SYNTHESIS AND CHARACTERIZATION OF POLY(L-GLUTAMIC ACID-co-L-ASPARTIC ACID)

Poly(amino acid)has been widely utilized in drug delivery,tissue engineering and biomedical materials.The biomaterials based on poly(glutamic acid)are usually modified via copolymerization with other monomers such as L-aspartic acid to improve the uncontrolled degradation rate.The ring-opening homo- and co-polymerization ofγ-benzyl-L-glutamate N-carboxyanhydride(BLG-NCA)andβ-benzyl-L-aspartate N-carboxyanhydride(BLA-NCA)were carried out in solution by using triethylamine(TEA)as initiator.The BLG-NCA homo...     

基于1,1’-二苯乙炔-3,3’,5,5’-四羧酸微孔铜配位聚合物的合成和气体吸附性质

本文报道了配合物[Cu2(EBTC)(H2O)2]·8H2O·DMF.DMSO(1,EBTC=1,1′-二苯乙炔-3,3′,5,5′-四羧酸根;DMF=N,N-二甲基甲酰胺;DMSO=二甲基亚砜)的合成、晶体结构和吸附性质。1拥有内径为0.85 nm和0.85 nm×2.15 nm的两种孔洞,分别被6个和12个四羧酸根桥联的[Cu2(CO2)4]螺旋桨式结构围绕,并被EBTC连接成三维超分子结构,该结构拥有可容纳溶剂分子的一维孔道。1为(3,4)-连接的fof(sqc1575)拓扑结构,具有非常大的孔体积,其值高达单位晶胞体积的72.8%。去除溶剂分子后的1a表现出永久孔性,其Langmuir表面积为2844 m2·g-1,BET表面积为1 852 m2·g-1。它对H2、CO2、CH4和C2H2具有可观的气体吸附量和相对较高的吸附焓。特别是,在迄今所有已报道的孔性金属-有机材料中,1a在273 K、1.0×105Pa下,表现出最高的乙炔吸附量(252 cm3·g-1)和很高的吸附焓(吸附量为1 mmol·g-1时的吸附焓为34.5 kJ·mol-1)。     

SYNTHESIS AND PROPERTIES OF POLYACETYLENES CONTAINING CARBAZOLE AND AMINO ACID MOIETIES

 Novel 9-proparylcarbazole monomers containing amino acid moieties, 2-N-(tert-butoxycarbonyl)-L-alanine-9-proparylcarbazole ester (1), 2-N-(tert-butoxycarbonyl)-L-O-cyclohexyl-L-glutamic acid-9-proparylcarbazole ester (2) and 2-N-(tert-butoxycarbonyl)-L-phenylalanine-9-proparylcarbazole ester (3) were synthesized and polymerized with (nbd)Rh+[η⁶-C₆H₅B–(C₆H₅)₃] to give the corresponding polymers with number-average molecular weights ranging from 7050 to 10500 in 70%-86% yields. The polymers were completely soluble in toluene, CHCl₃, CH₂Cl₂, THF and DMSO, but insoluble in hexane, diethyl ether and MeOH. The specific rotation studies revealed that poly(1)-(3) do not took predominantly one-handed helical structures in the solvents although they possess chiral groups. The polymers emitted fluorescence in 0.40%–2.35% quantum yields. The cyclic voltammograms of the polymers indicated that the polymers exhibited electrochemical properties.     

Gel spinning of poly(vinyl alcohol) from dimethyl sulfoxide/water mixture

Gel spinning of poly(vinyl alcohol) (PVA) was attempted from the PVA dope prepared from the mixture of dimethyl sulfoxide (DMSO) and water. The DMSO/H₂O = 80/20 (w/w) mixture and methanol were found to be the best solvent for the spinning dope and the coagulant, respectively, to give PVA fiber with the highest drawability. PVA fiber with the highest strength and Young's modulus were obtained from the undrawn gel fibers when subjected to hot two-stage drawing under conditions such as to produce maximum drawability. Furthermore, higher draw ratios of PVA fiber were attained at 6 wt % dope by lowering the coagulating temperature of methanol. In the present work, the highest tensile strength (2.8 GPa) and the highest Young's modulus (64 GPa) were realized, when the spinning dope was prepared from PVA with DP of 5,000 and the DMSO/H₂O (80/20) mixed solvent to have the PVA concentration of 6 wt %, the coagulating temperature of methanol was ?20°C, and the two-stage drawing was carried out at 160 (first) and 200°C (second). The PVA fiber prepared under this gel spinning condition could be elongated to 45 times draw ratio. The very high drawability of PVA fibers obtained from the DMSO/H₂O (80/20) mixture dope was ascribed to the ability of the DMSO/H₂O mixture to promote gelation. © 1994 John Wiley & Sons, Inc.     

