共查询到20条相似文献,搜索用时 15 毫秒
1.
Xiaowen Zhang Xingqi Zhu Fuyou Ke Lin Ye Er-qiang Chen Ai-ying Zhang Zeng-guo Feng 《Polymer》2009,50(18):4343-4351
A kind of novel amphiphilic triblock copolymers containing polyrotaxane (PR) as a central block was synthesized via the ATRP of poly(ethylene glycol) methyl ether methacrylate (PEGMA) initiated with polypseudorotaxanes made from a distal 2-bromopropionyl end-capped Pluronic F127 with a varying amount of β-CDs in the presence of Cu(I)Cl/N,N,N′,N″,N″-pentamethyldiethylenetriamine (PMDETA) at 25 °C in aqueous medium. The structure of the resulting copolymers was characterized in detail by 1H NMR, 2D ROESY NMR, GPC, DSC and WAXD analyses. The degree of polymerization of PEGMA oligomers appeared to be adjustable. As a typical sample, F-30β-CD-60 with a molar feeding ratio of Pluronic F127 to β-CD to PEGMA holding 1:30:60 was found to self-assemble into nano-sized aggregates in water. Its critical aggregation concentration was assessed by fluorescence probe technique. The corresponding hydrodynamic radius and radius of gyration were also determined by dynamic and static light scattering measurements. The transmission electron microscopy images further revealed that the sizes of the polymeric micelles of the selected copolymer were in nano-scale and smaller than those of the blank brush-like block copolymer. These nano-sized particles showed great potential to be used as carrier for the controlled release of Amphotericin B (AmB) holding 8.7% drug-loading content and 87% drug-loading efficiency with the cumulative release profile substantially longer than that of the blank brush-like block copolymer. 相似文献
2.
Pampa Mukherjee Michael G.B. Drew Vassilis Tangoulis Marta Estrader Carmen Diaz Ashutosh Ghosh 《Inorganic chemistry communications》2009,12(9):929-932
A new linear trinuclear nickel(II) complex, [Ni3(salme)2(OCn)4] (Hsalme = 2-[(3-methylamino-propylimino)-methyl]-phenol, OCn = cinnamate), showing weak ferromagnetic coupling (J = 1.8(1) cm−1) through phenoxo and a novel tridentate bridging mode (1κ2OO′:2κO′) of the cinnamate ligand has been synthesized and structurally characterized by X-ray crystallography. 相似文献
3.
A novel α-azide and ω-alkyne A–B type azobenzene monomer, 3′-ethynylphenyl[4-(4-azidobutoxy)phenyl]azobenzene (EAPA), was synthesized and used to generate a novel polymer via step-growth polymerization using 1,3-dipolar cycloaddition reaction under the catalysis of CuSO4·5H2O/sodium ascorbate/H2O (“Click” chemistry). The structure of the resultant main-chain azobenzene polymer, PEAPA, was characterized by GPC, 13C NMR, UV–vis and FT-IR spectra. Thermal stability and crystallinity of PEAPA powder were studied by TGA and WAXD. The photo-induced trans–cis isomerization of PEAPA and EAPA in N,N′-dimethyl formamide (DMF) solution was investigated. Furthermore, the thermal cis–trans isomerizations of PEAPA and EAPA were also observed at 60 °C in dark. Thermal stability and trans–cis–trans isomerization behavior of PEAPA was compared with its non-triazole analog, PDHA. 相似文献
4.
5.
Michail N. Elinson Alexey I. Ilovaisky Valentina M. Merkulova Dmitry V. Demchuk Pavel A. Belyakov Yuri N. Ogibin Gennady I. Nikishin 《Electrochimica acta》2008,53(28):8346-8350
Electrochemically induced catalytic multicomponent transformation of isatins, barbituric acid or N-alkyl barbiturates and malononitrile in alcohols in an undivided cell results in the formation of substituted 7′-amino-2,2′,4′-trioxo-1,1′,2,2′,3′,4′-hexahydrospiro[indole-3,5′-pyrano[2,3-d]pyrimidine]-6′-carbonitriles in 80–95% yields. The developed efficient electrocatalytic approach to corresponding spiro[indole-3,5′-pyrano[2,3-d]pyrimidine] system is beneficial from the viewpoint of diversity-oriented large-scale processes and represents a new example of the ecologically pure synthetic concept for electrocatalytic multicomponent reactions strategy. 相似文献
6.
