatives of Morpholinium with Copper(I) Halides: Synthesis and Crystal Structure of [C4H8ON(C3H5)2]+[Cu4Cl5]–, [C4H8ONH(C3H5)]+[CuBr2]–, and [C4H8ONH(C3H5)]+[CuBr1.41Cl0.59]–

The compounds [C₄H₈ON(C₃H₅)₂]⁺[Cu₄Cl₅]^– (I), [C₄H₈ONH(C₃H₅)]⁺[CuBr₂]^– (II), and [C₄H₈ONH(C₃H₅)]⁺[CuBr_1.41Cl_0.59]^– (III) were prepared for the first time by ac electrochemical synthesis from mono- and di-N-allyl derivatives of morpholinium and copper(I) halides in ethanol solution and structurally characterized. In the structure of I π-complex, the centrosymmetric Cu₈Cl₁₀ fragments are associated into layers perpendicular to the b axis. The N,N"-diallylmorpholinium cation functions as a bridge, which coordinates two copper atom of the adjacent inorganic fragments by both allyl groups. The trigonal-pyramidal surrounding of the Cu(I) atom, as well as the distorted tetrahedral coordination sphere of Cu(2), involves three chlorine atoms and the C=C bond, whereas the planar trigonal surrounding of the Cu(3) atom and trigonal-pyramidal surrounding of the Cu(4) atom involve only chlorine atoms. In the isostructural II and III σ-complexes, the edge-shared CuX₄ tetrahedra form the infinite copper-halide chains running along the a axis. The inorganic fragments and organic N-allylmorpholinium cations are united into the three-dimensional crystal structures by N–H···X and C–H···X (X = Cl, Br) hydrogen bonds.     

Comparative mass spectrometric investigation of transition metal polymethylcyclopentadienylcarbonyl complexes: II mass spectra of RnC5H5–nMN(CO)3 (R = CH3, n = 0–5; R = t-C(CH3)3, n = 1)

Investigation of π-(CH_3nC₅H_5–nMn(CO)₃ (Me_n-CpMnT) n = 0−5 and t-butyl CpMnT mass spectra showed that Me_nCpMnT molecular ion (M⁺) fragmentation occurs by a simpler scheme than that for Me_nCpReT M⁺ molecular ions. The reason is that MnCp and MnCO bonds are not as strong as the ReCp and ReCO bonds, and the relative “inertness” (compared to Re) of the Mn atom (ion), coordinated to the methylcyclopentadienyl ligand. Variations of M⁺ molecular ion intensity with different values of n are probably due to a complexity of electronic and spatial methyl-carbonyl group interactions in M⁺.     

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.     

2(3 H)呋喃酮向2(5 H)呋喃酮的转化研究

本文研究2(3H)呋喃酮的热转化和碱催化成2(5H)呋喃酮的过程。应用NMR跟踪技术测定了转化动力常数, 计算了活化能, 这对确定适宜的转化条件具有实际指导意义。还对碱催化下的转化机理进行了探讨。     

(C5H5)2NdCl·2LiCl 与正丁基锂的反应: [Li(DME)3][(C5H5)3Nd(μ-H)Nd(C5H5)3]的合成及其晶体结构

研究了(C5H5)2NdCl·2LiCl与正丁基锂在THF溶液中的反应, 并从该反应液中分离到了钕的氢化物[Li(DME)3][(C5H5)3Nd(μ-H)Nd(C5H5)3] 1. 化合物1经X射线单晶结构测定表明属单斜晶系, 空间群P21/c, 晶胞参数为a=0.9670(2) nm, b=2.1001(5) nm, c=2.1279(7) nm, β=90.89(2)°, Z=4, V=4.321 (2) nm3, Mr=957.36, Dc=1.47 g·cm-3, F(000)=1936, R=0.094, wR=0.100. 1的晶胞中包含两个独立的晶体分子, 每一分子由阴阳离子对[Li(DME)3]+和[(C5H5)3Nd(μ-H)Nd(C5H5)3]-组成. 钕原子与3个η5-C5H5基团配位, 且两个(C5H5)3Nd经氢桥键相连构成阴离子. Nd1-H和Nd2-H键长均为0.218(1) nm.     

