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1.
Model copolymers of poly(butadiene) (PB) and poly(dimethylsiloxane) (PDMS), PB‐b‐PDMS‐b‐PB, were synthesized by sequential anionic polymerization (high vacuum techniques) of 1,3‐butadiene and hexamethylciclotrisiloxane (D3) on sec‐BuLi followed by chlorosilane‐coupling chemistry. The synthesized copolymers were characterized by nuclear magnetic resonance (1H NMR), size‐exclusion chromatography (SEC), thermogravimetric analysis (TGA), and differential scanning calorimetry (DSC). SEC and 1H NMR results showed low polydispersity indexes (Mw/Mn) and variable siloxane compositions, whereas DSC and TGA experiments indicated that the thermal stability of the triblock copolymers depends on the PDMS composition. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 2726–2733, 2007  相似文献   

2.
This article deals with the hitherto unexplored metal complexes of deprotonated 6,12‐di(pyridin‐2‐yl)‐5,11‐dihydroindolo[3,2‐b]carbazole (H2L). The synthesis and structural, optical, electrochemical characterization of dimeric [{RuIII(acac)2}2(μ‐L.?)]ClO4 ([ 1 ]ClO4, S=1/2), [{RuII(bpy)2}2(μ‐L.?)](ClO4)3 ([ 2 ](ClO4)3, S=1/2), [{RuII(pap)2}2(μ‐L2?)](ClO4)2 ([ 4 ](ClO4)2, S=0), and monomeric [(bpy)2RuII(HL?)]ClO4 ([ 3 ]ClO4, S=0), [(pap)2RuII(HL?)]ClO4 ([ 5 ]ClO4, S=0) (acac=σ‐donating acetylacetonate, bpy=moderately π‐accepting 2,2’‐bipyridine, pap=strongly π‐accepting 2‐phenylazopyridine) are reported. The radical and dianionic states of deprotonated L in isolated dimeric 1 +/ 2 3+ and 4 2+, respectively, could be attributed to the varying electronic features of the ancillary (acac, bpy, and pap) ligands, as was reflected in their redox potentials. Perturbation of the energy level of the deprotonated L or HL upon coordination with {Ru(acac)2}, {Ru(bpy)2}, or {Ru(pap)2} led to the smaller energy gap in the frontier molecular orbitals (FMO), resulting in bathochromically shifted NIR absorption bands (800–2000 nm) in the accessible redox states of the complexes, which varied to some extent as a function of the ancillary ligands. Spectroelectrochemical (UV/Vis/NIR, EPR) studies along with DFT/TD‐DFT calculations revealed (i) involvement of deprotonated L or HL in the oxidation processes owing to its redox non‐innocent potential and (ii) metal (RuIII/RuII) or bpy/pap dominated reduction processes in 1 + or 2 2+/ 3 +/ 4 2+/ 5 +, respectively.  相似文献   

3.
The novel, stable, one‐dimensional coordination polymer [Hg3(dmap)6(μ‐OAc)2]n{(ClO4)4}n ( 1 ; dmap = 4‐(dimethylamino)pyridine) has been synthesized and characterized. Single‐crystal X‐ray analysis showed that the coordination sphere of the two pertinent, zig‐zag‐oriented HgII‐atoms is different. One type of Hg‐atom in the N2O4Hg HgN2O4 environment is seven‐coordinate, with a weak Hg Hg interaction. The other type of HgII‐atom in the trans‐HgN2O4 units is six‐coordinate.  相似文献   

