共查询到20条相似文献,搜索用时 15 毫秒
1.
CHENLi CHENXue-si DENGMing-xiao JINGXia-bin 《高等学校化学研究》2005,21(3):340-344
A biodegradable ABBA block copolymer was synthesized via the ring-opening co-polymerization of ε-Scaprolactone (CL, B) and glycolide (A) by means of step polymerization in the presence of ethylene glycol as an initiator and stannous octanoate as a catalyst at 110 ℃ for 48 h. The molecular length of the PCL prepolymer(BB) could be adjusted by controlling the molar ratio of the ethylene glycol initiator to ε-caprolactone monomer. The structure and the composition of the block copolymer were determined by the weight ratio of the monomer glycolide (A) to PCL pre-polymer(BB). The block copolymers were characterized by ^1H NMR, GPC, DSC and X-ray. The results confirm the successful synthesis of an ABBA block copolymer. 相似文献
2.
<正>A series of H-shaped(PS)_2PEG(PS)_2 block copolymers with different PS chain lengths were prepared.The influence of different confinements active on the crystallization and self-nucleation(SN) behavior of the PEG blocks was investigated by differential scanning calorimetry(DSC).When the content of the crystalline block was high,a classical SN behavior was obtained.The block copolymer with PEG content of 49%(by weight) showed a classical SN behavior with a narrow self-nucleation domain and had bimodal crystallization exotherms.When the PEG dispersed as separated microdomains in the block copolymer,the self-nucleation domain disappeared and only annealing was observed. 相似文献
3.
A block copolymer composed of hydrophilic and crystallinic polyethylene oxide and hydrophobic and non-crystallinic polymethyl methacrylate (PMMA) was prepared by sequential initiation of alkoxy-anion and charge transfer complex using p-aminophenol as parent compound. The structure of copolymer was characterized by GPC, IR, 1H NMR and DSC in detail. The propagation of PMMA chain is dependent on the molecular weight and concentration of the first block PEO and also the polarity of solvents. The reasons are discussed. 相似文献
4.
Bing-Yong Liu Cong Xie Cong-Wu Ge Meng-Meng Cui Wei Yang Zai-Fei Ma Xi-Ke Gao Yin-Hua Zhou Qing Zhang 《高分子科学》2022,40(2):147-156
Benzobisthiazole polymer with resonance-assisted hydrogen bonds(RAHBs)has been synthesized for both organic field-effect transistor and polymer solar cell applications.The properties of the hydrogen bonded polymer are compared with the reference polymer without RAHBs.Single-crystal X-ray diffraction analyses of the building block reveal that the RAHB interactions are formed between the carbamate hydrogen and imine nitrogen of the thiazoles.The hydrogen donor and acceptor are connected byπ-conjugated molecular framework and the hydrogen-bridged quasi aromatic rings lock the conformation of the building block.The building block adopted a layered sandwich packing in crystal instead of slipped herringbone stacking which was often found in the crystal of benzobisthiazole derivatives.The polymer PCBTZ-TT with RAHBs showed deeper HOMO/LUMO energy level(about 0.2 eV)than reference polymer.The PCBTZ-TT demonstrated the hole mobility of0.96 cm2·V-1·s-1 in field-effect transistor devices and achieved power conversion efficiency of 13.6%in solar cell devices with Y6 as acceptor without any additive. 相似文献
5.
Phosphatdylcholines and their analogs, the functional building block of the membrane, are recently found to mediate multiple physiological processes and exhibit a broad range of desirable pharmacological effects, which involve hydrophobic lipophilic interactions (HLI) between the phospholipid and the cell membrane. The HLI behavior of phosphatJdylcholines (Ln) and their analogues 1, 2-diacyl-sn-glycerol-3-phosphoric acid bromoethyl ester (Pn), have been investigated in MeOH-H20 binary systems of different volume fractions (designated as Φ) of the organic component, by employing α-nephthylethyl lauryl ether (Np-12) as fluorescent probe. A very interesting observation is that the Ln possesses double character, i. e., it behaves both as an aggregator and as a deaggregator. The effects of the structure and the environment on the coaggregation and deaggregtion are also discussed. 相似文献
6.
