共查询到20条相似文献,搜索用时 14 毫秒
1.
2.
金属-超分子聚合物是由金属离子与配体之间的相互作用形成的,是一类具有多样化几何构造和拓扑结构的新型功能高分子,它包括线型、接枝、交联、树枝等多种骨架结构.金属-超分子聚合物具有光、电、磁等特性,因此潜在的应用前景非常广阔,不仅可以在生物医用、分子器件、纳米材料,还可以在催化化学反应及吸附储氢等领域获得应用.由于吡啶基团为常用配体,且近年含吡啶基团的金属-超分子聚合物研究最为广泛,最为代表性,因此,本文以聚合物结构分类对近几年含吡啶基团的金属-超分子聚合物的研究进展作了简要综述. 相似文献
3.
It was established that linear polymers with quaternary ammonium groups are obtained by the reaction of chloromethylated polystyrene (CMPS) with hydroxyalkylic tertiary amines when the amines contain one or two hydroxyl groups, and that crosslinked polymers are obtained with aminoether groups when the amines have three hydroxyl groups, i.e., tris(2-hydroxyethy1)amine. The aminoether units appear by intramolecular rearrangement of quaternary ammonium structural units. Kinetic studies on the synthesis of polymers with quaternary ammonium groups from CMPS, poly(N,N-dimethylamino-ethylmethacrylate), and poly(N,N-dimethylaminopropylacrylamide), were performed. The main factors which influence the kinetics of reactions are steric hindrance of near neighboring groups, hydrophilic effect for hydroxyalkylamines and polymer-solvent interaction. 相似文献
4.
5.
6.
Endcapping of oligo(oxyethylene) glycols was carried out by transesterification of methyl N,N-dimethylaminobenzoate with sodium methoxide as the catalyst or by the reaction of sodium salicylate with the ditosyl ester of the oligo(oxyethyl-ene) glycols. Several other common reactions were tried for the endcapping of the oligo(oxyethylene) glycols but were found to be either more cumbersome or unsuccessful. All products were obtained in high yield and high purity. The reactions of tetraalkylammonium carboxylates with aliphatic halides were found to be very general and mild reactions for the preparation of esters in high yield and high purity. It was found that these reactions could be utilized for the preparation of esters on polymers even if the carboxylate group was directly attached to the polymer chain. It was also demonstrated that the aliphatic halide group could be on the polymer, as in the case of polyepichlorohydrin. Copolymers of epichlorohydrin and glycidyl N,N-dimethylaminobenzoate with up to 90% glycidyl benzoate as the comonomer were prepared, and poly(tetra-butylammonium methacrylate) was effectively transformed with 4-(2-bromoethoxy)-2-hydroxybenzophenone into the corresponding ester. The products were characterized by the usual spectral means. 相似文献
7.
Photoinduced Crosslinking of Polymers Containing Pendant Hydroxyl Groups by Using Bisbenzodioxinones
In the present study, it has been demonstrated that polymers containing pendant hydroxyl groups can undergo photoinduced crosslinking upon irradiation in the presence of bifunctional benzodioxinone. Irradiation of the copolymers of 2‐hydroxyethyl methacrylate (HEMA) and methyl methacrylate (MMA) in dichloromethane and THF solutions or in films containing bisbenzodioxinone, namely 5‐[9‐(4‐oxo‐2,2‐diphenyl‐4H‐benzo[d][1,3]dioxin‐5‐yloxy) nonyloxy]‐2,2‐diphenyl‐4H‐benzo[d][1,3]dioxin‐4‐one resulted in the formation of insoluble networks. Model studies using monofunctional napthodioxinone, namely 7‐hydroxy‐2,2‐diphenyl‐4H‐naphtho[2,3‐d][1,3]dioxin‐4‐one, revealed that crosslinking occurs via inter‐chain ester formation between photochemically generated keten intermediates and pendant hydroxyl groups.
8.
Three types of porous polymers containing different functional groups were synthesized as stationary phases for gas chromatography. The influence of functional groups in the copolymer skeletons on their selectivities was studied. To determine the selectivities of these copolymers, two procedures were applied: the selectivity triangle and the general selectivity. As a reference phase Porapak Q which does not contain any functional groups was used. 相似文献
9.
Abstract Two new methacryloyl ureas, 1-(2-methylacryloyl)-3-(2,2,6,6-tetra-methylpiperidin-4-yl)-urea and 1-butyl-3-(2-methylacryloyl)-1-(2,2,6,6-tetramethylpiperidin-4-yl)-urea (monomer I and monomer II), were prepared by the addition reaction of 2-methylacryloyl iso-cyanate with 2,2,6,6-tetramethylpiperidin-4-yl-amine or butyl-(2,2,6,6-tetramethylpiperidin-4-yl)-amine in a molar ratio of 1:1 at low or room temperature. In a similar way, the syntheses of two new methacryloyl carbamates, 1-(2,2,6,6-tetra-methylpiperidin-4-yl)-3-(2-methylacryloyl)-carbamate and l-(1,2,2,6,6-pentamethyl-piperidin-4-yl)-3-(2-methylacryloyl)-carbamate (monomer III and monomer IV), were completed by the reaction of 2,2,6,6-tetra-methylpiperidin-4-ol or 1,2,2,6,6-pentamethylpiperidin-4-ol with 2-methylacryloyl isocyanate in the presence of dibutyltin dilaurate as catalyst at 60°C. The four new monomers were homopolymerized, and copolymerized with styrene by AIBN as initiator at 70°C. The structures of the new monomers and their polymers were characterized by FT-IR and NMR spectroscopy and by GPC. 相似文献
10.
