共查询到20条相似文献,搜索用时 15 毫秒
1.
Li Yuguo Zhang Xiaodong Li Qingnuan Li Wenxin 《Journal of Radioanalytical and Nuclear Chemistry》2001,250(2):363-364
In this paper water-soluble fullerene derivative C60(OH)xOy was radioiodinated with the iodogen method. The labeling yield was determined by radio-TLC. The effects of pH value, reaction time, temperature and amount of the iodogen on the labeling yield were studied. The labeled product was purified by Sephadex G-25 column chromatography and then the stability of 125I-C60(OH)xOy was examined . The results showed that the radiochemical purity of 125I-C60(OH)xOy solution with benzylalcohol remained 82.7% after 43 hours. 相似文献
2.
Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 5, p. 1192, May, 1988. 相似文献
3.
The γ radiolysis of aqueous high molecular weight poly(ethylene oxide) solutions has been studied. The crosslinking and eventual gelation of these solutions appears to occur via an indirect effect. Solubility measurements on the gelled solutions showed that the ratio of crosslinking to degradation is about four. G(H2) increased from 1.3 in neutral solutions to 3.5 in 0.1N HCl solutions. In heavy water solutions, HD is the major gaseous product. Solvated electrons are not important precursors to hydrogen at neutral pH. Intramolecular crosslinking appears to be an important phenomenon in solutions of high molecular weight polymers. 相似文献
4.
S. Sabharwal H. Mohan Y. K. Bhardwaj A. B. Majali 《Radiation Physics and Chemistry》1999,54(6):175-653
Radiation induced crosslinking of poly(vinyl methylether) (PVME) has been investigated in aqueous solutions. The spectral and kinetic features of the transients involved in the crosslinking reaction have been studied by pulse radiolysis of dilute PVME solutions. H atoms reacts with PVME, like OH radicals, by abstracting an H atom predominantly from β-position with respect to ---OCH3 group, but the rate of reaction of H atom is an order of magnitude slower than that of OH reaction. The PVME radicals formed by H attack have been found to decay by usual 2nd-order kinetics unlike PVME radicals produced by OH attack that are reported to decay by a complex time-dependent kinetics that deviates strongly from 2nd-order kinetics. The rate constant of e−aq with PVME at pH 5.5 has been found to be 1.2×108 dm3 mol−1 s−1. From the decay behaviour of the transient species formed by reaction of e−aq with PVME, it has been shown that the transient initially reacts with solvent protons by a fast reaction to yield radical species which subsequently recombine by a slow mode. The dependence of gelation dose and radiation yields of crosslinking (Gx) of PVME on various factors such as polymer concentration, dose rate, pH, presence of oxygen and crosslinking agent has also been studied by steady-state radiolysis using an electron-beam accelerator. 相似文献
5.
SHI Zhan-Ling MAO Yi-Ping TONG Wei JIN Li-TongDepartment of chemistry East China Normal University Zhong Shan Road 《中国化学》1994,12(2):117-122
The construction of adsorptive type C60 modified electrode and its electrochemical reduction and oxidation behavior in aqueous solutions are described in this report. Four pairs of one-electron transfer reduction and oxidation cyclic voltammetry is obtained in aqueous solution containing 30% CH3CN and 2% (C2H5)4NOH. It is reported in this paper that the C60 modified electrode also catalyzes the electrochemical reduction of dissolved oxygen in 40% DMF and 2% (C2H5)4NOH aqueous solution and this might open a new field for the potential applications of C60 in electrochemistry and electroaualytical chemistry. 相似文献
6.
Horacio Corti Rosa Crovetto Roberto Fernández-Prini 《Journal of solution chemistry》1980,9(8):617-625
The conductivities of aqueous solutions of sodium borate at 25°C and lithium borate at various temperatures are reported.
The conductivity of the B(OH)
4
−
ion is 35.3 ±0.2 S-cm2-mole−1 at 25°C. The electrolytes are both associated, the lithium salt being more associated than the sodium salt. The mobilities
and association constants obtained from the conductivity data agree with a model recently proposed for the H2O−B(OH)
4
−
interactions. A discrepancy in the reported thermodynamic behavior of NaB(OH)4 aqueous solutions has been resolved by means of the association constants obtained in the present study. Thus the usefulness
of the conductivity measurements to determine excess chemical potentials of binary electrolytes in dilute solution is again
shown. 相似文献
7.
