STUDY ON THE KINETICS OF POLYMERIZATION OF MMA BY COPPER（Ⅱ） CHELATING RESINS

The polymerization of MMA initiated by copper(Ⅱ） chelating resins/CCl4 system was studied.From the kinetic data,the kinetic equation of polymerization can be expressed as Rp=Ke^-56400/RT[MMA]^1.57[CCl4]^m[RESIN-Cu]^0.18 where m:3-4.5,when[CCl4] 0.1-6.93M.The free radical polymerization mechanism is proposed.The primary radicals are formed by the process of complexation-chlorine transformation among the copper(Ⅱ) chelating resin,CCl4 and methacrylate.     

STUDY ON DETERMINATION OF TRACE Cu（Ⅱ） BY DDCT CHELATING RESIN PRECONCENTRATION AND THIN LAYER RESIN PHASE SPECTROPHOTOMETRY

A new method for determination of Cu(Ⅱ) by DDCT chelating resin preconcentration and thin layer resin phase spectrophotometry was developed. The method has a high sensitivity (ε435 =3.6×105 L/mol· cm), which is 33 times higher than that of liquid phase spectrophotometry. It has a good selectivity (most coexisting ions could not influence determination) and an ideal precision [30μg Cu(Ⅱ), n=6, RSD= 1.67%]. The content of Cu(Ⅱ) in water, high purity rare earth and its oxide was determined. The detection limit of Cu(Ⅱ) is 5.3μg/L, and the linear range is 0～7.2 μg/ml. The result is satisfactory.     

ADSORPTION BEHAVIOR OF Pb(Ⅱ) ON POTASSIUM HEXATITANATE WHISKER BY FAAS

Based on the advantage of high surface area and strong adsorption ability of potassium hexatitanate whisker, a method to determine trace Pb(Ⅱ) content by combining solid phase extraction with Flame atomic absorption spectrometry (FAAS) was established.The adsorptive behavior of potassium hexatitanate whisker to Pb(Ⅱ), primary influencing factors of adsorption and elation and effect of coexistence ions were investigated systemically.The optimal analytical conditions were discussed and examined.It was found that the adsorption rate of potassium hexatitanate whisker to Pb(Ⅱ) was 100% at pH 4.0.Pb(Ⅱ) could be elated from potassium tetratitanate whisker with HCI (2mol/L) under boiling water for 30min.The detection limit was 5.75ng/mL, and relative standard deviation was 1.66% (n=9, CPb=2.0μg/mL).     

A KIND OF FLUORESCENCE PROBE TO STUDY THE KINETICS OF POLYMERIZATION PROCESS

Fluorescence properties of 1-pheny1-3-(4'-nitrophenyl) pyrazoline (PNP) were studied inbulk polymerization process of methylmethacrylate (MMA). The fluorescence intensity of PNPwas enhanced and the emission maximum was blue shifted with the polymerization progress. Inthe period of auto-acceleration of the polymerization the enhancement of fluorescence intensityand blue shift of peak wavelength in spectra could be observed evidently. This means that thesolvatochromic properties of PNP are influenced not only by the solvent polarity but also by theviscosity of the medium (especially by the phase transitiott). In solid state PNP emits from thecharge transfer excited state without solvent relaxation. The transient emission spectra and theresults from Bakhshiev model of solvent relaxation coincide with that from the polymerizationexperiment.     

RADICAL POLYMERIZATION OF N, N-DI(2-2''''-METHYL-ACRYLOYLOXY-PROPYL)-PARA-TOLUIDINE FUNCTIONAL MONOMER

Functional monomer (MP)_2PT having tertiary aromatic amino group was systhesized from the reaction of N, N-di (2-hydroxypropyl)-p-toluidine with 2-methyl acryloyl chloride. In the presence of organic peroxide, the radical polymerization of (MP)_2PT in toluene took place. The kinetics of (MP)_2PT polymerization and the ESR spectra of LPO-(MP)2PT-MNP systems were determined respectively.     

