共查询到20条相似文献,搜索用时 15 毫秒
1.
Jia-you Shu Mo Zhu Yi Shu Qi-jun Liu Tong Li 《高分子科学》2006,(4):395-401
The new chelate resins, abbreviated as PNBMZs and PBBMZs based on epoxide polymer, were synthesized by polycondensation of N,N-diglycidyl-4-glycidyloxyaniline or 1,4-bis(2,3-epoxypropyl)benzene with the primary amine group of 1,3-bis(benzimidazol-2yl)propylamine (BBPAH). The ion exchangers contain 2.71-3.23 mmol of the ligand contents per gram of the resin. Batch extraction capacities were determined for the metal chloride salts in buffer solutions in the pH range from -1 to 6.0. The chelate resins were very selective for Cu^2+, Zn^2+, Cd^2+ in the presence of other divalent transition metal ions. The maximum uptake capacities of PNBMZ (synthetic molar ratio = 1:1.5) under non-competitive condition were found to be 0.94 mmol/g for Cu^2+ at pH = 2, 1.3 mmol/g for Cd^2+ at pH = 1 and 1.75 mmol/g for Zn^2+ at pH = -1 respectively. While in the case of PBBMZ, it was 1.39 mmol/g for Cd〉 at pH = 1. The metal-uptake behaviors for both of them showed strong pH dependence, and their extraction capacities increase with decreasing pH. The uptake of Cu^2+ by the resin PNBMZs at pH = 1 was found to be rather fast with t1/2 = 18 min. Metal-uptake experiments under competitive conditions also confirm that the chelate resins have a high selectivity for Cu^2+, Zn^2+, Cd^2+ and the contrary pH dependence. 相似文献
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Conventional chloromethylation, paraformaldehyde/hydrogen chloride in acetic acid medium, was applied to 1,2- dimethoxybenzene. Chloroform-soluble poly(3,4-dimethoxy-o-tolylene) was obtained with an intrinsic viscosity of 0.034 dL g^-1. The polymer was evaluated as a condensation redox polymer precursor formed by a Friedel-Crafts reaction. Cleavage of the methoxy groups present in this polymer resulted in poly(3,4-dihydroxy-o-tolylene) which manifested a great air-oxidation resistance. The redox property of the latter polymer was found to be 1017 mV by potentiometric titration with 0.05 N ceric ammonium nitrate at 25℃. This midpotential was compared to that of catechol, a monomeric analogue, under the same titration conditions. 相似文献
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Hui Jin Yan-bing Hou Xian-guo Meng Feng Teng 《高分子科学》2006,(6):553-558
In this paper, photoexcitation processes in the bilayer devices based on inorganic materials and poly(N-vinylcarbazole) (PVK) were investigated. In order to clarify the roles of inorganic materials in photoconductive properties of bilayer devices, TiO2 and ZnS were chosen to combine with PVK. A model for generation of photocurrent (Iph) in single layer device of PVK was obtained. It is deduced that the recombination rate constant (Pcomb) and the ionization rate constant (y) ofexcitons should be considered as the most important factors for Iph. For inorganic materials (TiO2 or ZnS)/PVK bilayer devices, in reverse bias of-4 V, the photocurrent of 115 mA/cm^2 in the TiO2/PVK device was observed, but the photocurrent in the ZnS/PVK device was only 10 mA/cma under the illumination light of 340 nm and the light intensity of 14.2 mW/cm^2. The weaker photocurrent is attributed to the absorption of ZnS within UV region and the energy offset at the interface between PVK and ZnS, which impedes the transport of charge carriers. 相似文献
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A new coordination polymer [Zn3(bpda)3(bpy)] 1 (H2bpda = 2,2'-biphenyldicar- boxylic acid, bpy = 4,4'-bipyridien) has been hydrothermally synthesized and characterized by single-crystal X-ray diffraction analysis, elemental analysis, TG analysis and IR spectrum. 1 Crystallizes in cubic crystal system, space group Ia 3, with a = 20.9687(9) A, V = 9219.7(3) A^3, Z = 8, and R(I 〉 2σ(I)) = 0.0431. Complex 1 is a three-dimensional framework involving a new building block, linear trinuclear {Zn3(CO2)6N2} cluster. In the structure, each bpda coordinates to four zinc atoms via its two bridging bidentate carboxylate groups. To the best of our knowledge, 1 implies a new coordination mode of 2,2'-biphenyldicarboxylic acid. The solid state fluorescent spectra show a strong emission peak at 451 nm (λex= 341 nm). 相似文献
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SYNTHESIS OF HYPERBRANCHED CONJUGATIVE POLY(ARYLENEETHYNYLENE)S BY ALKYNE POLYCYCLOTRIMERIZATION 总被引:2,自引:0,他引:2
A series of new hyperbranched poly(aryleneethynylene)s are synthesized by the copolycyclotrimerizations oftetraynes(Ⅰand Ⅱ)with aliphatic monoynes(A-C)catalyzed by tantalum-,niobium-,and cobalt-based catalysts.All thereactions proceed smoothly and soluble polymers of high molecular weights(M_w up to 3.8×10~4)are obtained in high yields(up to 97%). 相似文献
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《化学通报》2004,67(9):633-633
