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1.
The C60‐containing copolymers were prepared by reaction of styrene (St)/acrylamide (Am) copolymers with C60 in toluene. By means of UV‐Vis spectroscopy, the C60 content in the copolymers was determined to be up to 1.45 wt.‐%. The results show that with increasing the amide molar fraction in the copolymers, the C60 content increases and the molar ratio C60/amide group decreases. It was also revealed that the reactivity of the amide group with respect to C60 could be enhanced by increasing the reaction temperature. C60‐containing St/Am copolymers were characterized by DSC, GPC, XRD and UV‐Vis spectroscopy. Experimental results indicate that these C60‐containing polymers reveal good photoconductivity, with the t1/2 value of the better one (B8) being about 1.88 s, and photoconductivity could be enhanced on increasing the C60 content in the copolymers.  相似文献   

2.
Linear and symmetric star block copolymers of styrene and isoprene containing [C60] fullerene were synthesized by anionic polymerization and appropriate linking postpolymerization chemistry. In all block copolymers, the C60 was connected to the terminal polyisoprene (PI) block. The composition of the copolymers was kept constant (~30% wt PI), whereas the molecular weight of the diblock chains was varied. The polymers were characterized with a number of techniques, including size exclusion chromatography, membrane osmometry, and 1H NMR spectroscopy. The combined characterization results showed that the synthetic procedures followed led to well‐defined materials. However, degradation of the fractionated star‐shaped copolymers was observed after storage for 2 months at 4 °C, whereas the nonfractionated material was stable. To further elucidate the reasons for this degradation, we prepared and studied a four‐arm star copolymer with the polystyrene part connected to C60 and a six‐arm star homopolymer of styrene. These polymers as well as linear copolymers end‐capped, through ? N<, with C60 were stable. Possible reasons are discussed. © 2001 John Wiley & Sons, Inc. J Polym Sci Part A: Polym Chem 39: 2494–2507, 2001  相似文献   

3.
Multitopic dibenzylammonium derivatives ( 4 ) of C60 were prepared by Bingel reactions of C60 with a malonate diester ( 2 ) containing two t‐BOC protected dibenzylamine moieties, followed by deprotection and protonation. Self‐assembly of model pseudorotaxanes 5 from the multidibenzylammonium C60 derivatives with dibenzo‐24‐crown‐8 was studied by 1H NMR spectroscopy and mass spectrometry. Self‐assembly of linear and star‐shaped pseudorotaxanes 8 with up to 12 arms based on polystyrenes bearing terminal DB24C8 host units ( 7 ) and the guest functionalized C60 salts was demonstrated by 1H NMR spectroscopy and solution phase viscometry. These studies provide further evidence of the potential of supramacromolecular chemistry in construction of complex polymeric architectures. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 6472–6495, 2009  相似文献   

4.
Three novel low‐bandgap copolymers containing alkylated 4,7‐dithien‐2‐yl‐2,1,3‐benzothiadiazole (HBT) and different electron‐rich functional groups (dialkylfluorene (PFV‐HBT), dialkyloxyphenylene (PPV‐HBT) and dialkylthiophene (PTV‐HBT)) were prepared by Horner polycondensation reactions and characterized by 1H NMR, gel permeation chromatography, and elemental analysis. The alkyl side chain brings these polymeric materials good solubility in common organic solvents, which is critical for the manufacture of solar cells in a cost‐effective manner. The copolymers exhibit low optical bandgap from 1.48 to 1.83 eV. The highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) energy levels of the copolymers were measured by cyclic voltammetry. Theoretical calculations revealed that the variation laws of HOMO and the LUMO energy levels are well consistent with cyclic voltammetry measurement. The bulk heterojunction photovoltaic devices with the structure of ITO/PEDOT‐PSS/polymer:PCBM/LiF/Al were fabricated by using the three copolymers as the donor and (6,6)‐phenyl‐C61‐butyric acid methyl ester (PCBM) as the acceptor in the active layer. The device based on PTV‐HBT:PCBM (1:4 w/w) achieved a power conversion efficiency of 1.05% under the illumination of AM 1.5, 100 mW/cm2. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011.  相似文献   