POLYMERIZATION OF ETHYLENE WITH UNSYMMETRIC 2,6-BIS(IMINO)PYRIDINE IRON(Ⅱ)COMPLEX

An unsymmetric 2,6-bis(imino)pyridine iron(II) complex 1' was synthesized. The relationship between catalyststructure and its activity in ethylene polymerization is discussed. The kinetic behavior of ethylene polymerization and theeffects of polymerization conditions such as temperature, aluminum/iron molar ratio on the activity of catalyst and thecharacteristics of polyethylene were reported. The unsymmetric catalyst 1' has a good catalytic performance of 3.47×10~6 gPE·mol~(-1)·Fe·h~(-1) at 40℃ with aluminum/iron molar ratio = 2500. A dependence of catalyst activity on themethylaluminoxane (MAO) concentration and reaction temperature was found. The molecular weight (MW) of polyethylenewith broad dispersity is about 10~4-10~5 g/mol. The melting temperature and branching of polyethylenes vary with changingreaction temperature and aluminum/iron molar ratio.     

SYNTHESIS AND MAGNETISM OF BINUCLEAR COPPER(Ⅱ) COMPLEXES CONTAINING SALUCYLAMIDATOCUPRATE(Ⅱ)

New binuclear copper(Ⅱ) complexes, [Cu(samen)Cu(NO_2-phen)]·H_2O and [Cu(sampn)-Cu(NO_2-phen)]·2H_2O have been synthesized, where samen~(4-), sampn~(4-) and NO_2-phen denote N, N′-ethylenedisalicylamidate anion, N, N′-1, 2-propanedisalicylamidate anion and 5-nitro-1, 10-phenanthroline respectively. 3ased on IR, elemental analyses and electronic spectra, the complexes are proposed to have a phenoxy-bridged structure and to consist of the Cu(Ⅱ)ion in distorted planar environment. The complexes have been characterized with varlable-temperature magnetic susceptibility (4—300 K) and the observed data were fit to those from a modified Bleaney-Bowers equation by least-squares method, giving the exchange integral J=-63.0 cm~(-1) (samen) and J=-46.5cm~(-1) (sampn). This indicates the existence of antiferromagnetic spin exchange interaction among the metal ions.     

Synthesis and Properties of u-Oxamido Heterobinuclear Cu(Ⅱ)-Co(Ⅱ) Complexes

Three heterobinuclear complexes were synthesized, namely [Cu (oxpn) Co (L)2] (ClO4)2·xH2O(L= 2,2'-bipyridyl(bpy), 1,10-phenanthroline(phen) , and 5-nitro-1, 10-phenanthroline (NO2-phen)), where oxpn represents N, N'-bis(3-aminopropyl) oxam-ido. Based on 1R, elemental analysis, conductivity measurement and electronic spectra, these complexes were characterized by an extended oxamido-bridged structure with Cu(Ⅱ) in a planar environment and Co(Ⅱ) in a octahedral environment. The symmetry of the cation is very close to C2v.The complexes were also characterized with variable temperature (4~300K) magnetic susceptibility, and the data were fit for the susceptibility equation derived from spin Hamilton, H= -2JS1.S2-DSx12 by least square strategy. The exchange integral, J, was found to be -22.36 cm-1 (for bpy);-15.45 cm-1 (for phen); -19. 10cm-1(for NO2-phen), indicating that there is a weak antiferromagnetic spin-exchange interaction between the metal ions.     

2-AMINOMETHYLPYRIDINE NICKEL(Ⅱ) COMPLEXES—SYNTHESIS,MOLECULAR STRUCTURE AND CATALYSIS OF ETHYLENE POLYMERIZATION

A series of new nickel(Ⅱ)complexes with 2-aminomethylpyridine ligands,(2-PyCH_2NHAr)_2NiBr_2(Ar=2,6- dimethylphenyl 2a;2,6-diisopropylphenyl 2b,2,6-difluorophenyl 2c),have been synthesized and used as catalyst precursors for ethylene polymerization in the presence of methylaluminoxane(MAO).The catalysts containing ortho-alkyl-substituents afford high molecular weight branched polyethylenes as well as a certain amount of oligomers.Enhancing the steric bulk of the alkyl substituent of the catalyst resulted...     