Cyclooctaselenadiazole: synthesis,decomposition pathway,and reaction with (η5-C5H5) Co(L)2 (L = C2H4, PPh3). Crystal and molecular structure of [(η5-C5H5)CO]2(μ2-η3,η2-C8H6Se)

Thermolysis of cyclooctaselenadiazole (2) yields only selenium-containing products. Compound 2 reacts with CpCo sources to give [(η⁵-C₅H₅)CO]₂(μ₂η³,η²-C₈H₆Se), a fluxional compound whose structure has been determined by X-Ray crystallography.     

The reactions of (η5-C5H5)NiO(s)3(μ-H)3(CO)9 with group V donor ligands. Spectroscopic characterization of the disubstituted derivatives,and crystal structure of (η5-C5H5)NiO(s)3(μ-H)3(CO)7(PMe2Ph)2

The complex (η⁵-C₅H₅NiO(s)₃(μ-H)₃(CO)₉ (1 reacts with phosphines in the presence of Me₃NO to give monosubsituted derivatives, the main products, along with smaller amounts of disubstituted derivatives. The IR and NMR spectroscopic characterizations of two representative disubstituted derivatives are described.The crystal structure of (η⁵-C₅H₅)NiO(s)(μ-H)₃(CO)₇(PMe₂Ph)₂ has been determined by X-ray diffraction. The crystals are monoclinic, space group P2₁/a with Z = 4 in a unit cell of dimensions a 18.198(8), b 20.865(8), c 8.656(5) Å, β 99.67(2)°. The structure was solved by direct and Fourier methods and refined by full-matrix least-squares to R = 0.061 for 3139 observed reflections. The structure can be regarded as derived from that of 1 (which has a tetrahedral NiO(s) core with three hydride hydrogen atoms bridging the OsOs edges, a cyclopentadienyl group coordinated to the Ni atom,and nine terminal carbonyls bound to the Os atoms, three for each Os atom) by replacing two axial carbonyls by two PMe₂Ph ligands.     

Ab initio study of Eu3+–L (L=H2O,H2S,NH2CH3, S(CH3)2, imidazole) complexes

The ground states and binding energies of Eu³⁺–L (L=H₂O,H₂S,NH₂CH₃,S(CH₃)₂, imidazole) complexes has been determined using ab initio techniques. The binding is mostly electrostatic as expected. The empty f orbital is different for the S compounds, being a π-like orbital, while for the O and N containing ligands it is a σ-like orbital. However, the range in the binding energies for the different f holes is small.     

Concerning the silicon-germanium bond: mass spectral fragmentations of isomeric SiGe compounds R3EE′R3 (E  Si,E′  Ge,R  Ph,Me,(η5-C5H4)Fe (C5H5), (η5-C5H5)Fe(CO)2 and (η5-C9H7) Fe(CO)2)

Isomeric pairs of silicon-germanium compounds containing a SiGe bond (Me₃SiGePh₃ (I) and Ph₃SiGeMe₃ (II); FpSiMe₂GeMe₃ (III) and FpGeMe₂SiMe₃ (IV) (Fp = (η⁵-C₅H₅)Fe(CO)₂); IFpSiMe₂GeMe₃ (V) and IFpGeMe₂SiMe₃ (VI) (IFp = (η⁵-C₉H₇)Fe(CO)₂); IFpSiMe₂GePh₃ (VII) and IFpGeMe₂SiPh₃ (VIII) and the complex FcSiMe₂GeMe₂Fc (IX) (Fc = ferrocenyl) have been synthesized and examined by mass spectrometry.The R₃SiGeR′₃ compounds I and II exhibit considerable exchange of R groups to produce [R_3-nR′_nSi]⁺ and [R′_3-nR_nGe]⁺ ion in progressively lesser amounts as n = 1 → 2 → 3. For the metal-substituted complexes containing the grouping FeSiGe fragmentation occurs predominantly via SiGe bond cleavage with formation of ions containing the silylene ligand [FeSiR₂]⁺. Complexes with the FeGeSi backbone undergo preferential scission of the FeGe bond, illustrating the general bond strength trend FeSi > SiGe. Upon direct cleavage of the SiGe bond in R₃SiGeR₃ compounds, the percentage of the charge carried by [R₃Si]⁺ ions significantly exceeds that carried by [R₃Ge]⁺ ions, reflecting the greater electronegativity of Ge polarizing the SiGe bond.     

