The Reaction of Alkenes with Triangulo-Clusters [Pt3(μ-CO)3(PR3)3]

The reactions of the cluster complexes [Pt₃(-CO)₃L₃], where L=PPh₃ 1a, PPh₂Bz 1b and PCy₃ 1c, with activated mono-olefins have been studied under preparative and equilibrium conditions. At low temperature the olefins react quantitatively giving the adducts [Pt₃(-CO)₃L₃(olefin)] (olefin=trans-dicyanoethene, DCE 2a–2c, maleic anhydride, MA 3a–3c). The stereo-chemistry of these unstable clusters has been deduced from low temperature ³¹P, ¹³C, ¹⁹⁵Pt-NMR and I.R. spectra. At higher temperature these adducts in presence of excess of olefin convert quantitatively to stable mononuclear Pt(0) complexes [Pt(CO)L(olefin)] (olefin=DCE 4a–4c, MA 5a–5c, maleimide, MI 6a–6c and 1–4-naphthoquinone, NQ 7a, 7c).     

Synthesis and crystal structure of complex of Ce(NO_3)_3 with N-(3-methyl-pyridin-2-yl)-formimidoyl-(3-methyl-pyridin-2-yl) hydrazone

Rare earth complexes with organic ligands have been used as luminescence-material usually. Except their luminescent property, the complexes of trivalent lanthanide ions have low toxicity and powerful para-magnetic properties[1,2], so the lanthanide complexes are associated with important biological uses as diag-nostic tools and medicines[36]. Recently, there are some reports on Ce(III) complexes, some of which show anti-cancer activities[7]. S- tetrazines can be used as poly-dentate chelatin…     

Ligand substitution reaction of (μ-H)Os3(CO)10(μ-COMe) with 1,1'-bis(diphenylphosphino) ferrocene

Reaction of (μ-H)Os₃(CO)₁₀(μ-COMe) with 1,1'-bis(diphenylphosphino)-ferrocene (dppf) produces (μ-H)Os₃(CO)₈(μ-COMe){μ-η²-(η⁵-C₅H₄PPh₂)₂Fe} (1) and (μ-H)₂Os₃(CO)₇(μ-COMe){μ-η³-(η⁵-C₅H₃PPh₂)Fe(η⁵-C₅H₄PPh₂)} (2). Thermolysis of 1 leads quantitatively to 2. These compounds have been characterized by ¹H, ³¹P, and ¹³C NMR, IR, and mass spectroscopies. Compound 2 crystallizes in space group P 2₁/c with a = 11.898(2), b = 21.266(3), c = 18.262(3) Å, β = 104.71(1)°, V = 4469(1) ų, Z = 4, and R_F = 0.029.     

Further studies of M3(μ3-O)(μ-X)3(μ-O2CCH3)3L3 (M=Mo,W) type clusters with nine core electrons

Four new compounds having nine cluster electrons and cores of the types Mo₃OCl₃, Mo₃OBr₃, and W₃OCl₃ are reported. Compound (1) prepared by reduction of [Bu₄N][Mo₃OCl₆(OAc)₃] in THF with metallic zinc, was shown by X-ray crystallography to be Mo₃OCl₄(OAc)₃ (THF)₂ (1). It forms crystals in space groupP2₁ with unit cell dimensionsa=9.472(2) Å,b=13.546(4) Å,c=9.652(2) Å, =101.70(2)°,V=1201(1) Å₃,Z=2. The [Mo₃(₃-O)(-Cl)₃]⁴⁺ core is surrounded by three -O₂CCH₃ anions, one Cl^–, and two THF and has Mo-Mo distances of 2.620(1) Å, 2.613(1) Å, and 2.530(1) Å, with the shortest bond between the two Mo atoms to which the THF molecules are coordinated. Compounds [Bu₄N]₂ [Mo₃OBr₆(O₂CCH₃)₃] · Me₂CO, (2) and [Mo₃OBr₃(O₂CCH₃)₃(PMe₃)₃]₃ · BF₄, (3) are the first two nine-electron Mo₃ species with a [Mo₃(₃-O) Br₃]⁴⁺ core. Both were obtained by zinc reduction of [Mo₃OBr₆(O₂CCH₃)₃]^– in the presence of (NBu₄) Br (2) or PMe₃ and NaBF₄ (3), and each was characterized crystallographically. Compound (2) crystallized in space group Cc with unit cell dimensionsa=25.037(5) Å,b=12.827(2) Å,c=21.484(4) Å, =122.96(1)⁰,V=5790(3) ų,Z=4. While the anion has no crystallographically required symmetry, its virtual symmetry is C_3v . The Mo-Mo distances are 2.619(2) Å, 2.610(3) Å, 2.644(2) Å, with a mean value of 2.624[14] Å. Compound (3) crystallized in space groupP2₁/c with unit cell dimensionsa=10.846(2) Å,b=25.033(5) Å,c=12.641(5) Å, =94.74(2)⁰,V=3420(2) ų,Z=4. The cation occupies a general position but has virtual C_3v symmetry, with Mo-Mo distances of 2.601(2) Å, 2.610(2) Å, 2.627(2) Å, with a mean value of 2.613[14] Å. Thus the anionic and cationic Mo₃ clusters in (2) and (3), respectively, have average Mo-Mo distances that are equal within experimental error. Compound (4), [NEt₄]₂ [W₃OCl₆(O₂CCH₃)₃] is the first 9-electron compound of this type containing tungsten. It was prepared by reduction of [Et₄N][W₃OCl₆(OAc)₃] in benzene with Na/Hg. It crystallized in space groupP2₁2₁2₁ with unit cell dimensionsa=11.076(2) Å,b=14.345(2) Å,c=21.026(3) Å,V=3574(1) ų,Z=4. The anion resides on a general position but has virtual C_3v symmetry, with W-W distances of 2.577(1) Å, 2.612(1) Å, 2.584(1) Å and a mean value of 2.591[15] Å.     

