Formation and isomerization of cis,cis-Ir(H)2(--Ph)(CO)(PPh3)2 and cis,cis-Ir(H)(--Ph)2(CO)(PPh3)2 in oxidative addition of hydrogen and phenylacetylene to trans-Ir(CO)(--Ph)(PPh3)2

Oxidative addition of H–R (H--Ph and H₂) to trans-Ir(--Ph)(CO)(PPh₃)₂ (2) gives the initial products, cis, cis-Ir(H)(--Ph)₂(CO)(PPh₃)₂ (3a) and cis, cis-Ir(H)₂(--Ph)(CO)(PPh₃)₂ (3b), respectively. Both cis-bis(PPh₃) complexes, 3a and 3b undergo isomerization to give the trans-bis(PPh₃) complexes, trans, trans-Ir(H)(--Ph)₂(CO)(PPh₃)₂ (4a) and cis, trans-Ir(H)₂(--Ph)(CO)(PPh₃)₂ (4b). The isomerization, 3b→4b is first order with respect to 3b with k₁=6.37×10⁻⁴ s⁻¹ at 25°C under N₂ in CDCl₃. The reaction rate (k₁) seems independent of the concentration of H₂. A large negative entropy of activation (ΔS^≠=−24.9±5.7 cal deg⁻¹ mol⁻¹) and a relatively small enthalpy of activation (ΔH^≠=14.5±3.3 kcal mol⁻¹) were obtained in the temperature range 15∼35°C for the isomerization, 3b→4b under 1 atm of H₂.     

Stereoelectronic interactions in cyclohexane, 1,3-dioxane, 1, 3-oxathiane, and 1,3-dithiane: W-effect, sigma(C)(-)(X) <--> sigma(C)(-)(H) interactions, anomeric effect-what is really important?

Stereoelectronic effects proposed for C-H bonds in cyclohexane, 1, 3-dioxane, 1,3-oxathiane, and 1,3-dithiane were studied computationally. The balance of three effects, namely, sigma(C)(-)(X) --> sigma(C)(-)(H)()eq, sigma(C)(-)(H)()eq --> sigma(C)(-)(X), and n(p)(X) --> sigma(C)(-)(H)()eq interactions, was necessary to explain the relative elongation of equatorial C(5)-H bonds. The role of homoanomeric n(p) --> sigma(C(5))(-)(H)()eq interaction is especially important in dioxane. In dithiane, distortion of the ring by long C-S bonds dramatically increases overlap of sigma(C(5))(-)(H)()eq and sigma(C)(-)(S) orbitals and energy of the corresponding hyperconjugative interaction. Anomeric n(p)(X) --> sigma(C)(-)(H)()ax interactions with participation of axial C-H bonds dominate at C(2), C(4), and C(6). The balance of hyperconjugative interactions involving C-H(ax) and C-H(eq) bonds agrees well with the relative bond lengths for all C-H(ax)/C-H(eq) pairs in all studied compounds. At the same time, the order of one-bond spin-spin coupling constants does not correlate with the balance of stereoelectronic effects in dithiane and oxathiane displaying genuine reverse Perlin effect.     

Reaction of Mercury(II) Trifluoroacetate with Deprotonated (η6-Toluene)-, (η6-Diphenylmethane)-, and (η6-Triphenylmethane)(η5-cyclopentadienyl)iron(II) Complexes. Mercuration of Some Cationic (Arene)(cyclopentadienyl)iron(II) Complexes

Treatment with mercury(II) trifluoroacetate of deprotonated (⁶-toluene)- and (⁶-diphenyl- methane)(⁵-cyclopentadienyl)iron(II) complexes gave mono-, di-, and trisubstituted [from (⁶-toluene)(⁵-cyclopentadienyl)iron(II) cation] mercury-containing salts. The reaction of mercury(II) trifluoroacetate with deprotonated (⁶-triphenylmethane)(⁵-cyclopentadienyl)iron(II) afforded only the corresponding sym- metric mercury derivative. The same product was obtained by direct mercuration with mercury(II) trifluoroacetate of (⁶-triphenylmethane)(⁵-cyclopentadienyl)iron(II) on heating the reactants in boiling unhydrous ethanol. Reactions of the resulting mercury-containing compounds with acids, symmetrizing bases, and acylating agents were studied.     