Gibbs energies of transferring triglycine from water into H2O-DMSO solvent

The Gibbs energies of transferring triglycine (3Gly, glycyl-glycyl-glycine) from water into mixtures of water with dimethyl sulfoxide (χ_DMSO = 0.05, 0.10, and 0.15 mole fractions) at 298.15 K are determined from the interphase distribution. An increased dimethyl sulfoxide (DMSO) concentration in the solvent slightly raises the positive values of Δ_tr G ^○(3Gly), possibly indicating the formation of more stable 3Gly-H₂O solvated complexes than ones of 3Gly-DMSO. It is shown that the change in the Gibbs energy of transfer of 3Gly is determined by the enthalpy component. The relationship of 3Gly and 18-crown-6 ether (18C6) solvation’s contributions to the change in the Gibbs energy of [3Gly18C6] molecular complex formation in H₂O-DMSO solvents is analyzed, and the key role of 3Gly solvation’s contribution to the change in the stability of [3Gly18C6] upon moving from H₂O to mixtures with DMSO is revealed.     

大比表面积钛黑颜料的制备和表征

本文首次通过pH值控制沉淀法制备前驱物丁二酸钛肼复盐,并进一步热分解制备大比表面积钛黑颜料-黑色钛氧化物。通过比表面积(BET)、电子能谱(EDS)、X射线光电子能谱分析(XPS)、X射线粉末衍射(XRD)、场发射扫描电子显微镜(HRSEM)、物理吸附仪、激光粒度仪和Color i5型台式分光测色仪对黑色钛氧化物进行了表征,确定了黑色钛氧化物的组成为2TiO2·Ti2O3,其表面积为53.854 4 m2·g-1。并考察了酸源、水合肼用量、酸钛比、反应时间、pH、NaOH浓度和煅烧温度等各种反应参数对黑色钛氧化物的颗粒尺寸、分布均匀性和黑色度的影响。用元素分析仪和等离子体光谱仪测定了前驱物组成,确定其组成为[Ti(C4H4O4)2]0.85·2Ti2O3·6N2H4·3H2O,并探讨了黑色钛氧化物形成机理,为新型混合价材料黑色钛氧化物的制备提供重要参考依据。     

12-钼磷酸的BrÖnsted酸位和Lewis酸位

研究了加热、抽空等预处理对固态12-钼磷酸(PMA)酸位的影响。发现了PMA上除存在B-酸位外,还可生成L-酸位。研究了PMA上L-酸位的成因,水在两类酸位形成过程中的作用,L-酸位与B-酸位的相对强度,以及PMA上酸强度的分布。据此,对Miscno等认为PMA中只存在质子酸和酸强度分布均匀的观点提出了不同的看法。     

Cationic ring-opening polymerization of tetrahydrofuran with Keggin-type heteropolycompounds as solid acid catalysts

<正>Three Keggin-type heteropolyanions,namely H_3PMo_(12)O_(40)·13H_2O,(NH_4)_3PMo_(12)O_(40)·4H_2O and H_3PW_(12)O_(40)·13H_2O were prepared and tested in the ring-opening polymerization reaction of tetrahydrofuran.The effects of the counter-cation (H~+,NH_4~+) and the peripheral atoms(Mo,W) on the polymerization were investigated.It has been found that when the protons of H_3PMo_(12)O_(40)·13H_2O were replaced by the ammonium cations the polymerization rate decreased dramatically. Whereas,when the peripheral atoms(Mo) were replaced by their homologous(W),the polymerization rate increased twofold.As for the viscosity average molecular weight(M_v) of polymer products,it was found that the high molecular weight(7930) was obtained by using H_3PW_(12)O_(40)·13H_2O.The molecular weight(M_v) obtained by H_3PMo_(12)O_(40)·13H_2O and (NH_4)_3PMo_(12)O_(40)·4H_2O was 6470 and 6810,respectively.     

