Synergistic Catalytic Action of Cobalt（ Ⅱ ） Hydroxamates and N-Hydroxyphthalimide in the Aerobic Oxidation ofp-Xylene

The catalytic performance of a series of cobalt( Ⅱ ) hydroxamates (COL2) and the synergistic catalytic action of the cobalt complexes combined with N-hydroxyphthalimide (NHPI) in the aerobic oxidation ofp-xylene top-toluic acid (PTA) were investigated. The results showed that the existing synergistic action in the catalytic oxidation can shorten the induction period of theradical reaction and improve the yield of PTA.     

PREPARATION OF NONIONIC WATER-SOLUBLE PHOSPHINES AND THEIR RHODIUM COMPLEXES FOR CATALYTC HYDROFORMYLATION OF OLEFIN

Two kinds of nonionic water-soluble phosphine complexes:tri(o-polyglycol ether phenyl) phosphine(Ⅰ) and tri(p-polyglycol ether phenyl)phosphine(Ⅱ) (n=3～12) were prepared. Their thodium complexes preparedin sitn were used in aqueous/organic solvent two-phase system for catalytichydroformylation of olefin. The results implied that the surfactant phosphineligands for the biphasic hydroformylation of olefin shows good catalytic activityand selectivity,At 100 C and 6.0 MPa total pressure (CO/H_2=1:1) theconversion of (?) dodecene and selectivity to aldehyde were higher than 85%.The effects of different conditions on the hydrofurmylation reaction wereexamined.     

Novel cobalt(Ⅱ) complexes of amino acids-Schiff bases catalyzed aerobic oxidation of various alcohols to ketones and aldehyde

<正>Two cobalt(Ⅱ) complexes 1 and 2 of Schiff bases derived from amino acids were synthesized and used for oxidation of benzyl alcohol with molecular oxygen at different conditions of pH,solvent,temperature and complex/alcohol molar ratio to optimize reaction conditions and to evaluate the catalytic efficiency of new cobalt Schiff base complexes.Under obtained optimum conditions,various alcohols were oxidized to corresponding aldehydes and ketones.     

Studies on PNPP Hydrolysis Catalyzed by Schiff Base Cobalt（Ⅱ） Complexes

Two cobalt（Ⅱ） complexes of the Schiff base with morpholino or aza-crown ether pendants, CoL^1 and CoL^2, as mimic hydrolytic metalloenzyme, were used in catalytic hydrolysis of carboxylic ester （PNPP）. The analysis of specific absorption spectra of the hydrolytic reaction systems indicates that key intermediates, made up of PNPP and Co（Ⅱ） complexes, have been formed in reaction processes of the PNPP catalytic hydrolysis. The mechanism of PNPP catalytic hydrolysis has been proposed based on the analytic result of specific absorption spectrum. A kinetic mathematical model, applied to the calculation of the kinetic parameter of PNPP catalytic hydrolysis, has been established based on the mechanism proposed. The acid effect of buffer solution, structural effect of the complexes, and effect of temperature on the rate of PNPP hydrolysis catalyzed by the complexes have been also discussed.     

Catalytic Oxidation of Dimethyl Ether to Hydrocarbons over SnO2/MgO and SnO2/CaO Catalysts

A novel reverse microemulsion method was used to prepare SnO2/MgO and SnO2/CaO catalysts. It was found that both the catalysts were active for the reaction of catalytic oxidation of dimethyl ether (DME) in the temperature range of 275 to 300℃. SnO2/CaO catalyst exhibits much higher activity than SnO2/MgO. On SnO2/CaO catalyst, DME conversion of 21.8% was obtained at 300℃, while selectivities to methyl formate (MF) and dimethoxyethane (DMET) of 19.1% and 59.0% respectively were obtained at 275℃.     

PREPARATION AND MAGNETIC PROPERTIES OF POLY(SCHIFF BASE) COMPLEXES CONTAINING PHENANTHROLINE UNITS

Two poly(Schiff base)s (PDBT and PDPE) were synthesized by polycondensation of 1,10-phenanthroline-5,6- dione (PD) with 2,2′-diamino-4,4′-bithiazole (DABT) and 4,4′-diaminodiphenyl ether (DAPE),respectively.The structures of the polymers were determined by FTIR and element analysis.The metal (Fe~(2+),Ni~(2+)) complexes were prepared from the polymers with FeSO_4 or NiSO_4,and the metal contents of the complexes were measured by complexometric titration.The magnetic behaviors of the complexes were examine...     