新的不对称催化剂Rh(acac)(-)-(diop)的催化氢化反应

1970年Monsanto研究组从前手性烯烃不对称催化氢化得到L-Dopa.特别是可用不对称催化剂催化合成维生素、药物、香料和其它精细化学品后,不对称催化反应的研究引起人们极大兴趣.1971年巴黎研究组从酒石酸出发首次合成Diop,即2,3-异亚丙基-2,3-二羟基-1,4-双(二苯膦基)-丁烷[2,3-Isopropylidene-2,3-dihydroxy-1,4-bis(diphenylphosphino)butane](图1)和不对称催化剂[Rh(COD)(-)-(diop)]C1,以后陆续报道HRh( )-(diop)_2,[Rh(COD)( )-(diop)]C1,和Rh(nbd)(diop》C1的合成和催化反应.     

(S)-(-)-norlaudanosine和(S)-(-)-O,O-dimethylcoclaurine的合成

以高藜芦胺为起始原料,经N-磺酰化反应制得高藜芦磺酰胺(2);2分别与芳乙烯甲醚经对甲苯磺酸催化的Pictet-Spengler反应后用金属钠脱除Ts基团合成了(±)-norlaudanosine(5a)和(±)-O,O-dimethylcoclaurine(5b);使用半量拆分法,以N-乙酰-L-苯丙氨酸为拆分剂,制得(S)-(-)-5a和(S)-(-)-5b,其结构经1H NMR,13C NMR,IR,MS和HR-ESI-MS确证。     

(S)-(4-溴-2-甲苯)(3-甲基吗啉)甲酮的合成

以(S)-2-氨基丙醇和氯乙酰氯为起始原料,经酰化和环合反应制得(S)-5-甲基吗啉-3-酮（4）; 4经还原制得(S)-3-甲基吗啉(5); 5与4-溴-2-甲基苯甲酸酰化缩合合成了(S)-(4-溴2-甲基苯基)(3-甲基吗啉)-甲酮,总收率57%,其结构经¹H NMR 和 ¹³C NMR确证。     

Synthesis,crystal structure,and magnetic properties of a new end-to-end thiocyanato-bridged dicobalt(II) complex CoII(dien)(H2O)(NCS)(μ1,3-NCS)CoII(dien)(NCS)2 (dien = diethylenetriamine)

Synthesis, characterization, crystal structure, and magnetic properties of the first single µ_1,3-thiocyanato-bridged dicobalt(II) compound, [Co^II(dien)(H₂O)(NCS)(µ_1,3-NCS)Co^II(dien)(NCS)₂] (1; dien = diethylenetriamine), are described. In 1, cobalt(II) is six coordinate with distorted-octahedral geometry. The Co(1) ··· Co(2) distance is 5.99 Å. The magnetic properties of 1 have been investigated by variable-temperature magnetic susceptibility measurements. The metal centers are coupled by weak ferromagnetic interaction (J = 1.14 cm^?1). The structure and magnetic properties are compared with related thiocyanate-bridged compounds.     

Charged, but Found "Not Guilty": Innocence of the Suspect Bridging Ligands [RO(O)CNNC(O)OR](2-) = L(2-) in [(acac)(2)Ru(μ-L)Ru(acac)(2)](n), n = +,0,-,2-