Iodination of B12H11OC(O)CH2–3, B12H11OH2–, and B12H11SCN2–

Reactions of iodination of monosubstituted derivatives of B₁₂H₁₁X^2–anion (X = OC(O)CH₃, OH, SCN) were studied. The reactions were shown to proceed smoothly to give B₁₂H₁₀(OC(O)CH₃)I^2–((carboxy)(iodo)[decahydro[I _h1551-²⁰-closo]dodecaborate(2–)] anion), B₁₂H₁₀(OH)I^2–((hydroxo)(iodo)[decahydro[I _h1551-²⁰-closo]dodecaborate(2–)] anion), and B₁₂H₁₀(SCN)I^2–((thiocyanato)(iodo)[decahydro[I _h1551-²⁰-closo]dodecaborate(2–)] anion) in high yields, irrespective of the solvent used (benzene, H₂O–ROH, where R = C₂H₅, CH₂CH₂CH₃).¹     

Si5H3,Si5H6,Si5Li3及Si5Na3原子簇结构的理论研究

利用Gaussian-94计算程序中的B3LYP方法，在6—311 G(2d)6d基组下，对Si5，Si5H3，Si5H6，Si5Li3和Si5Na33原子簇的几何结构进行优化和频率计算．结果表明，Si5原子簇中最稳定的具有D3h对称性的结构中，位于同一平面上的3个Si原子确实具有剩余的成键能力，可以与3个H，Li，Na原子和6个H原子形成稳定的化合物．研究还发现，虽然H，Li和Na都属同一主族，但它们与Si5原子簇中Si原子的键连方式却不同，而且它们的加入，对Si5原子簇的“三角双锥”结构也有不同的影响．     

A convenient,one-step synthesis of the cationic η3-allyl-molybdenum complex [(η5-C5H5)2Mo(η3-C3H5)]+[p-CH3C6H4SO3]−

[(η⁵-C₅H₅)₂Mo(η³-C₃H₅)]⁺ [p-CH₃C₆H₄SO₃]⁻ is conveniently synthesized by the reaction of (η⁵-C₅H₅)₂MoH₂ with allyl alcohol in the presence of p-toluene sulfonic acid, the mechanism of which is explained by the electrophilic cleavage of the allylO bond of the coordinated allyl alcohol.     

Critical temperatures,pressures, and densities for the mixtures CO2–C3H8, CO2–nC4H10, C2H6–C3H8, and C3H8–nC4H10

A simple method is developed to estimate mixture critical temperatures (T_c), pressures (P_c), and densities (ρ_c) as a function of overall composition (X) from near critical region experimental coexistence data. This three-step method is applied to four mixtures, CO₂–C₃H₈, CO₂–nC₄H₁₀, C₂H₆–C₃H₈, and C₃H₈–nC₄H₁₀. Isothermal liquid–vapor coexistence data, which includes temperature, vapor pressure, coexisting densities (ρ^ℓ and ρ^v), and coexisting compositions for the more volatile component (x₁^v and x₁^ℓ) are used. In the first step, the difference of the saturated liquid and vapor densities (ρ^ℓ−ρ^v) is fitted to an empirical function in ((P_c−P)/P_c) to obtain P_c. Then P/P_c and ((ρ^ℓ+ρ^v)/2ρ_c) are simultaneously fitted to functions of a polynomial in (X₁−(x₁^v+x₁^ℓ)/2) yielding estimates of ρ_c and X₁. Finally, the discrete estimated critical data points are fitted with an equation to provide a continuous representation of the critical lines. The method is successfully tested for the mixtures, CO₂–C₃H₈ and CO₂–nC₄H₁₀, for which there is a reasonable amount of isothermal data. The procedure is then applied to the mixtures, C₂H₆–C₃H₈ and C₃H₈–nC₄H₁₀, for which there are sparse data. For all four mixtures, the critical temperature line, T_c vs. X₁, matches literature values within ±0.5%. The critical pressure line, P_c vs. X₁, and critical density line, ρ_c vs. X₁, match literature values, in general, within ±2%.