In this article,three novel and simple molecular structure with donor-acceptor(D-A) type copolymers via only head-to-head alkoxy(OR) and/or alkylthio(SR) side chains onto the bithiophene(BT) as donor units and fluorin...In this article,three novel and simple molecular structure with donor-acceptor(D-A) type copolymers via only head-to-head alkoxy(OR) and/or alkylthio(SR) side chains onto the bithiophene(BT) as donor units and fluorinated benzotriazole(FBTA) as acceptor unit,namely,PBTOR-FBTA,PBTOSR-FBTA and PBTSRFBTA,were successfully designed and synthesized.The impacts of sulfur-oxygen(S…O) or sulfur-sulfur(S-S) noncovalent interactions on their physicochemical properties,molecular stacking,carrier mobility,morphologies of blend films,as well as their photovoltaic performance were deeply and systematically studied.The introduction of SR side-chains suddenly lowered the highest occupied molecular orbital(HOMO) energy levels,blue-shifted absorption,enhanced π-π stacking,as well as improved morphology of the photoactive layer blends in comparison with the re ference polymer without SR side-chain.Polymer solar cells(PSCs) were fabricated to estimate their photovoltaic performance of the polymers.Under an optimized blend ratio of PBTSR-FBTA:PC71BM(1:0.8,w/w),the PBTSR-FBTAbased device exhibits a higher power conversion efficiency(PCE) of 6.25%,which is about 3.34 and 1.87 folds than that of the PBTOR-FBTA and PBTOSR-FBTA-based devices,respectively.Our research results demonstrate that the modification of the simple and low-cost SR side chains is an effective strategy to improve the photovoltaic performance of the polymers.展开更多
Acryloyl terminated Poly (ethyleneoxide)macromonomers (PEO-A) with different PEO chain lengths have been prepared by deactivation of PEO alkoxide with acryloyl chloride. A new kind of amphiphilic polystyrene-g-poly (e...Acryloyl terminated Poly (ethyleneoxide)macromonomers (PEO-A) with different PEO chain lengths have been prepared by deactivation of PEO alkoxide with acryloyl chloride. A new kind of amphiphilic polystyrene-g-poly (ethylene oxide)graft copolymer containing both microphase separated and PEO side chain structures has been synthesized from radical copolymerization of PEO-A macromonomer with styrene. After careful purification by a newly-developed method called 'selective dissolution', the well-defined structure of the purified copolymers was confirmed by IR, ~1H-NMR and GPC. Various experimental parameters controlling the copolymerization were studied in detail. The results indicated that the feed ratio of styrene to macromonomer(S/M) was the most important determining factor for the composition of the copolymers. A detailed 'comb- model' was proposed to describe the molecular structure of the graft copolymers. Finally, this amphiphilic graft copolymers may readily form microphase separated structures as clearly indicated by transmission electron microscopy.展开更多
Two series of novel derivatives of imidazo[4,5-b]pyridine were synthesized. These compounds could be used as side chains of semisynthesised ketolide antibiotics. The side chains have free amine group which can attache...Two series of novel derivatives of imidazo[4,5-b]pyridine were synthesized. These compounds could be used as side chains of semisynthesised ketolide antibiotics. The side chains have free amine group which can attached to ketolide core. Macrolides with this kind of side chains will show obvious activities against erythromycin-resistant strains. The structure of the side chains was confirmed by ^1H, ^13C NMR, MS, HMBC spectra. 2007 Ping Sheng Lei. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All rights reserved.展开更多
Two kinds of side chain liquid crystalline polysiloxanes containing crown ether and benzyl ether were synthesized and characterized by optical polarization microscopy. Both the monomeric liquid crystals and polymeric ...Two kinds of side chain liquid crystalline polysiloxanes containing crown ether and benzyl ether were synthesized and characterized by optical polarization microscopy. Both the monomeric liquid crystals and polymeric liquid crystals show smectic phases.展开更多