Synthesis and Magnetism of 2-Hydroxy-1,3-propylene-bis(oxamato)-bridged Co~ⅡCu~ⅡCo~Ⅱ Complexes

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EFFECTS OF CONFORMATION OF POLYMER LIGANDS IN COPPER(Ⅱ) COMPLEXES ON CATALYLIC ACTIVITIES AND MECHANISM OF OXIDATIVE COUPLING OF β-NAPHTHOL

Copper(Ⅱ) complexes of sericin, chitosan, 6-and 2-aminodeoxystarch were used as catalysts in oxidative coupling of β-naphthol, the effects of conformation of the polymer ligands in these complexes on activities of the catalysts and mechanisms of the reaction were studied. It was found that if the catalysts react with the substrate by mechanism similar to the enzymic catalysis they must be composed of polymer ligands with highly coiled, especially with densely helicoidal, conformations. While catalysts composed of loosely coiled or helicoidal hgands react with the substrate through molecular collision and have relatively lower activities only. Under nitrogen, catalysts from sericin and chitosam reacting with β-naphthol give optically active β-binaphthol, rotating polarized light to right, but the stereoselectivities are rather low.     

SYNTHESIS, STRUCTURE AND MAGNETISM OF μ-OXAMIDO BINUCLEAR COPPER(Ⅱ) COMPLEXES

Two new binuclear copper(Ⅱ) complexes, [Cu(oxpn)CuL](ClO_4)_2, have been synthesizedand characterized, where oxpn is N,N' bis(3-aminopropyl)oxamido and L is 1,10-phenan-throline (phen) or 5-nitro-1,10-phenanthroline (NO_2-phen). The crystal structure and vari-able-temperature magnetic susceptibility (4- 300 K) of the Complex (L=phen) have beendetermined. Crystal data: orthorhombic system, space group Pnma, with a = 10.433(1), b11.458(2), c = 21.999(2)A, z = 4. Every copper(Ⅱ) ion is in a square pyramidal environment.The two copper(Ⅱ) ions are linked by μ-oxamido bridge and the separation of them is 5.208A. The singlet-triplet energy gap J was found equal to -452.92cm~(-1), indicating that astrongantiferromagnetic spin-exchange interaction operates between the copper(Ⅱ) ions.     

DNA Cleavage by Copper (Ⅱ) Complexes Without added Coreactants

Thedevelopmentofreagentswhichhydrolyticallycleave11ucleicacids"lidermildconditionsiscurrentlyattractinggreatinterestillthetieldofartiticialnucleases'-'.Whilemall}lreagentshavebeedsuccessfullyapplied.toDNAhydrolysis;.illershavebeenit-c'l'ersuccesseswithDNA'duetoitsrelativel}'highh}idrolyticstabilit}"(thepseudo-firsl-orderrateconstantt'Orthenollenzymatichydrolysisofphospllodiestersisextropolatedtobe2x10-"'h-=at24tandPH7.4').Theexceptionalstabilit}fofphosphodiestershasbeensuggestedasonereason…     

Synthesis,characterization and magnetism of copper(Ⅱ)-lan-thanide(Ⅲ) heterobimetalic complexes with N,N'-oxamidobis-(benzoato) cuprate (Ⅱ)

Seven new μ-oxamido copper(Ⅱ)-lanthanide(Ⅲ)hetero-bitnetalic complexes described by the fonnula Cu(obbz)Ln-(Ph-phen)2NO3(Ln=La,Nd,Eu,Gd,Tb,Ho,Er),where obbz denotes the oxamidobis(benzoato)and Ph-phen represents 5-phenyl-1,10-phenanthroline,have been synthesized and characterized by the elemental analyses,spectro-scopic(IR,UV,ESR)studies,magnetic moments(at room temperature)and molar conductivity measurement.The temperature dependence of the magnetic susceptibility of Cu(obbz)Gd(Ph-phen)2NO3 complex has been measured over the range 4.2-300 K.The least-squares fit of the experimental susceptibilities based on the spin Hamiltonian operator,H=-2JS1 S2,yielded J= 1.28 cm-1,a weak ferromagnetic coupling.A plausible mechanism for a ferromagnetic coupling between Gd(Ⅲ)-Cu(Ⅱ)is discussed in terms of spin-polarization.     

Synthesis and properties of the copper(Ⅱ) complexes with stable radical

Four novel copper(Ⅱ) complexes have been synthesized,namely Cu(hfac)2NITPhNO2 (1),Cu(hfac)2NITPhCH3 (2),Cu(pfpr)2NITPhNO2,(3) and Cu(Pfpr)2NITPhCH3 (4),where hfac= hexafluoro-acetylacetonate,pfpr=pentafluoropropionate,NITR.=2-R-4,4,5,5-tetraniethyl-4,5-dihydro-1H-imidazolyl-1-oxyl-3-oxide.(R=4-nitrophenyl,4-methylphenyl).These complexes were rharicter-ized by elemental analyses,IR,electronic spectra and molar conductance.The temperature-dependent magnetic susceptibility of complexes 1 and 3 have been studied in the 4 300 K range,giving I he exchange integral J=10.56 cm-1 for complex 1 and J =-30.9 cm-1 for complex 3.     