Neutral diastereoisomeric diruthenium(III) complexes, meso- and rac-[(acac)(2)Ru(μ-adc-OR)Ru(acac)(2)] (acac(-) = 2,4-pentanedionato and adc-OR(2-) = dialkylazodicarboxylato = [RO(O)CNNC(O)OR](2-), R = tert-butyl or isopropyl), were obtained from electron transfer reactions between Ru(acac)(2)(CH(3)CN)(2) and azodicarboxylic acid dialkyl esters (adc-OR). The meso isomer 3 with R = isopropyl was structurally characterized, revealing two deprotonated and N-N coupled carbamate functions in a reduced dianionic bridge with d(N-N) = 1.440(5) ?. A rather short distance of 4.764 ? has been determined between the two oxidized, antiferromagnetically coupled Ru(III) centers. The rac isomer 4 with R = isopropyl exhibited stronger antiferromagnetic coupling. While the oxidation of the neutral compounds was fully reversible only for 3 and 4, two well-separated (10(8) < K(c) < 10(10)) reversible one-electron reduction steps produced monoanionic intermediates 1(-)-4(-) with intense (ε ≈ 3000 M(-1) cm(-1)), broad (Δν(1/2) ≈ 3000 cm(-1)) absorptions in the near-infrared (NIR) region around 2000 nm. The absence of electron paramagnetic resonance (EPR) signals even at 4 K favors the mixed-valent formulation Ru(II)(adc-OR(2-))Ru(III) with innocently behaving bridging ligands over the radical-bridged alternative Ru(II)(adc-OR(?-))Ru(II), a view which is supported by the metal-centered spin as calculated by density functional theory (DFT) for the methyl ester model system. The second reduction of the complexes causes the NIR absorption to disappear completely, the EPR silent oxidized forms 3(+) and 4(+), calculated with asymmetrical spin distribution, do not exhibit near infrared (NIR) activity. The series of azo-bridged diruthenium complex redox systems [(acac)(2)Ru(μ-adc-R)Ru(acac)(2)](n) (n = +,0,-,2-), [(bpy)(2)Ru(μ-adc-R)Ru(bpy)(2)](k) (k = 4+,3+,2+,0,2-), and [(acac)(2)Ru(μ-dih-R)Ru(acac)(2)](m) (m = 2+,+,0,-,2-; dih-R(2-) = 1,2-diiminoacylhydrazido(2-)) is being compared in terms of electronic structure and identity of the odd-electron intermediates, revealing the dichotomy of innocent vs noninnocent behavior.     

X@(HAINH)_(12)和X(HAINH)_(12)(X=F~-,Cl~-,Br~-,O~(2-),S~(2-),Se~(2-))复合物的结构和稳定性

用DFT的B3LYP方法在6-31G(d)基组的水平上,对闭式多面体簇合物(HA1NH)12及其内含式X@(HA1NH)12外接式X(HA1NH)12(X=F-,Cl-,Br-,O2-,S2-,Se2-)复合物的结构进行了构型优化和能量计算,并讨论了几何构型、自然键轨道(NBO)、振动频率、能量参数及NMR数据与结构的关系,最后得到复合物结构的稳定性信息,具有Th对称性的X@(HA1NH)12(X=F-,Cl-,Br-,S2-,Se2-)复合物和具有C3对称性的O2-@(HA1NH)12复合物为内含式的基态结构,从能量角度分析,内含式复合物比外接式复合物的结构稳定.     

A structural and Mössbauer study of complexes with Fe(2)(micro-O(H))(2) cores: stepwise oxidation from Fe(II)(micro-OH)(2)Fe(II) through Fe(II)(micro-OH)(2)Fe(III) to Fe(III)(micro-O)(micro-OH)Fe(III)