In recent years, due to the rapid development of high-performance small molecule acceptor (SMA) materials, the researches on p-type electron donor materials for matching with current efficient SMAs have become importa...In recent years, due to the rapid development of high-performance small molecule acceptor (SMA) materials, the researches on p-type electron donor materials for matching with current efficient SMAs have become important. By means of asymmetric strategies to optimize the energy levels and inter/intramolecular interactions of molecules, we designed and synthesized an asymmetric aromatic side chain quinoxaline-based polymer donor TPQ-0F. Meanwhile, we took advantage of F atom which could form noncovalent interaction and strong electron-withdrawing property, to obtain the optimized quinoxaline-based polymer donors TPQ-1F, TPQ-1Fi and TPQ-2F. Eventually, the binary device based on TPQ-2F achieved an efficient power conversion efficiency (PCE) of 16.27%, which attributed to balanced hole/electron mobilities, less charge carrier recombination, and more favorable aggregation morphology. Our work demonstrates the great potential of asymmetric aromatic side chain quinoxaline-based polymer donors on optimizing the morphology of blending films, improving inter/intramolecular interactions, and subtly tuning energy level, finally for more efficient organic solar cells.展开更多
Two new stationary phases : (Ⅰ) [bikis(2,6-di-O-pentyl-3-O-hex-6O-pentyl-3-O-methyl)-β-CD-polysiloxane] and (Ⅱ) [heptkis(2,6-di-O-methyl-3-O-hex-6-enyl)-β-CD-polysiloxane] were synthesized and successfully used fo...Two new stationary phases : (Ⅰ) [bikis(2,6-di-O-pentyl-3-O-hex-6O-pentyl-3-O-methyl)-β-CD-polysiloxane] and (Ⅱ) [heptkis(2,6-di-O-methyl-3-O-hex-6-enyl)-β-CD-polysiloxane] were synthesized and successfully used for GC separation of chiral isomers.The possess high column efficiency and exhibit fine chiral separation ability.展开更多
A stereocontrolled construction of the side chain of brassinclide and homobrassinolide has been achieved via the tandem vicinal dialkylation of the pyranone moiety as a key step.
In order to find novel antibacterial agents with superior antibacterial activity and overcoming multidrug resistance,a series of pleuromutilin derivatives with novel C（14） side chain were synthesized and evaluated f...In order to find novel antibacterial agents with superior antibacterial activity and overcoming multidrug resistance,a series of pleuromutilin derivatives with novel C（14） side chain were synthesized and evaluated for their in vitro antibacterial activities.The results of antibacterial acticities indicated that most of the derivatives showed potent activities against Gram-positive organisms.In particular,compound lOd exhibited the most potent inhibitory activity compared with pleuromutilin and linezoid,emerged as potential molecule for further investigation.展开更多
This paper reports the synthesis and characteristics of a series of alkyl-substituted planar polymers. The physical properties are carefully tuned to optimize their photovoltaic performance. Depending on the length of...This paper reports the synthesis and characteristics of a series of alkyl-substituted planar polymers. The physical properties are carefully tuned to optimize their photovoltaic performance. Depending on the length of soluble alkyl side chains which modify the structural order and orientation substantially in polymer backbones, the device performance can be improved significantly. The tuning of HOMO energy levels optimized polymers＇ spectral coverage of absorption and their hole mobility, as well as miscibility with fullerene; all these efforts enhanced polymer solar cell performances. The short- circuit current, Jsc for polymer solar cells was increased by adjusting polymer chain packing ability. It was found that films with well distributed polymer/fullerene interpenetrating network exhibit improved solar cell conversion efficiency. Enhanced efficiency up to 5.8% has been demonstrated. The results provide important insights about the roles of flexile chains in structure-property relationship for the design of new polymers to be used in high efficient solar cells.展开更多