Laus S Sitharaman B Tóth E Bolskar RD Helm L Asokan S Wong MS Wilson LJ Merbach AE 《Journal of the American Chemical Society》2005,127(26):9368-9369
A combined proton relaxivity and dynamic light scattering study has shown that aggregates formed in aqueous solution of water-soluble gadofullerenes can be disrupted by addition of salts. The salt content of fullerene-based materials will strongly influence properties related to aggregation phenomena, therefore, their behavior in biological or medical applications. In particular, the relaxivity of gadofullerenes decreases dramatically with phosphate addition. Moreover, real biological fluids present a rather high salt concentration which will have consequences on fullerene aggregation and influence fullerene-based drug delivery. 相似文献
8.
Radiolysis of aqueous DCH18C6 solutions at 77 K 总被引:1,自引:0,他引:1
O. A. Zakurdaeva S. V. Nesterov V. I. Feldman 《Journal of Radioanalytical and Nuclear Chemistry》2009,279(2):647-653
Low-temperature (77 K) γ- and X-ray radiolysis of aqueous DCH18C6 solutions was studied by ESR-spectroscopy. OH radicals, trapped electrons and macrocyclic
radicals -CH2-CH-O- resulting from H-atom abstraction from methylene groups of polyether ring were identified as predominant radiolysis
products. Increasing the crown ether concentration in aqueous solution leads to the growth of relative yields of the trapped
electron and macrocyclic radicals as well as the decrease of that of hydroxyl radical. Neither radical products of macrocycle
rupture nor H-atom abstraction from cyclohexane rings were observed. 相似文献
9.
Amat MC Van Lier G Solà M Duran M Geerlings P 《The Journal of organic chemistry》2004,69(7):2374-2380
In the present work a quantum chemical study of a series of substituted hydrofullerenes, C(60)HR, and a series of methanofullerenes, C(60)(CHR), is presented. Their reactivity and geometrical, energetic, electronic, and magnetic properties, as well as the influence of the substituent, are discussed. As a probe of the reactivity, the acidic properties of these fullerene derivatives were predicted, based on the calculated deprotonation energies, with a previously set up scheme. The electronic delocalization upon deprotonation was described, and the global (magnetizabilities) and local aromaticity (nucleus-independent chemical shifts) was analyzed and compared with respect to the group properties for the series of functional groups. The geometries of both acidic and basic forms were fully optimized at the AM1 level, and all property calculations were performed at the HF/3-21G and the B3LYP/6-31G* level of theory. 相似文献
10.
Summary Coagulation rate measurements of Ca3Al2(OH)12 in different aqueous electrolyte solutions (NaOH, NaNO3, Ca(OH)2) show that, at concentrations lower than 0.1 M NaNO3 and 0.3 M NaOH respectively, the stability increases with increasing ionic strength. This fact cannot be explained as either primary or secondary coagulation according to the DLVO theory. However, polymeric ions such as poly-aluminate ions, present in the liquid phase can cause the observed coagulation behaviour at these concentrations. At NaNO3 concentrations higher than 0.1 M NaNO3 the coagulation behaviour can be explained as primary coagulation according to the DLVO theory assuming = withA
1(2) = 0.03 X 10–20J. Assuming a distance between the plane with average potentialgs and of 0.3 to 0.4 nm,A
1(2) =0.28 -0.30 x 10–20J depending on the conditions between these two layers.
With 8 figures and 1 table 相似文献
Zusammenfassung Koagulationgeschwindigkeitsmessungen an Ca3 Al2(OH)12-Suspensionen zeigen, daß in wässerigen Elektrolytlösungen (NaOH, NaNO3, Ca(OH)2) bei Konzentrationen niedriger als 0.1 M NaNO3 bzw. 0.3 M NaOH die Stabilität größer wird, wenn die Elektrolytkonzentration zunimmt. Weder primäre noch sekundäre Koagulation nach der DLVO-Theorie kann diesen Effekt erklären. Die Anwesenheit von polymeren Ionen (z. B. Polyaluminationen) in der Lösung kann das beobachtete Koagulationsverhalten bei diesen Konzentrationen aber deuten. Bei NaNO3-Konzentrationen größer als 0.1 M kann das Koagulationsverhalten erklärt werden als primäre Koagulation nach der DLVO-Theorie mit der Annahme, daß= und A1(2)=0.03 X 10–20 J. Nimmt man an, daß der Abstand zwischen den Flächen mit durchschnittlichen Potentialen und etwa 0.3–0.4 nm beträgt, so wird A1(2)=0.28–0.30 x 10–20 J, abhängig vom Zustand zwischen diesen Flächen.
With 8 figures and 1 table 相似文献
11.
