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1.
Yu Zhang Keke Gao Zhongfu Zhao Dongmei Yue Yanming Hu Toshio Masuda 《Journal of polymer science. Part A, Polymer chemistry》2013,51(24):5248-5256
Novel acetylenic monomers containing Schiff‐base and amino groups, (S)‐N‐(4‐ethynylbenzylidene)‐1‐phenylethanamine ( 1a ), (R)‐N‐(4‐ethynylbenzylidene)‐1‐phenylethanamine ( 1b ), N‐(4‐ethynylbenzylidene)‐1‐phenylethanamine ( 1c ), (R)‐N‐(4‐ethynylbenzyl)‐1‐phenylethanamine ( 1d ), and (R)‐N‐(4‐ethynylbenzyl)‐1‐phenylethanamine ( 1e ) were synthesized and polymerized with [(nbd)RhCl]2/Et3N catalyst to afford the corresponding polymers 2a ‐ e with moderate molecular weights (Mn = 9000–60,000) in high yields (85–97%). All the polymers were soluble in common organic solvents including toluene, CHCl3, CH2Cl2, THF, and DMF. Large optical rotations and strong CD signals demonstrated that 2a , 2b , 2d , and 2e take helical structures with a predominantly one‐handed screw sense. The effects of solvents and temperature revealed that these polymers took dynamic helical structure based on the steric effect of side groups. The CD patterns of 2d and 2e containing free amino moieties were completely inverted by the addition of benzoic acid. Upon further addition of NaOH, the CD pattern returned to the original one, indicating the reversible conformational change of these polymers according to pH. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2013 , 51, 5248–5256 相似文献
2.
Erwin Abdul Rahim Fumio Sanda Toshio Masuda 《Journal of polymer science. Part A, Polymer chemistry》2006,44(2):810-819
Novel optically active amino acid based polyacetylenes bearing eugenol and fluorene moieties were synthesized, and their properties, including chiroptical ones, were analyzed. N‐[1‐(3,4‐Dimethoxyphenyl)‐2‐propyloxycarbonyl]‐L ‐alanine N′‐propargylamide ( 1 ), N‐[1‐(3,4‐dimethoxyphenyl)‐2‐propyloxycarbonyl]‐L ‐alanine propargyl ester ( 2 ), N‐(9‐fluorenylmethoxycarbonyl)‐L ‐alanine N′‐propargylamide ( 3 ), and N‐(9‐fluorenylmethoxycarbonyl)‐L ‐alanine propargyl ester ( 4 ) were polymerized with a rhodium‐zwitterion catalyst in tetrahydrofuran to afford the corresponding polymers with moderate molecular weights ranging from 10,800 to 17,300 in good yields. Because of the large specific rotation and circular dichroism (CD) signal, it was concluded that the poly(N‐propargylamide)s [poly( 1 ) and poly( 3 )] took a helical structure with a predominantly one‐handed screw sense. The solvent and temperature could tune the helical structure of poly( 1 ). On the other hand, the poly(propargyl ester)s [poly( 2 ) and poly( 4 )] exhibited only small specific rotations and CD signals. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 810–819, 2006 相似文献
3.
Jianping Deng Xiaofeng Luo Weiguo Zhao Wantai Yang 《Journal of polymer science. Part A, Polymer chemistry》2008,46(12):4112-4121
This article presents two novel artificial helical polymers, substituted polyacetylenes with urea groups in side chains. Poly( 4 ) and poly( 5 ) can be obtained in high yields (≥97%) and with moderate molecular weights (11,000–14,000). Poly( 4 ) contains chiral centers in side chains, and poly( 5 ) is an achiral polymer. Both of the two polymers adopted helical structures under certain conditions. More interestingly, poly( 4 ) exhibited large specific optical rotations, resulting from the predominant one‐handed screw sense. The helical conformation in poly( 5 ) was stable against heat, while poly( 4 ) underwent conformational transition from helix to random coil upon increasing temperature from 0 to 55 °C. Solvents had considerable influence on the stability of the helical conformation in poly( 4 ). The screw sense adopted by the helices was also largely affected by the nature of the solvent. Poly( 4 ‐co‐ 5 )s formed helical conformation and showed large optical rotations, following the Sergeants and Soldiers rule. By comparing the present two polymers (with one ? N? H groups) with the three polymers previously reported (with two ? N? H groups in side chains), the nature of the hydrogen bonds formed between the neighboring urea groups played big roles in the formation of stable helical conformation. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 4112–4121, 2008 相似文献
4.
