STUDY OF CARBONYLATION OF METHANOL TO ACETIC ACID AND ACETIC ANHYDRIDE OVER A BIDENTATE POLYMER BOUND CIS-DICARBONYLRHODIUM COMPLEX AS CATALYST

Copolymer of 2-vinylpyridine and vinylacetate coordinated with dicarbonylrhodium used as a catalyst for carbonylation of methanol to acetic acid and anhydride has been studied. The structural characteristics of the copolymer ligand and complex, and the influences of the reaction conditions on the carbonylation catalyzed by this polymer complex have been investigated. In comparison with small molecule catalyst of Rh complex, the bidentate copolymer coordinated complex has better thermal stability. The reaction mechanism of the carbonylation reaction is also illustrated.

Dimerization of Propylene by Nickel (Ⅱ) and Cobalt (Ⅱ) Catalysts Based on Bidentate Nitrogen-phosphino Chelating Ligands

The catalytic property of propylene dimerization by several nickel (Ⅱ), cobalt (Ⅱ) complexes containing N-P bidentate ligands was studied in combination with organoaluminum co-catalysts. The effects of the type of aluminum co-catalysts and its relative amount, the nature of precursors in terms of ligand backbone and metal center were investigated. The results indicated that precursor I (N,N-dimethyl-2-(diphenylphosphino)aniline nickel (Ⅱ) dichloride) exhibited high activity in propylene dimerization in the presence of the strong Lewis acid Et3Al2Cl3, whereas low productivity by its cobalt analogues was observed under identical reaction conditions.

Synthesis and Characterization of a Palladium Complex Supported by Bidentate Ligand and Catalysis of the Vinyl Polymerization of Norbornene

The title complex N,O-bis{[2-[（2,4-dimethylphenyl）imino]-5-methoxyl]-phenol}-palladium（Ⅱ）（CC_（32）H_（32）N_2O_4Pd） has been synthesized by the reaction of 2-[（2,4-dimethylphenyl）imino]-5-methoxyl-phenol with Pd（CH_3COO）_2,and characterized by elemental analysis,IR spectrum and single-crystal X-ray diffraction analysis.The crystal belongs to the monoclinic system,space group P2_1/c with a = 12.058（2）,b = 8.3624（17）,c = 14.735（3） ？,β = 107.66（3）°,V = 1415.7（5）？~3,C_（32）H_（32）N_2O_4Pd,Mr = 615,Z = 2,D_c = 1.443 Mg/m^3,μ = 0.695 mm^（-1）,F（000） = 632,T = 293（2） K,the final R = 0.0514 and w R = 0.1356（I 〉 2s（I））.Under the co-catalysis of methylaluminoxane（MAO）,the palladium compound exhibited favorable catalytic activity for the polymerization of norbornene（NB）.

Ethylene Oligomerization by (dppe)MCl_2 [M = Fe(II), Co(II),Ni(II)] Complexes/EAO

The catalytic properties of a series of (dppe) MCl2 [M = Fe(II), Co(II), Ni(II)] in combination with EAO (ethylaluminoxane) for ethylene oligomerization have been investigated. Treatment of the bidentate phosphine metal complexes with EAO in toluene generated in situ active catalysts which catalyze oligomerizaton of ethylene to low-carbon olefins. The effects of reaction temperature, ratios of n(Al) : n(M) and reaction periods on catalytic activity and product distribution have been studied. The activity of cobalt complex with EAO at 200C was 4021 g/g(Co)h, and the selectivity of C4-10 olefins is 95.5%.

One-dimensional Copper（Ⅱ） Complex Constructed with Nitrate Counter-anion as Bitopic Connector

Coordination polymer {[Cu（NPPCA）3（NO3）（H20）]-NOyH20}n 1 （ NPPCA = N-（4＇- nitrophenyl）-4-pyridinecarboxamide） has been synthesized by the reaction of NPPCA with copper（H） nitrate in ethanol-water solution and characterized by X-ray diffraction. 1 crystallizes in the monoclinic space, group P21/n, a = 17.341（6）A, b = 6.744（2）A, c = 34.555（12）A, β = 100.493（6）°, V = 3974（2） A^3, Z = 4. Each copper（H） ion has a distorted octahedral coordination geometry. Nitrate anion adopts the unusual coordination mode linking two adjacent copper（H） ions to form a one-dimensional coordination polymer and these chains are further linked by noncovalent interactions.

