共查询到7条相似文献,搜索用时 0 毫秒
1.
Binuclear dichlorido(η6‐p‐cymene)ruthenium(II) complexes with bis(nicotinate)‐ and bis(isonicotinate)‐polyethylene glycol ester ligands 下载免费PDF全文
Thomas Eichhorn Evamarie Hey‐Hawkins Danijela Maksimović‐Ivanić Marija Mojić Jürgen Schmidt Sanja Mijatović Harry Schmidt Goran N. Kaluđerović 《应用有机金属化学》2015,29(1):20-25
Neutral binuclear ruthenium complexes 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 of the general formula [{RuCl2(η6‐p‐cym)}2 μ‐(N∩N)] (N∩N = bis(nicotinate)‐ and bis(isonicotinate)‐polyethylene glycol esters: (3‐py)COO(CH2CH2O)nCO(3‐py) and (4‐py)COO(CH2CH2O)nCO(4‐py), n =1–4), as well as mononuclear [RuCl2(η6‐p‐cym)((3‐py)COO(CH2CH2OCH3)‐κN)], complex 9 , were synthesized and characterized using elemental analysis and electrospray ionization high‐resolution mass spectrometry, infrared, 1H NMR and 13C NMR spectroscopies. Stability of the binuclear complexes in the presence of dimethylsulfoxide was studied. Furthermore, formation of a cationic complex containing bridging pyridine‐based bidentate ligand was monitored using 1H NMR spectroscopy. Ligand precursors, polyethylene glycol esters of nicotinic ( L1 · 2HCl– L4 · 2HCl and L9 · HCl) and isonicotinic acid dihydrochlorides ( L5 · 2HCl– L8 · 2HCl), binuclear ruthenium(II) complexes 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 and mononuclear complex 9 were tested for in vitro cytotoxicity against 518A2 (melanoma), 8505C (anaplastic thyroid cancer), A253 (head and neck tumour), MCF‐7 (breast tumour) and SW480 (colon carcinoma) cell lines. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
2.
Talukder MM Takeyama T Hayashi Y Wu JC Kawanishi T Shimizu N Ogino C 《Applied biochemistry and biotechnology》2003,110(2):101-112
The activity and stability of Chromobacterium viscosum lipase (glycerolester hydrolase, EC 3.1.1.3)-catalyzed olive oil hydrolysis in sodium bis (2-ethyl-1-hexyl)sulfosuccinate (AOT)/isooctane reverse micelles is increased appreciably when low molecular weight polyethylene
glycol (PEG 400) is added to the reverse micelles. To understand the effect of PEG 400 on the phase behavior of the reverse
micellar system, the phase diagram of AOT/PEG 400/water/isooctane system was studied. The influences of relevant parameters
on the catalytic activity in AOT/PEG 400 reverse micelles were investigated and compared with the results in the simple AOT
reverse micelles. In the presence of PEG 400, the linear decreasing trend of the lipase activity with AOT concentration, which
is observed in the simple AOT reverse micelles, disappeared. Enzyme entrapped in AOT/PEG reverse micelles was very stable,
retaining>75% of its initial activity after 60 d, whereas the half-life in simple AOT reverse micelles was 38 d. The kinetics
parameter maximum velocity (V
max)exhibiting the temperature dependence and the activation energy obtained by Arrhenius plot was suppressed significantly by
the addition of PEG 400. 相似文献
3.
L. Ya. Zakharova F. G. Valeeva A. R. Ibragimova L. A. Kudryavtseva Yu. F. Zuev L. V. Avvakumova V. I. Kovalenko A. I. Konovalov 《Russian Chemical Bulletin》2007,56(1):62-69
The kinetics of alkaline hydrolysis of O-ethyl O-p-nitrophenyl chloromethylphosphonate in a sodium bis(2-ethylhexyl)sulfosuccinate—n-nonane—polyethylene glycol—water reverse micellar system was studied in a wide range of concentrations of the surfactant
and water. The sign of the catalytic effect of micelles is inverted in the presence of the polymer. A sharp change in the
apparent rate constant of hydrolysis of the phosphonate was found in a region of the temperature percolation threshold.
Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 1, pp. 60–67, January, 2007. 相似文献
4.