Zhigang Zhang Jianping Deng Weiguo Zhao Jianmin Wang Wantai Yang 《Journal of polymer science. Part A, Polymer chemistry》2007,45(3):500-508
A novel chiral N‐propargylsulfamide monomer ( 1a ) and its enantiomer ( 1b ) were synthesized and polymerized with (nbd)Rh+B?(C6H5)4 as a catalyst providing poly(1) (poly( 1a ) and poly( 1b )) in high yields (≥99%). Poly(1) could take stable helices in less polar solvents (chloroform and THF), demonstrated by strong circular dichroism signals and UV–vis absorption peaks at about 415 nm and the large specific rotations; but in more polar solvents including DMF and DMSO, poly(1) failed to form helix. Quantitative evaluation with anisotropy factor showed that the helical screw sense had a relatively high thermal stability. These results together with the IR spectra measured in solvents showed that hydrogen bonding between the neighboring sulfamide groups is one of the main driving forces for poly(1) to adopt stable helices. In addition, copolymerization of monomer 1a and monomer 2 was conducted, the solubility of poly(1) was improved drastically. However, the copolymerization had adverse effects on the formation of stable helices in the copolymers. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 500–508, 2007 相似文献
5.
Synthesis,Characterization, and thermoresponsive properties of Helical Polypeptides Derivatized from Poly(γ−4‐(3‐chloropropoxycarbonyl)benzyl‐L‐glutamate) 下载免费PDF全文
Yong Deng Xi Wang Qiulin Yuan Mengxiang Zhu Ying Ling Haoyu Tang 《Journal of polymer science. Part A, Polymer chemistry》2015,53(21):2469-2480
A series of side‐chain‐functionalized α‐helical polypeptides, i.e., poly(γ‐4‐(3‐chloropropoxycarbonyl)benzyl‐L‐glutamate) (6) have been prepared from n‐butylamine initiated ring‐opening polymerization (ROP) of γ‐4‐(3‐chloropropoxycarbonyl)benzyl‐L‐glutamic acid‐based N‐carboxyanhydride. Polypeptides bearing oligo‐ethylene‐glycol (OEG) groups or 1‐butylimidazolium salts were prepared from 6 via copper‐mediated [2+3] alkyne‐azide 1,3‐dipolar cycloaddition or nuleophilic substitution, respectively. CD and FTIR analysis revealed that the polymers adopt α‐helical conformations both in solution and the solid state. Polymers bearing OEG (m = 3) side‐chains showed reversible LCST‐type phase transition behaviors in water while polymers bearing 1‐butylimidazolium and I? counter‐anions exhibited reversible UCST‐type transitions in water. Variable‐temperature UV‐vis analysis revealed that the phase transition temperatures (Tpts) were dependent on the main‐chain length and polymeric concentration. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2015 , 53, 2469–2480 相似文献
6.