4.
We report on a cytotoxic half‐sandwich iridium(III) complex [Ir(η5‐Cpph)(phen)(PB)]PF6 ( 1‐PB ), containing a monodentate coordinated O‐donor 4‐phenylbutyrato ligand (PB) belonging to the family of histone deacetylase inhibitors (HDACi); HCpph = (2,3,4,5‐tetramethylcyclopenta‐2,4‐dien‐1‐yl)benzene, phen = 1,?10‐phenanthroline. The solution behaviour studies indicated that complex 1‐PB partially hydrolysed in the mixture of methanol and water (1:4, v/v), resulting in the release of the PB ligand. The extent of the PB ligand release increased in the presence of 2 molar equiv. of the reduced glutathione (GSH). Complex 1‐PB exhibited comparable in vitro cytotoxicity against the cisplatin‐sensitive (IC50 = 15.8 μM) and ‐resistant (IC50 = 13.0 μM) variants of the A2780 human ovarian carcinoma cells, while its potency against the MRC‐5 human normal fibroblast cells was markedly lower (IC50 = 124.1 μM). The cytotoxicity studies revealed an ability of complex 1‐PB to overcome the acquired resistance against cisplatin, with the resistance factor (RF = 0.8) being markedly lower than for complex 1‐Cl (RF = 1.8) and cisplatin (RF = 2.9). The A2780 cell‐based flow cytometry experiments showed different cell cycle modification induced by complex 1‐PB and cisplatin, induction of production of reactive oxygen species, and higher mitochondria membrane potential depleted cell populations after the treatment by complex 1‐PB as compared with cisplatin. In the cell‐free assay, complex 1‐PB inhibited the HDAC activity to ca 66% as compared to ca 74% valid for NaPB. The [Ir(η5‐Cpph)(phen)(H2O)]2+ species ( 1‐OH 2 ), representing the hydrolysis product of both complexes 1‐PB and 1‐Cl , induced hydroxyl radical from the hydrogen peroxide, as proved by the EPR spin trapping studies with the 5‐(diethoxyphosphoryl)‐5‐methyl‐1‐pyrroline‐N‐oxide (DEPMPO) spin trap.  相似文献   

5.
The tertiary chlorine (Clt) content of vinyl chloride/2‐chloropropene copolymers [P(VC‐co‐2CP)] was determined by NMR spectroscopy. Copolymers containing 6.8–47.0 Clt's per P(VC‐co‐2CP) chain were used to initiate the cationic grafting of α‐methylstyrene, norbornadiene, indene, and norbornene with Et2AlCl under various conditions. Grafting was demonstrated by selective solvent extraction, and the effect of the experimental conditions on the grafting efficiency was examined. Select rheological and thermal characteristics of P(VC‐co‐2CP) grafts, including the glass‐transition temperature, heat deflection temperature, and discoloration upon heating, were studied. P(VC‐co‐2CP) carrying 7–11 poly(α‐methylstyrene) or polynorbornadiene branches per chain raised the glass‐transition temperature to, or above, that of a blend control. P(VC‐co‐2CP)s fitted with polyindene or polynorbornene branches were less effective in raising the mechanical properties. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 3644–3651, 2002  相似文献   

6.
A two‐dimensional MnII coordination polymer (CP), poly[bis[μ2‐2,6‐bis(imidazol‐1‐yl)pyridine‐κ2N3:N3′]bis(thiocyanato‐κN)manganese] [Mn(NCS)2(C11H9N5)2]n, (I), has been obtained by the self‐assembly reaction of Mn(ClO4)2·6H2O, NH4SCN and bent 2,6‐bis(imidazol‐1‐yl)pyridine (2,6‐bip). CP (I) was characterized by FT–IR spectroscopy, elemental analysis and single‐crystal X‐ray diffraction. The crystal structure features a unique two‐dimensional (4,4) network with one‐dimensional channels. The luminescence and nitrobenzene‐sensing properties were explored in a DMF suspension, revealing that CP (I) shows a strong luminescence emission and is highly sensitive for nitrobenzene detection.  相似文献   