5.
Enzymatic complexes, constructed by linear‐dendritic copolymers and laccase, are used for the unprecedented one‐pot biotransformation of fullerene (C60) into epoxide‐ and hydroxyl‐derivatives under mild and environmentally friendly reaction conditions (45 °C and aqueous medium). The reaction is catalyzed by mediator pairs ‐ N‐hydroxy‐5‐norbornene‐2,3‐dicarboxylic acid imide/1‐Hydroxybenzotriazole or 2,2′‐Azino‐bis(3‐ethylbenzothiazoline‐6‐sulfonic acid)/1‐Hydroxybenzotriazole used in equimolar amounts. After 24 and 48 h, the biotransformation products ? C60On, C60(OH)n, C60(H)n(OH)n, and/or C60On(H)m(OH)m range between 50 and 78%, respectively. Their structure is revealed by FTIR, NMR, and mass‐spectrometry. The mechanism of the process is discussed and elucidated. The reaction procedure allows the repeated usage of the enzyme/linear‐dendritic complex, which retains its catalytic activity after several cycles. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012  相似文献   

6.
The 2‐(hydroxymethyl)pyridine modified C60 (PY‐C60) and methoxydiglycol modified C60 (MDG‐C60) are synthesized using Bingel‐Hirsch reaction and characterized by nuclear magnetic resonance (NMR) and mass spectra. PY‐C60 and MDG‐C60 can bind to glucose oxidase (GOx) and quench the fluorescence of tryptophan (Trp) residue in GOx through static mechanism. The conformation of GOx is disturbed after formation of complex with these fullerene derivatives. Kinetic analysis indicates that PY‐C60 and MDG‐C60 may affect the catalytic activity of GOx with a partial mixed‐type inhibition mechanism. In the plasma glucose concentration range (3.6–5.2 mmol·L?1), PY‐C60 may significantly accelerate the catalytic velocity of GOx, however, MDG‐C60 exerts almost no obvious change to the initial velocity of GOx, suggesting that elaborate design of molecular structure of fullerene derivative is very important for regulating the biological activity of fullerene‐enzyme complex.  相似文献   

7.
Two alkylthio‐substituted poly(p‐phenylenevinylene) (AT–PPV) derivatives, poly(2‐octylthio‐p‐phenylenevinylene) (OT–PPV) and poly[5‐methoxy‐2‐(2′‐ethyl‐hexylthio)‐p‐phenylenevinylene] (MEHT–PPV), were synthesized by a Heck coupling reaction for the investigation of the effect of alkylthio groups on the optoelectronic properties of poly(p‐phenylenevinylene) derivatives. The absorption peaks of OT–PPV and MEHT–PPV solutions were located at 431 and 438 nm, respectively. As for solid films, an OT–PPV film showed an absorption maximum wavelength at 444 nm, 13 nm redshifted in comparison with its solution value, whereas an MEHT–PPV film displayed the same absorption peak position as its dilute solution; this indicated that there was no interchain interaction in the MEHT–PPV film. Polymeric light‐emitting diodes (PLEDs) and polymer solar cells (PSCs) based on OT–PPV and MEHT–PPV were fabricated and characterized. Very narrow bandwidths of the electroluminescence (EL) spectra of the two AT–PPVs were found, with the full width at half‐maximum of the emission being 40 and 47 nm for OT–PPV and MEHT–PPV, respectively. The maximum EL efficiency of the single‐layer PLED based on MEHT–PPV with Al as a cathode reached 1.49 cd/A. The PSC based on a blend of OT–PPV and [6,6]‐phenyl‐C61 butyric acid methyl ester (PCBM) showed the power conversion efficiency of 1.4% under the illumination of AM1.5 (80 mW/cm2). © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 1279–1290, 2006  相似文献   

8.