In the present paper the synthesis of block copolymers via the transformation from living anionic polymerization (LAP) to atom transfer radical polymerization (ATRP) was described. Α-Bromine-terminated polystyrenes(PStBr) in the LAP step was prepared by using n-BuLi as initiator, tetrahydrofuran (THF) as the activator, α-methylstyrene (α-MeSt) as the capping group and liquid bromine (Br2) as the bromating agent. The effects of reaction conditions such as the amounts of α-MeSt, THF, and Br2 as well as molecular weight of polystyrene on the bromating efficiency (BE) and coupling extent (CE) were examined. The present results show that the yield of PStBr obtained was more than 93.8% and the coupling reaction was substantially absent. PStBr was further used as the macroinitiator in the polymerization of methyl-methacrylate(MMA) in the presence of copper(Ⅰ) halogen and 2,2-bipyridine(bpy) complexes. It was found that the molecular weight of the resulted PSt-b-PMMA increased linearly with the increase of the conversion of MMA and the polydispersity was 1.2-1.6. The structures of PStBr and P(St-b-MMA) were characterized by 1H NMR spectra. 相似文献
7.
Curcurbit[n]uril(Q[n])-based supramolecular frameworks(QSFs) constructed from the outer surface interaction of Q[n]s(OSIQ) have the characteristic of simplicity,diversity and modulability.Their simplicity is reflected in their simple composition and preparation methods used for QSFs.The diversity of supramolecular organic frameworks(SOFs) is reflected in the synthesis methods and structural characteristics of the as-obtained QSFs,as well as the variety of structural directing agents and basic building blocks used to prepare QSFs.The modulability is reflected by the controllable channel size in the QSFs,which can be adjusted using different sizes of Q[n]s.In this work,the first re ported cucurbituril Q[6]was selected as the basic building block and three Q[6]-based su p ramolecular frameworks were obtained from aqueous HCl solutions in the presence of [CdCl4]2-respectively.The OSIQs are the main driving forces for the formation of these frameworks.This study shows the diversity of the QSFs. 相似文献
8.
SITU Yue HUANG Shao-Bin 《结构化学》2003,(4)
1 INTRODUCTION The design of heterometallic complexes of photoluminescnece is of current interest for the inorganic chemists[1, 2]. The coordination flexibility of -dppm ligand as well as the easy substitution of weakly coordinated solvate donors by stronger donors makes the binuclear compound [M2(m- dppm)2(sol)2]2+ excellent building block for con- structing various molecular materials with desired properties[3~5]. We are devoted to developing heterometallic photoluminescent transitio… 相似文献
9.
The asymmetric reaction of the chiron 2(5H )-furanones (4a-4c) with the Horner-Emmons reagents (5a-5b) has been investigated. The newly chirai organophosphorus derivatives 6 and 7 were obtained using the phosphoryl-stabilized carbanion as a building block in DMSO under mild conditions. Through the asymmetric introduction, the Horner-Emmons reagent could be transformed to a chiral building block to afford the novel functionalized phosphorus derivatives. The structures of the synthesized compounds 6 and 7 were identified on the basis of their elementary and spectroscopic data, such as IR,^1H NMR, ^13C NMR, MS and X-ray crystallography. These resuits provided a valuable approach to the synthesis of potentially interesting chirai organophosphorus derivatives and probing their biological activities. 相似文献
10.
Polyazoamide(PAA) was used as initiator to prepare block copolymer P(MMA-b-St) byfree radical polymerization. The fraction of block copolymer was about 50%. The structureof the block-copolymer was characterized by IR and the results of ~1H-NMR and GPCshowed that the content of the block and the molecular weight (M_w) of the prepolymerand block copolymer could be controlled by varying the mol ratio of styrene/PAA andMMA/prepolymer. DSC and TEM results revealed that the block copolymer has twoseparated glass transition temperatures and phase separation within the domain structure. 相似文献
11.