戴安邦院士 (190 1~ 1999)《化学》创办人 ,193 4~ 1948任总编辑王序院士 (1912~ 1984)1952~ 1956任主编鲁宝重 (190 3~ 1966)1957~ 1958任主编恽子强院士 (1899~ 1963 )1959~ 1963任主编陈光旭 (190 5~ 1987)1964~ 1966任主编柳大纲院士 (190 3~ 1991)1973~ 1986任主编胡亚东 (192 7~ )1987~ 1994任主编朱道本院士 (1942~ )1995~任主编《化学》——《化学通报》历任总编辑和主编(1934~2004)… 相似文献
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198 4年陈宗淇和戴闽光两位教授编撰了一本供高等学校研究生使用的教科书《胶体化学》。十几年来 ,这本书一直为国内大多数高等学校研究生教学所采用。随着科技的发展 ,胶体化学的内容不断丰实 ,无论是理论 ,抑或实用 ,在此领域都有了长足的进步。为了适应我国研究生教育发展的需要 ,本世纪初 ,我国教育部研究生工作办决定组织国内各学科的教育专家和著名学者编写一批可供高等学校研究生使用的教材 ,由陈宗淇、王广信、徐桂英三位教授编撰的《胶体与界面化学》就是其中之一。新出版的《胶体与界面化学》保留了《胶体化学》的主要特点 ,内容… 相似文献
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LIU Bo LI Xiu-Mei LI Chuan-Bi 《结构化学》2007,26(6):679-682
A novel metal-organic coordination polymer [Cd2(dpphen)2(BDC)0.5Cl3]n (dpphen = 4,7-diphenyl-1,10-phenanthroline, BDC = terephthalate) 1 has been obtained by using hydrothermal synthesis and characterized by elemental analysis, IR, fluorescence spectrum and single-crystal X-ray diffraction. The complex crystallizes in triclinic, space group P1 with a = 9.981(5), b = 10.436(5), c = 21.104(10) , α = 94.640(7), β = 103.160(7), γ = 92.958(8)o, V = 2127.8(17) 3, C52H34Cd2Cl3N4O2, Mr = 1077.98, Dc = 1.682 g/cm3, μ(MoKα) = 1.237 mm-1, F(000) = 1074, Z = 2, the final R = 0.0314 and wR = 0.0757 for 7358 observed reflections (I > 2σ(I)). Furthermore, compound 1 shows blue photoluminescent property at room temperature. 相似文献
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This paper presents a Density Functional or Time Dependent Density Functional (DFT/TDDFT) study of the molecular and electronic structures, optical absorption and emission spectra of three linkage isomers: bis(isothiocyanato-S)(2,2^1-bipyridyl) platinum(II) ([Pt(SCN)2(bpy)]), (isothiocyanato-S)(thiocyanato-N)-(2,2^1-bipy- ridyl) platinum(II) ([Pt(SCN)(NCS)(bpy)]), and bis(thiocyanato-N)(2,2^1)-bipyridyl)platinum(II) ([Pt(NCS)2(bpy)]), in which different coordination ligands based on the N- and S-coordination of the thiocyanato ligands control the luminescent color. The electronic structures were studied using the B3LYP functional. Optimized geometries Were compared to the experimentally observed structures. TDDFT calculation was carded out to investigate the excited singlet and triplet states. Calculations have been performed both in vacuo and in solvents, using a polarized continuum model (PCM) to account for solute-solvent interactions. Inclusion of the solvent led to a significant energy change, and as a consequence, the computed spectrum calculated in the presence of the solvent was in good agree- ment with the experimental determinations. The first two absorptions were found to originate from mixed plati- num-SCN (or NSC) to bipyridyl-n* transitions rather than pure metal-to-ligand-charge-transfer (MLCT) transitions, whereas the higher-energy bands arose from intraligand n→π* transitions. The stretching frequencies of C≡N have been calculated both in the ground and excited states, which are relative to the charge transition during the excitation. In addition, different sizes of basis sets were also discussed in this paper. 相似文献
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The oxidative polycondensation reaction conditions of 4-[(4-hydroxybenzylidene)amino]phenol(4-HBAP)were studied with H_2O_2,air oxygen and NaOCl in an aqueous alkaline medium between 50 and 90℃.The structures of the obtained monomer and polymer were confirmed by FT-IR,UV-Vis,~1H-and ~(13)C-NMR and elemental analysis.The characterization was made by TG-DTA,size exclusion chromatography(SEC)and solubility tests.At the optimum reaction conditions,the yield of poly[4-(4-hydroxybenzylidene amino)phenol](P-4-HBAP)was found to be 48.3%(for H_2O_2 oxidant),80.5%(for air O_2 oxidant)and 86.4%(for NaOCl oxidant).According to the SEC analysis,the number-average molecular weight(M_n),weight-average molecular weight(M_w)and polydispersity index(PDI)values of P-4-HBAP was found to be 8950,10970 g mol~(-1) and 1.225,respectively,using H_2O_2;and 11610,15190 g mol~(-1) and 1.308 respectively, using air O_2 and 7900,9610 g mol~(-1) and 1.216,respectively,using NaOCl.According to TG-DTA analyses,P-4-HBAP was more stable than 4-HBAP against thermal decomposition.The weight loss of P-4-HBAP was found to be 49.27% at 1000℃. The highest occupied molecular orbital(HOMO)and the lowest unoccupied molecular orbital(LUMO)values calculated from electrochemical measurement.Electrochemical energy gaps(E′_g)of 4-HBAP and P-4-HBAP were found to be-5.46, -5.28;-2.26,-2.67;3.20 and 2.61 eV,respectively.According to UV-Vis measurements,optical band gap(E_g)of 4-HBAP and P-4-HBAP were found to be 3.34 and 3.01 eV,respectively.Also,antimicrobial activities of 4-HBAP and P-4-HBAP were examined against selected some bacteria.The electrical conductivity of the polymer was measured after doping with iodine. 相似文献
12.