7.
N‐vinyl‐2‐pyrrolidone/methyl acrylate (V/M) copolymers were prepared by free‐radical bulk polymerization using benzoyl peroxide as an initiator. The copolymer composition of these copolymers was calculated from 1H NMR spectra. The radical reactivity ratios for N‐vinyl‐2‐pyrrolidone (V) and methyl acrylate (M) were rV = 0.09, rM = 0.44. These reactivity ratios for the copolymerization of V and M were determined using the Kelen–Tudos and nonlinear least‐squares error‐in‐variable methods. The 13C{1H} and 1H NMR spectra of these copolymers overlapped and were complex. The complete spectral assignment of the 13C and 1H NMR spectra were done with distortionless enhancement by polarization transfer and two dimensional 13C‐1H heteronuclear single quantum correlation spectroscopic experiments. The two‐dimensional 1H‐1H homonuclear total correlation spectroscopic NMR spectrum showed the various bond interactions, thus inferring the possible structure of the copolymers. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 2225–2236, 2002  相似文献   

8.
N‐vinyl‐2‐pyrrolidone/methyl acrylate (V/M) copolymers were prepared by free‐radical bulk polymerization using benzoyl peroxide as an initiator. The copolymer composition of these copolymers was calculated from 1H NMR spectra. The radical reactivity ratios for N‐vinyl‐2‐pyrrolidone (V) and methyl acrylate (M) were rV = 0.09, rM = 0.44. These reactivity ratios for the copolymerization of V and M were determined using the Kelen–Tudos and nonlinear least‐squares error‐in‐variable methods. The 13C{1H} and 1H NMR spectra of these copolymers overlapped and were complex. The complete spectral assignment of the 13C and 1H NMR spectra were done with distortionless enhancement by polarization transfer and two dimensional 13C‐1H heteronuclear single quantum correlation spectroscopic experiments. The two‐dimensional 1H‐1H homonuclear total correlation spectroscopic NMR spectrum showed the various bond interactions, thus inferring the possible structure of the copolymers. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 2225–2236, 2002  相似文献   

9.
Novel series of conjugated copolymers, incorporating cyclopentadithiophene (CPDT) and the biselenophene ( R‐CPDT‐Se2 ), were synthesized by Pd‐catalyzed Stille coupling polymerization. The optical, electrochemical, field‐effect carrier mobilities, and photovoltaic properties of the R‐CPDT‐Se2 were investigated and compared with cyclopentadithiophene (CPDT) and the bithiophene ( EHex‐CPDT‐T2 ). The highest hole mobility of thin film transistor devices fabricated with new p‐type polymer semiconductors, Oct‐CPDT‐Se2 , was 1.3 × 10?3 cm2/Vs with an on/off ratio of about 105. The maximum power conversion efficiency of polymer solar cell fabricated with the blend of EHex‐CPDT‐Se2 /C71‐PCBM reached 1.86% with an open circuit voltage (VOC) of 0.55 V, a short circuit current density (Jsc) of 7.27 mA/cm2, and a fill factor (FF) of 0.47 under AM 1.5G irradiation (100 mW/cm2). © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2009  相似文献   

10.
An expanded graphite‐epoxy composite electrode (EG‐Epoxy) was employed for the simultaneous determination of 4‐chlorophenol (4‐CP) and oxalic acid (OA) by using cyclic voltammetry (CV), chronoamperometry (CA), and differential pulse voltammetry (DPV). The results indicated that OA could be determined in the presence of the same concentrations of 4‐CP within the concentration range of 0.1 mM to 0.5 mM with a relative standard deviation (RSD) smaller than 5%. Electrode fouling occurred during CA for 4‐CP concentrations larger than 0.5 mM. The DPV method was used for the simultaneous determination of 4‐CP and OA before and after electrochemical oxidation by chronopotentiometry under galvanostatic conditions (j=0.04 mA cm?2, t=2 h) of a tap water sample spiked with 0.19 mM 4‐CP and 0.1 M Na2SO4.  相似文献   