Dioxygen Affinities and Biomimetic Catalytic Oxidation Performance of Transition-metal Complexes with Unsymmetrical Bis-Schiff Bases

Bis-Schiff base complexes as mimetic monooxgenase have been extensively reported1, 2. The bis-Schiff bases transition-metal complexes modified by crown ethers ring or pseudo-macrocylic polyethers have significantly improved dioxygen affinities and biomimetic catalytic performance in comparison with uncrowned analogues3, 4. However, most of them were symmetric and oxacrown ether substituted, the bis-Schiff bases bearing an azacrown ether, with special configuration and possibility to approach…     

Study on catalytic oxidation of planar binuclear copper phthalocyanine on 2-mercaptoethanol

Mononuclear copper phthalocyanine (CuPc) and binuclear copper phthalocyanine (Cu2Pc2) were synthesized by the phenylanhydride-urea route, and their catalytic oxidation activity on 2-mercaptoethanol was studied. Based on the experimental results, a catalytic mechanism of Cu2Pc2 on 2-mercaptoethanol has been proposed. Furthermore, the effects of pH, Cu2Pc2 concentration, and temperature on the catalytic oxidation activity were evaluated. The results showed that CuPc has no catalytic activity, while Cu2Pc2 has high catalytic oxidation activity towards 2-mercaptoethanol with the optimal activity at pH 11. The reaction can further be enhanced by increasing Cu2Pc2 concentration and temperature, due to its endothermic characteristics.     

Dioxygen affinities and catalytic oxidation performance of cobalt（Ⅱ） hydroxamates with benzo-15-crown-5 pendants

The oxygenation constants(Ko_2)of cobalt(Ⅱ)hydroxamates(CoL_2~1-CoL_2~3)with benzo-15-crown-5(B15C5)pendants were measured over the range of-5 to 20℃,and the values of thermodynamic parameters(ΔH~0 andΔS~0)were calculated based on these(No_2)values.Meanwhile,these crowned complexes were employed to the oxidation for p-xylene to p-toluic acid with air at 110Δunder normal atmospheric pressure.The effects of B15C5 pendant and the length of chain bonded to B15C5 in these complexes on the O_2-binding capabilities and oxidation for p-xylene were investigated with the comparison of crown-free analogues CoL_2~4.     

Rare-earth metal amido complexes supported by bridged bis(β-diketiminato) ligand as efficient catalysts for hydrophosphonylation of aldehydes and ketones

A series of rare-earth metal amides supported by a cyclohexyl-linked bis(β-diketiminato) ligand were synthesized,and their catalytic activities for hydrophosphonylation of aldehydes and ketones were developed.Reaction of [(Me3Si)2N]3 RE(Cl)Li(THF)3 with the cyclohexyl-linked bis(-diketimine) H2L(1)(L=Cy[NC(Me)CHC(Me)NAr]2,Cy = cyclohexyl,Ar=2,6-i-Pr2C6H3) gave the rare-earth metal amides LREN(SiMe3)2(RE = Nd(2),Sm(3),Dy(4),Er(5),Y(6)).All complexes were fully characterized by elemental,spectroscopic and single-crystal X-ray analyses.Investigation of the catalytic properties of the complexes reveals that these complexes exhibited a high catalytic activity towards the hydrophosphonylation of aldehydes and ketones in the presence of a very low loading of rare-earth metal amides(0.1-1 mol%) at room temperature in a short time.     

Synthesis,characterization, and catalytic ethylene oligomerization of pyridine-imine palladium complexes

Two neutral five-membered pyridine-imine palladium complexes with the bulky dibenzhydryl (CH(Ph)2) substituted aniline were synthesized and fully characterized by nuclear magnetic resonance (NMR) and X-ray crystal diffraction.Well-defined cationic palladium complexes were further obtained by treatment of chloromethylpalladium complexes with sodium tetrakis(3,5-bis(trifluoromethyl)phenyl)borate (NaBArF) in CH3CN.Cationic palladium complexes were capable of catalyzing ethylene oligomerization without any cocatalysts.The influences of catalyst structure,reaction temperature,and ethylene pressure on ethylene oligomerization were studied in detail.The introduction of bulky benzhydryl (CH(Ph)2) on the ortho position of the aniline moiety enhanced catalytic activity,thermal stability of the catalyst,and molecular weight of the obtained products.Highly branched oligomers with molecular weights of 600-800 g/mol and narrow polydispersities (1.03-1.12) were produced.     