Synthesis and Photoluminescence of New Europium Complex Eu(DBM)3 (DPPZ) with Dipyridophenazine Ligand

Dipyrido[3,2-a:2′,3′-c] phenazine moiety has been introduced as neutral lignad in europium complex.Therefore a new europium complex with saturate emission,strong fluorescnet intensity and good solubility was designed and synthesized for the first time.Its photoluminescence and UV properties were examined.The experimental results showed that this new Eu-complex could be used as red electroluminescnet materials.     

Reaction of the heteronuclear cluster RuOs3(μ-H)2(CO)13 with azulenes

Reaction of the heteronuclear cluster RuOs₃(μ-H)₂(CO)₁₃ (1) with azulene under thermal activation afforded the novel clusters RuOs₃(μ-H)(CO)₉(μ₃,η⁵:η²:η²-C₁₀H₉) (3) and Ru₂Os₃(μ-H)₂(CO)₁₃(μ-CO)(μ₃,η⁵:σ²-C₁₀H₈) (5a), with 4,6,8-trimethylazulene to give RuOs₃(μ-H)(CO)₈(μ-CO)(μ,η⁵:η⁴-C₁₀H₆Me₃) (4) and Ru₂Os₃(μ-H)₂(CO)₁₃(μ-CO)(μ₃,η⁵:σ²-C₁₀H₅Me₃) (5b), and with guaiazulene to give Ru₂Os₃(CO)₁₁(μ₃,η⁵:η³:η³-C₁₀H₅Me₂ⁱPr) (6), respectively. In 3–5, cluster-to-ligand hydrogen transfer appears to have taken place, with the organic moiety capping a trimetallic face in 3, bridging a metal–metal bond in 4 and via a μ₃,η⁵:σ² bonding mode in 5a and 5b. Cluster 6 contains a trigonal bipyramidal metal framework with the guaiazulene ligand over a triangular metal face. All five clusters have been completely characterised, including by single-crystal X-ray diffraction analysis.     

Synthesis of 1-(4-Antipyrinyl)-3-(3-Chlorophenyl)-Triazene and Its Colour Reaction with Mercury

TheantiPyrinldiazoaminoreagentsweresensitivefOrCd(II)andHg(II)11-3l-Receatly,anewreagrntlK4-antiPyrinl)-3<3-Chlorophenylytrime(APPT)wasSynthsized.ThecolourreahonofAnCPTwithmerCurywasstUdied-ThemethodfordeterminingmicroaznountofmempwithAPCPTwasmoresensitiveandhighlyselective.AnditwasusedtodeterIninemercmpcoboinnatUralwaterwithsatisfactryresults.ExperimeutalAPP~:Model75lspectrophotOmeter,ModelpH-2meter(madeinShanghai).Sbodard~solution:DissolveHgCl2(A.R.)inWate.AddseveraldroPso…     

An unprecedented luminescent polynuclear gold(I) μ(3)-sulfido cluster with a thiacrown-like architecture

An unprecedented Au(18) thiacrown directed by Au(I)···Au(I) interactions and supported by tridentate phosphine (dpepp) and μ(3)-sulfido ligands that highly resembles the 18-membered thiacrown ether [18]aneS(6) in appearance has been synthesized. The sulfides of the Au(3)(μ(3)-S) units in the central cavity point toward each other and are located on the same plane, allowing them to bind the soft Ag(+) ion with immediate and pronounced spectroscopic changes. Reversible binding and spectroscopic changes can be readily achieved upon addition of CH(3)CN without disruption of the Au(18) macrocycle.     