Jinqing Qu Toru Fujii Toru Katsumata Yuji Suzuki Masashi Shiotsuki Fumio Sanda Masaharu Satoh Jun Wada Toshio Masuda 《Journal of polymer science. Part A, Polymer chemistry》2007,45(23):5431-5445
2,2,6,6‐Tetramethyl‐1‐piperidinyloxy (TEMPO)‐ and 2,2,5,5‐tetramethyl‐1‐pyrrolidinyloxy (PROXYL)‐containing (R)‐1‐methylpropargyl TEMPO‐4‐carboxylate ( 1 ), (R)‐1‐methylpropargyl PROXYL‐3‐carboxylate ( 2 ), (rac)‐1‐methylpropargyl PROXYL‐3‐carboxylate ( 3 ), (S)‐1‐propargylcarbamoylethyl TEMPO‐4‐carboxylate ( 4 ), and (S)‐1‐propargyloxycarbonylethyl TEMPO‐4‐carboxylate ( 5 ) (TEMPO, PROXYL) were polymerized to afford novel polymers containing the TEMPO and PROXYL radicals at high densities. Monomers 1–3 and 5 provided polymers with moderate number‐average molecular weights of 8200–140,900 in 49–97% yields in the presence of (nbd)Rh+[η6‐C6H5B?(C6H5)3], whereas 4 gave no polymer with this catalyst but gave polymers possessing low Mn (3800–7500) in 56–61% yield with [(nbd)RhCl]2‐Et3N. Poly( 1 ), poly( 2 ), and poly( 4 ) took a helical structure with predominantly one‐handed screw sense in THF and CHCl3 as well as in film state. The helical structure of poly( 1 ) and poly( 2 ) was stable upon heating and addition of MeOH, whereas poly( 4 ) was responsive to heat and solvents. All of the free radical‐containing polymers displayed the reversible charge/discharge processes, whose capacities were in a range of 43.2–112 A h/kg. In particular, the capacities of poly( 2 )–poly( 5 )‐based cells reached about 90–100% of the theoretical values regardless of the secondary structure of the polymer, helix and random. Poly( 1 ), poly( 2 ), and poly( 4 ) taking a helical structure exhibited better capacity tolerance towards the increase of current density than nonhelical poly( 3 ) and poly( 5 ) did. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 5431–5445, 2007 相似文献
7.
Jianli Hua Jacky Wing Yip Lam Xiaoming Yu Lijun Wu Hoi Sing Kwok Kam Sing Wong Ben Zhong Tang 《Journal of polymer science. Part A, Polymer chemistry》2008,46(6):2025-2037
Perylene (Py)‐containing polyacetylenes with different skeleton structures ? [HC?C(C6H4)CO2? Py]n? (P 1 ), ? [HC?C(CH2)8CO2? Py]n? (P 2 ), and ? {[(C6H5) C?C(CH2)9NH2]? co? [(C6H5)C?C(CH2)9? Py]}n? (P 3 ) are synthesized in satisfactory yields by Rh‐catalyzed polymerization (for P 1 and P 2 ) and polymer reaction (for P 3 ). All the polymers are soluble and possess high molecular weights (Mw up to 2.8 × 105). Their structures and properties are characterized and evaluated by IR, NMR, UV, TGA, PL, and photovoltaic (PV) analyses. The polymers are thermally stable, losing little of their weights when heated to 330 °C. When their solutions are irradiated, their perylene pendants emit intense red fluorescence at 610 nm. PV cells with a configuration of ITO/PEDOT:PSS/polymer/LiF/Al are fabricated, which show maximum current density of 10.3 μA/cm2. The external quantum efficiency is sensitive to the polymer structure, with P 3 exhibiting the highest value of 0.23%. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 2025–2037, 2008 相似文献
8.