Accurate evaluation method of the polymer content in Monomethoxy(polyethylene glycol) modified proteins based on Amino acid analysis 总被引:2,自引:0,他引:2
Luciana Sartore Paolo Caliceti Oddone Schiavon Cristina Monfardini Francesco M. Veronese 《Applied biochemistry and biotechnology》1991,31(3):213-222
To overcome the uncertainty of the colorimetric or fluorimetric method so far employed for the evaluation of monomethoxy(polyethylene glycol) (MPEG) covalently bound to protein, a direct method based on amino acid analysis is proposed. The method exploits the use of MPEG, which was bounded with the unnatural amino acid norleucine (MPEG-Nle). MPEG-Nle was activated at its carboxylic group to succinimidyl ester for the binding to the amino groups of protein. After acid hydrolysis, the amino acid content is evaluated by conventional amino acid analyzer or by reverse-phase HPLC as phenylthiocarbamyl derivative. The number of bound MPEG chains is calculated from the amino acid composition, since one norleucine residue is released from each bound polymer chain. The method was verified with several proteins in comparison with colorimetric ones, also in the case of proteins that contain chromophores in the visible range, such cytocrome C. It was observed that in most of the cases, the colorimetric methods give an overestimation of the degree of protein modification. 相似文献
5.
Li+3 ion beam irradiation studies on 4-n-(nonyloxy) benzoic acid (NOBA) have been carried out. Thermodynamic measurements demonstrate that all the phase transition temperatures are depressed for low value of irradiation fluence as compared to those for the pure NOBA and thereafter increase linearly with increase in irradiation fluence. It has also been observed that the temperature range of N and SmC phases in the heating and cooling cycles is improved due to irradiation. Dielectric investigations show that both the transverse as well as the longitudinal components of the dielectric permittivity are increased as compared with those of the pure sample due to irradiation. The observed change in the thermodynamic and dielectric parameters is attributed to the increased concentration of NOBA monomers over the NOBA dimers due to fragmentation of the hydrogen bonding in some of the NOBA dimers. 相似文献
6.
David Rinaldi Thierry Hamaide Christian Graillat Franck D'Agosto Roger Spitz Sébastien Georges Martin Mosquet Philippe Maitrasse 《Journal of polymer science. Part A, Polymer chemistry》2009,47(12):3045-3055
RAFT polymerization of poly(ethylene glycol) methyl ether methacrylate (PEGMA, 1100 g mol?1) was first performed using cyanoisopropyl dithiobenzoate (CPDB). The control of PEGMA homopolymerization, carried out in THF ([PEGMA] = 40 wt %) at 65 °C (reflux) using 2,2′‐Azobis(isobutyronitrile) (AIBN) as initiator, was shown by the linear increase of molar masses and the low polydispersity indices (PDI) observed with conversion and also by the determination of a high chain transfer constant (Ctr = 9.1) for CPDB in this system. Copolymerization of PEGMA with methacrylic acid (MAA) ([PEGMA]/[MAA] = 40/60) was then undertaken first in dioxane at 85 °C. High conversion (89%) was obtained in 3 h without any composition drift and with a good level of control (PDI < 1.40). When the polymerization was performed in water, a strong increase in polymerization rate was observed with almost quantitative conversion (98%) in 2 h without affecting the level of control of the final copolymers (PDI ~ 1.30). These last results were tentatively explained by the formation of hydrophobic domains in which the polymerization occurred as in bulk. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 3045–3055, 2009 相似文献
7.
《Analytica chimica acta》2003,484(2):243-251
A new method for the determination of tin(II) in presence of tin(IV) is described. The method is based on differential pulse polarography on the hanging mercury drop electrode (HMDE). The effect of citric acid and hydrochloric acid concentrations on the polarographic peaks of tin(II) and tin(IV) has been studied. In 1 M HCl, the total quantity of tin can be determined, as under these conditions, in the absence of complexing agents, eventual variations in the oxidation states, in any concentration ratio, do not affect the peak height and the peak potential. In 0.2 M HCl and 0.2 M citric acid, tin(II) can be determined selectively in presence of tin(IV), as under these conditions, tin(IV) does not present polarographic response, while a well-defined peak is observed for tin(II). The method is applied to determine tin(II) and total tin in the activating solutions of the electroless plating of polymers. 相似文献