The general strategy to construct D-A type conjugated polymers is alternating copolymerization of electron-donating(D)monomer and electron-accepting(A) monomer. In this article, we report a new strategy to develop D-A type conjugated polymers, i.e. first fuse the D and A units into a polycyclic structure to produce a building block and then polymerize the building block with another unit. We develop a new building block with ladder structure based on B←N unit, B←N bridged dipyridylbenzene(BNDPB). In the skeleton of BNDPB, one diamine-substituted phenylene ring(D unit) and two B←N-linked pyridyl rings(A unit) are fused together to produce the polycyclic structure. Owning to the presence of intramolecular D-A character, the building block itself exhibits narrow bandgap of 1.74 eV. The conjugated polymers based on BNDPB show unique electronic structures, i.e. localized HOMOs and delocalized LUMOs, which are rarely observed for conventional D-A conjugated polymers. The polymers exhibit smaller bandgap than that of the building block BNDPB and display near-infrared(NIR)light absorption(λabs=ca. 700 nm). This study thus provides not only a new strategy to design D-A conjugated polymers but also a new kind of building block with narrow bandgap. 相似文献
12.
A novel and simple procedure for the enantiospecific synthesis of penehyclidine hydrochloride (8018) isomers and the R configuration derivatives was described. The intramolecular asymmetric cyclization of the monosulfonate of compound 1,2-diol was applied to the execution of the synthesis of the key chiral building block for the first time. The aimed products were obtained with moderate yield in〉99% ee. 相似文献
13.
《Journal of Energy Chemistry》2015,(6)
A n-type small molecule DC-IDT2 F, with 4,4,9,9-tetrakis(4-hexylphenyl)-indaceno[1,2-b:5,6-b]dithiophene as a central building block, furan as π-bridges, and 1,1-dicyanomethylene-3-indanone as end acceptor groups,was synthesized and used as an electron acceptor in solution-processed organic solar cells(OSCs). DC-IDT2 F exhibited good thermal stability, broad and strong absorption in 500–850 nm, a narrow bandgap of 1.54 e V,LUMO of –3.88 eV, HOMO of –5.44 eV and an electron mobility of 6.5 × 10–4cm2/(V·s). DC-IDT2F-based OSCs with conventional and inverted structures exhibited power conversion efficiencies of 2.26 and 3.08%, respectively. The effect of vertical phase separation and morphology of the active layer on the device performance in the two structures was studied. 相似文献
14.
15.
Synthesis, Crystal Structure and Antibacterial Activity of 1-((2-Chloroquinolin-3-yl)-methyl)-pyridin-2(1H)-one 总被引:1,自引:0,他引:1
S. Mohana Roopan Venkatesha R. Hathwar F. Nawaz Khan Atul Kumar Kushwaha 《结构化学》2010,29(11):1612-1617
On the basis of the interesting structures and biological activities exhibited by several heterocyclic systems possessing the pyridone nucleus such as mappcine and camptothecin, we have planed to design the synthesis, crystal studies and antibacterial activity of the new 1-((2- chloroquinolin-3yl)-methyl)-pyridine-2(1H)-one building block. An X-ray analysis has provided valuable insight into the effect of steric factors on the three-dimensional shape of this compound which serves as a useful advanced intermediate in the synthesis of these biologically active molecules. A multistep synthesis of camptothecin (5) has been designed by retrosynthetic analysis as part of an ongoing program on lead anticancer drug. 相似文献
16.
Xin-tao Shuai Zbigniew Jedlinski Qiang Luo Nozirow Farhod Institute of Chemistry Chinese Academy of Sciences Beijing China Institute of Polymer Chemistry Polish Academy of Sciences - Zabrze Poland Institute of Synthetic Fibre Chinese Academy of Textile Sciences Beijing China 《高分子科学》2000,(1):19-23
A novel kind of copolymer with ABA-type block structure was synthesized by anionic ring-openingpolymerization of β-butyrolactone (β-BL) in the presence of a PEG-based dicarboxylates as macroinitiators which wereprepared by the esterification of aliphatic cyclic anhydride and poly(ethylene glycol) (PEG) oligomers (M_n=2000, 4000 and6000) and conversion of potassium dicarboxylates. The resultant copolymers as well as the intermediates were characterizedby IR,~1H-NMR and GPC. 相似文献
17.