Ryohei Kakuchi Ryotaro Shimada Yasuyuki Tago Ryosuke Sakai Toshifumi Satoh Toyoji Kakuchi 《Journal of polymer science. Part A, Polymer chemistry》2010,48(8):1683-1689
The colorimetric detection of anionic species has been studied for α‐amino acid‐conjugated poly(phenylacetylene)s, which were prepared by the polymerization of the ethyl esters of N‐(4‐ethynylphenylsulfonyl)‐L ‐alanine, L ‐isoleucine, L ‐valine, L ‐phenylalanine, L ‐aspartic acid, and L ‐glutamic acid using Rh+(2,5‐norbornadiene)[(η6‐C6H5)B?(C6H5)3] as the catalyst in CHCl3. The one‐handed helical conformations of all the sulfonamide‐functionalized polymers were characterized by Cotton effects in the circular dichroism spectra. The addition of anions with a relatively high basicity, such as tetra‐n‐butylammonium acetate and fluoride, induced drastic changes in both the optical and chiroptical properties. On the other hand, anions with a relatively low basicity, such as tetra‐n‐butylammonium nitrate, azide, and bromide, had essentially no effects on the helical conformation of all the sulfonamide‐functionalized polymers. The anion signaling property of the sulfonamide‐functionalized polymers possessing α‐amino acid moieties was significantly affected by the installed residual amino acid structures. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 1683–1689, 2010 相似文献
9.
Shi Wu Nianfa Yang Liwen Yang Jing Cao Ji Liu 《Journal of polymer science. Part A, Polymer chemistry》2010,48(6):1441-1448
New α,β‐unsaturated ketone monomers, menthyl vinyl ketone (MVK), and 1‐menthylbut‐3‐en‐2‐one (MBEK) were synthesized. The monomers were polymerized using butyllithium as an initiator. The polymer derived from MVK (poly‐MVK) had a tremendous specific optical rotation [α], which was as 32 times large as that of its monomer MVK. Poly‐MVK was confirmed to keep a prevailing helicity of backbone in solution by means of comparing the specific optical rotation and the CD spectra with that of MVK and the model compound such as ethyl menthyl ketone (EMK) and n‐hexyl menthyl ketone (n‐HMK). This conclusion was also confirmed by the fact that the specific optical rotation and the CD signal intensity of poly‐MBEK were not enough large due to backbone flexibility caused by the effective isolation of the main chain from the bulky menthyl. The excess value of one‐handed helicity of poly‐MVK decreased with the increase of polymerization temperature. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 1441–1448, 2010 相似文献
10.
Jing‐Lun Zhou Xiao‐Fang Chen Xing‐He Fan Chun‐Xiang Lu Qi‐Feng Zhou 《Journal of polymer science. Part A, Polymer chemistry》2006,44(20):6047-6054
A chiral azobenzene‐containing N‐propargylamide monomer, that is, (R)‐2‐(4‐phenylazophenoxy)‐n‐prop‐2‐ynyl‐propionamide, was prepared and polymerized in the presence of a rhodium catalyst to yield an optically active polyacetylene. The 1H NMR analysis of the polymer indicated a predominant cis structure of the backbone (cis concentration = 80%); and the chiroptical property studies showed an enhanced optical rotatory power and a strong Cotton effect, indicating the formation of a secondary helical conformation. A reversible optical modulation of chiroptical properties of the polymer due to the reversible photoisomerization of the azobenzene was observed. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 6047–6054, 2006 相似文献
11.
Lei Ding Xuefeng Jiao Jianping Deng Weiguo Zhao Wantai Yang 《Macromolecular rapid communications》2009,30(2):120-125
Ten hydrophobic, substituted, acetylene monomers were examined as to their abilities to form an inclusion complex with hydroxypropyl‐β‐cyclodextrin (HPCD). Only the monomers with suitable substitutents were found to form the monomer/HPCD complex, which was identified by NMR, FTIR, and UV‐vis spectroscopy. Polymerizations of the monomers were successfully carried out in aqueous solution by using the prepared monomer/HPCD inclusion complex and by using a water‐soluble Rh‐based catalyst, [Rh(cod)2BF4] or [Rh(nbd)(H2O)OTs]. Such polymerizations provided high‐yield (>90%) polymers with a cis content of approximately 100%. The as‐prepared polymers could take an ordered helical conformation, just like their counterparts obtained in organic solvents.
12.
