THE INFLUENCE OF AXIALLIGANDS ON THE ELECTRONIC ABSORPTION SPECTRA OF PHTHALOCYANINATOIRON(Ⅱ)

Axial ligation in solution by phthalocyaninatolron(Ⅱ)with a varicty of donor ligandshas been widely investigated by measuring the visible spectral changes.It has been foundthat the axial ligation does not influence the Q_ο-οband so much as the Ⅱ-band,the appearance and the red shift of the latter under the action of σ-donation of ligands could be attri-buted to the Charge transfer from the metal d-orbital toward e_σ(π)orbital of PC-ring:e_g(dπ)M→Cg(π)Pc.A linear relation was found to exist between the energy of Q_ο-οand that of Ⅱ-band of ligands containing the same donor atoms(O,N,S,).This may be corre-lated with the electronegativity of donoratoms.     

SYNTHESIS OF FUNCTIONAL POLYETHYLENE via COPOLYMERIZATION OF ETHYLENE AND SUBSTITUTED ALLENE USING BIS(β-ENAMINOKETONATO)TITANIUM CATALYSTS

Novel copolymerization of ethylene with substituted allenes(CH_2=C = CH—R,1:R = n-butyl,2:R =n-octyl) using bis(β-enaminoketonato)titanium catalysts[PhN = C(R_2)CHC(R_1)O]_2TiCl_2(1a:R_1 = CF_3,R_2 = CH_3;1b:R_1 = Ph,R_2 = CF_3) has been investigated.In the presence of modified methylaluminoxane,these catalysts can copolymerize ethylene with substituted allenes,affording copolymers with unimodal molecular weight distributions and homogeneous compositions.By varying the reaction conditions,the comonomer i...     

STUDIES ON THE CHAIN STRUCTURAL EFFECT OF PVDF AND VDF (52)/TrFE(48) COPOLYMER BY MEANS OF THE METHOD OF DIELECTRIC RELAXATION

Through improvements on a fully commercial and automatic system measuring frequency andtemperature spectra of the complex elastic, dielectric, and piezoelectric constants of polymerfilms, the precision for measuring complex dielectric constants achieved 2‰ from original 1%.The complex dielectric constants of PVDF, VDF (95 )/VF (5), VDF (52)/TrFE (48) and VDF(47. 5)/TrFE(47. 5)/HeFP (5) over a range of-120-140℃, 10-2-10~4Hz were measured bythe described system. The diminution of chain regularity due to 5mol% vinyl fluoride in the chainof PVDF led to disappearing of α-relaxation and increase in T_g (3℃) of VDF (95)/VF (5).Because of the spatial impediment of 5mol% HeFP in copolymer chain, the Curie point of VDF(52)/TrFE(48) decreased by 30℃ and T_g by 3℃. The behavior of dielectric relaxation indicatedthat 5mol% vinyl fluoride and HeFP made the relaxation strength of noncrystalline regionreduced, the activation energy of local relaxation increased and the relaxation time prolonged respectively.     

CONFORMATIONAL ANALYSIS ON ANTICHOLINERGIC DRUG (Ⅰ) MOLECULAR MECHANICS MMPM CALCULATION OF ATROPINE AND OTHER ALKALOIDS IN THE BELLADONNA PLANT

Alkaloids of balladonna plant were studied by molecular mechanics MMPM calculation. The results showed that the ideal conformation was quite different from the structure found in the crystals of the alkaloids in belladonna plant. The intramolecular hydrogen bond was present between the hydroxy group and carbonyl oxygen atom in the ideal conformation for these alkaloids. The origin of asymmetrical molecules in nature obeys the lowest energy principle. This may be a reason why only S-(-) not R-(+)-isomer, only hyoscyamine not pseudotropine were found to be present in natural belladonna plant, The model of four recognition sites between anticholinergic drug-receptor interaction in mydriasis was suggested, in which the hydroxy group with 8～9 A distanced from nitrogen atom is possibly necessary for maximum mydriasis activity.     