11.
We have synthesized three new donor–acceptor‐type monomers to achieve soluble and processable low‐band gap polymers, 4,7‐bis(4‐octyl‐2‐thienyl)‐2,1,3‐benzothiadiazole (B4TB), 4,7‐bis(3‐octyl‐2‐thienyl)‐2,1,3‐benzothiadiazole (B3TB), and 4‐(3‐octyl‐2‐thienyl)‐7‐(4‐octyl‐2‐thienyl)‐2,1,3‐benzothiadiazole (B34TB), by the Suzuki coupling reaction. Using B4TB and B3TB, two soluble high molecular weight regioregular head‐to‐head and tail‐to‐tail polymers poly[4,7‐bis(4‐octyl‐2‐thienyl)‐2,1,3‐ benzothiadiazole] (PB4TB) and poly[4,7‐bis(3‐octyl‐2‐thienyl)‐2,1,3‐benzothiadiazole] (PB3TB) were prepared via iron(III) chloride‐mediated oxidative polymerization. The structures of the polymers were confirmed by 1H and 13C NMR, and the molecular weights were determined by size exclusion chromatography. The optical properties (absorbance and fluorescence) of the monomers and polymers were studied and compared with unsubstituted analogues. The monomers and polymers bearing octyl substituents on the thiophene rings pointing away from the benzothiadiazole units (B4TB and PB4TB) possess a more planar structure, and their optical spectra appear redshifted as compared with those having the octyl chain nearer to the benzothiadiazole (B3TB and PB3TB). The optical band gaps of PB3BT (Eg = 2.01 eV) and PB4BT (Eg = 1.96 eV), however, are at much higher energy levels than that of the unsubstituted electrochemically polymerized PBTB material (Eg = 1.1–1.2 eV) as a result of steric effects of the octyl chains. The electrochemical properties of the monomers and polymers were examined using cyclic voltammetry and reflect the effect of alkyl substitution. B4TB and PB4TB were oxidized at a lower potential than B3TB and PB3TB, whereas their reduction potentials were less negative. The electrochemical band gap calculated from the onset of the reduction and oxidation process agreed with the optical band gap calculated from the absorption edges. © 2001 John Wiley & Sons, Inc. J Polym Sci Part A: Polym Chem 40: 251–261, 2002  相似文献   

12.
A type of fluorescent–magnetic dual‐function nanocomposite, Fe3O4@SiO2@P‐2, was successfully obtained by Cu+‐catalyzed click reaction between acetylene (C?C? H)‐substituted carbazole‐based conjugated polymer ( P‐2) and azide‐terminated silica‐coated magnetic iron oxide nanoparticles (Fe3O4@SiO2–N3). Optical and magnetization analyses indicate that Fe3O4@SiO2@P‐2 exhibits stable fluorescence and rapid magnetic response. The fluorescence of Fe3O4@SiO2@P‐2 was quenched significantly in the presence of I? and gave a detection limit (DL) of ~8.85 × 10?7 M. Given the high binding constant and matching ratio between Hg2+ and I?, the fluorescence of Fe3O4@SiO2@P‐2/I? complex recovered efficiently with the addition of Hg2+. A DL of ~4.17 × 10?7 M was obtained by this probing system. Recycling of Fe3O4@SiO2@P‐2 probe was readily achieved by simple magnetic separation. Results indicate that Fe3O4@SiO2@P‐2 can be used as an “on–off–on” fluorescent switchable and recyclable Hg2+ probe. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2013, 51, 3636–3645  相似文献   

13.
The quasi‐living copolymerization of ethylene with propylene was achieved by using N‐heterocyclic carbene (NHC) ligated vanadium complex ( V3 , VOCl3[1,3‐(2,6‐iPr2C6H3)2(NCH?)2C:]) due to the stabilization of active center by the introduction of bulky and electron rich NHC ligand with bulky isopropyl substituents at the ortho positions of the phenyl rings. The weight‐average molecular weight (Mw) of the resulting copolymer increases linearly with its weight in 20 min. The ultra‐high‐molecular‐weight (UHMW) ethylene‐propylene copolymer (Mw = 1612 kg mol?1) can be synthesized with V3 /Et3Al2Cl3 catalytic system. The novel complex V4′ (VCl3[1,3‐(2,4,6‐Me3C6H2)2(NCH?)2C:]·2THF) was constructed by the introduction of two coordinated tetrahydrofuran molecules and decrease in steric hindrance at the ortho positions of phenyl rings. The UHMW ethylene‐propylene copolymer (Mw = 1167 kg mol?1) can also be synthesized by using V4′ /Et3Al2Cl3 catalytic system. © 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2019 , 57, 553–561  相似文献   

