著者

Toshiyuki OSAKAI

出版者

The Japan Society for Analytical Chemistry

雑誌

Analytical Sciences (ISSN:09106340)

巻号頁・発行日

vol.35, no.4, pp.361-366, 2019-04-10 (Released:2019-04-10)

参考文献数

68

被引用文献数

5

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Many studies have been conducted by using the oil (O) | water (W) interface as a simple model for understanding ion transfer (IT) or electron transfer (ET) across biomembranes. In this review, we revisit the usability of the O | W interface as a biomembrane model. For understanding biomembrane IT, the O | W interface is the simplest and best suited model. For example, the standard Gibbs transfer energy of drug ions at the O | W interface is a useful measure for evaluating their membrane permeability in a conventional in vitro assay, called PAMPA. However, the O | W interface is not necessarily a good model for understanding biomembrane ET. This is because no net current can be observed with the O | W interface, owing to the ET-coupled proton transfer. In such a case, the self-assembled monolayer (SAM) formed on a metal electrode serves as a better model for understanding biomembrane ET.

著者

Aki TAKAZAKI Kazuo EDA Toshiyuki OSAKAI Takahito NAKAJIMA

出版者

Society of Computer Chemistry, Japan

雑誌

Journal of Computer Chemistry, Japan (ISSN:13471767)

巻号頁・発行日

vol.16, no.4, pp.93-95, 2017 (Released:2017-10-18)

参考文献数

6

被引用文献数

1

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By selectively investigating the effect of the bond valence using the hypothetical [(PO4)W12O36]3– species having various bond valences, we could clearly reveal the origin of the linear dependence of the LUMO energy (or the redox potential) on the bond valence. The LUMO of the Keggin-type polyoxotungstates mainly consists of W 5d. The energy of W 5d as well as of the LUMO goes down as the bond valence becomes large (i.e., as the net electron population on W decreases due to the electron-withdrawing effect of the μ4-O atoms). This is the origin of the linear dependence of LUMO energy on the bond valence.

著者

Hirohisa NAGATANI Satoshi DEJIMA Hiroki HOTTA Toru OZEKI Toshiyuki OSAKAI

出版者

The Japan Society for Analytical Chemistry

雑誌

Analytical Sciences (ISSN:09106340)

巻号頁・発行日

vol.20, no.11, pp.1575-1579, 2004 (Released:2005-03-03)

参考文献数

31

被引用文献数

5 8 2

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The photocurrent at the polarized water/1,2-dichloroethane (DCE) interface was successfully observed in the presence of a lipophilic sensitizer, 5,10,15,20-tetraphenylporphyrinato zinc (ZnTPP), in the organic phase. The photocurrent transient responses were apparently affected by the employed organic supporting electrolyte: tetrapenthylammonium tetraphenylborate (TPnATPB) or tris(tetraoctylammonium)tungstophosphate ((TOcA)3PW12O40). The photocurrent measured in the TPnATPB system exhibited rather slow responses associated with the ion transfer of photoproducts. On the other hand, the photoinduced heterogeneous electron transfer could be observed in the use of (TOcA)3PW12O40. The photocurrent intensity in the (TOcA)3PW12O40 system exhibited an apparent pH dependence and the photoreduction of hydrogen ions probably took place at the water/DCE interface. By analyzing the real and imaginary components of the photocurrent depending on the photoexcitation frequency, we roughly estimated the phenomenological rate constants of the product separation (kps) and recombination (krec) processes as log(kps/s-1) = 1.5 ± 0.2 and log(krec/s-1) = 1.8 ± 0.1, respectively.