SIMULATION MODELING ON THE COORDINATION MECHANISM OF ETHYLENE MONOMER ON VARIOUS PREREDUCED Cr(Ⅱ)O_x/SiO_2 PHILLIPS POLYETHYLENE MODEL CATALYSTS

As one of the most important catalysts in polyethylene industry,Phillips catalyst(CrO_x/SiO_2)was quite unique for its activation by ethylene monomer without using any activator like alkyl-aluminium or MAO.In this work,the density functional theory(DFT)calculation combined with paired interacting orbitals(PIO)method was applied for the theoretical studies on coordination reaction mechanism between ethylene monomer and two model catalysts namely Cr(Ⅱ)(OH)_2(M1) and silsesquioxane-supported Cr(Ⅱ)(M2)as sur...     

PREPARATION, PROPERTIES, AND MOLECULAR STRUCTURE OF trans-DICYANO BIS[BIS(DIPHENYLPHOSPHINO) METHANE]PALLADIUM (Ⅱ)

<正> The crystal structure of the title compound has been determined. PdC52H44N2P4, Mr = 927. 2, monoclinic, space group P21 /n, a =12. 102(2), b = 9.997(2), c=20. 254(5)(?),β=93. 80(2)°, V = 2445. 0(?)3, Z = 2, R =0. 075 and Rw = 0. 095 for 3535 observed reflections (I>3σ(I)), The palladium atom is located on the symmetric center and adopts a square planar coordination surroundings with two biphosphine ligands and two cyanide groups. The molecular structure in crystals is different from that in solution in which the molecule is very fluxional, probably due to the rapid alteration in coordination sites between the coordinated and uncoordinated phosphorus atoms of the biphosphine ligands. Their properties are also reported.     

STUDIES ON ORGANOMETALLIC COMPOUNDS OF TITANIUM,ZIRCONIUM AND HAFNIUM——THE CRYSTAL AND MOLECULAR STRUCTURES OF OXO-BRIDGED TETRAKIS(CYCLOPENTADIENYL)BIS (o.TOLYL)AND TETRAKIS(METYLCYCLOPEN-TADIENYL) BIS(p-TOLYL)BINUCLEATED ZIRCONIUM COMPOUNDS

This paper reports the crystal and molecular structures of tetrakis (cyclopentadienyl) bis(o-tolyl)-μ-oxo-dizirconium [dimer (Ⅰ)] and tetrakis (methylcyclopentadienyl) bis (p-tolyl)-μ-oxo-dizirconium [dimer (II)]. Both of them belong to monoclinic system and possess the same spacegroup C_2~5h- 2_1/a. The cell dimer (Ⅰ) containing four molecules is defined by a=19.122A,b=16.319A, c = 9.296A, β= 92°1′; the cell dimer (Ⅱ) containing two molecules is defined bya = 20.076A, b = 8.205A, c = 10.016A, β= 104°41′. The important difference of molecular configurations between the two dimers lies in thatthe dimer (Ⅰ) has no symmetry center and its Zn-O-Zr oxo-bridge presents a slightly bentconfiguration while the dimer (Ⅱ) takes the oxgen atom as a symmetry center and its oxo-bridge present linear linkage. In accordance with the above-mentioned molecular configuration, steric effect and elec-tronic structure have been further discussed.     

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...     

STUDY ON THE MOBILITY AND REACTIVITY OF OXYGEN OF CERIA-BASED OCM CATALYSTS BY TEMPERATUREPROGRAMMED PULSE REACTION(TPPR)

IntroductionThisprojectwassupportedbytheNationalNaturalScienceFoundationofChina.Becausemostofthecatalystsforoxidativecouplingofmethane(OCM)arecompositechides,thereactivitiesofdifferentkindsofoxygenspeciesareeXtensivelystudied.Generally,agoodOCMcatalystsho…     

A NOVEL SYNTHETIC METHOD AND STRUCTURE OF TETRAKIS(BENZOATE)BIS(TRIPHENYLPHOSPHINE OXIDE)DICOPPER(II).OXIDATIVE ADDITION OF DIBENZOYL ON METALLIC COPPER