We chose a series of isoindigo-based conjugated polymer（ⅡDDT,ⅡDDT-C3 and ⅡDDT-C4） with different length of side chains and bifurcation positions to investigate the relationship between the degree of alignment and...We chose a series of isoindigo-based conjugated polymer（ⅡDDT,ⅡDDT-C3 and ⅡDDT-C4） with different length of side chains and bifurcation positions to investigate the relationship between the degree of alignment and the length of side chains and bifurcation positions.We found that the dichroic ratio was increased from 2.37 to 5.23 when the side chain was longer and the bifurcation position was away from the backbone.The π-π stacking distance was decreased from 3.67 A to 3.61 A when the bifurcation position was away from the backbone because of its smaller hindrance and the d-spacing of the（100）was increased from 20.06 A to 25.21 A when the side chain was longer.All the polymers were adopted an edge-on orientation with the backbone paralleled with the long axis of fibers.The weak interaction of side-chain in ⅡDDT-C4 was beneficial for the molecules being rearranged in parallel during the contact line receding and the strong n-n interaction could accelerate the interchain assembly of the parallel molecules through π-π interaction to form aligned fibers.展开更多
Side chain liquid crystalline polysiloxanes containing benzyl ether linkingunits were synthesized by the hydrosilylation of poly (methylhydrosiloxane) with a series of4-(4-alkoxybenzyloxy)-4'-allyloxybiphenyl mono...Side chain liquid crystalline polysiloxanes containing benzyl ether linkingunits were synthesized by the hydrosilylation of poly (methylhydrosiloxane) with a series of4-(4-alkoxybenzyloxy)-4'-allyloxybiphenyl monomers [4-(4-methoxybenzyloxy )-4'-allyloxy-biphenyl(M_1), 4-(4-ethoxybenzyloxy)-4'-allyloxybiphenyl (M_2), 4-(4-propoxybenzyloxy)-4'-allyloxybiphenyl (M_3), 4-(4-butoxybenzyloxy)-4'-allylox(M_4), 4-(4-pentoxy-benzyloxy)-4'-allyloxybiphenyl (M_5), 4-benzyloxy-4'-allyloxybiphenyl (M_6)]. The phasebehavior of monomeric and polymeric liquid crystals was characterized by differential scan-ning calorimetry and optical polarization microscopy where the groups are ranged frommethoxy to pentoxy Both the monomeric and polymeric liquid crystals exhibit 1iquidcrystal behaviors.展开更多
A stereoselective synthesis of brassinolide and dolicholide, which involves construction of the side chain enantiomers by a highly stereoselective aldol reaction of aldehyde 5 with the anion of α-silyloxy ketone 6 is...A stereoselective synthesis of brassinolide and dolicholide, which involves construction of the side chain enantiomers by a highly stereoselective aldol reaction of aldehyde 5 with the anion of α-silyloxy ketone 6 is described.展开更多
The present paper covers the synthesis and characterization of several intermediate products, monomer, and polymers. 3-{ 2-[ 4-( 4-Nitrophenylazo ) phenoxy] ethyloxycarbonyl} propanoyloxy (2-hydroxy) propyl acrylate (...The present paper covers the synthesis and characterization of several intermediate products, monomer, and polymers. 3-{ 2-[ 4-( 4-Nitrophenylazo ) phenoxy] ethyloxycarbonyl} propanoyloxy (2-hydroxy) propyl acrylate (4) was prepared by the ring-opening reaction of glycidyl acrylate with the monoester of succinic acid (3). The polymers (5) with different molecular weights were prepared by the free-radical polymerization. The polymers (5) had liquid crystalline behavior without decomposition as revealed by DSC, optical microscope.展开更多
A novel biphenyl side-chained diamine with alkyloxy spacer and alkyloxy tail,4＇-butoxy-4-（3,5-diaminobenzoyloxy）hexyloxybiphenyl（C6BBC4）,was synthesized and characterized by FTIR and 1 H NMR.A series of polyimide...A novel biphenyl side-chained diamine with alkyloxy spacer and alkyloxy tail,4＇-butoxy-4-（3,5-diaminobenzoyloxy）hexyloxybiphenyl（C6BBC4）,was synthesized and characterized by FTIR and 1 H NMR.A series of polyimide（PI） films with different side chain contents was synthesized from biphenyltetracarboxylicdianhydride（BPDA）,4,4＇-oxydianiline（ODA） and C6BBC4,and their thermal properties,optical transparency and liquid crystal alignment property,and so on,were investigated by thermogravimetric analysis（TGA）,differential scanning calorimetry（DSC）,crystal rotation method,polarizing microscopy and UV-Vis spectra.With the content of side chained diamine increasing from 0 to 100%,the η inh of poly（amide acid）（PAA） decreased rapidly from 3.0 to 0.51,the glass transition temperature（T g） of polyimides（PIs） decreased from 274 ℃ to 203 ℃ and the Vis-light transmittance of alignment films substantially increased.As for the alignment properties,the pretilt angle of PI alignment films without rubbing could reach 90° when the content of C6BBC4 was 60% or more.At the same time,the alignment stability could meet the industrial requirements.It was considered that the alkoxy spacer,the biphenyl unit and the alkoxy tail may all play important roles in achieving a large pretilt angle even up to 90°,and the introduction of only the alkoxy spacer or alkoxy tail can also improve the pretilt angle,but not by much.展开更多