Ken‐ichi Shinohara Toshiki Aoki Takashi Kaneko 《Journal of polymer science. Part A, Polymer chemistry》2002,40(11):1689-1697
Three optically active phenylacetylene polymers with chiral bulky pinanyl groups, (?)‐poly[4‐(dimethylpinanylsilyl)phenylacetylene] [(?)‐poly(PSPA)], (+)‐poly{4‐[3‐(10‐pinanyl)tetramethyldisiloxy]phenylacethylene} [(+)‐poly(PDSPA)], and their copolymer [(?)‐copoly(PSPA/PDSPA)], were synthesized. We observed high chirality in the main‐chain chromophore of (?)‐poly(PSPA), due to the presence of a chiral helix, with circular dichroism spectroscopy. In contrast, (+)‐poly(PDSPA),with flexible SiOSi spacers between the chiral pinanyl group and the main chain, had lower chirality. (?)‐Poly(PSPA), with large circular dichroism signals, was prepared by polymerization with a rhodium catalyst and had a highly stereoregular main chain (high cis‐configuration percentage). However, (?)‐poly(PSPA) prepared with a tungsten catalyst had lower chirality and lower stereoregularity in the main chain. A membrane from (?)‐poly(PSPA) showed enantioselective permeability for tryptophan in an aqueous solution. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 1689–1697, 2002 相似文献
13.
Jing‐Lun Zhou Xiao‐Fang Chen Xing‐He Fan Chun‐Peng Chai Chun‐Xiang Lu Xiao‐Dong Zhao Qi‐Wei Pan Hao‐Yu Tang Long‐Cheng Gao Qi‐Feng Zhou 《Journal of polymer science. Part A, Polymer chemistry》2006,44(15):4532-4545
1‐Alkynes containing azobenzene mesogenic moieties [HC?C(CH2)9? O? ph? N?N? ph? O? R; R = ethyl ( 1 ), octyl ( 2 ), decyl ( 3 ), (S)‐2‐methylbutyl ( 4 ), or (S)‐1‐ethoxy‐1‐oxopropan‐2‐yl ( 5 ); ph = 1,4‐phenyl] were synthesized and polymerized in the presence of a Rh catalyst {(nbd)Rh+[B(C6H5)4]?; nbd = 2,5‐norbornadiene} to yield a series of liquid‐crystalline polymers in high yields (e.g., >75%). These polymers had moderate molecular weights (number‐average molecular weight ≥ 12,000), high cis contents in the main chain (up to 83%), good thermal stability, and good solubility in common organic solvents, such as tetrahydrofuran, chloroform, and dichloromethane. These polymers were thoroughly characterized by a combination of infrared, nuclear magnetic resonance, thermogravimetric analysis, differential scanning calorimetry, polarized optical microscopy, and two‐dimensional wide‐angle X‐ray diffraction techniques. The liquid‐crystalline behavior of these polymers was dependent on the tail group attached to the azobenzene structure. Poly‐ 1 , which had the shortest tail group, that is, an ethyl group, showed a smectic A mesophase, whereas poly‐ 2 , poly‐ 3 , and poly‐ 5 , which had longer or chiral tail groups, formed smectic C mesophases, and poly‐ 4 , which had another chiral group attached to the azobenzene structure, showed a chiral smectic C mesophase in both the heating and cooling processes. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 4532–4545, 2006 相似文献
14.
Poompat Rattanatraicharoen Yoko Tanaka Keiko Shintaku Takuro Kawaguchi Kazuhiro Yamabuki Tsutomu Oishi Kenjiro Onimura 《Journal of polymer science. Part A, Polymer chemistry》2013,51(6):1315-1322
Optically active poly(m‐phenylene)s substituted with chiral oxazoline derivatives have been synthesized by the nickel‐catalyzed Yamamoto coupling reaction of optically active (S)‐4‐benzyl‐2‐(3,5‐dihalidephenyl)oxazoline derivatives (X = Br or I). The structures and chiroptical properties of the polymers were characterized by spectroscopic methods and thermal gravimetric analyses. The polymers showed higher absolute optical specific rotation values than their corresponding monomer, and showed a Cotton effect at transition region of conjugated main chain. The optical activities of the polymers should be attributed to the higher order structure such as helical conformations. Moreover, the helical conformation could be induced by addition of metal salts into polymer solutions. The polymers showed good thermal stabilities, which was attributable to the oxazoline side chains. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2013 相似文献
15.
