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1.
Hideto Tsuji Yoshio Kawashima Hirofumi Takikawa 《Journal of Polymer Science.Polymer Physics》2007,45(16):2167-2176
The effects of solvent type and concentration of C60 on the crystallization of poly(L ‐lactide) (PLLA) during solvent evaporation, heating from room temperature, and cooling from the melt were investigated by polarized optical microscopy and differential scanning calorimetry. The addition of C60 enhanced the PLLA crystallization during solvent evaporation, during heating of the melt‐quenched films, and during cooling from the melt of As‐cast films, except for heating and cooling of the PLLA film with 1 wt % of C60 prepared with dichloromethane. In the case of solvent evaporation, the difference in crystallinity between the PLLA films with and without C60 became higher for the solvent with a lower boiling point. In the case of heating of melt‐quenched films, the addition of C60 had a small effect on the crystallinity of PLLA, whereas significantly lowered the peak top and ending temperatures of cold crystallization, except for melt‐quenched PLLA film with 1 wt % of C60 prepared with dichloromethane. The crystallinity of PLLA was determined by the solvent type, rather than by the C60 concentration. In the case of cooling from the melt of As‐cast films, the addition of C60 elevated the crystallinity and cold crystallization temperature values of PLLA films, except for PLLA films prepared with dichloromethane. © 2007 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 45: 2167–2176, 2007 相似文献
2.
The photochromic reaction of two derivatives of bisthiazolylindenols was investigated in three solvents of various polarities (C6D12, THF-d8 and CD3CN) by NMR spectroscopy. Photoirradiation can generate two diastereomeric closed forms. High conversion ratio and large diastereomer excess were obtained and the reasons of the excellent properties were discussed in terms of intramolecular hydrogen bonds, steric bulkiness of substituents, and solvent polarities. Two sets of intramolecular nitrogen–hydrogen interactions fix the conformation of the two investigated bisthiazolylindenols in favor of cyclization, which also lead to high diastereoselectivity. The N–H interactions are partially disrupted when polarity of the solvent increases. 相似文献
3.
N-Methyl-2-(4-N,N-diphenylaminophenyl)fulleropyrrolidine and N-methyl-2-(4-di-p-tolylaminophenyl)fulleropyrrolidine were synthesized via the 1,3-dipolar cycloaddition reactions under microwave irradiation. The molecular structures were identified and characterized by MS, UV-Vis, FT-IR, ^1H NMR and fluorescence spectra. Photoinduced intramolecular electron transfer process from C60 moiety to triphenylamine moiety have been studied by nanosecond laser flash photolysis. The optimized structure and the distribution of the frontier molecular orbitals for C60-TPA were obtained by using DFT method at B3LYP/6-31G(d) level. The results indicated that the intramolecular photoinduced electron transfer could occur in these compounds, which were in excellent agreement with the nanosecond transient absorption spectra observed experimentally in polar solvent. The electronic spectrum of the compound C60-TPA was studied by ZINDO method on the basis of the optimized geometrics, which was essentially consistent with experimental values. 相似文献
4.
Natalia V. Avramenko E. B. Stukalin M. V. Korobov 《Journal of Thermal Analysis and Calorimetry》2005,82(1):125-127
Summary The binary systems of C60with α-methyl- and α-chloronaphthalene have been studied by means of differential scanning calorimetry. C60was found to form the molecular complex of the van der Waals type with α-methylnaphthalene which melts incongruently below
the boiling point of the solvent at temperature 382.7±3.0 K. The enthalpy of the desolvation reaction is 14.1±0.5 kJ mol-1of C60. The molar ratio of fullerene to solvent in the solvate is 1:1.5. In the system C60-α-chloronaphthalene a two-stage incongruent melting process has been observed at temperatures 314.1±4.6 K and 375.7±7.4 K
with the enthalpies 8.1±2.6 kJ mol-1and 11.6±1.0 kJ mol-1, respectively. The composition of the most solvated phase equilibrated with the saturated solution at room temperature and
below the first of the incongruent melting transitions was determined as 1:1.5. Based on the results obtained the thermodynamic
characteristics of the incongruent melting reactions have been revealed and influence of solvate formation on solubility of
C60has been discussed. 相似文献
5.