[Cu3(dppm)3(μ 3-I)2][(0.5TCNQ)], a radical salt derived from a donor with a copper(I) trimer

A radical salt 1, [Cu₃(dppm)₃(μ ₃-I)₂][(0.5TCNQ)], has been prepared by reaction of CuI, dppm (diphenylphosphinomethane) and TCNQ (7,7′,8,8′-tetracyanoquinodimethane) with a molar ratio of 1 : 1 : 0.5 and characterized by IR, UV–Vis and solid-emission spectroscopy. Its structure was determined by X-ray crystallography. 1 also has photoluminescence (λ _max = 653 nm) at room temperature. Magnetic properties indicate that TCNQ is in the reduced state (TCNQ^2?).     

Theoretical Investigation for the Abstraction Reaction of H with (CH_3)_3GeH

The reaction of H atom with (CH3)3GeH is considered to play important role in chemical vapor deposition (CVD) processes used in the semiconductor industry 1-2. The reaction mechanism and kinetics nature for this reaction are therefore essential input data for computer-modelling studies directed towards obtaining an understanding of the factors controlling CVD processes. However, despite its importance, the kinetics work about this reaction was very limited. Only two groups studied exper…     

Hydrosilylation Catalyzed with Rh(PPh3)3Cl/Ionic-Liquid–Functionalized SiO2

Ionic liquid–modified silica has been prepared by a “one-pot” reaction of activated silica, 3-chloropropyltriethoxysilane, and alkylimidazole or pyridine. It was found that the catalytic activity and β-adduct selectivity of the supported catalyst Rh(PPh₃)₃Cl/ionic-liquid–modified-SiO₂ for the hydrosilylation reaction of alkenes with triethoxysilane was significantly improved. Furthermore, the catalyst system could be recovered easily.     

Reaction of Substituted Cyclopentadienyl-magnesium-Chloride with Carbonyl Compound ( Ⅰ )——Reaction of (1, 1-Dialkyl-3-Butenyl) Cyclopentadienyl-magnesium-chloride with Ketones

The substituted cyclopentadienyl-magnesium-chloride, obtained by exocyclic addition of 6,6-dialkylfulvene and allyl-magnesium-chloride, reacted with the ketone 3, the product was hydrolyzed and dehydrated to give the 2-(1 ,1-dialkyl-3-butenyl)-6,6-dialkyl-fulvene 5. The structure of 5 was determined by using the 1H NMR spectra of 5 and the adducts of 5 with tetracyanoethylene.     

Enhanced CO_2 Electrolysis with Mn-doped SrFeO_(3-δ) Cathode

Solid oxide carbon dioxide electrolysers are expected to play a key role in carbon-neutral energy landscape. However, the limited activity of traditional ceramic cathodes still restricts the electrochemical performance. Here we report the doping of Mn at the B site of SrFeO_(3-δ) cathode to improve CO_2 electrolysis. The oxygen vacancy concentration is increased by ～30% with Mn doping while the surface oxygen exchange coefficients are enhanced by ～10 times. The chemisorption of CO_2 indicates the presence of chemical intermediate state between CO_2 molecule and carbonate ion on the oxygen-deficient cathode surface which therefore leads to the desorption temperature of ～800 ℃. The Mn-doped SrFeO_(3-δ) enhances CO_2 electrolysis with no performance degradation being observed even after high-temperature operation of 100 hours.     

Conversion of Methane to Ethylene with BaCe_(0.9)Y_(0.1)Co_xO_(3-δ) Hydrogen Permeation Membrane

Dehydrogenation coupling of methane (DCM),which can be effectively used to produce low carbon alkenes,has the advantages of rich raw materials,simple reaction device,low energy consumption,etc.Herein,we report a series of Co doped perovskite porous-dense Ba Ce_(0.9)Y_(0.1)Co_xO_(3-δ)(BCYCx) membrane for DCM.After treatment in a reduced atmosphere,a large number of Co nanoparticles will exsolute on the surface of BCY.The metal-oxide interface is helpful to activate the C–H bonds,inhibit the carbon deposition,and so on.The XRD,SEM and XPS prove that Co nanoparticles homogeneously distributed on the BCYCx porous layers,which will create a large quantity of catalytic active sites.At 1100℃,the highest concentration of C_2 product was 5.66%(5.25%ethane+0.41%ethylene)in output gas when methane conversion reaches a maximum value of 24.8%,and the C_2 selectivity gets to 45.6%.We further demonstrate the catalytic performance of high-temperature DCM without obvious decrease after running for 30hours.     