Dioxygen Affinity and Catalytic Performance of Bis-(furaldehyde) Schiff Bases Co(II) Complexes in Cyclohexene Oxidation

As mimetic oxygen carrier or oxidation catalyst, Schiff base cobalt complexes such as Co (II) salen have been widely studied1-4. However their high-price greatly limited their application. The synthesis of cheap furaldehyde Schiff bases and their complexes with Co (II), as well as the dioxygen affinity and biomimetic catalytic oxidation performance of these complexes are worth trying to study. In this paper, the saturated dioxygen uptake of cobalt complexes with different bis-(furaldehyd…     

SYNTHETIC AND CATALYTIC PROPERTY STUDIES ON SILICA SUPPORTED BIS-(ACETYLACETONATO) COBALT(Ⅱ) COMPLEXES**

This paper reports mainly the preparation of silica supported acetylacetone ligands and their cobalt complexes, the characterization of their chemical structure, and the evaluation of their catalytic activity in the reaction for the preparation of ethers directly from alkanols and benzyl chloride. The results indicate that those silica supported β-diketone cobalt complexes (SACO) not only can simplify the reaction procedure of the ether preparation but also show a much higher catalytic activity in comparison with other homogeneous catalysts. In addition, SACO can be recovered and reused although their catalytic activity descend gradually as a result of the decrease in their cobalt content.     

DECARBOXYLATION OF ALLYL β-KETO ESTERS TO UNSATURATED KETONES ON POLYMER BOUND PHOSPHINE- PALLADIUM (0)COMPLEXES*

Polystyrylphosphine-Pd(0) and silica supported polysiloxane-phosphine-Pd(0) complexeswere synthesized and characterized. Their catalytic properties for the decarboxylation of allyl β-keto esters were investigated. It was found that these complexes have good catalytic activities undermild condition for this decarboxylation in which many novel unsaturated ketones were obtained.The selectivity of this catalytic decarboxylation depends on the polymer ligand and the P/Pd ratioof catalyst. The stabilities of polymer phosphine-Pd(O) complexes catalysts are better than theirhomogeneous analogue.     

SYNTHESIS OF DI（ETHYLMERCAPTOETHYL） AMINO GROUP—CONTAINING POLYSESQUISILOXANE PLATINUM COMPLEX AND ITS CATALYSIS IN HYDROSIL YLATION OF OLEFINS WITH TRIETHOXYSILANE

Three new polysesquisiloxane-bound platinum complexes were synthesized via hydrolysis of N,N-di(β-ethylmercaptoethyl)γ-(triethoxysilyl)propylamine or cohydrolysis of the monomer with dodecyltriethoxysilane or with phenylpropylthiethoxysilane and immobilixation on fumed silica,followed by reacting with potassium platinite in acetone under argon atmosphere.The platinum complexes exhibited high catalytic activity for the hydrosilylation of olefins by triethoxysilane. The effects of temperature and the amount of complex on the catalytic activity,as well as the recovery and reusability of the catalysts were investigated.     

Catalytic Kinetics of the Schiff Base Metal Complexes Bearing Side Chain of Cyclic morpholine in Carboxylic Ester Hydrolysis

It has been reported that two Schiff base transition metal complexes bearing the side chain of the morpholine ring were synthesized and characterized, and two complexes with the same base agent but different metal ions were used as a simulant hydrolase in the catalytic hydrolysis of p-nitrophenyl picolinate in this paper. The mechanism of PNPP catalytic hydrolysis is proposed and supported by the results of the spectral analysis and the kinetic calculation. A kinetic mathematical model, applied to the calculation of the kinetic and thermodynamics parameters of PNPP catalytic hydrolysis, has been established on the foundation of the mechanism proposed. The result of the study shows that the two complexes have a good catalytic activity in PNPP catalytic hydrolysis, and the rate of the PNPP catalytic hydrolysis was increased with the increase of the pH values in the buffer solution and affected by the polarization effect of metal ion of the complexes.     