Mauro Bassetti Ilaria Fratoddi Laura Lilla Chiara Pasquini Maria Vittoria Russo Ornella Ursini 《Journal of polymer science. Part A, Polymer chemistry》2012,50(24):5097-5106
Terminal aryl alkynes RC6H4C?CH with substituents of different electronic properties and ring position (R = H, 4‐CF3, 4‐OMe, 2‐CF3, 2‐OMe, 2‐Me) were exposed to γ‐radiation (50–400 kGy) in organic solvents (hexane, 1,4‐dioxane, ethylacetate, methanol, tetrahydrofuran), at room temperature. The effects arising from substituent, solvent, dilution, and radiation dose allowed to define the conditions suitable for polymerization, which was favored in methanol at increasing dilution of the alkyne. Ortho‐substitution represented the key structural element in the substrate, and the derived polyarylacetylenes were characterized in detail, including gel permeation chromatography, thermal analysis, infrared, NMR, UV–vis, fluorescence, and scanning electron microscope spectroscopy. The results are consistent with the formation of irregular polymers mainly composed of trans‐transoid chains. Controlled aggregation of the polymers by means of an osmosis‐based procedure in solvent/non‐solvent mixtures allowed the formation of nanostructured materials, in particular of hollow nanospheres from THF/water. The methodology sets the basis for the development of γ‐rays‐induced polymerization of alkynes, in a transition metal catalyst‐free environment. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012 相似文献
16.
Shouchun Yin Hongyao Xu Xinyan Su Gang Li Yinlin Song Jackywingyip Lam Benzhong Tang 《Journal of polymer science. Part A, Polymer chemistry》2006,44(7):2346-2357
Poly(1‐alkyne)s containing azobenzene pendant groups with different lengths of the spacer and terminal alkyloxy group {? [HC?C(CH2)mOCO? C6H4? N?N? C6H4? OCpH2p+1]n? , where m = 1, 2, 3, or 9 and p = 4, 7, or 12} were synthesized in satisfactory yields with the [Rh(nbd)Cl]2–Et3N catalyst. All the polymers were soluble in common organic solvents such as CHCl3 and tetrahydrofuran. Their structures and properties were characterized and evaluated with IR, NMR, thermogravimetric analysis, UV, and optical‐limiting and nonlinear optical analyses. All the polymers were thermally stable and decomposed at temperatures as high as ~300 °C. The optical‐limiting and nonlinear optical properties of the polymers were sensitive to their molecular structures. Polymers having shorter spacer lengths and longer terminal groups showed better performances and larger third‐order nonlinear optical susceptibility (up to 1.34 × 10?10 esu). © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 2346–2357, 2006 相似文献
17.
Lie Chen Yiwang Chen Daijun Zha Yan Yang 《Journal of polymer science. Part A, Polymer chemistry》2006,44(8):2499-2509
Liquid‐crystalline, monosubstituted polyacetylenes containing lateral pendants of bis(4‐alkoxyphenyl)terephthalate with no flexible spacers and alkoxy tails {RO, where R is CH3 [P(1)] or C6H13 [P(6)]} were synthesized, and the effects of the backbone structure and alkoxy tails on the properties of the polymers were investigated. The polymerizations of acetylene monomers were carried out with chloronorbornadiene rhodium(I) dimer as a 1,2‐insertion catalyst in toluene. The structures and properties of the monosubstituted polyacetylenes were characterized and evaluated with nuclear magnetic resonance, infrared spectroscopy, thermogravimetry, differential scanning calorimetry, polarized optical microscopy, ultraviolet spectroscopy, and photoluminescence analyses. The molecular weights of the polymers were measured by gel permeation chromatography. The polymer with long tails (p‐hexyloxy), that is, P(6), formed a smectic mesophase upon heating above the melting temperature, but the other one with short tails (p‐methoxy), that is, P(1), could not exhibit liquid crystallinity at elevated temperatures. The steric effect of bulky, liquid‐crystalline mesogens and a direct connection with the main chain prevented the planar conformation of the polyene backbone and, therefore, led to the lower absorption and emission wavelength of the polymers. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 2499–2509, 2006 相似文献
18.