Dinuclear non-heme iron clusters containing oxo, hydroxo, or carboxylato bridges are found in a number of enzymes involved in O(2) metabolism such as methane monooxygenase, ribonucleotide reductase, and fatty acid desaturases. Efforts to model structural and/or functional features of the protein-bound clusters have prompted the preparation and study of complexes that contain Fe(micro-O(H))(2)Fe cores. Here we report the structures and spectroscopic properties of a family of diiron complexes with the same tetradentate N4 ligand in one ligand topology, namely [(alpha-BPMCN)(2)Fe(II)(2)(micro-OH)(2)](CF(3)SO(3))(2) (1), [(alpha-BPMCN)(2)Fe(II)Fe(III)(micro-OH)(2)](CF(3)SO(3))(3) (2), and [(alpha-BPMCN)(2)Fe(III)(2)(micro-O)(micro-OH)](CF(3)SO(3))(3) (3) (BPMCN = N,N'-dimethyl-N,N'-bis(2-pyridylmethyl)-trans-1,2-diaminocyclohexane). Stepwise one-electron oxidations of 1 to 2 and then to 3 demonstrate the versatility of the Fe(micro-O(H))(2)Fe diamond core to support a number of oxidation states with little structural rearrangement. Insight into the electronic structure of 1, 2', and 3 has been obtained from a detailed M?ssbauer investigation (2' differs from 2 in having a different complement of counterions). Mixed-valence complex 2' is ferromagnetically coupled, with J = -15 +/- 5 cm(-)(1) (H = JS(1).S(2)). For the S = (9)/(2) ground multiplet we have determined the zero-field splitting parameter, D(9/2) = -1.5 +/- 0.1 cm(-)(1), and the hyperfine parameters of the ferric and ferrous sites. For T < 12 K, the S = (9)/(2) multiplet has uncommon relaxation behavior. Thus, M(S) = -(9)/(2) <--> M(S) = +(9)/(2) ground state transition is slow while deltaM(S) = +/-1 transitions between equally signed M(S) levels are fast on the time scale of M?ssbauer spectroscopy. Below 100 K, complex 2' is trapped in the Fe(1)(III)Fe(2)(II) ground state; above this temperature, it exhibits thermally assisted electron hopping into the state Fe(1)(II)Fe(2)(III). The temperature dependence of the isomer shifts was corrected for second-order Doppler shift, obtained from the study of diferrous 1. The resultant true shifts were analyzed in a two-state hopping model. The diferric complex 3 is antiferromagnetically coupled with J = 90 +/- 15 cm(-)(1), estimated from a variable-temperature M?ssbauer analysis.     

Mercuration with Mercury(II) Trifluoroacetate of (η6-Aniline)- or (N,N-dimethylaniline)(η5-cyclopentadienyl)iron(II)

The reaction of mercury(II) trifluoroacetate with the hexafluorophosphate of the ⁶-aniline-⁵cyclopentadienyliron(II) cation under reflux in dry ethanol gives rise to N-mono- and N,N-disubstituted mercury-containing salts of this cation. The same mercury-containing salts have been synthesized by the action of mercury(II) trifluoroacetate on the deprotonation product of the (⁶-aniline)(⁵-cyclopentadienyl)iron(II) cation. Direct mercuration of the [⁶-(N,N-dimethylaniline)](⁵-cyclopentadienyl)iron(II) cation into the para position of the benzene ring of the arene ligand has been performed. The reactivity of the compounds obtained has been studied.     

Evidence for hydrogen bond network formation in microsolvated clusters of Pt(CN)4(2-): collision induced dissociation studies of Pt(CN)4(2-)·(H2O)(n) n = 1-4, and Pt(CN)4(2-)·(MeCN)(m) m = 1, 2 cluster ions

Low-energy collision induced dissociation has been used to investigate the structure and stability of microsolvated clusters of the prototypical, aprotic multiply charged anion, Pt(CN)(4)(2-), i.e. Pt(CN)(4)(2-)·(H(2)O)(n) n = 1-4, Pt(CN)(4)(2-)·(MeCN)(m) m =1, 2, and Pt(CN)(4)(2-)·(H(2)O)(3)·MeCN. For all of the systems studied, the lowest energy fragmentation pathway was found to correspond to decay of the cluster with loss of the entire solvent ensemble. No sequential solvent evaporation was observed. These observations suggest that the Pt(CN)(4)(2-) solvent clusters studied here form hydrogen-bonded "surface solvated" structures. Electronic structure calculations are presented to support the experimental results. In addition, the detailed fragmentation patterns observed are interpreted with reference to the differential solvation of the ionic fragmentation and electron detachment potential energy surfaces of the core Pt(CN)(4)(2-) dianion. The results described represent some of the first experiments to probe the microsolvation of this important class of multiply charged anions.     