R. M. Nikonova M. A. Merzlyakova V. I. Lad’yanov V. V. Aksenova 《Russian Journal of Physical Chemistry A, Focus on Chemistry》2012,86(7):1121-1127
The thermal behavior of a mixture of fullerites C60/70 was studied by X-ray diffraction and IR and UV spectroscopy. The temperature range in which the molecular and crystal states degrade was determined (825?C875°C in a CO medium). In the C60/70 mixture, fullerenes decomposed at lower temperatures than in pure C60 and C70; the decomposition temperature depended on the impurity (oxygen and solvent) content. 相似文献
6.
A. M. Kolker N. I. Islamova N. V. Avramenko A. V. Kozlov 《Russian Journal of Physical Chemistry A, Focus on Chemistry》2006,80(10):1622-1625
The solubility of fullerene C60 in the tetrachloromethane-toluene system is measured over the entire range of compositions of the mixed solvent in the temperature range 298.15–338.15 K. An equation is proposed for describing the solubility of C60 as a function of the temperature and the composition of the mixed solvent. The equation is used for calculating the thermodynamic characteristics of solution of the fullerene. It is found that, in the investigated C60-CCl4/C6H5CH3 system, two types of solid solvates of the fullerene with the solvent are formed. The enthalpies and temperatures of incongruent melting of the crystalline solvates are determined by differential scanning calorimetry. The thermodynamic characteristics of solution and solvation of C60 in CCl4 and C6H5CH3 are obtained. It is shown that the entropy factor plays a decisive role in the temperature dependence of the Gibbs energy of solvation of the fullerene. 相似文献
7.
Kowalska E. Byszewski P. Diduszko R. Huczko A. Mieczkowski J. 《Journal of Thermal Analysis and Calorimetry》1998,54(1):197-202
The crystalline solvates containing fullerenes and (di)methylnaphthalenes were investigated by thermal analyses and X-ray
diffraction methods. It was found that C60 with (di)methylnaphthalenes forms two types of stable solvates: either at the molar ratio 1:2 decomposing at temperatures
close to 100°C or at 1:1 molar ratio decomposing in the temperature range 120–214°C. Crystalline lattice and thermal stability
of the solvates depends on the structure of the solvent molecules. The strong solute-solvent interaction is also manifested
by the modification of the C60 absorption spectra in solution. The results are discussed using semiempirical quantum chemistry methods.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
8.
This paper reports the gelation and liquid crystal properties of a class of new complexes between zinc and copper bisporphyrin and C60 derivatives. The bisporphyrins are induced by intramolecular hydrogen bonding to adopt a preorganized ‘U’-shaped conformation and therefore efficiently complex the C60 derivatives. As a result, the capacity of their mixtures to gelate alkanes is increased notably. The bisporphyrins themselves and their complexes with the C60 derivatives form the smectic liquid crystal phase. However, the glassy transition temperature of the complexes decreases considerably. 相似文献
9.
Itaru Natori Shizue Natori 《Journal of polymer science. Part A, Polymer chemistry》2008,46(10):3282-3293
The grafting reaction of poly(1,3‐cyclohexadienyl)lithium onto fullerene‐C60 (C60) was strongly affected by the nucleophilicity of poly(1,3‐cyclohexadiene) (PCHD) carbanions and the polymer chain microstructure, and progressed via step‐by‐step reactions. A star‐shaped PCHD, having a maximum of four arms, was obtained from poly(1,3‐cyclohexadienyl)lithium composed of all 1,4‐cyclohexadiene (1,4‐CHD) units. The rate of the grafting reaction was accelerated by the addition of amine. The grafting density of PCHD arms onto C60 decreased with an increase in the molar ratio of 1,2‐cyclohexadiene (1,2‐CHD) units. The electron‐transfer reaction from PCHD carbanions to C60 did not occur in either a nonpolar solvent or a polar solvent. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 3282–3293, 2008. 相似文献
10.
C60-doped silicon oxide thin films were prepared by spin-coating a viscous solution formed upon soaking at 40°C an acidic toluene/ethanol solution of C60, phenyltriethoxysilane, and tetraethoxysilane with a C60–to–Si molar ratio of 2.5 × 10–3. The films were submitted to annealing at 300–500°C in Ar to investigate variation in the size of C60 clusters embedded in the films by photoluminescence spectroscopy. The film before annealing was found to contain the clusters consisting of ca. 60 C60 molecules, suggesting that C60 is present well-dispersed in the film. The molecules in the film aggregated to increase the size with increasing annealing temperature, indicating that the molecules diffuse easily in the film upon heating and therefore the size of the clusters is controllable with the annealing temperature. 相似文献
11.