草酸根桥联的不对称双核铜(Ⅱ)和铜(Ⅱ)-锌(Ⅱ)配合物的合成与磁性

本文合成了一组新的不对称的双核配合物,[Cu_2(C_2O_4)_2terp]和〔Cu Zn(C_2O_4)_2terp〕(图1),terp表示联三吡啶。配合物〔Cu_2(C_2O_4)2terp〕的变温磁化率已测,其数值已用最小二乘法与Bleaney-Bowers方程拟合,求得交换积分J=-47.20cm~(-1)。文中还用Kahn理论解释了这种较弱的反铁磁自旋交换作用。     

Micelle‐catalyzed reaction of ninhydrin with DL‐valine in the absence and presence of organic solvents

Kinetics of the DL ‐valine‐ninhydrin reaction has been studied spectrophotometrically under varying conditions of [CTAB], [ninhydrin], [DL ‐valine], pH, temperature, and %(v/v) organic solvents (solvents used: 1‐propanol, methylcellosolve, acetonitrile, and dimethyl sulfoxide). Addition of CTAB and increase in the proportion of organic solvents, both showed catalyzing effect on the reaction. The effect of simultaneous presence of CTAB and DMSO in the reaction mixture has also been seen. The rate profiles obtained for solutions containing from 10% to 70% DMSO exhibited clear maxima that shifted progressively to higher concentrations of CTAB. The experimental results are explained in terms of specific solvent effects and the formation of stoichiometric hydrate DMSO · 2H₂O and the inhibitory effect of DMSO on micelle formation. © 2006 Wiley Periodicals, Inc. Int J Chem Kinet 38: 634–642, 2006     

Kinetic stability of tetrazaporphin in binary H2SO4-AcOH and H2SO4-DMSO solutions

The state and kinetic stability of tetrazaporphin (I) in acetic acid and in dimethyl sulfoxide (DMSO) in the presence of H₂SO₄ were investigated. Partial protonatiqn of I to give I-AcOH₂ associates occurs in acetic acid. The kinetic parameters of the reaction involving the destruction of tetrazaporphin in the presence of H₂SO₄ in acetic acid and DMSO solutions were determined. The mechanism of the destruction is discussed.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 932–936, July, 1984.     

Synthesis,characterization and crystal structure determination of iron(III) complexes containing 4,4′-dimethyl-2,2′-bipyridine,dimethyl sulfoxide and chloride, [Fe(dmbipy)Cl4][dmbipyH] and [Fe(dmbipy)Cl3(DMSO)]

[Fe(dmbipy)Cl₄][dmbipyH], 1 (dmbipy is 4,4′-dimethyl-2,2′-bipyridine), was prepared from reaction of FeCl₃ · 6H₂O with 4,4′-dimethyl-2,2′-bipyridine in 0.1 molar aqueous HCl. Treatment of 1 with dimethyl sulfoxide in methanol produced [Fe(dmbipy)Cl₃(DMSO)], 2 (DMSO is dimethyl sulfoxide). Both complexes were characterized by IR, UV-vis, and ¹H-NMR spectroscopies and their structures were studied by single crystal diffraction. Compounds 1 and 2 are high-spin with spin multiplicity of six.     

Preparation of no-carrier added 16-131I-hexadecanoic acid via halogen exchange: Comparison between two methods

A simple method for labelling of 16-Br-hexadecanoic acid (16-BrHDA) with radioactive iodine has been reported via nucleophilic¹³¹I-for-Br exchange in the dry state and in organic solvents. While preparation in some organic solvents such as acetic acid, dimethyl formamide (DMF) and dimethyl sulfoxide (DMSO) required reaction times of more than 2 hours to give yields of 20–50%, halogen exchange in dry state at temperature of about 100 °C gave rise to yields of about 94% of radiochemically pure 16-¹³¹IHDA within 5 min. The labelling product could be purified by high performance liquid chromatography (HPLC) and was shown to be free of significant radiochemical impurities.     

SYNDIOSPECIFIC POLYMERIZATION OF STYRENE WITH Ar[O,O/NH]Cp*TiCl ACTIVATED WITH MMAO

A series of titanium complexes Ar[O,E]Cp~*TiCl(Cp~*=C_5Me_5,Ar=1,2-phenylene,E=NH(1a);Ar=1,2- phenylene,E=O(1b);Ar=2.2'-diphenylene,E=O(1c);Ar=2,2'-dinaphthalene,E=O(1d)) has been prepared by the reaction of corresponding phenol derivatives with Cp~*TiCl_3 in the presence of excessive triethylamine.Under the conditions of low Al/Ti molar ratio(e.g.500) and high reaction temperatures(>70℃),all the titanium complexes display higher catalytic activities towards the syndiospecific polymerization of styrene,i...     

Determination of cholride in natural and potable water samples byturbidimetric descrete-sample automatic analysis.