Jang Yong Lee Yoon Jung Kwon Je-Wan Woo Doo Kyung Moon 《Journal of Industrial and Engineering Chemistry》2008,14(6):810-817
A solution processible fluorine–thiophene-based copolymers, namely poly[2,7-bis(4-octyl-2-thienyl)-9,9-dioctylfluorene-co-alt-5,5′-(2,2′-bithiophene)] (P1), poly[2,7-bis(3-octyl-2-thienyl)-9,9-dioctylfluorene-co-alt-5,5′-(2,2′-bithiophene)] (P2), poly[2,7-bis(3,3′-dioctyl-5,5′-bithien-2yl)-9,9′-dioctylfluorene-co-alt-5,5′-(2,2′-bithiophene)] (P3) were synthesized using Suzuki and Stille coupling reaction. The polymers showed weight loss starting around 400 °C indicative of good thermal stability. UV–vis properties and photoluminescence (PL) properties were investigated in toluene. P1, P2 and P3 exhibited the absorption maximum at 450, 428 and 435 nm and their PL spectrum peaked at 587, 559 and 560 nm, respectively. And all polymers, P1, P2 and P3, showed electroluminescence (EL) spectrum peaked at 592, 595 and 607 nm in the range of orange red. The polymers were electrochemically active in oxidation regions. P3 especially showed high oxidation stabilities in 1.17 V vs. Ag/Ag+. And P1 and P3 showed higher crystallinity than P2, because they have a repeated unit of 3,3-dialkyl-quaterthiophene. 相似文献
7.
Oswaldo Treu-Filho Jos C. Pinheiro Rodrigo A. de Souza Rogrio T. Kondo Raimundo D. de Paula Ferreira Antnio F. de Figueiredo Antonio E. Mauro 《Inorganic chemistry communications》2007,10(12):1501-1504
Theoretical molecular structures of the complexes cis-[PdCl2(tmen)] and cis-[Pd(N3)2(tmen)] (tmen = N,N,N′,N′-tetramethylethylenediamine) were investigated using B3LYP/DFT method. The calculated molecular parameters, bond distances and angles, revealed a square-planar geometry around the metallic center for both compounds with the azide being linear. The theoretical infrared spectra of C1 symmetry (electronic state 1A) of the compounds are in agreement with the experimental data. 相似文献
8.
Vermiculite (VMT) was modified with cetyl trimethylammonium bromide (CTAB). Superabsorbent nanocomposites were prepared by solution polymerization of natural guar gum (GG), partially neutralized acrylic acid (NaA) and organo-vermiculite (CTA+-VMT), ammonium persulfate (APS) as initiator and N,N′-methylene-bis-acrylamide (MBA) as crosslinking agent. FTIR spectra confirmed that NaA had been grafted onto GG and the OH groups of CTA+-VMT participated in the polymerization reaction. The intercalated-VMT was exfoliated during polymerization and uniformly dispersed in the GG-g-PNaA matrix. Swelling tests show that CTA+-VMT improved swelling and swelling rate more remarkably than VMT, and the nanocomposite exhibited distinct kinetic swelling behavior in NaCl and CaCl2 solution. Organo-VMT improved the gel strength of the nanocomposite compared to VMT, and the maximum storage modulus of the nanocomposite reached 658 Pa (γ = 0.5%, ω = 100 rad/s). 相似文献
9.
Bao-Cheng Wang Xiao-Li Chen Huai-Ming Hu Hong-Liang Yao Gang-Lin Xue 《Inorganic chemistry communications》2009,12(9):856-859
Two novel Zn(II) coordination polymers, [Zn5(pytpy)8(fum)4(H2O)4(OH)2]n · n(CH3OH) · 2n(H2O) (1) and [Zn3(pytpy)4 (btc)2]n · 2n(H2O) (2) (pytpy = 4′-(4-pyridyl)-3,2′:6′,3″-terpyridine, H2fum = fumaric acid, H3btc = 1,3,5-benzenetricarboxylic acid) have been hydrothermally synthesized and structurally characterized. Complex 1 is a 2D layer structure, which is constructed from linear pentanuclear Zn(II) subunits interconnected via bidentate-bridging pytpy ligands and tridentate-bridging fum2− anions. Complex 2 is a 3D network structure, μ2-pytpy ligands link the layers based on the heart-like hexanuclear subunits to form the 3D network. Both complexes show strong fluorescence emission upon excitation at 310 nm in solid state. Additionally, these two complexes possess great thermal stabilities, especially for 2, the framework is stable up to 350 °C. 相似文献
10.