Some nucleoside carhoxylic acid derivatives,such as(±)ethyl ester of griseolic acid (4)and 9-(2'-deoxy-2'-(benzyloxycarbonyl)-methylene-β-D-rihohept-2'-enofuranosyluranate)adenine (11),were synthesiz...Some nucleoside carhoxylic acid derivatives,such as(±)ethyl ester of griseolic acid (4)and 9-(2'-deoxy-2'-(benzyloxycarbonyl)-methylene-β-D-rihohept-2'-enofuranosyluranate)adenine (11),were synthesized.The formation of lactone of 5'-deoxy-adenosineacetic acid(AAA,3)was investigated by using different reagents for lactonization from AAA,but all of the efforts failed, and sone unexpected compounds were obtained.展开更多
Recent advances in non-fullerene acceptors(NFAs),typically Y6,have driven power conversion efficiency(PCE) of single-junction orga nic solar cells(OSCs) over 16%.Mea nwhile,it becomes essential to know how to adopt si...Recent advances in non-fullerene acceptors(NFAs),typically Y6,have driven power conversion efficiency(PCE) of single-junction orga nic solar cells(OSCs) over 16%.Mea nwhile,it becomes essential to know how to adopt simple strategies to further improve device performance.In this work,a new A-DA'D-A acceptor derivative,Y19-N3 employing 3-ethylheptyl branched at the 3^(rd)-position instead of 2-ethylhexyl on the pyrroles of Y19 is reported.The selection of an appropriate solvent in casting device is implemented to maximize the photovoltaic performance.PBDB-T:Y19-N3-based OSCs treated with a ternary solvent of CF/CB(1:3,v/v) and 0.8% DIO exhibit the optimal PCE of 13.77% here,with the significantly improved V_(oc)(0.78 V) and FF(0.72) as well as the high J_(sc)(24.46 mA/cm^(2)).Further characterizations indicate that this ternary solvent-treated PBDB-T/Y19-N3 film exhibits the more appropriate morphological features with the highly efficient charge generation and collection as well as the more balanced electron and hole mobilities.This work combines molecular design and device engineering to improve the photovoltaic properties,which is important to the development of OSCs.展开更多
A new side chain liquid crystalline poly[4 (methacryloxy)hexanoloxy 4′ benzyloxy biphenyl] was synthesized. The phase behavior of the monomer and homopolymer was studied. The monomer shows a smectic B phase, while...A new side chain liquid crystalline poly[4 (methacryloxy)hexanoloxy 4′ benzyloxy biphenyl] was synthesized. The phase behavior of the monomer and homopolymer was studied. The monomer shows a smectic B phase, while the homopolymer shows a nematic phase. The nonmesogenic nonlinear optical group was introduced to synthesize a series of side chain liquid crystalline copolymers which also show a nematic phase. Owing to the liquid crystallinity of the copolymer has been the orientational stability improved, down the relax of the orientation slowed and the nonlinear optical properties enhanced.展开更多
The kinetics of I-->N transition of a side chain nematic polymethacrylate has been studied by small angle depolarized light scattering intensity measurements using a charge coupled device linear image sensor. The p...The kinetics of I-->N transition of a side chain nematic polymethacrylate has been studied by small angle depolarized light scattering intensity measurements using a charge coupled device linear image sensor. The polymer shows the transition temperatures K52N79I in degreesC, The H-v scattering intensity T(q,t) during the transition I (at 80.2degreesC)-->N (at 75.8degreesC) shows that T(q) is independent of q for all t, and during the initial stage (in 6 s) T(t) increases exponentially with t. In the later stage of the transition T(t) approaches a saturation value in 2 min. This experimental result indicates that the I-->N transition of a liquid crystalline polymer is a spinodal type of phase transition mediated by orientation fluctuation.展开更多