STUDIES ON ORGANO-MOLYBDENUM AND TUNGSTEN COMPOUNDS(Ⅲ)——CATALYTIC POLYMERIZATION OF ACETYLENE BY M-O-C BOND-CONTAINING COMPLEXES OF Mo AND W

Catalytic polymerization of acetylene in the presence of n5-C5H5-M-(CO)3 R (M=Mo,W;R=CH3-,C2H5-) has been studied.The results show that these complexes possess catalytic activities for the polymerization and copolymerization of monosubstituted acetylene.The catalytic mechanism has been preliminarily discussed.It is suggested that the active species be metal-car-bene.In our previous publications we reported the synthesis of some new Fischer's molybdenum and tungsten-carbene complexes and catalytic activity for alkyne polymerization.The results show that the activity of Fischer's molybdenum-carbene is higher than that of tungsten.The catalytic polymerization of alkyne by M-σ-c bond-containing complexes of molybdenum and tungsten has not been reported yet in literature.Therefore,four M-σ-C bondontaining complexes of molybdenum and tungsten were synthesized by using the method reported in the literature,and catalyst polymerization of alkyne by these complexes was examined.     

水杨醛缩2-氨基-4-苯基噻唑及其配合物的合成与仿酶催化活性研究

The new containing Surfur Schiff base Salicylaldelye-2-amino-4-Phenylthiazole(SAPTZ) and its Cu(Ⅱ)、Zn(Ⅱ)、Ni(Ⅱ) and Co(Ⅱ) compelexes were synthesized. The structures of the complexes were characterized by elemental analysis, IR and UV-vis. The peroxidase-like activity of the complexes for the oxidation of Vc with H₂O₂ was determined.     

Catalytic Oxidative Conversion from Naphthol to 2-Hydroxy-1, 4-naphthoquinone over Iron Porphyrin Catalysts by Molecular Oxygen in an Alkaline 2-Propanol Solution

In an alkaline 2-propanol solution with 5, 10,15,20-tetra (4-methoxyl phenyl) porphyrin iron chloride (TOMPPFeCl) as a catalyst and oxygen as a cheap green oxidant, 2-naphthol was conversed to 2-hydroxy-1 ,4-naphthoquinone(HNQ) with a yield of 62. 17% and a selectivity of 100%, and the conversion number of TMOPPFeCl catalyst was 8.32/min. The catalytic oxidation products were characterized by means of UVVis, IR, GC-MS, ^1H NMR and melting point determination. In this catalytic oxidation, the catalytic activity of TMOPPFeCl was researched in detail and the reacting conditions were optimized. A possible reaction mechanism is summarized based on in situ EPR determination.     

Crystal structures and thermal decomposition kinetics of lanthanide complexes with 3,4,5-trimethoxybenzoic acid and 1,10-phenanthroline

A series of lanthanide complexes with the 3,4,5-trimethoxybenzoic acid(3,4,5-tmoba) and 1,10-phenanthroline(phen),[Ln(3,4,5-tmoba) 3 phen] 2(Ln = Pr(1),Nd(2) and Ho(3)),have been synthesized and characterized by a series of techniques including elemental analysis,IR spectra,X-ray crystallography and TG/DSC-FTIR technology.The three complexes have two kinds of coordination modes,in which the Pr 3+ and Nd 3+ cations are nine-coordinated and the Ho 3+ cation is eight-coordinated.The three-dimensional IR accumulation spectra of gaseous products for complexes 1-3 were analyzed and the gaseous products were identified by the typical IR spectra obtained from the 3D surface graphs.Meanwhile,we obtained the activation energy E of the first steps of complexes 1-3 by the integral isoconversional non-linear(NL-INT) method and discussed the non-isothermal kinetics of complexes 1-3 using the Malek method.Finally,SB(m,n) was defined as the kinetic method of the first-step thermal decomposition.The thermodynamic parameters △G≠,△H≠ and △S≠ of activation at the peak temperature were also calculated.