THE DISMUTATION OF SUPEROXIDE ANION BY COPPER(Ⅱ)COMPLEX OF 1,4,7,10-TETRAAZACYCLOTRIDECANE-11,13-DIONE—A KINETIC STUDY BY MEANS OF PULSE RADIOLYSIS

The dismutation kinetics of superoxide anion by copper complex of 1,4,7,10-tetranza-cyctotridecane-11,13-dione was studied by pulse radiolysis.The dismutation rate constants atvarious pH and concentration of complex were obtained.     

Studies of copper (Ⅱ) complexes as catalysts for the hydrolysis of DNA

Hydrolysis of DNA is an important enzymatic reaction , but it is exceedingly difficult to mimic in the laboratory because of the stability of hydrolysis of DNA. In this paper, the cleavage activity of complexes formed between Cu(Ⅱ) and four different amino acid or amino acid methyl ester on DNA is studied by gel elec-trophoresis. It is found that DNA could be cleaved by Cu(Ⅱ)-L-His and Cu(Ⅱ)-L-His methyl ester complexes and the efficiency of cleavage is largely dependent on the metal ion-to-ligand ratio. Further experiments show that the cleavage of DNA mediated by Cu(Ⅱ)-L-His complexes occurs via a hydrolytic mechanism and the active chemical species that affects DNA cleavage is proposed to be MI2H and ML2H22 .     

STUDY ON DETERMINATION OF TRACE Cu(Ⅱ) BY DDCT CHELATING RESIN PRECONCENTRATION AND THIN LAYER RESIN PHASE SPECTROPHOTOMETRY

1. INTRODUCTION Resin phase spectrophotometry belongs to solid spectrophotometry. It is a new kind of luminosity analysis technology, which comes from the combination of solid extraction technology and luminosity analysis technology. This method is especially suitable for analyzing low component environment water sample, high purity substance and complicated sample component because it incorporates sensitivity (associated by ion exchange), concentration, separation and determination. So m…     

Synthesis and Conductivity of a One-dimensional Polymer of a Copper(Ⅱ)-porphyrazine with Sulfur Bridges

Phthalocyanines(Pcs)andtheirpolyinershavebeenasubjectofgreatinterestduetotheirhighthermalstabilityanduniquephotoelectricpropertiesl4.Ithasbeenfoundthatsomeelectronicfunctionsofthemetalthioporphyrazinesandtheirconjugatedpolymers,suchasgas-sensitivityphotosensitivity,photoconductivityandelectrocatalyticactivity,aremorepeculiarthancorrespondingPcs5'6.Oneofourinterestsistodesignanovelpolymerofmetalporphyrazines(PMPzs)withswitchingpointsunderthecontrolofachangingexternalfieIdorenvironment.Inthepr…     

A STUDY ON CONFIGURATION-ACTIVITY RELATIONSHIP OF DIAMMINEDICHLOROPLATINUM (Ⅱ) BY THE PSEUDOPOTENTIAL VALENCE ELECTRON-ONLY ab initio CALCULATION METHOD

We investigated the cis- and trans-isomers of Pt(NH_3)_2Cl_2 and [Pt(NH_3)_2]~(2+) using a quantum chemical non-empirical calculation method, the pseudopotcntial valence electron only ah initio method. The electronic structure and electrostatic potential counter maps were in turn determined through the wave functions so obtained. There was a sharp difference between the dipole moments of the cis- and trans-isomers. The electrostatic counter maps of the isomers also had remarkably different features. Based on the interaction between the platinum (Ⅱ) coordination compound and the base pairs of nucleic acid, the difference in antitumour activity of the isomeric compounds was discussed, It is pointed out that the key factor for antitumour activity is that the platinum (Ⅱ) coordination compound must be mutually complementary with the target acceptor in both configuration and bonding activity. This mutualcomplementary requirement includes a bonding ability of the platinum complex with two negative centers i