The efficiency of nonlinear optical responses is highly influenced by the state of molecular assembly and aggregation. Introduction of bulky alkyl groups on an organic chromophore enhances its molecular dispersion in solution and, thus, simultaneous multiphoton absorptivity. Accordingly, sterically hindered fullerenyl chromophore triads C60(>DPAF‐C9)2 and pentads C60(>DPAF‐C9)4 were designed and synthesized for the use as optical limiting materials. Photoinduced molecular polarization is a crucial parameter for the enhancement of nonlinear optical responses. For this purpose, we synthesized these conjugates by attaching one or several diphenylaminofluorene moieties to methano[60]fullerene via a covalent keto linkage. The motif increases electronic interactions of DPAF‐Cn rings with the C60 cage in close vicinity. Synthesis of C60(>DPAF‐C9)n (n=1, 2, or 4) was carried out by a four‐step reaction procedure starting from 2‐bromofluorene via dialkylation at C9 position of fluorine ring and followed by attachment of a diphenylamino group at C2 position of dialkylated fluorene, acylation of α‐bromoacetyl group at C7 position of diphenylaminodialkylfluorene, and subsequent Bingel cyclopropanation of DPAF‐acyl bromide with C60. All C60‐DPAF‐Cn derivatives were fully characterized by various spectroscopic analyses. Molecular compositions of these conjugates were clearly confirmed by MALDI‐TOF mass spectra. A method of relative proton counting was applied on the samples of complex C60(>DPAF‐C9)2 and C60(>DPAF‐C9)4 derivatives using DABCO as an internal standard for the calibration of proton integration in 1H‐NMR spectroscopic analyses.  相似文献   

9.
Electrospray ionization mass spectrometry/mass spectrometry (ESI/MS/MS) and multiple stage mass spectrometry (MSn, n > 2) were used in the positive ion mode, with two different types of mass spectrometers, a quadrupole time‐of‐flight and an ion trap, to characterize two sets of different types of C60‐aminopyrimidine exohedral derivatives. In one set, the pyrimidine moiety bears an amino acid methyl ester residue, and in the other the pyrimidine ring is part of a nucleoside‐type moiety, the latter existing as two separated diastereoisomers. We have found that retro‐cycloaddition processes occur for the closed shell protonated species formed by electrospraying C60 derivatives synthesized by Diels–Alder reactions, whereas for the C60 derivatives synthesized via 1,3‐dipolar cycloadditions, these processes did not occur. Formation of diagnostic ions allowed the differentiation between the two groups of fullerene derivatives, and between the diastereoisomers of C60 derivatives with a nucleoside‐type moiety. In general, the fragmentation processes are strongly dependent on the protonation sites and on the structure of the exohedral moieties. Copyright © 2009 John Wiley & Sons, Ltd.  相似文献   

10.
Highly water soluble [60]fullerene (C60) end‐capped vinyl ether (VE) oligomers with well‐defined structure were synthesized by living cationic polymerization technique. The addition reaction between 1‐octynylfulleride anion and oligomeric cationic species of VEs with pendant acetoxyl or malonic ester functions afforded the precursor C60 end‐capped oligomers. The living VE oligomers were prepared by living cationic polymerization of diethyl 2‐(vinyloxy)ethylmalonate (VOEM) and 2‐acetoxyethyl vinyl ether (AcOVE) by the CH3CH(OR)Cl/ZnI2 [R = CH2CH2OCOCH3 and CH2CH2CH(COOEt)2, respectively] initiating system. The precursors were obtained as dark brown gummy solid in 33 and 72% yield for AcOVE and VOEM, respectively. UV‐vis and 13C NMR spectroscopy indicated the formation of 1,2‐disubstituted dihydrofullerene derivatives. Hydrolysis of the precursors proceeded quantitatively to give the water‐soluble C60 end‐capped oligomers having oligo(sodium 2‐vinyloxyethylmalonate) [oligo(VOEMNa)] and oligo(2‐hydroxyethyl vinyl ether) [oligo(HOVE)] moieties. Solubility measurements revealed the water‐soluble C60 end‐capped oligomer with oligo(VOEMNa) chain to have the excellent aqueous solubility compared to that of the water‐soluble C60 derivatives thus far known; the maximum solubility in water is 96.6 mg/mL, which corresponds to 25.9 mg/mL of the C60 moiety. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 38: 3578–3585, 2000  相似文献   