V. V. Aksenova R. M. Nikonova V. I. Lad’yanov V. V. Mukhgalin I. V. Sterkhova 《Russian Journal of Physical Chemistry A, Focus on Chemistry》2013,87(6):1002-1008
The C60-toluene and C70-toluene complexes were studied by IR-Fourier spectroscopy. The complexes were obtained by crystallization from a toluene solution at room temperature. The changes in the IR spectra caused by the deformation of toluene molecules in the complexes allowed us to study the phase transitions in the fullerene-aromatic solvent systems. 相似文献
12.
Nicola Armaroli Gianluca Accorsi JohnN. Clifford Jean‐Franois Eckert Jean‐Franois Nierengarten 《化学:亚洲杂志》2006,1(4):564-574
Oligophenylenevinylene (OPV)‐terminated phenylenevinylene dendrons G1 – G4 with one, two, four, and eight “side‐arms”, respectively, were prepared and attached to C60 by a 1,3‐dipolar cycloaddition of azomethine ylides generated in situ from dendritic aldehydes and N‐methylglycine. The relative electronic absorption of the OPV moiety increases progressively along the fullerodendrimer family C60G1 – C60G4 , reaching a 99:1 ratio for C60G4 (antenna effect). UV/Vis and near‐IR luminescence and transient absorption spectroscopy was used to elucidate photoinduced energy and electron transfer in C60G1 – C60G4 as a function of OPV moiety size and solvent polarity (toluene, dichloromethane, benzonitrile), taking into account the fact that the free‐energy change for electron transfer is the same along the series owing to the invariability of the donor–acceptor couple. Regardless of solvent, all the fullerodendrimers exhibit ultrafast OPV→C60 singlet energy transfer. In CH2Cl2, the OPV→C60 electron transfer from the lowest fullerene singlet level (1C60*) is slightly exergonic (ΔGCS≈0.07 eV), but is observed, to an increasing extent, only in the largest systems C60G2 – C60G4 with lower activation barriers for electron transfer. This effect has been related to a decrease of the reorganization energy upon enlargement of the molecular architecture. Structural factors are also at the origin of an unprecedented OPV→C60 electron transfer observed for C60G3 and C60G4 in apolar toluene, whereas in benzonitrile, electron transfer occurs in all cases. Monitoring of the lowest fullerene triplet state by sensitized singlet oxygen luminescence and transient absorption spectroscopy shows that this level is populated through intersystem crossing and is not involved in photoinduced electron transfer. 相似文献
13.
Kyosuke Matsumoto Shunsuke Kusaba Yuya Tanaka Yoshihisa Sei Munetaka Akita Kazushi Aritani Masa‐aki Haga Michito Yoshizawa 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(25):8551-8555
Synthesis of molecular containers capable of incorporating multiple fullerenes remains challenging. Reported here is that room‐temperature mixing of metal ions with W‐shaped bispyridine ligands featuring polyaromatic panels results in the quantitative formation of a peanut‐shaped M2L4 capsule. The capsule reversibly converts into two molecules of an ML2 double tube in response to changes in the solvent. Notably, the capsule allows the incorporation of two fullerene molecules into the connected two spherical cavities at room temperature. The close proximity yet non‐contact of the encapsulated C60 molecules, with a separation of 6.4 Å, was revealed by X‐ray crystallographic analysis. The resultant, unusual fullerene dimer undergoes sequential reduction within the capsule to generate (C60.?)2, C60.??C602?, and (C602?)2 species. Furthermore, temperature‐controlled stepwise incorporation of two C60 molecules into the capsule is demonstrated. 相似文献
14.
Prof. Dr. Tomokazu Umeyama Tomoya Ohara Dr. Yusuke Tsutsui Shota Nakano Prof. Dr. Shu Seki Prof. Dr. Hiroshi Imahori 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(29):6726-6735
Few-layered antimonene (FLSb) nanosheets were noncovalently functionalized with fullerene C60 clusters by quick addition of a poor solvent (i.e., acetonitrile) into a mixed dispersion of FLSb and C60 in a good solvent (i.e., toluene). In a flash-photolysis time-resolved microwave conductivity (FP-TRMC) measurement, the FLSb-C60 composite, (FLSb+C60)m, showed a rapid rise in transient conductivity, whereas no conductivity signal was observed in the single components, FLSb and C60. This demonstrated the occurrence of photoinduced charge separation between FLSb and C60 in (FLSb+C60)m. Furthermore, a photoelectrochemical device with an electrophoretically deposited (FLSb+C60)m film exhibited an enhanced efficiency of photocurrent generation, compared to those of the single-components, FLSb and C60, due to the photoinduced charge separation between FLSb and C60. This work provides a promising approach for fabrication of antimonene–organic molecule composites and paves the way for their application in optoelectronics. 相似文献
15.
