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111.
112.
113.
Rita Das Nigamananda Das Anadi C. Dash Ansuman Roy Shyamal K. Sarkar 《Transition Metal Chemistry》1996,21(1):90-94
Summary The reaction of ()-(tetren)CoOH2+ with S2O
3
2-
in the 7.25–8.28 pH range at 20–40 °C yielded S- (yellow) and O- (purple) bonded thiosulfato(tetren)cobalt(III) complexes, the former in larger quantities. The rate determining step is preceded by diffusion-controlled ion-pair [(tetren)CoOH2+,S2O
3
2-
] formation. Replacement of coordinated OH- by S2O
3
2-
is interpreted in terms of an internal conjugate base mechanism: (tetren)CoOH2+ (tetren-H)CoOH
2
2+
, the reactive amido conjugate base being generated by intramolecular proton transfer from the coordinated NH site.In acid medium the S-bonded (tetren)Co(S2O3)+ is highly stable to redox decomposition, in contrast to its pentaammine analogue. The complex however, undergoes base hydrolysis yielding the corresponding hydroxo complex. The rate and activation parameters for the base hydrolysis have been reported. Photolysis of O- and S-bonded isomers of [(tetren)CoS2O3]+ in acidic medium at 254 and 313 nm, respectively, yielded aquation products accompanied by some decomposition of S2O
3
2-
. 相似文献
114.
W. Krakow N. M. Rivera R. A. Roy R. S. Ruoff J. J. Cuomo 《Applied Physics A: Materials Science & Processing》1993,56(3):185-192
Thin films (25-2500 Å) of C60 molecules have been deposited on both (001) NaCl and mica substrates at varying temperatures by resistive evaporation. Both electron diffraction and high resolution microscopy have been used to assess the degree of crystallinity, the orientational ordering and the nature of the defects present in these face-centered-cubic films. For NaCl, optimum conditions yielded polycrystalline films with a tendency towards a 110 orientation, while for mica, extended single crystal films have been fabricated which exhibit a 111 direction normal to the film surface. 相似文献
115.
Atiya MS Chiang IH Frank JS Haggerty JS Ito MM Kycia TF Li KK Littenberg LS Sambamurti A Stevens A Strand RC Louis WC Akerib DS Marlow DR Meyers PD Selen MA Shoemaker FC Smith AJ Blackmore EW Bryman DA Felawka L Kitching P Konaka A Kuno Y Macdonald JA Numao T Padley P Poutissou JM Poutissou R Roy J Soluk R Turcot AS 《Physical review letters》1993,70(17):2521-2524
116.
117.
118.
Jarroux N Keller P Mingotaud AF Mingotaud C Sykes C 《Journal of the American Chemical Society》2004,126(49):15958-15959
A new inisurf (acting as surfactant and initiator) molecule for ring-opening metathesis polymerization (ROMP) was synthesized and used in aqueous solution in order to control the size and shape of polymer nodules grown from liposomes. Nodules were observed to grow in size with conversion of monomer, and depending on the monomer used, they adopted either a spherical or comet-like shape. Here, we investigate polymer production from a liposome surface. We use a hydrophobic derivative of the Grubbs catalyst positioned at the liposome surface to allow for ROMP of monomers dissolved in the aqueous outer phase. We obtain nodules of polymer that can grow up to tens of micrometers, unveiling new efficient possibilities of polymerization from a membrane in an aqueous solution. 相似文献
119.
Carbonnelle S Loco JV Overmeire IV Windal I Wouwe NV Leeuwen SV Goeyens L 《Talanta》2004,63(5):1255-1259
Differences between chemical activated luciferase gene expression (CALUX) bioassay and chemoanalyses results are observed.This paper shows that calculations of the TEQ values using REP values instead of WHO TEF values give different results. The REP values do affect the results obtained by the CALUX technique. These differences are more marked for the dioxin like PCB compounds (CALUX TEQ values are lower than WHO TEQ values) than for the dioxin compounds (CALUX TEQ values are higher than WHO TEQ values).The CALUX results were compared with the concentrations of the congeners’ spiked into the oil. 相似文献
120.
Michael J. Bunegar Roy Fields Robert N. Haszeldine 《Journal of fluorine chemistry》1980,15(6):497-509
Fluoroallene and 1, 3-difluoroallene are prepared in good overall yield by the addition of dichlorocarbene to vinyl fluoride and 1, 2-difluoroethylene respectively, followed by pyrolysis of the dichlorocyclopropanes and treatment of the resulting dichloropropenes with zinc. Pyrolysis of 1, 1-dichloro-2-fluorocyclopropane over zinc gives fluoroallene directly.The reaction of allene with 2, 2, 3-trifluoro-3-trifluoro- methyloxiran at 180°C as a source of difluorocarbene gives both 1, 1-difluoro-2-methylenecyclopropane and its rearrangement product 1-(difluoromethylene)cyclopropane, the latter reacting more readily with a second difluorocarbene to give 2, 2, 3, 3- tetrafluorospiropentane. In an analogous way, fluoroallene reacts with dichlorocarbene, generated from trifluoro(trichloromethyl) silane at 140°C, to give - and -1, 1-dichloro-2- (fluoromethylene)cyclopropane, 1-(dichloromethylene)-2-fluorocyclopropane, and 2, 2, 3, 3-tetrachloro-4-fluorospiropentane. 相似文献