A new method to synthesize a degradable terminal amino group-containing copolymer,poly(ethylene glycol)-b- poly(ε-caprolactone)(MPEG-PCL-NH_2),was developed in the following three steps:(1)the ring-opening polymerization (ROP)ofε-caprolactone from the Schiff base prepared from benzatdehyde and ethanolamine(Ph-CH=NCH_2CH_2OH)used as an initiator to obtain heterobifunctional poly(ε-caprolactone)with one terminal Schiff base group and one hydroxyl group (HO-PCL-CH_2CH_2N=CH-Ph);(2)the coupling reaction of two reactive precursors,a hydroxy-terminated HO-PCL- CH_2CH_2N=CH-Ph andα-monocarboxy-ω-monomethoxy poly(ethylene glycol)(CMPEG)to synthesize MPEG-PCL- CH_2CH_2N=CH-Ph;(3)the conversion of the -N=CH-Ph end-group into NH_2 end-group by acidification of acetic acid to obtain MPEG-PCL-NH_2.The structures from the precursors to the terminal amino group-containing copolymer were confirmed by ~1H-NMR and their molecular weights were measured by gel permeation chromatography.The amphiphilic terminal amino group-containing copolymer could self-assemble into micelles in an aqueous system with PCL block as the core and PEG block as the shell.The micelle formation of the terminal amino group-containing block copolymer was studied by fluorescent probe technique and the existence of critical micellar concentration(cmc)confirmed the amphiphilic nature of the resulting copolymer.ESEM and DLS analysis of the micelles revealed a homogeneous spherical morphology and a unimodal size distribution. 相似文献
18.
Zhang Kai Liu ShengJian Guan Xing Duan ChunHui Zhang Jie Zhong ChengMei Wang Lei Huang Fei Cao Yong 《中国科学:化学(英文版)》2012,55(5):765-770
A series of alkali metal salts doped pluronic block copolymer F127 were used as electron injection/transport layers (ETLs) for polymer light-emitting diodes with poly[2-(4-(3′,7′-dimethyloctyloxy)-phenyl)-p-phenylenevinylene] (P-PPV) as the emission layer. It was found that the electron transport capability of F127 can be effectively enhanced by doping with alkali metal salts. By using Li2CO3 (15%) doped F127 as ETL, the resulting device exhibited improved performance with a maximum luminous efficiency (LE) of 13.59 cd/A and a maximum brightness of 5529 cd/m2, while the device with undoped F127 as ETL only showed a maximum LE of 8.78 cd/A and a maximum brightness of 2952 cd/m2. The effects of the doping concentration, cations and anions of the alkali metal salts on the performance of the resulting devices were investigated. It was found that most of the alkali metal salt dopants can dramatically enhance the electron transport capability of F127 ETL and the performance of the resulting devices was greatly improved. 相似文献
19.
Lys(z)-NCA was synthesized in the presence of triphosgene, amphiphilic triblock copolymers poly(N^c-CBZ-Lysine)-PEG-poly(N^c-CBZ-Lysine) were synthesized in DMF using amino-end ended PEG as initiator with the mechanism of anion ring opening polymerization. The structures of block copolymers were characterized by IR, ^1H-NMR,GPC and DSC. The results showed triblock copolymers with expected structure and low polydispersity in molecular weight could be synthesized by this method. At the same time, the self-assembling behaviors of block copolymer were investigated by TEM. A novel helical aggregates were found to be formed in DMF. Because of biocompatibility of two components of block copolymers, these block copolymers have potential applications in the field of biomaterials. 相似文献
20.
A series of multicomponent hydrogels were prepared by the copolymerization of hydrophobic silicon-containing monomer 3-bis(trimethylsilyloxy) methylsilylpropyl glycerol methacrylate(Si MA) with the solvent-responsive monomers 2-hydroxyethyl methacrylate(HEMA) and N-vinyl pyrrolidone(NVP) and thermosensitive monomer N,N-dimethyl acrylamide(DMA). 2-Hydroxy-2-methyl phenyl acetone(D-1173) was chosen as UV initiator and five different dienes/triene monomers were selected as crosslinking agent in order to select the best crosslinker. The ethanol extraction experiments as well as the FTIR, DSC and TG results showed that the copolymerization was effective. The optical, permeability, and mechanical analysis results demonstrated that the obtained hydrogels were highly transparent with good oxygen permeability and mechanical properties. And the impact of crosslinker on the mechanical properties of the hydrogels was also discussed in detail. The basic results demonstrated that the obtained hydrogels had good stimuli-responsive effects to both p H value and solvent. 相似文献