Lo Ming Lai Jacky W. Y. Lam Ben Zhong Tang 《Journal of polymer science. Part A, Polymer chemistry》2006,44(21):6190-6201
1‐Pentynes containing different amino acid moieties and pendant terminal groups {HC?C(CH2)2CONHC(R′)HCO2CH3, where R′ = CH3, CH2CH(CH3)2, CH2C6H5, and HC?C(CH2)2CONHC[CH2CH(CH2)3]HCO2‐(1R,2S,5R)‐(+)‐menthol} have been designed and synthesized. The polymerizations of the monomers are effected by organorhodium catalysts, giving soluble polymers with moderate molecular weights in satisfactory yields. The structures and properties of the polymers have been characterized and evaluated with infrared, nuclear magnetic resonance, thermogravimetric analysis, circular dichroism, and ultraviolet analyses. All the polymers are thermally stable (≥300 °C) and show strong circular dichroism signals at ~310 nm because of the helicity of the polyene backbone. The circular dichroism and ultraviolet absorptions of the polymers can be tuned with a solvent. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 6190–6201, 2006 相似文献
19.
Zheng Hong Zhou Yi Long Tang Kang Ying Li Bing Liu Chu Chi Tang 《Heteroatom Chemistry》2003,14(7):603-606
A series of optically active N‐protected α‐aminoketones were synthesized via the Grignard reaction of the Weinreb amides of the N‐tert‐butoxycarbonyl amino acids. Reduction of the α‐aminoketones by sodium borohydride resulted in the corresponding 1,2‐amino alcohols. © 2003 Wiley Periodicals, Inc. Heteroatom Chem 14:603–606, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.10195 相似文献
20.
Dongmei Yue Toru Fujii Kayo Terada Junichi Tabei Masashi Shiotsuki Fumio Sanda Toshio Masuda 《Journal of polymer science. Part A, Polymer chemistry》2007,45(8):1515-1524
Novel chiral N‐propargylphosphonamidate monomers (HC?CCH2NHP(?O)R? O? menthyl, 1 : R = CH3, 2 : R = C2H5, 3 : R = n‐C3H7, 4 : R = Ph) were synthesized by the reaction of the corresponding phosphonic dichlorides with menthol and propargylamine. Pairs of diastereomeric monomers 1 – 4 with different ratios were obtained due to the chiral P‐center and menthyl group. One diastereomer could be separated from another one in the cases of monomers 1 and 2 . Polymerization of 1 – 4 with (nbd)Rh+[η6‐C6H5B?(C6H5)3] as a catalyst in CHCl3 gave the polymers with number‐average molecular weights ranging from 5000 to 12,000 in 65–85%. Poly( 1 )–poly( 4 ) exhibited quantitative cis contents, and much larger specific rotations than 1 – 4 did in CHCl3. The polymers showed an intense Cotton effect around 325 nm based on the conjugated polyacetylene backbone. It was indicated that the polymers took a helical structure with predominantly one‐handed screw sense, and intramolecular hydrogen bonding between P?O and N? H of the polymers contributed to the stability of the helical structure. Poly( 1a ) and poly( 2a ) decreased the CD intensity upon raising CH3OH content in CHCl3/CH3OH. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 1515–1524, 2007 相似文献