《高等学校化学研究》2005,21(6):F0003-F0003
“Chemical Research in Chinese Universities”, sponsored by Jilin University mandated by the Education Ministry of P. R. China and published by Higher Education Press in China, is a comprehensive academic journal in the field of chemistry. The journal contains original papers, research notes, letters and reviews written by faculty members, scientific researchers, postgraduates and graduate students of universities and colleges, and scientific institutes all over China and the world, and reports the latest and most creative resuits of important fundamental research in all aspects of chemistry and of developments with significant consequences across subdisciplines. 相似文献
13.
1980年5月,我从新华书店买到<化学教育>第1期杂志,如获珍宝,爱不释手,之后连年订阅,至今一期不缺,她是我的良师益友,已经伴我30年. 相似文献
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《化学通报》创刊于 1 93 4年 1月 ,原名《化学》 ,1 952年 7月改为现名。 1 966年 8月 ,《化学通报》随着“文化大革命”的来临而停刊 ,后于 1 973年 8月复刊。《化学通报》是我国复刊最早的化学期刊 ,我伴着《化学通报》走过了 3 0多年的历程。(一 )《化学通报》复刊后 ,1 973年出版 2期 ,1 974年起为双月刊 ,从第 1期开始向国内外公开发行。1 980年改为月刊。复刊时 ,1 973年第 1期发行 490 0册 ,以后逐年增加 ,到 1 979年 ,国内发行 61 4 0 0册 ,国外发行 670册。复刊后的《化学通报》 ,是以马列主义、毛泽东思想为指导方针 ,努力反映国… 相似文献
17.
KhalilFaghihi AzizollahMirsamie 《高分子科学》2005,(1):63-69
Eight novel poly(amide-imide)s were synthesized under microwave irradiation by using a domestic microwaveoven from the polycondensation reactions of N,N′-(pyromellitoyl)-bis-L-alanine diacid chloride (1) with eight different derivatives of hydantoin compounds (2a-h) in the presence of a small amount of a polar organic medium such as o-cresol. The polycondensation proceeded rapidly, compared with the conventional solution polycondensation and was completed within 8-10min, producing a series of new poly(amide-imide)s (3a-h) with inherent viscosities about 0.35-0.68dL/g in high yields. The obtained PAIs (3a-h) were fully characterized by means of FT-IR spectroscopy, elemental analyses, inherent viscosity (ηinh), solubility and specific rotation measurements. All of the resulting polymers show optical rotation and are optically active. Thermal properties of the poly(amide-imide)s were investigated by using thermal gravimetric analysis(TGA). 相似文献
18.
The Systemic Approach in Teaching and Learning Chemistry (SATLC)was established in 1997^[1-3].Our interest in developing the SATL strategy arose from the recognition of the increasing globalization of a wide specturm of human activities such as economics,media,politics,and entertainment,Systemics is our attempt to provide the student with a global view of his/her studies of chemistry. 相似文献
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哲学家和物理学家都喜欢研究和讨论“时间” ,时间之矢告诉人们光阴冉冉不复返 ,矢者失也。然而人们却总想回忆 ,寻找那些美好的或沮丧的过去 ,是安慰或自娱吧。我一直相信生活总是向前的 ,社会总是进步的 ,就和宇宙不停地膨胀一样。《化学通报》复刊已经 3 0年了 ,既然是复刊 ,必然先有停刊。历史总是把破坏和重建放在一起考虑的 ,才能找出规律。人们都说 2 0世纪是自然科学大发达的时代 ,然而 2 0世纪又是人类社会灾难最多的时代。正因如此 ,才促使科学多极化地、多样性地发展起来 ,从欧洲到美洲到亚洲 ,一点点 ,慢慢地扩散开来 ,也许 ,真… 相似文献
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The stereocontrolled synthesis of the C(17)--C(28) fragment 3 of didemnaketal B was accomplished in 21 steps from the natural (R)-(+)-pulegone and (S)-(--)-citronellal. The key steps involved diastereoselective construction of two chiral carbon centers through the intramolecular chiral induction and uncommon Julia olefination of ketone forming the E-trisubstituted C(22)--C(23) double bound. 相似文献