11.
High oxidation potential perfluorinated zinc phthalocyanines (ZnFnPcs) are synthesised and their spectroscopic, redox, and light‐induced electron‐transfer properties investigated systematically by forming donor–acceptor dyads through metal–ligand axial coordination of fullerene (C60) derivatives. Absorption and fluorescence spectral studies reveal efficient binding of the pyridine‐ (Py) and phenylimidazole‐functionalised fullerene (C60Im) derivatives to the zinc centre of the FnPcs. The determined binding constants, K, in o‐dichlorobenzene for the 1:1 complexes are in the order of 104 to 105 M ?1; nearly an order of magnitude higher than that observed for the dyad formed from zinc phthalocyanine (ZnPc) lacking fluorine substituents. The geometry and electronic structure of the dyads are determined by using the B3LYP/6‐31G* method. The HOMO and LUMO levels are located on the Pc and C60 entities, respectively; this suggests the formation of ZnFnPc.+–C60Im.? and ZnFnPc.+–C60Py.? (n=0, 8 or 16) intra‐supramolecular charge‐separated states during electron transfer. Electrochemical studies on the ZnPc–C60 dyads enable accurate determination of their oxidation and reduction potentials and the energy of the charge‐separated states. The energy of the charge‐separated state for dyads composed of ZnFnPc is higher than that of normal ZnPc–C60 dyads and reveals their significance in harvesting higher amounts of light energy. Evidence for charge separation in the dyads is secured from femtosecond transient absorption studies in nonpolar toluene. Kinetic evaluation of the cation and anion radical ion peaks reveals ultrafast charge separation and charge recombination in dyads composed of perfluorinated phthalocyanine and fullerene; this implies their significance in solar‐energy harvesting and optoelectronic device building applications.  相似文献   

12.
Electrophilic trisubstituted ethylene monomers, some ring‐substituted 2‐phenyl‐1,1‐dicyanoethylenes, RC6H4CH?C(CN)2 (where R is 3‐C6H5O, 4‐C6H5O, 3‐C6H5CH2O, 4‐C6H5CH2O, 4‐CH3CO2, 4‐CH3CONH, 4‐(C2H5)2N) were synthesized by piperidine catalyzed Knoevenagel condensation of ring‐substituted benzaldehydes and malononitrile, and characterized by CHN elemental analysis, IR, 1H‐ and 13C‐NMR. Novel copolymers of the ethylenes and vinyl acetate were prepared at equimolar monomer feed composition by solution copolymerization in the presence of a radical initiator (ABCN) at 70°C. The composition of the copolymers was calculated from nitrogen analysis, and the structures were analyzed by IR, 1H and 13C‐NMR, GPC, DSC, and TGA. High T g of the copolymers, in comparison with that of polyvinyl acetate, indicates a substantial decrease in chain mobility of the copolymer due to the high dipolar character of the trisubstituted ethylene monomer unit. The gravimetric analysis indicated that the copolymers decompose in the 190–700°C range.  相似文献   

13.
Acrylonitrile/pentyl acrylate (A/P) copolymers of different monomer composition were prepared by solution polymerization using benzoyl peroxide as initiator. Copolymer compositions were determined by elemental analysis and quantitative 13C1H‐NMR spectroscopy. The comonomer reactivity ratios, determined by both Kelen Tudos (KT) and nonlinear error in variables (EVM) methods are rA = 0.75 and rp = 0.45. 2‐D heteronuclear correlation spectroscopy (HSQC) was used to simplify the complex 1H spectra of A/P copolymers in terms of configurational and compositional sequences. The microstructure was obtained in terms of the distribution of A‐ and P‐ centered triad sequences from 13C1H‐NMR spectra of the copolymers. The copolymerization mechanism was found to follow a first order Markov Model. © 1999 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 37: 533–543, 1999  相似文献   

