18412-81-2Relevant academic research and scientific papers
Three-Phase Model of Micellar Reactions. Methylation of Thymidine by (Long-chain-alkyl)dimethylsulfonium Iodides
Yamauchi, Kiyoshi,Hisanaga, Yorisato,Kinoshita, Masayoshi
, p. 538 - 545 (1983)
Micellar methylation of thymidine to 3-methylthymidine was studied by using mainly n-octadecyldimethylsulfonium iodide at pH 7-12 and 60-75 deg C.The reaction exhibited the presence of an induction period as long as 1 h, a bell-shaped pH dependence of the methylation rate with an optimum pH ca. 10, and competitive inhibitory effects of added salts on the micellar reaction, etc.A three-phase model was proposed to analyze the micellar events, assuming that (i) the anions (dT-) of thymidine, the active species of the nucleoside, diffuse from the aqueous bulk phase to the Stern layer across the Gouy-Chapman layer, (ii) dT- ions concentrate in the Stern layer to obey the Langmuir adsorption isotherm theory, and (iii) the dT- ions in the layer are mediated in a bimolecular fashion with the dimethylsulfonium ions, the head groups of the micelles.The model furnished apparent kinetic constants such as binding constants of counterions (dT-, I-, OH-, etc.) to the micelle, a diffusion rate constant of dT- and Me-dT from the Stern layer.The effects of temperature on these constants were studied carefully to estimate the respective thermodynamic constants.The three-phase model was compared with other micellar models reported.The micellar methylation was discussed briefly in connection to the enzymatic methylation that utilizes S-adenosylmethionine as a cofactor.
Molten and Solid Trialkylsulfonium Iodides and Their Polyiodides as Electrolytes in Dye-Sensitized Nanocrystalline Solar Cells
Paulsson, Helene,Hagfeldt, Anders,Kloo, Lars
, p. 13665 - 13670 (2007/10/03)
The overall solar-to-electric energy conversion efficiencies in solar simulators, and the incident monochromatic photon-to-current-efficiencies (IPCE) was measured for a selection of molten salt electrolytes to reveal their possible use as electrolytes in dye-sensitized nanocrystalline solar cells (DNSC). The IPCE results of (Et2MeS)I and (Bu2MeS)I were stable above 55% from 400 to 550 nm and then decreased on the red side of the spectra. The addition of iodine to (Bu2MeS)I and (Bu2EtS)I indicated increasing IPCE values at 520-540 nm; from 55 to 60% and 38 to 46%, respectively. (Te2MeS)I, (Bu2MeS)I, and (Bu2EtS)I showed good conducting abilities at ambient conditions and provided good light-to-electricity conversion efficiencies while used as electrolytes in DNSC. The liquid electrolytes (Et2MeS)I provided the highest conversion efficiencies at room temperature.
Micellar Methylating Agents: (Long-chain-alkyl)dimethylsulphonium Iodides
Yamauchi, Kiyoshi,Hisanaga, Yorisato,Kinoshita, Masayoshi
, p. 1941 - 1942 (2007/10/02)
Dodecyl-, hexadecyl-, and octadecyl-dimethylsulphonium iodide were found to methylate efficiently various nucleosides, hydroxy aromatic compounds, and thiols at pH 8-11 and 50 - 70 deg C.The optimum conditions and the mechanism of the reaction are discussed briefly in relation to the micellar reaction characteristics.