Five kinds of side chain liquid crystalline polymers with a chiral component in the pendant group were synthesized and characterized by GPC, polarizing microscopy, DSC, X-ray diffraction ano Dielectric Relaxation Spec...Five kinds of side chain liquid crystalline polymers with a chiral component in the pendant group were synthesized and characterized by GPC, polarizing microscopy, DSC, X-ray diffraction ano Dielectric Relaxation Spectroscopy. The liquid crystalline behaviour of the polymers is affected by the length of flexible spacer, which links the mesogenic side chain to the polymer backbone and mesogenic moiety. The characteristic of smectic phase is observed for all the polymers.展开更多
基金financially supported by grants from the National Natural Science Foundation of China(Nos.51573154,51673031)The Natural Science Foundation of Jiangsu Higher Institutions of China(No.18KJA480001)+2 种基金the Youth Science and Technology Foundation of Sichuan Province(No.2013JQ0032)the key Laboratory of Environment-Friendly Chemistry and Applications of Ministry of Education(No.2018HJYH01)the Natural Science Foundation of Jiangsu Province(No.BK20141151)。
文摘In this article,three novel and simple molecular structure with donor-acceptor(D-A) type copolymers via only head-to-head alkoxy(OR) and/or alkylthio(SR) side chains onto the bithiophene(BT) as donor units and fluorinated benzotriazole(FBTA) as acceptor unit,namely,PBTOR-FBTA,PBTOSR-FBTA and PBTSRFBTA,were successfully designed and synthesized.The impacts of sulfur-oxygen(S…O) or sulfur-sulfur(S-S) noncovalent interactions on their physicochemical properties,molecular stacking,carrier mobility,morphologies of blend films,as well as their photovoltaic performance were deeply and systematically studied.The introduction of SR side-chains suddenly lowered the highest occupied molecular orbital(HOMO) energy levels,blue-shifted absorption,enhanced π-π stacking,as well as improved morphology of the photoactive layer blends in comparison with the re ference polymer without SR side-chain.Polymer solar cells(PSCs) were fabricated to estimate their photovoltaic performance of the polymers.Under an optimized blend ratio of PBTSR-FBTA:PC71BM(1:0.8,w/w),the PBTSR-FBTAbased device exhibits a higher power conversion efficiency(PCE) of 6.25%,which is about 3.34 and 1.87 folds than that of the PBTOR-FBTA and PBTOSR-FBTA-based devices,respectively.Our research results demonstrate that the modification of the simple and low-cost SR side chains is an effective strategy to improve the photovoltaic performance of the polymers.
基金Supported by the National Natural Science Foundation of China and the State Education Committee of China
文摘Acryloyl terminated Poly (ethyleneoxide)macromonomers (PEO-A) with different PEO chain lengths have been prepared by deactivation of PEO alkoxide with acryloyl chloride. A new kind of amphiphilic polystyrene-g-poly (ethylene oxide)graft copolymer containing both microphase separated and PEO side chain structures has been synthesized from radical copolymerization of PEO-A macromonomer with styrene. After careful purification by a newly-developed method called 'selective dissolution', the well-defined structure of the purified copolymers was confirmed by IR, ~1H-NMR and GPC. Various experimental parameters controlling the copolymerization were studied in detail. The results indicated that the feed ratio of styrene to macromonomer(S/M) was the most important determining factor for the composition of the copolymers. A detailed 'comb- model' was proposed to describe the molecular structure of the graft copolymers. Finally, this amphiphilic graft copolymers may readily form microphase separated structures as clearly indicated by transmission electron microscopy.
基金Finacial support of this research by the National Natural Science Foundation of China （No. 30572275） ；Natural Science Foundation of Beijing （No. 7062047） are gratefully acknowledged by the authors.
文摘Two series of novel derivatives of imidazo[4,5-b]pyridine were synthesized. These compounds could be used as side chains of semisynthesised ketolide antibiotics. The side chains have free amine group which can attached to ketolide core. Macrolides with this kind of side chains will show obvious activities against erythromycin-resistant strains. The structure of the side chains was confirmed by ^1H, ^13C NMR, MS, HMBC spectra. 2007 Ping Sheng Lei. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All rights reserved.