Formation of Amino Acid Bridged Zinc Bisporphyrinethylenediamine Linear Supramolecular Array: UV-visible and ~1HNMR evidence

Coordination behavior of bidentate ligand ethylenediamine with a new chiral zine bisporphyrin O.O-C,-AA-C,-(TPP),Zn, was investigated by Uv-Vis titration and 'H-NMRspectroscopy. which further evidenced that ac-c,-AA-c,-(TPP)Zn, tends to form linear assemblywith ethylenediamine in chloroform.

Synthesis and Characterization of 2,2’-Bipyridyl-5,5’-Dialdehyde Schiff Bases from O,S,N and F-Containing Amines

Design and synthesis of organic chelating agents containing nitrogen and sulfur as donor atoms and their metal complexes is an interesting field of research for their different types of activities. The bi-dentate N,N chelating agent such as 2,2-Bipyridal has been playing a vital role in synthetic and medicinal chemistry. 2,2-Bipyridal has been used to prepare many mixed-ligand complexes. Different ligand complexes prepared from 2,2-Bipyridyl are used in different areas such as molecular catalysis, solar energy conversion, calorimetric analysis, herbicides, molecular recognition, self-assembly, antineoplastic agents, and nucleic acid probes. Another important property of these types of compounds is the triplet state photosensitizing character of bipyridyl nucleus, which is shown in metal complexes. It is also found that compounds containing O,S,N atoms have received considerable attention because of their pharmacological studies like anticancer, antibacterial, and antitumour activities. Therefore, it has been decided to synthesize Schiff bases derived from 2,2’- bipyridyl-5,5’-dicarbaldehyde compounds with O,S,N and F-containing amines and study their antibacterial properties. Several new Schiff bases have been synthesized and fully characterized by spectral data. This paper presents the synthesis and characterization of newly designed Schiff bases.

说文解字话英语 三十七——以牙还牙(tooth)

成语a tooth for a tooth经常跟在an eye for an eye后面连用,汉语成语“以眼还眼,以牙还牙”就是从英语翻译过来的译借词语。表示“牙齿”的tooth是单数名词,它的复数形式是teeth;这种不规则的名词变化形式在英语中还有单数的foot(脚)和复数的feet。至于单数名词food(食物)的一个对立形式feed就是个动词了,表示“喂食”的意思。由tooth构成的复合词很多,例如:toothache(牙痛),tooth-brush(牙刷),toothcomb(细齿梳),toothglass(漱口杯),

牛膝细胞转化苗的田间培植

经过近1年的实验室工作,于1997年5月得到发育良好的牛膝细胞转化苗.1997年6月将室内培植14日的6棵幼苗移栽至田间.种植1O日后去弱保留3棵.1997年1O月收获种子.一部分留样,一部分于1998年5月进行田间播种,扩大种植.

Composition, Stability and Probable Structure of a Colourless Organometallic Complex (Gd(III)-Malic Acid)

The formation of colourless gadolinium complexes (x,y,z), between x gadolinium ions, y ligands and z protons, of some organic acids, has been studied in aqueous solution. In this work we present the results of investigations on the interaction of the gadolinium ion (Gd3+) with malic acid (C4H6O5, a-hydroxyl dicarboxylic acid), in dilute aqueous solution for pH values between 5.5 and 7.5. Colourless gadolinium complexes of malate ions have no absorption band UV-visible, the indirect photometric detection (IPD) technique was used and studies have identified a major tri-nuclear complex of malate ion (﹣OOC-CH2-CHOH-COO﹣). The formation of this new colourless complex is derived from three Gd(III) ions that react with two malate ions and two hydronium ions (H3O+), giving for this colourless complex, a (3,2,2) composition and apparent stability constant depends on the acidity of the medium, with logK'322 = 18.88 ± 0.05 at pH = 6.30. To complement previous results and to propose a probable structure for this new complex detected in solution, studies of IR spectroscopy have been conducted to identify the chelation sites for both ligands. The results were analysed and show that this organometallic gadolinium complex, contains two different sites, respectively, two lateral tetradentate mono-nuclear sites and a single central bidentate mono-nuclear site. From these results, the reaction of formation, the stability constant and the probable structure of this new colourless organometallic gadolinium complex are proposed.