Polypropylene samples with fullerene C60, fullerenol C60(OH)24, 1010, C60/168, C60-OH/168 and 1010/168 as antioxidants were prepared by extrusions. MFR, YI, TGA and OIT of all the samples were tested. According to the results of MFR, during the melt extrusion, fullerene showed excellent stability effect on PP. The antioxidative ability of fullerene was comparable to the traditional antioxidant 1010. The antioxidative ability of fullerenol was not significant in the first extrusion and it accelerated the degradation of PP in the second and the third extrusions. TGA and OIT tests showed that the stability effects of fullerene and fullerenol were slightly lower than antioxidant 1010. In the first time, antioxidant 168 was reported to show great synergistic effects with fullerene and fullerenol as antioxidants, which sussested a simple way to enhance the antioxidative abilities of fullerene and fullerenol. 相似文献
12.
Changyuan Lu Side Yao Wenfeng Wang Yongpeng Tong Weizhen Lin Tingwen Rong Nianyun Lin 《中国科学B辑(英文版)》1998,41(3):259-265
Fullerols of C60 and of C70 [C60(OH)n, C70(OH)m], water-soluble fullerene derivatives, unlike some other fullerene derivatives (such as C60 (C4H6O), C60 (C3H7N) and C60 [C(COOEt)2]x), do not result in excited triplet state but in ionization via monophotonic process in aqueous solutions with 248 nm laser.
The quantum yields of formation of hydrated electron (Φe
−) are determined to be 0.08 and 0.11 for fullerols of C60 and of C70 respectively at room temperature (ca. 15°C) with KI solution used as reference. By laser flash photolysis and oxidation of
sulfate radical anion SO4
−, the fullerol radical cation or neutral radical of C60 is confirmed to be existent and the transient absorption spectra of fullerol radical cation of C70 are observed for the first time.
Project supported by the National Natural Science Foundation of China 相似文献
13.
1INrnODUCTIoNlnthepreviouspapers,wehavereportedthesynthesisandcrystalstructureofseveralcrownetherpolyoxometalates"-",nowwestudythestructureofthetitlecomplexandcompareitwithsomeothercrownetherpolyoxometalatecomplexes.2EXPERmENTALToal5OmLaqueoussolutioncontaining32g(1OOmol)Na,WO#.2H,Opre-justedtopH=3.5withchloricacid,14g(4Ommol)(n-Bu)'NBrwasadded,thenwhitepowderwasformed.ThewhiteprecipitateobtainedwithafiltrationwaskeptasthenewmaterialAinnextstep.AmixtureoflgAandO.3g(O.8mmol)DB18… 相似文献
14.
1,2-Fullerenols C(60)(OCOR)(OH) have been facilely synthesized via the one-step reaction of [60]fullerene with acid chlorides promoted by ferric perchlorate. A possible reaction mechanism for the product formation is proposed. 相似文献
15.
A salt-free catanionic surfactant system, tetradecyltrimethylammonium laurate (TTAL), was constructed by mixing tetradecyltrimethylammonium hydroxide (TTAOH) and lauric acid (LA). The H+ and OH- counterions form water (TTAOH+LA-->TTAL+H2O), leaving the solution salt-free. The phase behaviors at fixing the total surfactant concentration (cTTAL) to be 33.0 and 55.0 mmol L(-1), respectively, were studied through varying the molar ratio of r=nLA/nTTAOH from 0.70 to 1.20. With an increasing value of r, one observed an L1-region, an Lalpha/L1 two-phase region with a birefringent Lalpha-phase at the top, and finally a single Lalpha-phase. The ability to solubilize a fullerene mixture of C60 and C70 of different phases in different regions was tested. The colloidal stability and phase behavior of different phases with embedded fullerenes were investigated as a function of r, cTTAL, and weight ratio of fullerene to surfactant (WF/WTTAL). The 33.0 or 55.0 mmol L(-1) zero-charged vesicle-phase at r=1.00 could solubilize a considerable amount of fullerenes without macroscopic phase separation and obvious vesicular structure breakage. However, these colloidal solutions became unstable at lower concentrations of surfactants, and a precipitate would be observed at the bottom. The micellar (L1-phase) solubilization at the TTAOH-rich side was less pronounced compared to the vesicular solubilization of the zero-charged vesicle-phase, and the solubilizing ability decreased at higher r values. In the Lalpha/L1 two-phase region, a brown or dark-brown Lalpha-phase was usually found at the top of a colorless or yellowish L1-phase, indicating that most of the fullerenes were embedded in the upper Lalpha-phase. The influence of fullerene incorporation on the property of the zero-charged TTAL vesicle-phase was also investigated, and evidence has been found that the system tended to be more fluid after fullerenes were incorporated into the hydrophobic microdomains of aggregates. 相似文献
16.