基金This project was financially supported by the National Natural Science Foundation of China(Approved No.29775006)
文摘Two kinds of side chain liquid crystalline polysiloxanes containing crown ether and benzyl ether were synthesized and characterized by optical polarization microscopy. Both the monomeric liquid crystals and polymeric liquid crystals show smectic phases.
基金supported by the National Natural Science Foundation of China(Nos.21875286 and 52125306,)J.Yuan acknowledges the National Natural Science Foundation of China(No.22005347)+2 种基金the Natural Science Foundation of Hunan Province(No.2021JJ20068)L.Jiang acknowledges the Open Sharing Fund for the Large-scale Instruments and Equipments of Central South University(No.CSUZC202218)the Natural Science Foundation of Hunan Province(No.2021JJ30793).
文摘In recent years, due to the rapid development of high-performance small molecule acceptor (SMA) materials, the researches on p-type electron donor materials for matching with current efficient SMAs have become important. By means of asymmetric strategies to optimize the energy levels and inter/intramolecular interactions of molecules, we designed and synthesized an asymmetric aromatic side chain quinoxaline-based polymer donor TPQ-0F. Meanwhile, we took advantage of F atom which could form noncovalent interaction and strong electron-withdrawing property, to obtain the optimized quinoxaline-based polymer donors TPQ-1F, TPQ-1Fi and TPQ-2F. Eventually, the binary device based on TPQ-2F achieved an efficient power conversion efficiency (PCE) of 16.27%, which attributed to balanced hole/electron mobilities, less charge carrier recombination, and more favorable aggregation morphology. Our work demonstrates the great potential of asymmetric aromatic side chain quinoxaline-based polymer donors on optimizing the morphology of blending films, improving inter/intramolecular interactions, and subtly tuning energy level, finally for more efficient organic solar cells.
文摘Two new stationary phases : (Ⅰ) [bikis(2,6-di-O-pentyl-3-O-hex-6O-pentyl-3-O-methyl)-β-CD-polysiloxane] and (Ⅱ) [heptkis(2,6-di-O-methyl-3-O-hex-6-enyl)-β-CD-polysiloxane] were synthesized and successfully used for GC separation of chiral isomers.The possess high column efficiency and exhibit fine chiral separation ability.
文摘A stereocontrolled construction of the side chain of brassinclide and homobrassinolide has been achieved via the tandem vicinal dialkylation of the pyranone moiety as a key step.
基金National Science and Technology Major Project for the support of this researchsupported by Key New Drug Creation and Manufacturing Program,China(No:2009ZX09301-001)
文摘In order to find novel antibacterial agents with superior antibacterial activity and overcoming multidrug resistance,a series of pleuromutilin derivatives with novel C（14） side chain were synthesized and evaluated for their in vitro antibacterial activities.The results of antibacterial acticities indicated that most of the derivatives showed potent activities against Gram-positive organisms.In particular,compound lOd exhibited the most potent inhibitory activity compared with pleuromutilin and linezoid,emerged as potential molecule for further investigation.
基金financially supported by the Postdoctoral Starting Foundation of Henan Normal University(01026500105)Young Scientists Foundation of Henan Normal University(01026400061)Henan Province basic and frontier technology research projects(1323004100247)
文摘This paper reports the synthesis and characteristics of a series of alkyl-substituted planar polymers. The physical properties are carefully tuned to optimize their photovoltaic performance. Depending on the length of soluble alkyl side chains which modify the structural order and orientation substantially in polymer backbones, the device performance can be improved significantly. The tuning of HOMO energy levels optimized polymers＇ spectral coverage of absorption and their hole mobility, as well as miscibility with fullerene; all these efforts enhanced polymer solar cell performances. The short- circuit current, Jsc for polymer solar cells was increased by adjusting polymer chain packing ability. It was found that films with well distributed polymer/fullerene interpenetrating network exhibit improved solar cell conversion efficiency. Enhanced efficiency up to 5.8% has been demonstrated. The results provide important insights about the roles of flexile chains in structure-property relationship for the design of new polymers to be used in high efficient solar cells.