Pd-Catalyzed Ortho-Directed C-H Glycosylation of Arenes Using N-linked Bidentate Auxiliaries

Main observation and conclusion A set of Pd-catalyzed ortho-directed C-H glycosylation reactions with glycosyl chloride donors using various N-linked bidentate auxil-iaries has been developed for synthesis of C-aryglycosides.A broad range of pyranose and furanose moieties can be installed on the ortho position of arylamine,carbazole,indole and benzylamine type substrates in high yield and with high regio-and diastereoselec-tivity.These auxiliaries can be readily installed and removed under relatively mild conditions.

Influence of bidentate structure of an aryl phosphine oxide ligand on photophysical properties of its Eu~Ⅲ complex

The bidentate phosphine oxide ligand 1,8-bis(diphenylphosphino) naphthalene oxide (NAPO) and its EuⅢ complex 1 Eu(TTA)3(NAPO) (TTA=2-thenoyltrifluoroacetonate) were chosen to study the effect of bidentate phosphine oxide ligand on the photophysical properties of the corresponding complex. The intramolecular energy transfer processes of 1 were studied. The investigation showed that with bidentate structure NAPO could suppress solvent-induced quenching by enforcing the ligand-ligand interaction and the rigidi...

SYNTHESIS, CHARACTERIZATION AND STRUC-TURE OF BIS(1,8-NAPHTHYRIDINE-N-OXIDE) STRONTIUM NITRATE CON-TAINING DOUBLE BIDENTATE AND BRIDGING NITRATE GROUP

A new complex formed from strontium nitrate and 1,8-naphthyridine-N-oxide with a 1:2 stoichiometry has been synthesized and characterized by elemental analyses, infrared spectra, Raman spectra, fluorescence spectra, DTA-TG, solubility and molar conductance measurements. A single crystal X-ray structural analysis indicates that a kind of double bidentate and bridging nitrate group which has never been reported in literature is present in the new complex. The coordination number of the strontium ion is 10.

1,3-Dinitro-2-chloro-5-trifluorotoluene and its bridged derivatives Ⅰ.An investigation on the displacement reactions of bidentate nucleophiles towards aromatic rings

The reactions of 1,3-dinitro-2-chloro-5-trifluorotoluene(DNCTT)(1)and its bridged com- pounds with bidentate nucleophiles have been investigated.Primary or secondary diamines and diethylene glycol react with 1 and its bridged derivatives by replacing the substituent grouppara to CF_3, whereas ethanedithiol reacts either by replacing the substituent group para to CF_3 or by displacing both groups and a nitro group.The results have been rationalized in terms of electronic effects and nucleophilicity of the nucleophiles.

Promotional effects of cerium doping and NO_x on the catalytic soot combustion over MnMgAlO hydrotalcite-based mixed oxides

A series of MnMgA10 samples with different amounts of Ce doping were facilely prepared using coprecipitation method and their catalytic soot combustion activity was evaluated by temperature programmed oxidation reaction （TPO）. The methods of X-ray diffraction （XRD）, Brumauer-Emmett-Teller （BET）, H2-TPR, NO-TPO and in situ 1R were used to characterize the physio- chemical properties of these samples. Dopant Ce improved the soot combustion performance of MnMgA10 catalyst due to the en- hanced redox ability. Introduction of NOx led to the further increase of catalytic soot oxidation activity on these samples. Over Ce-containing samples, the catalytic activity was slightly decreased as the amount of dopant Ce increased in 02. Diftbrently, in NO＋O2, a certain amount of dopant Ce was much more favorable and excess amount of Ce resulted in a sharp drop of the catalytic soot combustion activity. Both NO： and nitrates were found to have great contributions to the effects of NOx on the soot combustion activity of Ce-doped catalysts. More NO2 was generated as dopant Ce increased. When appropriate amount of Ce was introduced, the as-formed NO2 was stored as bridging bidentate nitrate on Mn-Ce site, which was confirmed to have higher reactivity with soot than nitrite or monodentate nitrate on Mn and/or Ce sites. Overall, Mno.sMg2.sCeo.lAlo.90 was considered as the most potential catalyst for soot combustion.