14.
A liquid‐crystalline mixed [5 : 1]hexa‐adduct of [60]fullerene was synthesized by addition of two different malonate derivatives onto C60. The hexa‐adduct derivative 2 was prepared by a stepwise synthetic procedure (fullerene→mono‐adduct of C60→hexa‐adduct of C60). Cyanobiphenyl and octyloxybiphenyl derivatives were selected as mesogens. The malonate derivatives showed either a monotropic nematic phase or a monotropic smectic A phase, and the hexa‐adduct derivative gave rise to an enantiotropic smectic A phase.  相似文献   

15.
C60 carboxylic acid derivatives can be readily adsorbed on the surface of nanocrystalline TiO2 film. The C60 carboxylic acids adsorbed on nanocrystalline TiO2 films act as charge‐transfer sensitizer. The electron transport from TiO2 to the C60 derivatives results in the generation of the cathodic photocurrent. The short‐circuit photocurrent of a C60 tetracarboxylic acid is 0.45 μA/cm2 under 464 nm light illumination. The photoelectric behaviour of ITO electrodes modified by the same C60 carboxylic acids is different from that of the modified TiO2 electrodes, and shows anodic photocurrent.  相似文献   

16.
The synthesis of a stereochemically pure concave tribenzotriquinacene receptor ( 7 ) for C60 fullerene, possessing C3 point group symmetry, by threefold condensation of C2‐symmetric 1,2‐diketone synthons ( 5 ) and a hexaaminotribenzotriquinacene core ( 6 ) is described. The chiral diketone was synthesized in a five‐step reaction sequence starting from C2h‐symmetric 2,6‐di‐tert‐butylanthracene. The highly diastereo‐discriminating Diels–Alder reaction of 2,6‐di‐tert‐butylanthracene with fumaric acid di(?)menthyl ester, catalyzed by aluminium chloride, is the relevant stereochemistry introducing step. The structure of the fullerene receptor was verified by 1H and 13C NMR spectroscopy, mass spectrometry and single crystal X‐ray diffraction. VCD and ECD spectra were recorded, which were corroborated by ab initio DFT calculations, establishing the chiral nature of 7 with about 99.7 % ee, based on the ee (99.9 %) of the chiral synthon ( 1 ). The absolute configuration of 7 could thus be established as all‐S [(2S,7S,16S,21S,30S,35S)‐( 7 )]. Spectroscopic titration experiments reveal that the host forms 1:1 complexes with either pure fullerene (C60) or fullerene derivatives, such as rotor 1′‐(4‐nitrophenyl)‐3′‐(4‐N,N‐dimethylaminophenyl)‐pyrazolino[4′,5′:1,2][60]fullerene ( R ). The complex stability constants of the complexes dissolved in CHCl3/CS2 (1:1 vol. %) are K([ C60 ? 7 ])=319(±156) M ?1 and K([ R ? 7 ])=110(±50) M ?1. With molecular dynamics simulations using a first‐principles parameterized force field the asymmetry of the rotational potential for [ R ? 7 ] was shown, demonstrating the potential suitability of receptor 7 to act as a stator in a unidirectionally operating nanoratchet.  相似文献   

17.
Efficient photoinduced electron transfer was observed across a [10]cycloparaphenylene ([10]CPP) moiety that serves as a rigid non‐covalent bridge between a zinc porphyrin and a range of fullerenes. The preparation of iodo‐[10]CPP is the key to the synthesis of a porphyrin–[10]CPP conjugate, which binds C60, C70, (C60)2, and other fullerenes (KA>105 m ?1). Fluorescence and pump–probe spectroscopy revealed intramolecular energy transfer between CPP and porphyrin and also efficient charge separation between porphyrin and fullerenes, affording up to 0.5 μs lifetime charge‐separated states. The advantage of this approach towards electron donor–acceptor dyads is evident in the case of dumbbell‐shaped (C60)2, which gave intricate charge‐transfer behavior in 1:1 and 2:1 complexes. These results suggest that [10]CPP and its cross‐coupled derivatives could act as supramolecular mediators of charge transport in organic electronic devices.  相似文献   