14.
Fe(0) was firstly used as single‐electron transfer‐living radical polymerization catalyst for acrylonitrile polymerization using carbon tetrachloride as initiator, hexamethylenetetramine as N‐ligand, and N,N‐dimethylformamide as the solvent at 65 °C. First‐order kinetic studies indicated that this polymerization proceeded in a “living”/controlled manner. The living nature of the polymerization was also confirmed by chain extension of methyl methacrylate with polyacrylonitrile (PAN) as macroinitiator. Furthermore, PAN was modified with NH2OH·HCl to generate amidoxime groups for extraction of heavy metal ions (Hg2+) from aqueous solutions. Fourier transformed infrared spectroscopy was performed to characterize chemical composition and structure. The adsorption property of Hg2+ was investigated at different pH values of aqueous solutions and distilled water. The maximal saturated adsorption capacity of Hg2+ was 4.8 mmol g?1. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011  相似文献   

15.
A new donor–acceptor (D‐A) conjugated copolymer (PBDTT(ff)‐ttTPD) based on fluorine‐substituted benzodithiophene (BDT) and 6‐alkylthienothienyl thieno[3,4‐c]pyrrole‐4,6‐dione (ttTPD) has been synthesized via a Stille cross‐coupling reaction. As a control, the nonfluorinated BDT‐based ttTPD copolymer (PBDTT‐ttTPD) was also synthesized by using the same polymerization method. The number‐average molecular weights (M n) of PBDTT(ff)‐ttTPD and PBDTT‐ttTPD were found to be 48,000 g/mol (? = 2.2) and 43,000 g/mol (? = 2.1), respectively. The HOMO levels of PBDTT(ff)‐ttTPD and PBDTT‐ttTPD were calculated to be ?5.65 and ?5.45 eV, respectively. The inclusion of fluorinated BDT units is a very effective approach to lowering the polymer's HOMO level. The SCLC mobilities of PBDTT(ff)‐ttTPD and PBDTT‐ttTPD were determined to be 5.9 × 10?4 and 3.0 × 10?4 cm2/Vs, respectively. Polymer solar cell devices prepared with PBDTT(ff)‐ttTPD and PBDTT‐ttTPD as their active layers were found to exhibit power conversion efficiencies of 7.45 and 6.79% with open circuit voltages of 0.98 and 0.84 V, respectively. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017 , 55 , 2506–2512  相似文献   

16.
New deep‐red light‐emitting phosphorescent dendrimers with hole‐transporting carbazole dendrons were synthesized by reacting tris(2‐benzo[b]thiophen‐2‐yl‐pyridyl) iridium (III) complex with carbazolyl dendrons by DCC‐catalyzed esterification. The resulting first‐, second‐, and third‐generation dendrimers were found to be highly efficient as solution‐processable emitting materials and for use in host‐free electrophosphorescent light‐emitting diodes. We fabricated a host‐free dendrimer EL device with configuration ITO/PEDOT:PSS (40 nm)/dendrimer (55 nm)/BCP (10 nm)/Alq3 (40 nm)/LiF (1 nm)/Al (100 nm) and characterized the device performance. The multilayered devices showed luminance of 561 cd/m2 at 383.4 mA/cm2 (12 V) for 15 , 1302 cd/m2 at 321.3 mA/cm2 (14 V) for 16 , and 422 cd/m2 at 94.4 mA/cm2 (18 V) for 17 . The third‐generation dendrimer, 17 (ηext = 6.12% at 7.5 V), showed the highest external quantum efficiency (EQE) with an increase in the density of the light‐harvesting carbazole dendron. Three dendrimers exhibited considerably pure deep‐red emission with CIE 1931 (Commission International de L'Eclairage) chromaticity coordinates of x = 0.70, y = 0.30. The CIE coordinates remained very stable with the current density. The integration of rigid hole‐transporting dendrons and phosphorescent complexes provides a new route to design highly efficient solution‐processable materials for dendrimer light‐emitting diode (DLED) applications. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 7517–7533, 2008  相似文献   