An in situ infrared study of dimethyl carbonate synthesis from carbon dioxide and methanol over well-shaped CeO2

The mechanism of dimethyl carbonate（DMC） formation from CO2 and methanol is investigated using three well-shaped CeO2 catalysts, nanorod, nanocube and octahedron, which are packed with different crystal planes. In situ Fourier Transform Infrared Spectroscopy（FTIR） is employed to probe each reaction step in the DMC synthesis. The number of –OH groups and the species of CO2 adsorptions on ceria surface have significant influence on the activity of ceria with different morphologies. Rod-ceria has favorable catalytic activity because of the large amount of –OH groups and the formation of bidentate carbonate species.

Ca^2+ and SO4^2- interactions with dissolved organic matter: Implications of groundwater quality for CKDu incidence in Sri Lanka

It has recently been proposed that recalcitrant dissolved organic carbon(DOC) in groundwater plays a potent etiological role in the peculiar distribution of chronic kidney disease of unknown etiology(CKDu).This study aims to elucidate the interactions of Ca^2+and SO4^2-with a model organic fraction of humic acid(SHA) to determine the possible relationship of CKDu incidence with the DOC in drinking water.XPS and FT-IR methods respectively determined the surface functional groups and chemical composition of protonated dissolved organic carbon(HDOC) in a CKDu high-risk zone(HR) of Sri Lanka and in SHA.Higher surface C composition(87.9%) and lower O(11.4%) were observed for HDOC from the HR region than for SHA(C: 73.8%, O: 24.7%).Aromatic C with less Ocontaining functional groups was observed in HDOC.The IR band at 1170 cm^-1 confirms the formation of organic sulfonate(C–SO3^-) on SHA.A band at 1213 cm^-1 due to organic sulfonate in HDOC from the CKDu HR region was also identified.The IR band at 866 cm^-1 evidenced the formation of CaCO3 on SHA above pH 7.4.XPS data confirmed the presence of sulfur oxidation states corresponding to SO3^2-and SO4^2-at 168.9 eV and 170.1 eV binding energies,respectively.The binding energies at 347 eV and 351 eV for Ca 2p3/2 and Ca 2p1/2 eV,respectively, confirmed the bidentate complexation of Ca^2+with COO-and sulfonate groups on SHA.The organic sulfonate formed is postulated as a uremic toxicant.

Dinitrogen Functionalization Affording Structurally Well-Defined Cobalt Diazenido Complexes

Cobalt-bis(dinitrogen)complexes[LCo(N_(2))_(2)]−(3,4)with simple and commercially available bidentate phosphine ligands(L:Cy_(2)PCH_(2)CH_(2)PCy_(2))were synthesized and structurally characterized.Further N2 functionalization by treating the complex 3b with i Pr_(3)SiCl afforded the first structurally characterized cobalt diazenido complex 5.These complexes 3–5 were found to be effective catalysts for the transformation of N2 into N(SiMe_(3))_(3).The electronic structure of the cobalt diazenido complex 5 is supported by quantum computational calculations based on stateof-the-art energy decomposition analysis(EDA)in conjunction with the natural orbitals for chemical valence(NOCV)method.

SYNTHESIS AND CRYSTAL STRUCTURE OF COMPLEX OF Er(Ⅲ) WITH BENZENE-1, 2, 4, 5-TETRACARBOXYLIC ACID

We have first synthesized [NH4]+[ErC6H2（COO）43H2O]-. 4H2O and determined its structure. The crystal is monoclinic, space group P21/n, with Z=4. Lattice parameters are: α= 10.330（4）, b=10.282（5）, c=16.446（8）（?）, β=98.75（4）°. The heavy

A NOVEL HIGH ACTIVE IRON CATALYST Fe(naph)_2-AI(i-Bu)_3-HALIDES FOR POLYMERIZATION OF BUTADIENE

In recent years some kinds of iron catalysts for the polymerization of diolefins have been reported. In all of the known iron catalysts, a donor, such as P-com- pound, S-compound, N-compound or O-compound, has to be used as the third com- ponent besides iron compound and AlR3. Moreover, high catalytic activity occurs only when the third component is a bidentate nitrogen compound which can coordinate with the center iron ion to form a five- or six-membered chelate ring.