Crystal structure of barium α-(Ethylenediamine-N,N-diacetato)malonatocobaltate(III) perchlorate pentahydrate Ba[Co(Edda)(Mal)(ClO4) · 5H2O

The crystal structure of [Co (Edda)(Mal)](ClO₄) · 5H₂O is determined by X-ray diffraction analysis (the crystals are triclinic: a = 10.1363(12) Å, b = 11.0801(13) Å, c = 11.3173(13) Å, α = 101.129(13)°, β = 108.594(13)°, γ = 112.883(13)°, Z = 2, space group P $\overline 1 $ ). The Co³⁺ ion coordinates two O atoms of the malonate ion, as well as two N atoms and two trans-O atoms of the ethylene-N,N-diacetate ion. The [(H₂O)₄Ba(ClO₄)]⁺ subunits interact with the [Co(Edda)(Mal)]^? complexes to form infinite ribbons, and each complex is bonded with three Ba atoms through the O atoms of the carboxyl groups. The coordination number of the Ba atom is nine (four O atoms of the water molecule, one O atom of the perchlorate ion, and four O atoms of three adjacent complexes).     

Chiral or not chiral? A case study of the hexanuclear metalloprisms [Cp(6)M(6)(micro(3)-tpt-kappaN)(2)(micro-C2O4-kappaO)(3)]6+ (M = Rh, Ir, tpt = 2,4,6-tri(pyridin-4-yl)-1,3,5-triazine)

Cationic hexarhodium and hexairidium complexes with a trigonal prismatic architecture have been synthesised in good yield by self-assembly of the dinuclear oxalato-bridged complexes [Cp(2)M(2)(micro-C(2)O(4)-kappaO)Cl(2)] (M = Rh; 1: Ir; 2) with 2,4,6-tri(pyridine-4-yl)-1,3,5-triazine (tpt) in the presence of AgO(3)SCF(3). The trigonal prismatic cations [Cp(6)Rh(6)(micro(3)-tpt-kappaN)(2)(micro-C(2)O(4)-kappaO)(3)](6+) (3) and [Cp(6)Ir(6)(micro(3)-tpt-kappaN)(2)(micro-C(2)O(4)-kappaO)(3)](6+) (4) have been isolated as their triflate salts. The single-crystal X-ray structure analysis of [3][O(3)SCF(3)](6) shows two enantiomers in the racemic crystal (space group C2/c), the chirality being due to a twist of the two tpt units. By contrast, the single-crystal X-ray structure analysis of [4][O(3)SCF(3)](6) shows a perfectly eclipsed conformation of the tpt units, so that is not chiral in the crystal state (space group Fd3[combining macron]c). However, in solution, enantiodifferentiation in the presence of the chiral anion Delta-BINPHAT is observed by (1)H NMR spectrometry not only in the case of 3, but also in the case of 4. This suggests that the iridium derivative 4, which is not chiral in the solid state, adopts chiral conformations in solution.     

Synthesis,spectroscopy, magnetism and X-ray structure of μ-(bipyrimidine)-bis[aqua(bipyrimidine)(saccharinato)copper(II)] bis(saccharinate) tetrahydrate

The compound [Cu₂(bipym)₃(sac)₂(H₂O)₂](sac)₂(H₂O)₄ (bipym = 2,2-bipyrimidine and sac = saccharin) crystallizes in the space group P-1, with a = 10.710(3), b = 10.725(3), c = 13.637(5) Å, a = 70.07(3), = 80.31(2), g = 82.87(3)° and Z = 2. The geometry in the centrosymmetric dinuclear complex around each Cu^II ion is a distorted octahedron, in which the equatorial plane is formed by a nitrogen atom of a bis-didentate bridging bipym ligand, two nitrogen atoms of a didentate bipym ligand, and the nitrogen atom of a coordinating sac ligand. The axial positions in the octahedron are occupied by a second nitrogen of the bis-didentate bridging bipym ligand and a water molecule. The lattice contains two saccharinate anions and four water molecules held together in a hydrogen-bonded network. The i.r vibrations of the bipym ligand are found as a quasi-symmetric doublet at 1558 and 1580 cm^–1, while the most important i.r vibrations of the sac ligand are observed at 1629 and 1644 cm^–1 (carbonyl vibrations) and at 1285 and 1159 cm^–1 (sulfonyl vibrations). The magnetic exchange interactions between the Cu ions is very weak and is ferromagnetic (J < 0.1 cm^–1).     