17.
In this paper, a simple strategy to change the emission behaviour of luminogenic materials was developed. Tetraphenylethene (TPE)‐functionalised benzothiazolium salts with different counteranions (TPEBe?X; X=I?, ClO4? and PF6?) were designed and synthesised. All the luminogens show weak red emission in the solution state that originates from intramolecular charge transfer from TPE to the benzothiazolium unit. Whereas aggregate formation enhances the light emission of TPEBe?ClO4 and TPEBe?PF6, that of TPEBe?I is quenched, thus demonstrating the phenomena of aggregation‐induced emission and aggregation‐caused quenching. TPEBe?I works as a light‐up fluorescent sensor for Hg2+ in aqueous solution with high sensitivity and specificity owing to the elimination of the emission quenching effect of the iodide ion by the formation of HgI2 as well as the induction in aggregate formation by the complexation of Hg2+ with the S atom of the benzothiazolium unit of TPEBe?I. A solid film of TPEBe?I was prepared that can monitor the level of Hg2+ in aqueous solution with a detection limit of 1 μM .  相似文献   

18.
To further extend temperature range of application and low temperature performance of the ethylene‐styrene copolymers, a series of poly(ethylene‐styrene‐propylene) samples with varying monomer compositions and relatively low glass‐transition temperatures (Tg = −28 – 22 °C) were synthesized by Me2Si(Me4Cp)(N‐t‐Bu)TiCl2/MMAO system. Since the 13C NMR spectra of the terpolymers were complex and some new resonances were present, 2D‐1H/13C heteronuclear single quantum coherence and heteronuclear multiple bond correlation experiments were conducted. A complete 13C NMR characterization of these terpolymers was performed qualitatively and quantitatively, including chemical shifts, triad sequence distributions, and monomer average sequence lengths. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2018 , 56, 340–350  相似文献   

19.
A solution of deprotonated 1,3‐bis(4‐bromophenyl)triazene reacts with Hg(CH3COO)2 in methanol / tetrahydrofurane to give yellow crystalline needles of {HgII[NNN(PhBr)2]2}n, a triazenide complex polymer of HgII with metal‐η22‐arene π‐interactions, performed by coordinated single triazenide chains. The crystal structure of the new polymeric complex of HgII belongs to the monoclinic space group P21/n. The lattice of [HgII(BrPhNNNPhBr)2]n can be viewed as a one‐dimensional assembling of planar tectons [HgII(BrPhNNNPhBr)2] linked through metalocene alike HgII‐η22‐arene π‐interactions along the crystallographic b axis.  相似文献   

20.
Strongly asymmetric chlorinated polybutadiene‐b‐polystyrene, [P((CB)xb‐(PS)y)] diblock copolymers with increasing x/(x + y) ratios (up to 5.2 mol %) have been synthesized by the selective chlorination of the polybutadiene (PB) block in solution. Chlorination has been performed in anhydrous dichloromethane added with an antioxidant [2,2′‐methylenebis‐(6‐tert‐butyl‐4‐methyl‐phenol)], at −50°C, under a continuous Ar flow and in the dark. Under the optimized experimental conditions, the PB chlorination is not complete, but the PS block is left unmodified. Even in the presence of a large chlorine excess (Cl2/butene unit molar ratio of 2.5), the experimental degree of chlorination of homo PB does not exceed 85%. The chlorinated copolymers have been characterized by 1H‐NMR, IR spectroscopy, size‐exclusion chromatography, and elemental analysis. The chlorinated copolymers have also been studied by DSC and SAXS after annealing at 150°C. Although at this temperature the parent homopolymers are immiscible, no microphase separation has been observed for the block copolymers. © 1999 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 37: 233–244, 1999  相似文献   

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