Tube C(60)H(60) (5) with fused five-membered rings is more stable than the cage isomer (1) with isolated five-membered rings. Introduction of endo C-H bonds into structure 5 results in further stabilization, but the most stable tube structure with four endo C-H bonds (7) is higher in energy than the most stable cage structure with ten endo C-H bonds (3) by 74.2 kcal/mol. A comprehensive comparison of C(60)H(60) with C(60)F(60) has been made. 相似文献
17.
M. Lal 《Journal of Radioanalytical and Nuclear Chemistry》1985,90(1):105-112
The separation of the trivalent metal ions Am(III) and Eu(III) by extraction chromatography employing TBP impregnated macroporous XAD-4 resin as the stationary phase was examined; some parameters affecting the distribution ratio (Kd) and the column resolution (Rs) of Am(III) and Eu(III) were investigated. These parameters are the effect of TBP loading, aqueous nitrate concentrations, and flow rate. Both Kd andRs increase with the TBP loading. 相似文献
18.
The study of the degree of association of biologically active disubstituted fullerene derivatives at different substance concentrations
in an aqueous solution using the diffusion method showed that the nature of substituents exerts the strongest effect on the
degree of association of the fullerene derivatives. 相似文献
19.
Mekawy Zakaria A. Moussa Saber I. Mousa Abeer M. Dakroury Gehan A. Allan Karam F. 《Journal of Radioanalytical and Nuclear Chemistry》2022,331(5):2331-2347
Journal of Radioanalytical and Nuclear Chemistry - Nano ZnO is biosynthesized using Lactobcillus sp. Poly Acrylic acid-co-Acrylonitrile/ZnO, PAACAN/ZnO, and poly Acrylic acid-co-Maleic acid/ZnO,... 相似文献
20.
Trajković S Dobrić S Jaćević V Dragojević-Simić V Milovanović Z Dordević A 《Colloids and surfaces. B, Biointerfaces》2007,58(1):39-43
Polyhydroxylated fullerenes, named fullerenols (C(60)(OH)(n); n=12-26) are excellent antioxidants. Harmful effects of ionizing radiation on living organism are mainly mediated by free radical species and fullerenols attract an attention as a potential radioprotectors. Our preliminary investigations on mice and rats subjected to radiation injury show that fullerenol C(60)(OH)(24) provides high survival rate of irradiated small rodents. Radioprotective effect was comparable to that of the standard radioprotector amifostine. The aim of this study was to compare the efficacy of fullerenol C(60)(OH)(24) (10 and 100mg/kg i.p.) and amifostine (300 mg/kg i.p.) in protection of rats against harmful effects of ionizing radiation. The animals were whole-body irradiated by X-rays (8 MV). Both compounds were given 30 min before irradiation. In order to evaluate the general radioprotective efficacy of fullerenol and amifostine rats were irradiated with an absolutely lethal dose of X-rays (8 Gy) and their survival and body mass gain were monitored during the period of 30 days after irradiation. The aim of the second part of the study is to investigate the tissue-protective effects of tested compounds (100 mg/kg i.p. of fullerenol and 300 mg/kg i.p. of amifostine, 30 min before irradiation). It was carried out on rats irradiated with a sublethal dose of X-rays (7 Gy). Influence of ionizing radiation on hematopoesis as well as the radioprotective efficiency of the compounds given were evaluated by determining blood cell count during 28 days after irradiation. For this purpose the blood was taken from tail vein before irradiation and on the 3rd, 7th, 14th, 21st and 28th day after irradiation. In order to estimate the radioprotective effects of fullerenol and amifostine on other rat tissue, the animals were sacrificed on the 7th and 28th day after irradiation and their main organs (lung, heart, liver, kidney, small intestine and spleen) were taken for histopathological analysis. In the experiment in which the general radioprotective efficacy of fullerenol and amifostine was examined, fullerenol given in a dose of 100mg/kg produced better protection than given in a dose of 10mg/kg. This effect was comparable to that of amifostine. The results of hematological investigations showed that fullerenol better than amifostine prevented radiation-induced reduction in the white cell count (granulocytes and lymphocytes), particularly in the first 7 days after irradiation. Pathohistology examinations revealed better radioprotective effects of fullerenol compared to those of amifostine on the spleen, small intestine and lung, while amifostine had better radioprotective effects than fullerenol in protection of the heart, liver and kidney. These results confirm satisfactory radioprotective efficacy of fullerenol and encourage further investigations as a potential radioprotector. 相似文献