18.
Novel phenylene-bridged zinc bisporphyrins (1-4), fulleropyrrolidines (C60-m, C60-h) and their N-oxides (C60-mo, C60-ho) were synthesized. The fluorescence quenching processes of bisporphyrins in toluene solution by fulleropyrrolidines and their N-oxides were investigated by steady-state fluorescence spectra. The fluorescence quenching constants proved that the fluorescence quenching ability was decreased as reduction of the pyrrolidine functional groups of fullerene surface: C60-h〉C60-m〉C60, and the fluorescence quenching ability was increased about 1.3-7.4 times by utilizing fulleropyrrolidine N-oxides (C60-mo, C60-ho) compared to fulleropyrrolidine compounds (C60-m, C60-h). The results revealed photoinduced electron transfer (PET) efficiency between bispor-phyrin and fullerene derivatives could be tunable by change of functional groups on fullerene surface.  相似文献   

19.
A new series of 2,1,3‐benzothiadiazole (BT) acceptors with different conjugated aryl‐vinylene side chains have been designed and used to build efficient low‐bandgap (LBG) photovoltaic copolymers. Based on benzo[1,2‐b:3,4‐b′]dithiophene and the resulting new BT derivatives, three two‐dimensional (2D)‐like donor (D)–acceptor (A) conjugated copolymers have been synthesised by Stille coupling polymerisation. These copolymers were characterised by NMR spectroscopy, gel‐permeation chromatography, thermogravimetric analysis and differential scanning calorimetry. UV/Vis absorption and cyclic voltammetry measurements indicated that their optical and electrochemical properties can be facilely modified by changing the structures of the conjugated aryl‐vinylene side chains. The copolymer with phenyl‐vinylene side chains exhibited the best light harvesting and smallest bandgap of the three copolymers. The basic electronic structures of D–A model compounds of these copolymers were also studied by DFT calculations at the B3LYP/6‐31G* level of theory. Polymer solar cells (PSCs) with a typical structure of indium tin oxide (ITO)/poly(3,4‐ethylenedioxythiophene) (PEDOT):poly(styrenesulfonate) (PSS)/copolymer:[6,6]‐phenyl‐C61(C71)‐butyric acid‐methyl ester (PCBM)/calcium (Ca)/aluminum (Al) were fabricated and measured under the illumination of AM1.5G at 100 mW cm?2. The results showed that the device based on the copolymer with phenyl‐vinylene side chains had the highest efficiency of 2.17 % with PC71BM as acceptor. The results presented herein indicate that all the prepared copolymers are promising candidates for roll‐to‐roll manufacturing of efficient PSCs. Suitable electronic, optical and photovoltaic properties of BT‐based copolymers can also be achieved by fine‐tuning the structures of the aryl‐vinylene side chains for photovoltaic application.  相似文献   

20.
While WCl_6-Ph_4Sn fails to polymerize 1-phenyl-1-propyne (PP) at room temperature, highmolecular weight (M_w up to 410×10~3) polymers are obtained in high yields (up to 80%) when thepolymerizations of PP are carried out in the presence of C_(60) using the W catalyst under the same conditions.The polymers are soluble in common organic solvents such as THF, chloroform, and toluene. Molecularstructures of the polymers are characterized by FT-IR, UV, NMR, GPC and XRD, and it is found that C_(60) iscopolymerized with PP. Thus C_(60) plays the dual roles of comonomer and cocatalyst in the polymerizationreaction. C_(60) contents of the copolymers can be easily changed by varying the C_(60) amounts in the feedmixtures. The copolymers effectively limit strong 532 nm laser pulses, whose limiting performance issuperior to that of parent C_(60).  相似文献   

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