Dibenzoyl peroxide undergoes oxidative addition on metalliccopper with triphenylphosphine in a mixed solvent(acetone,dichloromethaneand trichloromethane),and affords the binuclear copper complex(Cu(C_6H_5COO)_2(OPPh_3))_2.Crystals are monoclinic,space group A_2/a,withcell parameters,a=24.337(3),b=10.566(1),c=21.579(2),β= 93.18(1)°,V=5540(1)~3,Z=4,R=0.042,and Rw=0.044 for 5872 observed reflections.Each copper ion is coordinated by four bridging benzoato ligands and onetriphenylphosphine oxide group to form binuclear complexes.     

A THEORETICAL STUDY OF THE EFFECT OF OXYGEN ATOM ON THE C-C BOND LENGTH AND BOND ORDER IN A SERIES OF C_2O_nY_(4-n) COMPOUNDS

<正> A series of CaOnY4-n molecules have been studied by means of MNDO method. From the results of calcuation it can be seen that the bond orders of C-C bond linked with one or more oxygen atoms are reduced while the bond lengths are increased. The main thange of C-C bond orders comes from σ-bond.     

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.     

ELECTRONIC ENERGY BAND STRUCTURE OF MOLECULAR CRYSTALS MCI·(TCNQ)_2 AND ITS RELATIONSHIP WITH THE ELECTRICAL CONDUCTION

The structure of electronic energy bands, electric charge distribution and the amount of charge transfer of molecular crystals 1-MCI·(TCNQ)_2 (Ⅰ) and 2-MCI· (TCNQ)_2 (Ⅱ) have been studied. The results are: (ⅰ) The dominant contributions to the electrical conductivities for crystals Ⅰ and Ⅱ are from TCNQ molecular columns, and the charge carriers are electrons. (ⅱ) The electrical conduction is mainly due to the hopping of charge carriers between the seats of lattice. (ⅲ) The considerable difference of the electrical conductivities between crystals Ⅰ and Ⅱ is due to the differences between (a) the concentrations of charge carriers n_(AⅠ)~C= 0.9988-|e|/cell and n_(AⅡ)~C=0.0340-|e|/cell; (b) the widths of the energy bands △E_(AⅠ)~(LU)=0.88 eV and △E_(AⅡ)~LU=0.040 eV; (c) the first derivative of E with respect to k, (dE/dk)_(K_FAⅠ)~(LU)=0.27 eV· and (dE/dk)_(K_FAⅡ)~LU=0.0048 eV·; and (d) the difference of energy barriers for the hopping of charge carriers ∈_Ⅱ-∈Ⅰ=2.5-8.8 kJ/mol.     

CRYSTAL AND MOLECULAR STRUCTURE OF THE ADDUCT OF BIS (1,1,1 TRIFLUORO 3-2-2'''' THENOYLACETONATO) COPPER (II) WITH PYRIDINE

<正> Mr=666.12, triclinic, Pl, a=8.868(1), b=9.719(2), c=10.861(1) A,α=58.23(1)°, β =64.06(1)° r =71.63(1)°; V =711.2 A3; 2=1, Dc=1.555 g.cm-3,for 3724 reflections with I≥ 3σ(I). In the title compound, the copper atomhas a distorted octahedral coordination with four Cu-O long bonds and twoCu-N short bonds. ,     

STUDY ON THE MECHANISM OF INTERFERON ACTION (Ⅺ)——EFFECT OF pppA2''''p5''''A2''''p5''''A ON THE LEVEL OF cAMP AND cGMP IN MACROPHAGES

In this paper, the increase of cellular cAMP and cGMP levels in macrophages induced bypppA2'p5'A2'p5'A (briefly 2'-5'P_3A_3) is first reported. The optimal concentration of 2'-5'P_3A_3 for the elevation of cellular cGMP to the highest level is 10~(-7)-10~(-6)mol/L, while thatfor cAMP is 10~(-7)mol/L. The time for cGMP to reach its peak value is 15 min and that forcAMP is 2 h, when the cells are treated with 2'-5' P_3A_3 at 10~(-7)mol/L, which is the optimalconcentration for developing biological effect of macrophages (phagocytosis). These resultssuggest that cGMP and cAMP may be related to, or may be the mediators for, 2'-5'P_3A_3action.     

