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951.
Enolesters as chain end-functionalizing agents for the living ring opening metathesis polymerization
Peng Liu Mohammad Yasir Helena Kurzen Nils Hanik Mark Schäfer Andreas F. M. Kilbinger 《Journal of polymer science. Part A, Polymer chemistry》2017,55(18):2983-2990
Functional enolethers have previously been used to introduce functional end groups at the chain end of ruthenium carbene complex initiated living ring opening metathesis polymers. Here, we investigated whether the weaker π-donating enolesters could equally be used in regio selective reactions with ruthenium carbene complexes and thus as polymer end-functionalization reagents. Enolesters such as vinyl acetate, butenyl acetate, 3-(4-(tert-butoxy)phenyl)propenyl acetate and 6-(((benzyloxy)carbonyl)amino)hex-1-en-1-yl acetate were used as living ROMP terminating agents. All gave the expected end groups proving that enolesters are synthetically easily accessible targets for living ROMP end-functionalization. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017 , 55, 2983–2990 相似文献
952.
Reactivity Ratios and Sequence Distribution Characterization by Quantitative 13C NMR for RAFT Synthesis of Styrene‐Acrylonitrile Copolymers 下载免费PDF全文
Md. Mahbub Alam Hui Peng Kevin S. Jack David J. T. Hill Andrew K. Whittaker 《Journal of polymer science. Part A, Polymer chemistry》2017,55(5):919-927
The kinetics and reactivity ratios of styrene‐acrylonitrile (SA) copolymerization have been studied extensively in bulk and in a variety of solution media using conventional free radical polymerizations (FRPs). Due to the significant difference in the two reactivity ratios for this monomer pair, at certain feed ratios the copolymers display composition drift with conversion due to monomer depletion. In this study, the kinetics of SA copolymerization using Reversible Addition‐Fragmentation Chain Transfer (RAFT) has been studied in bulk at 80 °C. The reactivity ratios for the terminal model were calculated from the comonomer sequence distributions for the RAFT process at low conversion for nine different compositions and found to be in the same range as those reported for conventional FRP of SA. The changes in the composition and sequence distribution with conversion were studied for three feed compositions. The copolymers show compositional drift with conversion, except at the azeotropic composition, and match the predictions from the reactivity ratios obtained at low conversion. From quantitative 13C NMR the triad distributions of these copolymers were estimated and found to match the predicted triad distributions as conversion increased. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017 , 55, 919–927 相似文献
953.
Jingshan S. Du Peng‐Cheng Chen Dr. Brian Meckes Dr. Zhuang Xie Jinghan Zhu Yuan Liu Prof. Vinayak P. Dravid Prof. Chad A. Mirkin 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2017,129(26):7733-7737
Multicomponent nanoparticles can be synthesized with either homogeneous or phase‐segregated architectures depending on the synthesis conditions and elements incorporated. To understand the parameters that determine their structural fate, multicomponent metal‐oxide nanoparticles consisting of combinations of Co, Ni, and Cu were synthesized by using scanning probe block copolymer lithography and characterized using correlated electron microscopy. These studies revealed that the miscibility, ratio of the metallic components, and the synthesis temperature determine the crystal structure and architecture of the nanoparticles. A Co‐Ni‐O system forms a rock salt structure largely owing to the miscibility of CoO and NiO, while Cu‐Ni‐O, which has large miscibility gaps, forms either homogeneous oxides, heterojunctions, or alloys depending on the annealing temperature and composition. Moreover, a higher‐ordered structure, Co‐Ni‐Cu‐O, was found to follow the behavior of lower ordered systems. 相似文献
954.
955.
He Quan Lei Han Luo Suxin Tang Ping Peng Xin Wang Xi 《Research on Chemical Intermediates》2017,43(1):353-360
Research on Chemical Intermediates - Ischemia modified albumin detection has great significance in early diagnosis and treatment of myocardial ischemia. In this study, anti-IMA was immobilized on... 相似文献
956.
基于对中西部地区15个省市农业转移人口就近城镇化意愿的问卷调查数据,以社会认同度为研究视角,构建多群组结构方程模型分析中西部地区人口就近城镇化的受教育程度差异及其影响因素。研究结果表明:个人特征差异性对中西部地区不同受教育程度的农业转移人口的就近城镇化意愿影响显著;中西部地区不同受教育程度的农业转移人口的社会认同度与其就近城镇化意愿显著正相关,且社会认同度对中西部地区小学及以下学历的农业转移人口就近城镇化意愿的影响最显著,大专及以上学历的农业转移人口的就近城镇化意愿受社会认同度的影响最小。 相似文献
957.
The one-dimensional spin 1 bilinear-biquadratic model is re-expressed in a symmetrically frustrated SU(3) model, which facilitates us to introduce a fermionic representation and related bond-operator mean-field theory. By analyzing the gap and the static spin susceptibility, we shows that this treatment can easily capture the commensurate and incommensurate Haldane gap phases. 相似文献
958.
959.
生长因子受体结合蛋白2(Grb2)在致癌基因Ras活化的信号传导通路中起着关键作用,目前被广泛认为是抗肿瘤药物设计的优秀靶标.对Grb2-SH2抑制剂的研究进展进行了综述,主要针对关键残基磷酸酪氨酸的高电荷性和多肽结构的低生物相容性两个缺陷,基于天然配体与Grb2-SH2相互作用的结构特征,围绕提高活性和简化结构开展的系统构效关系和合理结构优化研究,为进一步开发磷酸酪氨酸介导的Grb2-SH2抑制剂成为新型抗肿瘤药物提供结构和理论基础. 相似文献
960.