Cs8U(IV)(U(VI)O2)3(Ge3O9)3·3H2O: a mixed-valence uranium germanate with 9-ring channels

A mixed-valence uranium(IV,VI) germanate has been synthesized under high-temperature, high-pressure hydrothermal conditions. The structure contains discrete U(IV)O(6) octahedra and U(VI)O(6) tetragonal bipyramids, which are connected by three-membered single-ring Ge(3)O(9)(6-) anions to form a three-dimensional framework with 9-ring channels. The U 4f X-ray photoelectron spectroscopy spectrum was measured to identify the valence states of the uranium.     

Palladium-catalyzed allylic substitution with (η6-arene-CH2Z)Cr(CO)(3)-based nucleophiles

Although the palladium-catalyzed Tsuji-Trost allylic substitution reaction has been intensively studied, there is a lack of general methods to employ simple benzylic nucleophiles. Such a method would facilitate access to "α-2-propenyl benzyl" motifs, which are common structural motifs in bioactive compounds and natural products. We report herein the palladium-catalyzed allylation reaction of toluene-derived pronucleophiles activated by tricarbonylchromium. A variety of cyclic and acyclic allylic electrophiles can be employed with in situ generated (η(6)-C(6)H(5)CHLiR)Cr(CO)(3) nucleophiles. Catalyst identification was performed by high throughput experimentation (HTE) and led to the Xantphos/palladium hit, which proved to be a general catalyst for this class of reactions. In addition to η(6)-toluene complexes, benzyl amine and ether derivatives (η(6)-C(6)H(5)CH(2)Z)Cr(CO)(3) (Z = NR(2), OR) are also viable pronucleophiles, allowing C-C bond-formation α to heteroatoms with excellent yields. Finally, a tandem allylic substitution/demetalation procedure is described that affords the corresponding metal-free allylic substitution products. This method will be a valuable complement to the existing arsenal of nucleophiles with applications in allylic substitution reactions.     

New Fe3+/Cr3+ perovskites with anomalous transport properties: the solid solution La(x)Bi(1-x)Fe(0.5)Cr(0.5)O3 (0.4 ≤ x ≤ 1)

In this work, the sol-gel synthesis, structural characterization, and transport properties of a new solid solution of the general formula La(x)Bi(1-x)Fe(0.5)Cr(0.5)O(3) (0.4 ≤ x ≤ 1) are presented. The solubility limit x has been determined and variation of the lattice parameters measured through profile fitting. The cell parameters, space group, and atomic positions, as obtained by the Rietveld refinement of X-ray diffraction data, are reported. This analysis and electron diffraction studies as well do not reveal any evidence of Fe/Cr ordering. Regarding the transport properties, magnetic and electric characterizations are described. The electrical response with the temperature and frequency has been studied, and a "positive temperature coefficient" for the resistivity has been found for temperatures between 270 and 400 °C. The magnetic behavior is striking because, for all materials studied, zero-field-cooling curves appear above field-cooling ones, an anomalous feature that is interpreted as being due to complex ferromagnetic/antiferromagnetic interactions in the B perovskite sublattice.     

Synthesis,Crystal Structure and Photoluminescence of a Three-dimensional Zinc(Ⅱ) Coordination Polymer with(20~3)_2(20)_3 Topology

The title compound,[Zn2(H2C4BIm)(ox)2]·2H2O(1,H2C4BIm = 2,2'-(1,4-bu-tanediyl)bis(1H-benzimidazole),has been synthesized by the hydrothermal reaction of Zn(NO3)2·6H2O with H2C4BIm and Na2C2O4 in water solution.It crystallizes in the triclinic system,space group P1 with a = 9.445(9),b = 9.598(9),c = 14.962(14) ,α = 72.160(10),β = 79.905(12),γ = 83.680(11)°,Mr = 633.18,V = 1269(2) 3,Z = 2,Dc = 1.657 g/cm3,F(000) = 644,μ = 1.953 mm-1,the final R = 0.0671 and wR = 0.1689.X-ray crystal structure analysis revealed that 1 is a 3D network with(203)2(20)3 topology in which the ZnII atom can be considered as a 3-connected node and both ox2-and H2C4BIm serve as the linear linkers.     

α-aminoazoles in synthesis of heterocycles: IV. Regiodirection of 3(5)-amino-5(3)-methylpyrazole reaction with hexafluoroacetylacetone

The reaction of 3(5)-amino-5(3)-methylpyrazole with hexafluoroacetylacetone depending on the process conditions led to the formation either of pyrazolo[1,5-a]pyrimidine or pyrazolo[3,4-b]-pyridine. By means of 2D NMR spectroscopy the structure was established of a stable intermediate product, 2-methyl-5,7-bis(trifluoromethyl)-4,5,6,7-tetrahydropyrazolo[1,5-a]-pyrimidine-5,7-diol, whose dehydration yielded the above compounds.