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61.
Photoreaction of 2,3-benzo-1,1-diphenyl(or dimethyl)-1-sila-2-cyclobutene with an aldehyde or ketone results in 1:1 cycloadduct of [4+2] type, the formation of which is accountd for in terms of SH2 process, i.e., attack of a triplet carbonyl compound on the silicon of the benzosilacyclobutene. 相似文献
62.
Hyoung Sik Kim Min Kang Min Woo Song Jin Won Park Byoung Ryul Min 《Reaction Kinetics and Catalysis Letters》2004,81(2):251-257
Pt-Pd bimetallic catalysts were prepared in order to develop and investigate catalysts having excellent activity and stability
for benzene destruction. The effect of Pt addition to Pd catalysts is studied by XPS analysis.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
63.
Reaction of 1,6-enynes with a hydrosilane in the presence of immobilized cobalt/rhodium bimetallic nanoparticles gives 2-methyl-1-silylmethylidene-2-cyclopentanes in the absence of carbon monoxide and 2-formylmethyl-1-silylmethylidene-2-cyclopentanes under 1 atm of carbon monoxide, respectively. [reaction: see text] 相似文献
64.
Tae?Shin?Chung Young?Mee?Na Shin?Won?Kang Ok-Sang?JungEmail author Young-A?Lee 《Transition Metal Chemistry》2005,30(5):541-545
Hydrogen peroxide oxidation of platinum(II) compounds containing labile groups such as Cl, OH, and alkene moieties has been carried out and the products characterized. The reactions of [PtII (X)2 (N–N)] (X = Cl, OH, X2 = isopropylidenemalorate (ipm); N–N 2,2-dimethyl-1,3-propanediamine [(dmpda), N-isopropyl-1,3-propanediamine (ippda)] with hydrogen peroxide in an appropriate solvent at room temperature affords [PtIV (OH)(Y)(X)2(N–N)] (Y = OH, OCH3). The crystal structures of [PtIV(OH)(OCH3)(Cl)2(dmpda)]·2H2O (P-1 bar, a = 6.339(2) Å , b = 9.861(1) Å, c = 11.561(1) Å, a = 92.078(9)°, β = 104.78(1)°, γ=100.54(1)°, V = 684.3(2) Å3, Z = 2R = 0.0503) and [PtIV(OH)2(ipm)(ippda)]·3H2O (C 2/c, a = 27.275(6) Å, b=6.954(2) Å, c = 22.331(4) Å, β = 118.30(2)°, V = 3729(2) Å3, Z = 8, R = 0.0345) have been solved and refined. The local geometry around the platinum(IV) atom approximates to a typical octahedral arrangement with two added groups (OH and OCH3; OH and OH) in a transposition. The platinum(IV) compounds with potential labile moieties may be important intermediate species for further reactions. 相似文献
65.
R. Dustan Myrex Gary M. Gray Young-Jin Wright Prakash C. Bharara Keith E. Branham 《European Polymer Journal》2003,39(6):1105-1115
Polymeric phosphonate esters are an interesting class of organophosphorus polymers because both the polymer backbone and phosphorus substituents can be modified. These polymers have been prepared by ring-opening polymerizations of cyclic phosphites, stoichiometric polycondensations of dimethyl phosphonate with diols in conjunction with diazomethane treatment and by transesterification of polyphosphonate oligomers. Our initial attempts to prepare high molecular weight polymeric phosphonate esters by the transesterification methods were unsuccessful. Results indicate that the reactions of dimethyl phosphonate with diols to form polyphosphonate oligomers with only methyl phosphonate end groups are plagued by a serious side reaction that forms phosphonic acid end groups. These end groups do not participate in the transesterification reaction and limit the molecular weights of the polymers that can be obtained. The phosphonic acid end groups can be converted into reactive methyl phosphonate end groups by treatment with diazomethane, however diazomethane is explosive and the polymerization is slow. An alternative route for the production of high molecular weight polymers is the transesterification of the 1,12-bis(methyl phosphonato)dodecane, formed by the reaction of excess dimethyl phosphonate and 1,12-dodecanediol, with a Na2CO3 promoter. This allows polymers with molecular weights of up to 4.5×104 to be prepared, and no phosphonic acid end groups are observed in these polymers. Thermal analyses of the poly(1,12-dodecamethylene phosphonate) have shown that this polymer has reasonable thermal stability (onset of thermal decomposition at 273 °C). This polymer also undergoes a cold crystallization process at 15 °C similar to that which has been observed in some polyesters, polyamides and elastomers. 相似文献
66.
A three-step one-pot synthesis of fenestranes from a readily available enyne and an alkyne diester has been carried out with cobalt nanoparticles and palladium(II) as catalysts. 相似文献
67.
Kang SO VanderVelde D Powell D Bowman-James K 《Journal of the American Chemical Society》2004,126(39):12272-12273
Multiple deuterium exchange between DMSO-d6 and amide hydrogens in two hexaamido cryptand fluoride receptors has been verified by 19F and 2H NMR and FAB mass spectral studies. Structural results for one of the complexes indicate a tricapped trigonal prism hydrogen bond coordination geometry around an encapsulated fluoride, with hydrogen bonds from fluoride to six amide and three phenyl hydrogens. 相似文献
68.
Dicobalt octacarbonyl catalyzed silyl-hydroformylation of oxetanes can be controlled by the choice of trialkylsilane. Triethylsilane gives 1,4--silyl ethers while -butyl-dimethylsilane yields silyl enol ethers. 相似文献
69.
Two new three-dimensional oxychlorides are reported, Te(4)M(3)O(15).Cl (M = Nb(5+) or Ta(5+)). The isostructural materials were synthesized by chemical transport reactions utilizing TeO(2), M(2)O(5), and MCl(5) (M = Nb(5+) or Ta(5+)) as reagents. The compounds exhibit a three-dimensional cationic tunnel framework, with Cl(-) anions occupying the tunnels. Crystal data: monoclinic, space group C2/c, a = 18.9944(7) A, b = 7.8314(3) A, c = 21.1658(8) A, beta = 116.6400(10) degrees, Z = 8 (T = 295 K). 相似文献
70.
Yu Liu Yong Chen Shi-Zhao Kang Li Li Chun-Hua Diao Heng-Yi Zhang 《Journal of inclusion phenomena and macrocyclic chemistry》2003,47(1-2):91-95
Two novel benzo-15-crown-5 tethered β-cyclodextrins 1 and 2have been synthesized by coupling substituted benzo-15-crown-5 with correspondingβ-cyclodextrin derivatives. Their inclusion complexation behavior withrepresentative guests, such as cyclohexanol, cyclohexane carboxylic acid, cyclohexaneacetic acid, sodium cyclohexane carboxylate, and potassium cyclohexane carboxylate,was investigated in aqueous solution by means of fluorescence spectrometry. As compared with parent β-cyclodextrin, benzo-15-crown-5 tethered β-cyclodextrins 1–2 display significantly enhanced molecular binding abilities and selectivities towards model substrates, especially towards substrates containing alkali-metal cations. These results indicate that, bearing two recognition sites in a single molecule, these supramolecular architectures can strongly enhance the molecular binding ability of parent β-cyclodextrin by the cooperative binding of the β-cyclodextrin cavity and the crown ether moiety. Possessing a shorter linker, crown ether-β-cyclodextrin 2 shows much higher binding affinity with guest molecules than crown ether-β-cyclodextrin 1, which may be attributed to the binding size and molecular multiple recognition behavior between host and guest. 相似文献