The reduction of the uranyl-mellitate complex at the dropping mercury electrode has been studied in aqueous and dimethyl sulfoxide solution. In aqueous solution, besides the reduction waves of the uranyl-mellitate complex, corresponding to the reduction of U(VI) to U(V), and of U(V) to U(III), an adsorption wave and a catalytic hydrogen wave were obtained; the species formed below pH 4.0 was UO₂(H₃A)^- and above pH 4.0 was UO₂(OH)(H₃A)^2-. In dimethyl sulfoxide solution, two well-defined waves were observed; the first wave is due to reduction of a uranyl-mellitate-DMSO complex, and the second to reduction of mellitic acid. The species involved are UO₂(DMSO)₆²⁺ below pH 2.2 and UO₂(H₃A)(DMSO)₅^-1 above pH 2.2. The activation energies of the reduction process were determined.     

SYNTHESIS OF AMPHIPHILIC COMB-SHAPED COPOLYMERS USED FOR SURFACE MODIFICATION OF PVDF MEMBRANES

The synthesis of a novel amphiphilic comb-shaped copolymer consisting of a main chain of styrene-(N-(4- hydroxyphenyl) maleimide)(SHMI) copolymer and poly(ethylene glycol) methyl ether methacrylate(PEGMA) side groups was achieved by atom transfer radical polymerization(ATRP).The amphiphilic copolymers were characterized by ~1H-NMR, Fourier transform infrared(FTIR) spectroscopy and gel permeation chromatography(GPC).From thermogravimetric analysis (TGA),the decomposition temperature of SHMI-g-PEGMA is low...     

线性变位极谱法研究 ⅩⅥ.铀(Ⅵ)-5-Br-PADAP-磺基水杨酸的配位吸附波

本文提出了铀(Ⅵ)-5-Br-PADAP-磺基水杨酸三元配合物的极谱配位吸附波。在pH为7.5-8.2的醋酸、三乙醇胺、乙醇底液中,该波的峰电位在-0.6855V(vs.SCE)。在1.00×10^-7-1.00×10^-5mol·dm^-3范围内,铀(Ⅵ)浓度与峰电流呈线性关系。对极谱波的电流、电位性质进行了研究,测定了配合物的组成、表观稳定常数和离解及生成速率常数。     

Synthesis,Characterization, and Crystal Structure of new Macromolecule Iron(III) Complex Containing Dimethyl Phosphate,Acetate, and Dimethyl sulfoxide

The reaction between a solution of [Fe₃O(μ‐OAc)₆(H₂O)₃]Cl·6H₂O ( 1 ) (OAc = acetate) and TMP (TMP = trimethyl phosphate) in absolute ethanol and DMSO (DMSO = dimethyl sulfoxide), led to the coordination macromolecule ‐[Fe₁₆(μ₃O)₈(μ₃‐OH)₄(μ‐OH)₄(μ‐DMP)₁₂(μ‐OAc)₁₂(DMSO)₄]·2DMSO·1.5H₂O ( 2 ) (DMP = dimethyl phosphate). This complex was characterized by elemental analysis, IR spectroscopy, and single‐crystal structure. Crystal data for 2 at ?153 °C: triclinic, space group , a = 18.185(2), b = 18.349(2), c = 21.976(3) Å, α = 91.633(3)°, ß = 103.833(3)° γ = 96.486(3)°, Z = 2 and R1 = 0.0655.     

A Comprehensive Study and Characterization of Colloidal Emeraldine-Base

Soluble emeraldine-base (PANI-EB) was prepared and its structure was characterized using ¹H, ¹³C and 2D (COSY, HMQC and HMBC) NMR. The solubility of the polymer in two solvents (N-methylpyrrolidone (NMP) and dimethyl sulfoxide (DMSO), the structure of the solution (aggregation) and the behavior of polyaniline were studied by viscometry and by dynamic light scattering (DLS) in dilute solution. Viscometric behavior in NMP and Huggins constant determination confirm supramolecular interactions also evidenced by DLS; at end, the molecular weight of the soluble fraction of PANI-EB is determined.     

Effect of dimethyl sulfoxide on electrochemical and antiradical properties of ascorbic acid

Solvent effect of dimethyl sulfoxide (DMSO) on the oxidation-reduction properties of ascorbic acid (AA) was studied by the electroanalytical method of differential pulse voltammetry (DPV) in a three-electrode cell at 37 °C. Dimethylsulfoxide was found to considerably decrease the oxidation ability of AA due to the formation of molecular complexes between AA and DMSO through the intermolecular hydrogen bonds and shift the anodic peak potential toward the positive values, with its intensity being decreased. Kinetic spectrophotometric measurements in the UV-vis regions of the reaction of the stable free radical 2,2-diphenyl-1-picrylhydrazyl (DPPH^·) with AA confirmed the stabilizing effect of the Lewis base DMSO on the reactivity of the neutral form of AA and its intermediates with respect to DPPH^·. The mechanism of oxidation of AA with the radical DPPH· in the presence of DMSO was considered.