Synthesis and characterization of soluble copoly(arylene ether sulfone phenyl-s-triazine)s containing phthalazinone moieties in the main chain 总被引:1,自引:0,他引:1
A series of new poly(arylene ether sulfone phenyl-s-triazine) copolymers containing phthalazinone moieties in the main chain (PPESPs) were prepared by a direct solution polycondensation of 4-(4-hydroxylphenyl)(2H)-phthalazin-1-one (HPPZ) with 2-phenyl-4,6-bi(4-fluorophenyl)-1,3,5-triazine (BFPT) and 4,4′-dichlorodiphenyl sulfone (DCS). Model reactions monitored by HPLC indicated that BFPT had slightly higher reactivity than DCS in nucleophilic displacement reactions. The obtained random copolymers were characterized by FTIR, NMR, elemental analysis and GPC. The presence of sulfone and phthalazinone in the polymer chain results in an improvement in the solubility of poly(arylene ether phenyl-s-triazine)s in common organic solvents, such as N-methylpyrrolidone, N,N-dimethyl acetamide (DMAc), chloroform, sulfolane and pyridine. Thermal analysis reveal that the copolymers exhibit high glass transition temperatures (Tgs) ranging from 271–300 °C, and excellent thermal stability associated with decomposition temperatures for 5% mass-loss exceeding 503 °C. All copolymers are amorphous except PPESP28 as evidenced by WAXD. Their Tgs and solubility increase with an increase in sulfone content in the polymer backbone, while the crystallinity and overall thermal stability appear to decrease. This kind of phthalazinone-based copoly(arylene ether sulfone phenyl-s-triazine)s may be considered a good candidate for using as high-performance structural materials. 相似文献
11.
MnIII(J-salen)Cl (Jacobsen catalyst) with J-salen=N,N′-bis(3,5-di-tert.-butylsalicylidene)-1,2-diaminocyclohexane dianion in CHCl3 is photooxidized by the solvent to a MnIV(J-salen) complex, presumably MnIV(J-salen)Cl2, with φ=0.002 at λirr=333 nm. 相似文献
12.
Polyacrylamide (PAAm) hydrogels possessing a very large extensibility at break have been prepared via micellar crosslinking copolymerization of acrylamide monomer and N,N′-methylenebis(acrylamide) crosslinker in the presence of hydrophobic comonomers. N-butyl-, N-hexyl-, N-octyl-, and N,N-dihexylacrylamides were used as the hydrophobes in the hydrogel preparation. Incorporation of hydrophobes with an alkyl chain length x > 4 results in an increase in the loss factor tan δ of hydrogels due to the formation of temporary junction zones inside the gel network. The number NH of the hydrophobes per hydrophobic block together with the alkyl chain length x of the pendant hydrophobic group were used to tune the loss factor of the hydrogels over two orders of magnitude. Tensile mechanical measurements show that increasing NH or x also increases the degree of toughness of PAAm hydrogels. Keeping constant the hydrophobe level (20 mol%) at an alkyl chain length x = 6, increasing NH from 9 to 30 increased the elongation ratio at break from 125 to 250%. Hydrogels exhibiting a high toughness, i.e., about 300% elongation ratio at break were obtained by modification of PAAm network chains with 10 mol% N-octylacrylamide. 相似文献
13.