Asymmetric Synthesis of Highly Enantiomerically Enriched (S)(-)-β-Bisabolene

(S)-β-Bisabolene, (S)-1, was synthetized by a synthetic route in which (S)-4-methyl-3-cyclohexene carboxylic acid, (S)-10, which was the key intermediate, was prepared via a highly diastereoselective TiCl₄-catalyzed Diels-Alder reaction between isoprene and the acrylate of commercial (R)-pantolactone, followed by hydrolysis. Compound (S)-10 was then converted into ketone (S)-13 using two different procedures. The best one of these, as regards the degree of stereospecificity, involved the reaction of (S)-10 with 2 equiv of 4-methyl-3-penten-1-yllithium, 14, in the presence of CeCl₃, and gave (S)-13 having ca. 84% ee. The Zr-promoted methylenation of this ketone afforded highly enantiomerically enriched (S)-1.     

Synthesis of Platinum-Triruthenium Clusters Using the Zero-Valent Platinum Reagent Pt(nb)3: X-Ray Crystal Structures of Ru3Pt(CO)11(P-iPr3)2, Ru3Pt(μ-H)(μ3-η3-MeCCHCMe)(CO)9(P-iPr3), Ru3Pt(μ3-η2-PhCCPh)(CO)10(P-iPr3), Ru3Pt(μ-H)(μ4-N)(CO)10(P-iPr3) and Ru3Pt(μ-H)(μ4-η2-NO)(CO)10(P-iPr3)

The complexes Pt(nb)_3-n(P-iPr₃)_n (n=1, 2, nb=bicyclo[2.2.1]hept-2-ene), prepared in situ from Pt(nb)₃, are useful reagents for addition of Pt(P-iPr₃)_n fragments to saturated triruthenium clusters. The complexes Ru₃Pt(CO)₁₁(P-iPr₃)₂ (1), Ru₃Pt(-H)(₃-³-MeCCHCMe)(CO)₉(P-iPr₃) (2), Ru₃Pt(₃-²-PhCCPh)(CO)₁₀(P-iPr₃) (3), Ru₃Pt(-H)(₄-N)(CO)₁₀(P-iPr₃) (4) and Ru₃Pt(-H)(₄-²-NO)(CO)₁₀(P-iPr₃) (5) have been prepared in this fashion. All complexes have been characterized spectroscopically and by single crystal X-ray determinations. Clusters 1–3 all have 60 cluster valence electrons (CVE) but exhibit differing metal skeletal geometries. Cluster 1 exhibits a planar-rhomboidal metal skeleton with 5 metal–metal bonds and with minor disorder in the metal atoms. Cluster 2 has a distorted tetrahedral metal arrangement, while cluster 3 has a butterfly framework (butterfly angle=118.93(2)°). Clusters 4 and 5 posseses 62 CVE and spiked triangular metal frameworks. Cluster 4 contains a ₄-nitrido ligand, while cluster 5 has a highly unusual ₄-²-nitrosyl ligand with a very long nitrosyl N–O distance of 1.366(5) Å.     

6-甲基-4-羟基-喹啉酸盐羟基钒(V)(英文)

V anadium髨coordination com pound1is achievedby the hydrotherm al reaction of V2O5and ethyl6-m ethyl-4-hydroxy-3-quinolinecarboxylate(em hq)w ithwater as solvent.X-ray single crystal diffraction studyof com pound1(Fig.1)shows that com pound1crystal-lizes …     

6-甲基-4-羟基-喹啉酸盐羟基钒(Ⅴ)(英)

The central V atom in bis[6-methyl-4-hydroxy-3-quinolinecarboxylate] mono(oxo)mono-hydroxy-vanadium(Ⅴ) (1), synthesized by the hydrothermal treatment of ethyl 6-methyl-4-hydroxy-3-quinolinecarboxylate and V₂O₅, has a distorted octahedral coordination geometry formed by six oxygen atoms from two oxygen atom of two hydroxy groups and two oxygen atoms of two carboxylate groups as well as one oxo group and hydroxy group. CCDC: 285592.