从皮秒瞬态吸收测量中探究水溶液中 OH- 离子的溶剂化和结构动力学。

Probing the dynamics of solvation and structure of the OH- ion in aqueous solution from picosecond transient absorption measurements.

机构信息

Laboratoire de Spectrochimie Infrarouge et Raman (UMR 8516 de l'Université et du CNRS), Centre d'Etudes et de Recherches Lasers et Applications (FR 2416 du CNRS), Bât. C5, Université des Sciences et Technologies de Lille, 59655 Villeneuve d'Ascq, France.

出版信息

Molecules. 2010 May 7;15(5):3366-77. doi: 10.3390/molecules15053366.

DOI:10.3390/molecules15053366

PMID:20657486

原文链接:https://pmc.ncbi.nlm.nih.gov/articles/PMC6263321/

Abstract

The reaction of intracomplex proton transfer (44BPY(-.)...HO-H) (R)-->44BPYH(.)+ OH(-) that follows the photoreduction of 4,4'-bipyridine (44BPY) into its anion radical 44BPY(-) in the presence of 1,4-diazabicyclo[2.2.2]octane (DABCO) is investigated in acetonitrile-water mixtures by using picosecond transient absorption. The dependence of the appearance kinetics of the 44BPYH(.) radical on the water content reveals a highly diffusional proton transfer process that is controlled by the dynamics of solvation of the released hydroxide ion. The results are interpreted on the basis of a two-step mechanism where an intermediate solvation complex (44BPYH(.))OH(-)(H(2)O)(3) is formed first before evolving toward a final four-water hydration structure OH(-)(H(2)O)(4).

摘要

在 1,4-二氮杂二环[2.2.2]辛烷 (DABCO) 的存在下，研究了 4,4'-联吡啶 (44BPY) 光还原为其阴离子自由基 44BPY(-) 后，内配合物质子转移 (44BPY(-.)...HO-H) (R)-->44BPYH(.)+ OH(-) 的反应在乙腈-水混合物中通过皮秒瞬态吸收进行。 44BPYH(.)自由基出现动力学对含水量的依赖性揭示了一个高度扩散的质子转移过程，该过程受释放的氢氧根离子溶剂化动力学控制。结果基于两步机制进行解释，首先形成中间溶剂化配合物 (44BPYH(.))OH(-)(H(2)O)(3)，然后再演变为最终的四个水分子水合结构 OH(-)(H(2)O)(4)。