Acrylamide-based, hydrophobically modified polysulfobetaines containing 3-[N-(2-methacroyloylethyl)-N,N-dimethylammonio]-propane sulfonate (DMAPS) and varying amounts of the hydrophobic monomer stearyl methylacrylate (SMA) were
synthesized by micellar copolymerization. The basic physico-chemical properties of the synthesized copolymers were studied
by means of surface tension, dynamic laser light scattering, and rheological measurements. All the copolymers showed surface
activity when the copolymer concentration was above 0.07 wt%. The dynamic laser light scattering measurement revealed that
both zwitterionic and hydrophobic associations were important in copolymer aggregation. The rheological properties of the
copolymers in aqueous solution depended on the content of hydrophobic monomer, the copolymer concentration and the addition
of salt, which were characteristic of hydrophobically modified polyacrylamide and acrylamide-based polyzwitterions. The critical
aggregation concentration of the copolymers was in the range of 0.07–0.1 wt%. 相似文献
14.
Peng Ren Na Xu Chen Chen Hai-Bin Song Wei Shi Peng Cheng 《Inorganic chemistry communications》2008,11(7):730-732
1D cobalt(II) and nickel(II) coordination polymers {[Co(dba)(H2O)4] · H2O}n (1) and {[Ni(dba)(H2O)4] · H2O}n (2) (H2dba = 2,5-dihydroxy-p-benzenediacetic acid) were synthesized under low temperature solvothermal condition. When 4,4′-bipyridine (bpy) was introduced to the synthetic systems of 1 and 2, respectively, two novel 2D coordination polymers {[Co(dba)(bpy)] · 0.5H2O}n (3) and [Ni(dba)(bpy)(H2O)2]n (4) with different structures were obtained. All of the compounds were characterized by elemental analysis, FT-IR, UV–Vis spectra and single crystal X-ray diffraction. 相似文献
15.
Su-Zhen Zhang Zhi-Hui Zhang Cheng-Peng Li Miao Du 《Inorganic chemistry communications》2009,12(10):1038-1041
Reaction of potassium N′-(pyridine-4-carbonyl)-hydrazinecarbodithioate ([K+(H2L)−]) with HgII or MnII inorganic salt in the presence of 1,10-phenanthroline (phen) or 4,4′-bipyridine (bipy), yields complexes [Hg(pyt)2(phen)] (1) and {[Mn(pyt)2(H2O)2]·(bipy)·(H2O)2}n (2), in which the pyt ligand (Hpyt = 5-(4-pyridyl)-1,3,4-oxadiazole-2-thiol) is obtained by in situ ligand formation from the acyclic precursor [K+(H2L)−]. Single crystal X-ray diffraction suggests that the pyt anionic ligands in 1 and 2 behave as thiolate and thione isomers, respectively, and display S- and μ-Npyridyl, Noxadiazole-binding fashions. Complex 1 shows a 1-D fishbone-like supramolecular array via strong aromatic stacking interactions between the discrete mononuclear coordination motifs, whereas 2 has a 2-D layered host coordination framework with the inclusion of bipy and water guests in the cavities. 相似文献
16.
Edwin C. Constable Catherine E. Housecroft Elaine A. Medlycott Markus Neuburger Federica Reinders Sbastien Reymann Silvia Schaffner 《Inorganic chemistry communications》2008,11(7):805-808
The solid state structure of [Ru(Phtpy)2][PF6]2 · 4MeCN has been determined (Phtpy = 4′-phenyl-2,2′:6′,2″-terpyridine); [Ru(Phtpy)2]2+ cations pack into sheets by virtue of {M(tpy)2}2 embraces, and the MeCN solvent molecules are involved in NH–C interactions which prevent the efficient packing of adjacent sheets. Comparisons with related structures lead to some generalizations about packing motifs in salts containing [M(Phtpy)2]2+ or [M(pytpy)2]2+ cations (pytpy = 4′-pyridyl-2,2′:6′,2″-terpyridine). 相似文献
17.