基金supported by the National Natural Science Foundation of China (Nos. 21334006, 51577138, 21474113)the Strategic Priority Research Program of the Chinese Academy of Sciences (No. XDB12020300)
文摘We chose a series of isoindigo-based conjugated polymer（ⅡDDT,ⅡDDT-C3 and ⅡDDT-C4） with different length of side chains and bifurcation positions to investigate the relationship between the degree of alignment and the length of side chains and bifurcation positions.We found that the dichroic ratio was increased from 2.37 to 5.23 when the side chain was longer and the bifurcation position was away from the backbone.The π-π stacking distance was decreased from 3.67 A to 3.61 A when the bifurcation position was away from the backbone because of its smaller hindrance and the d-spacing of the（100）was increased from 20.06 A to 25.21 A when the side chain was longer.All the polymers were adopted an edge-on orientation with the backbone paralleled with the long axis of fibers.The weak interaction of side-chain in ⅡDDT-C4 was beneficial for the molecules being rearranged in parallel during the contact line receding and the strong n-n interaction could accelerate the interchain assembly of the parallel molecules through π-π interaction to form aligned fibers.
基金This project was financially supported by the National Natural Science Foundation of China (Approved No.29775006)
文摘Side chain liquid crystalline polysiloxanes containing benzyl ether linkingunits were synthesized by the hydrosilylation of poly (methylhydrosiloxane) with a series of4-(4-alkoxybenzyloxy)-4'-allyloxybiphenyl monomers [4-(4-methoxybenzyloxy )-4'-allyloxy-biphenyl(M_1), 4-(4-ethoxybenzyloxy)-4'-allyloxybiphenyl (M_2), 4-(4-propoxybenzyloxy)-4'-allyloxybiphenyl (M_3), 4-(4-butoxybenzyloxy)-4'-allylox(M_4), 4-(4-pentoxy-benzyloxy)-4'-allyloxybiphenyl (M_5), 4-benzyloxy-4'-allyloxybiphenyl (M_6)]. The phasebehavior of monomeric and polymeric liquid crystals was characterized by differential scan-ning calorimetry and optical polarization microscopy where the groups are ranged frommethoxy to pentoxy Both the monomeric and polymeric liquid crystals exhibit 1iquidcrystal behaviors.
基金supported by the National Natural Science Foundation of China(Grant No.20072012)the Special Research Grant for Doctoral Sites in Chinese Universities(Grant No.20010730001).
文摘A stereoselective synthesis of brassinolide and dolicholide, which involves construction of the side chain enantiomers by a highly stereoselective aldol reaction of aldehyde 5 with the anion of α-silyloxy ketone 6 is described.
文摘The present paper covers the synthesis and characterization of several intermediate products, monomer, and polymers. 3-{ 2-[ 4-( 4-Nitrophenylazo ) phenoxy] ethyloxycarbonyl} propanoyloxy (2-hydroxy) propyl acrylate (4) was prepared by the ring-opening reaction of glycidyl acrylate with the monoester of succinic acid (3). The polymers (5) with different molecular weights were prepared by the free-radical polymerization. The polymers (5) had liquid crystalline behavior without decomposition as revealed by DSC, optical microscope.
基金Supported by the National Natural Science Foundation of China(Nos.50773044,50973073)
文摘A novel biphenyl side-chained diamine with alkyloxy spacer and alkyloxy tail,4＇-butoxy-4-（3,5-diaminobenzoyloxy）hexyloxybiphenyl（C6BBC4）,was synthesized and characterized by FTIR and 1 H NMR.A series of polyimide（PI） films with different side chain contents was synthesized from biphenyltetracarboxylicdianhydride（BPDA）,4,4＇-oxydianiline（ODA） and C6BBC4,and their thermal properties,optical transparency and liquid crystal alignment property,and so on,were investigated by thermogravimetric analysis（TGA）,differential scanning calorimetry（DSC）,crystal rotation method,polarizing microscopy and UV-Vis spectra.With the content of side chained diamine increasing from 0 to 100%,the η inh of poly（amide acid）（PAA） decreased rapidly from 3.0 to 0.51,the glass transition temperature（T g） of polyimides（PIs） decreased from 274 ℃ to 203 ℃ and the Vis-light transmittance of alignment films substantially increased.As for the alignment properties,the pretilt angle of PI alignment films without rubbing could reach 90° when the content of C6BBC4 was 60% or more.At the same time,the alignment stability could meet the industrial requirements.It was considered that the alkoxy spacer,the biphenyl unit and the alkoxy tail may all play important roles in achieving a large pretilt angle even up to 90°,and the introduction of only the alkoxy spacer or alkoxy tail can also improve the pretilt angle,but not by much.