Changchun Wang Zhenghong Tao Wuli Yang Shoukuan Fu 《Macromolecular rapid communications》2001,22(2):98-103
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
16.
Absorption spectrums of C60 fullerene in 10 various organic solvents in the range of 300–620 nm was studied. In all the solvents the C60 fullerene has four absorption maxima in the range under study. When an aromatic solvent has an ionization potential of 8.1 eV or lower a new additional absorption band appears in the absorption spectrum of C60 fullerene, caused by the formation of a charge-transfer complex (CTC) of the solvent and C60 fullerene. 相似文献
17.
M. Plass M. Weychert I. Wawer B. Piekarska-Bartoszewicz A. Temeriusz 《Journal of carbohydrate chemistry》2013,32(8):1059-1074
ABSTRACT Ten N-(2-amino-2-deoxy-β-D-glucopyranoside)-N'-carbamoyl-L-dipeptidylesters with different amino acid sequences in the dipeptide unit were studied by means of IR and 1H NMR spectroscopy. In the IR spectra three bands at 3453, 3420 and 3390 cm-1 were observed which could be assigned to the free NH, the intramolecularly hydrogen bonded NH species forming five-membered, C5, and seven-membered, C7, rings, respectively. Comparing the NH band positions which correspond to the C7 rings of the Gly-Xaa and the Xaa-Gly dipeptidylesters, the signals of the Xaa-Gly sequence were shifted by 10 cm-1 to lower wave numbers indicating stronger hydrogen bonds. The temperature effect dv/dT was an order of magnitude larger for the C7 associates than for C5 showing the highest enthalpy of the C7 hydrogen bond. The 1H NMR spectra give three separate signals for the NH groups. The temperature coefficient ?δ/?T was the largest for N-1-H indicating the formation of less stable hydrogen bonds (C7). The solvent induced changes of the chemical shift of the NH signals was lowest for the N-3-H signal. Obviously the deshielding properties on this function do not vary in dependence of the solvent polarity. The hydrogen/deuterium exchange rate was lowest for the N-6-H proton indicating the lower accessibility of this proton. Combining the results of both spectroscopic methods it can be concluded that the N-1-H forms only C7 rings whereas N-6-H can participate in C5 and C7 intramolecular hydrogen bonds. The strength of the formed C7 associates depends on the amino acid sequence in the dipeptide residue. 相似文献
18.
Saeed Yousefinejad Fatemeh Honarasa Fatemeh Abbasitabar Zeinab Arianezhad 《Journal of solution chemistry》2013,42(8):1620-1632
Because of the importance of the solubility of buckminsterfullerene, C60, as the most well-known carbon nanomaterial, a multiparameter linear model is proposed for C60 solubility in different solvents using solvent empirical parameters. The obtained model covers more than 81 and 87 % of the variance in the training and test sets, respectively. On the other hand, because of the potential of solvent empirical parameters for probing different aspects of the solvent–solute interactions, some information about the solubility of C60 in solution phase was obtained. The results showed that hydrogen bond donation ability, basicity scale and dispersion interactions were some of the effective parameters for correlating the solubility of C60 in various solvents. 相似文献
19.
Using time-resolved cw EPR and pulsed EPR techniques, a study was made of the characteristics of the photoexcited triplet state of C60 adsorbed in silica gel pores and embedded in a polymethylmethacrylate matrix. It was found that the time-resolved spectra from 3C60 in these matrices at room temperature retain the absorption/emission features of spectra from 3C60 in frozen solution (≤120 K). Apparently, the combination of molecular rotation and pseudo rotation (resulting from interconversion between Jahn-Teller states) is not fast enough, to lead to complete averaging of the dipole-dipole interaction between the unpaired electrons. The study explored the effect of introduction of solvent molecules in the silica gel pores on the 3C60 spectrum and quenching of the triplet by electron donors. 相似文献
20.
近十几年来,纳米管引起了人们越来越多的关注,不仅仅是由于它独特的性质,也因为它们在电、磁以及光电器件上具有广泛的应用前景。纳米管的制备方法大体上分为两种:自组装法[1 ̄3]和模板法[4 ̄7]。尽管自组装法已成功地制得了一些纳米管,但由于它对构造纳米管的材料有着较严格的 相似文献