GuillermoR. Labadie LilianaE. Luna RaquelM. Cravero Manuel Gonzlez‐Sierra 《Helvetica chimica acta》2006,89(11):2732-2737
The partial structure 2 of the bisketal‐type, tetracyclic saudin ( 1 ), an important natural product, was de novo synthesized. A key step was the Jones oxidation of the epoxide 3 , which gave rise to epoxide‐ring opening, followed by acetal hydrolysis, alcohol oxidation, and, finally, intramolecular acetal formation. The resulting key intermediate was finally oxidized to the target lactone 2 . 相似文献
11.
用后功能化方法合成了两类连有吲哚二阶非线性光学发色团侧基的高分子.通过核磁、红外、紫外-可见、示差扫描量热分析、分子量测定等手段对所得高分子进行了鉴定.此合成方法简便易行,易于产物的分离提纯,为二阶非线性光学材料的合成提供了一种新方法. 相似文献
12.
发光聚合物一般是由具有大p电子系统的共轭基元作为发光单元, 通过共价键连接而成的高分子. 近年来, 研究者发现: 另一类仅含有脂肪胺、羰基、酯基、酰胺等传统意义上的助色团的聚合物在适当条件下也能发射强的荧光. 树枝状聚酰胺胺(PAMAM)和超支化聚酰胺胺(hb-PAMAM)是最早和最广泛被研究的含非典型性荧光生色团的聚合物. 最近, 这类聚合物被扩展到含有叔胺基元的聚氨酯、聚醚酰胺、聚脲体系. 这些体系的生色团被认定为其结构中的叔胺基元, 叔胺的氧化是荧光产生的根源. 同时, 也有文献报道马来酸酐与醋酸乙烯酯交替共聚物、异丁烯与顺丁烯二酸酐共聚物、聚多糖动态高分子、聚酰腙以及通过RAFT试剂制备的含聚三硫碳酸酯的多嵌段共聚物等也可以发射荧光. 这些聚合物的一个共同特点是结构中不含叔胺基元, 而仅含羰基和酯基, 其发光机理通常用多个羰基聚集效应或羰基和苯环之间的相互作用来解释. 相似文献
13.
Preparation of second order nonlinear optic (NLO) materials based on cellulose diacetate and melamine derivatives was tried. The NLO chromophore sodium [4′‐(N, N‐dihydroxyethyl) amino] phenyl‐4‐azo‐benzene sulfonate incorporated into the crosslinking network resulted from cellulose diacetate and trimethylolmelamine or hexamethylolmelamine. The poled and cured NLO materials exhibited the electrooptic coefficient r13 of 1.72 pm/V or 1.15 pm/V at the laser wavelength of 1550 nm, modulation frequency of 12.7 kHz, and the r13 value decreased to 71.5% or 81.5% of the initial values after 4 days. The laser transmission loss was 0.94 dB or 1.76 dB. The crosslinking materials showed better temporal stability than the material of the host/guest type. The results of FTIR, dielectric relaxation, and TGA proved the formation of the crosslinking structure and that the dielectric relaxation was suppressed by higher crosslinking density. 相似文献
14.
Jia‐Hui Pan Juan‐Juan Deng Yi‐Guang Chen Jun‐Ping Gao Yong‐Cheng Lin Zhi‐Gang She Yu‐Cheng Gu 《Helvetica chimica acta》2010,93(7):1369-1374
A new lactone, 1,8‐dihydroxy‐10‐methoxy‐3‐methyldibenzo[b,e]oxepine‐6,11‐dione ( 1 ), and two new xanthones, 1‐hydroxy‐8‐(hydroxymethyl)‐6‐methoxy‐3‐methyl‐9H‐xanthen‐9‐one ( 2 ) and 1‐hydroxy‐8‐(hydroxymethyl)‐3‐methoxy‐6‐methyl‐9H‐xanthen‐9‐one ( 3 ), were isolated from a mangrove endophytic fungus Phoma sp. SK3RW1M collected from the South China Sea. This is the first report on xanthone derivatives isolated as secondary metabolites from Phoma species. Their structures were elucidated by spectroscopic methods, mainly 1D‐ and 2D‐NMR techniques, and the structure of compound 2 was confirmed by X‐ray crystallography. Cytotoxicity assays showed that compounds 1 – 3 were inactive against KB and KBv200 cells. 相似文献
15.
16.
17.
18.
19.