基金The project was supported by the National Natural Science Foundation of China.
文摘Some nucleoside carhoxylic acid derivatives,such as(±)ethyl ester of griseolic acid (4)and 9-(2'-deoxy-2'-(benzyloxycarbonyl)-methylene-β-D-rihohept-2'-enofuranosyluranate)adenine (11),were synthesized.The formation of lactone of 5'-deoxy-adenosineacetic acid(AAA,3)was investigated by using different reagents for lactonization from AAA,but all of the efforts failed, and sone unexpected compounds were obtained.
基金supported by the Fundamental Research Funds for the Central Universities of Central South University(No.2019zzts443)the National Key Research and Development Program of China(No.2017YFA0206600)the National Natural Science Foundation of China(No.21875286)。
文摘Recent advances in non-fullerene acceptors(NFAs),typically Y6,have driven power conversion efficiency(PCE) of single-junction orga nic solar cells(OSCs) over 16%.Mea nwhile,it becomes essential to know how to adopt simple strategies to further improve device performance.In this work,a new A-DA'D-A acceptor derivative,Y19-N3 employing 3-ethylheptyl branched at the 3^(rd)-position instead of 2-ethylhexyl on the pyrroles of Y19 is reported.The selection of an appropriate solvent in casting device is implemented to maximize the photovoltaic performance.PBDB-T:Y19-N3-based OSCs treated with a ternary solvent of CF/CB(1:3,v/v) and 0.8% DIO exhibit the optimal PCE of 13.77% here,with the significantly improved V_(oc)(0.78 V) and FF(0.72) as well as the high J_(sc)(24.46 mA/cm^(2)).Further characterizations indicate that this ternary solvent-treated PBDB-T/Y19-N3 film exhibits the more appropriate morphological features with the highly efficient charge generation and collection as well as the more balanced electron and hole mobilities.This work combines molecular design and device engineering to improve the photovoltaic properties,which is important to the development of OSCs.
文摘A new side chain liquid crystalline poly[4 (methacryloxy)hexanoloxy 4′ benzyloxy biphenyl] was synthesized. The phase behavior of the monomer and homopolymer was studied. The monomer shows a smectic B phase, while the homopolymer shows a nematic phase. The nonmesogenic nonlinear optical group was introduced to synthesize a series of side chain liquid crystalline copolymers which also show a nematic phase. Owing to the liquid crystallinity of the copolymer has been the orientational stability improved, down the relax of the orientation slowed and the nonlinear optical properties enhanced.
基金This work was supported by the National Key Projects for Fundamental Research, "Macromolecular Condensed State" of Ministry of Science and Technology of China.
文摘The kinetics of I-->N transition of a side chain nematic polymethacrylate has been studied by small angle depolarized light scattering intensity measurements using a charge coupled device linear image sensor. The polymer shows the transition temperatures K52N79I in degreesC, The H-v scattering intensity T(q,t) during the transition I (at 80.2degreesC)-->N (at 75.8degreesC) shows that T(q) is independent of q for all t, and during the initial stage (in 6 s) T(t) increases exponentially with t. In the later stage of the transition T(t) approaches a saturation value in 2 min. This experimental result indicates that the I-->N transition of a liquid crystalline polymer is a spinodal type of phase transition mediated by orientation fluctuation.
文摘Five kinds of side chain liquid crystalline polymers with a chiral component in the pendant group were synthesized and characterized by GPC, polarizing microscopy, DSC, X-ray diffraction ano Dielectric Relaxation Spectroscopy. The liquid crystalline behaviour of the polymers is affected by the length of flexible spacer, which links the mesogenic side chain to the polymer backbone and mesogenic moiety. The characteristic of smectic phase is observed for all the polymers.