Min-Hua Zong Hong Wu Zi-yang Tan 《Chemical engineering journal (Lausanne, Switzerland : 1996)》2008,144(1):75-78
Novozym 435-catalyzed regioselective acylation of 1-β-d-arabinofuranosylcytosine (ara-C) with vinyl caprylate for the preparation of its 5′-O-acyl derivative has been performed in six co-solvent mixtures and three pure polar solvents for the first time. Novozym 435 displayed low activity towards 1-β-d-arabinofuranosylcytosine in pure polar solvents, although those solvents can dissolve the nucleosides well. When a hexane–pyridine co-solvent system was adopted, both the initial rate and the substrate conversion were enhanced markedly. The most suitable co-solvent, initial water activity, reaction temperature and the molar ratio of vinyl caprylate to ara-C were hexane/pyridine (28/72, v/v), 0.03, 40 °C and 15, respectively. Under these conditions, the initial rate, the substrate conversion and the regioselectivity were as high as 99.0 mmol h−1, 98% and >99%, respectively. The product of the Novozym 435-catalyzed reaction was characterized by 13C NMR and confirmed to be 5′-O-octanoyl 1-β-d-arabinofuranosylcytosine. 相似文献
18.
A.V. Linde V.V. Grachev R.-M. Marin-Ayral 《Chemical engineering journal (Lausanne, Switzerland : 1996)》2009,155(1-2):542-547
Cubic niobium nitrides δ-NbNx with different x = 0.87–1.015 were prepared by the self-propagating high-temperature synthesis (SHS) under nitrogen pressures of P(N2) = 48–230 MPa.Nitrogen composition x as a function of P(N2) was determined in weight gain experiments and compared with that determined by chemical (Kjeldahl) analysis. For powders with different x, the superconducting transition temperature Tc was measured as a function of lattice parameter a. The Tc values were found to grow linearly with increasing a. A maximum value of Tc = 15.0 K for cubic niobium nitride corresponded to a maximum value of a = 4.3901 Å. 相似文献
19.
Yingxue Zhou Jianhua Ma Chaofeng Gao Xiaodong Fan Najeeb ur Rehman Lashari Junpeng Li 《应用聚合物科学杂志》2021,138(38):50984
Electrospun nanofibers from copolymers composed of ferrocene side chains and PEO100-PPO65-PEO100 (F127) were fabricated in chloroform and N,N–dimethyl formamide solutions (V/V = 95:5) at room temperature. Ferrocene-containing multiblock copolymers (PFcMAn-F127-PFcMAn) were synthesized through reversible addition-fragmentation chain transfer polymerization using s-1-dodecyl-s''- (α, α'-dimethyl-α''-acetic acid) trithiocarbonate (DDMAT) modified F127 with 2- (methacryloyloxy) ethyl ferrocencarboxylate (FcMA). The structures of as-obtained chemicals were characterized by FTIR, 1H NMR, and 13C NMR. Additionally, the block copolymers molecular weight and polydispersity were measured using gel permeation chromatography. The electrochemical responsiveness of the polymers was investigated using cyclic voltammetry as well as the thermal stabilities of polymers and precursors were tested through DSC and TGA. The morphologies of electrospun fibers were observed through field emission scanning electronic spectroscopy and a fibrous diameter of 300–1100 nm was obtained. The results indicated that the suitable molecular weight of ferrocene -containing polymer would be processed in nanofibrous. 相似文献
20.
Junwei Zhao Qiuxia Han Pengtao Ma Lijuan Chen Jingping Wang Jingyang Niu 《Inorganic chemistry communications》2009,12(8):707-710
A 65·8 CdSO4-like 3-D framework [Cu(en)2]3[α-AsW11NaO39]·2H2O (1) constructed by monosodium-substituted Keggin arsenotungstates and copper(II)-ethylenediamine complexes (en = ethylenediamine) has been synthesized by reaction of Na8[α-HAsW9O34]·11H2O, CuCl2·2H2O and ethylenediamine under hydrothermal conditions and structurally characterized by elemental analysis, IR spectroscopy, thermogravimetric analysis and single-crystal X-ray diffraction. Crystal data for 1: C12H52AsCu3N12NaO41W11, monoclinic, Cc, a = 20.409(9) Å, b = 16.737(8) Å, c = 16.561(7) Å, β = 104.607(7)°, V = 5474(4) Å3, T = 296(2) K; Z = 4, μ = 24.860 mm−1, GOOF = 1.086, R1 = 0.0284, wR2 = 0.0759. To the best of our knowledge, 1 represents the first 65·8 CdSO4-like 3-D monovacant Keggin arsenotungstate derivative in polyoxometalate chemistry. 相似文献