DESENSITIZING EFFECT OF ISOMERIC METALLORGANIC PALLADIUM (Ⅱ) COMPOUNDS WITH THIOSEMICA-RBAZIDE ON THE DEVELOPMENT PROCESS OF SILVER HALIDE PHOTOGRAPHIC MATERIALS

Some chemical compounds can be used in the chemical photographic development process of silver halide panchromatic motion picture materials to decrease their sensitivity upon exposure whereby their development is possible at relatively bright illumination^[1].     

STUDIES ON THE REACTION OF SULFUR,SELENIUM AND TELLURIUM WITH SODIUM HYDROXIDE UNDER PHASE TRANSFER CATALYSIS(Ⅱ).A CONVENIENT METHOD FOR THE SYNTHESIS OF BI(ACYL)DISULFIDES

A simple and general method for the synthesis of bi(acyl)disulfides isreported.Sulfur is allowed to react with sodium hydroxide to give sodium disulfideat 65℃ under PTC,which can react with acyl halides to afford bi(acyl)disulfides ingood to excellent isolated yields.The effects of solvents and phase transfercatalysts are discussed.     

CRYSTAL AND MOLECULAR STRUCTURE OF THE ADDUCT OF BIS [4,4,4-TRIFLUOR-1-(2-THIENYL) Butandion-1,3] COPPER (Ⅱ) WITH DIMETHYLFORMAMIDE, [Cu(TTA)_2(DMF)]

<正> [Cu(C8H4F3O2S)2(C3H7NO)], Mr = 579. 0, monoclinic, P21/c, a = 9. 4851(6), b = 26. 6574(6), c=9.2619(6) A ,β=96.08(3)°, V = 2328.7A3, Z=4, Dc=1. 65gcm-3, μ(MoKa) = 7. 2cm-1, F (000) = 1172, MoKa radiation, final R = 0. 074 and Rw = 0. 068 for 1841 reflections with I≥3σ(Ⅰ). The Cu(Ⅱ) atom is coordinated by five oxygen atoms, one of which from DMF is in the axial position, to form a square pyramidal geometry. That the thenoyl groups in the ligands take the cis-form around the Cu(Ⅱ) atom is explained by the hydrogen bonding effect.     

INFLUENCE OF TRACES OF WATER ON THE SYNTHESIS AND ELECTROLUMINESCENCE PROPERTIES OF POLY(2-METHOXY, 5- (2'''' -ETHYLHEXYL OXY)- 1, 4-PHENYLENE VINYLENE)

It was found that traces of water in the reaction medium would result in a great increase of gel and a decrease ofmolecular weight of the poly(2-methoxy, 5-(2'-ethylhexyloxy)-1, 4-phenylene vinylene) during the polymerization, whichultimately led to inferior film qualities and device properties. The device (ITO/PEDOT/MEH-PPV/Ba/Al) with MEH-PPVprepared under dry conditions has an external quantum efficiency of above 2.0%.     

REGULATION OF GLUCOCORTICOID RECEPTOR BY GLUCOCORTICOIDS(Ⅱ) ——THE STUDIES ON RAT LIVER, BRAIN AND SPLEEN

The concentration of glucocorticoids (GC) in plasma was maintained at stress level, 20--40μg/dl, for 3 days by subcutaneous injection of hydrocortisone (F) in polyvinyl alcohol (PVA) into rats, and the specific binding of [~3H]Dexamethasone (Dex) in liver, spleen and brain was determined before and after injection. The binding capacity of glucocorticoid receptor (GR) in liver and spleen was decreased significantly 1 h after injection and maintained at low level for several days after the concentration of GC in plasma had returned to the normal level. The K_d was not altered. The changes of GR in brain was not significant. Thus it may be concluded that GC can down-regulate GR in rats, but with different characteristics in various target organs.