Control and Function of Hydrogen Bond of Bioactive Quinones on the Charge Separation

生物活性醌氢键对电荷分离的控制及其作用

• 批准号: 13672258
• 负责人: UNO Bunji
• 金额: $ 1.92万
• 依托单位: Gifu Pharmaceutical University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 2001
• 资助国家: 日本
• 起止时间: 2001 至 2002
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-13672258/
• 关键词: Bioactive quinone; Charge separation; Hydrogen bond; Quinone-modified electrode; Molecular orbital calculation; Quinone radical anion; Phenol radical anion; 電荷分離; キノンアニオンジカル; 自己組織化膜電極; アントラキノン修飾電極; ナフトキノン修飾電極

It is well known that self-assembled monolayer (SAM) electrodes are applied to electroorganic syntheses, biosensors, and investigation on the electron transfer at an electrode interface. In this study the SAM-anthraquinone (SAM-AQ) and SAM-naphthoquinone (SAM-NQ) gold electrodes were prepared, and the function of hydrogen bonds for electron transfer to the hydrogen-donating guests was investigated with the aid of electrochemical measurements with the SAM electrodes, combined with molecular orbital calculations.1. The SAM-AQ and SAM-NQ electrodes gave reversible waves on the cyclic voltammograms, corresponding to the generation of the AQ and NQ radical anions, respectively. The presence of the guest molecule of 4-substituted phenols allowed the waves to be irreversible, showing the mediation current. The mediation depended upon the hydrogen donating ability of the guests. Spectroelectrochemistry of the phenols showed that their radical anions generated on the electrodes at the reduction potential of quinones.2. The function of hydrogen bonds for the electron transfer has been discussed on the basis of MO calculations. It has been found that the apparently up-hill charge separation form the quinone on the electrode to the guests gets energy balance caused by large stabilization and potential shift arising from hydrogen bonding between the quinone radical and the neutral phenol.3. Mechanism on the control of the redox potentials with restrict of the structure of the hydrogen-bonding complexes has been demonstrated in the o-quinone hydrogen-bonding system with dimethylurea. Electrochemical measurements and molecular orbital calculations have revealed that the redox potentials in the system are controlled by the entropy driven stabilization for the hydrogen-bond formation.The results obtained here are important for the extended discussion on the function of biological quinones as a charge separator.

自组装单层膜电极在有机电合成、生物传感器和电极界面电子传递研究等方面有着广泛的应用。本研究制备了SAM-蒽醌（SAM-AQ）和SAM-萘醌（SAM-NQ）金电极，利用电化学方法结合分子轨道计算研究了氢键在电子转移给氢客体中的作用. SAM-AQ和SAM-NQ电极在循环伏安图上给出可逆波，分别对应于AQ和NQ自由基阴离子的产生。4-取代酚类客体分子的存在使波不可逆，显示出介导电流。介导作用依赖于客体的供氢能力。苯酚的光谱电化学研究表明，在醌的还原电位下，苯酚在电极上产生自由基阴离子.在分子轨道计算的基础上讨论了氢键在电子转移中的作用。研究发现，电极上的醌分子与客体分子之间明显的电荷分离是由于醌自由基与中性苯酚分子之间的氢键作用而产生的大的稳定性和电位移动引起的能量平衡.在邻醌与二甲基脲的氢键体系中，证明了氢键复合物结构对氧化还原电位的控制机理。电化学测量和分子轨道计算表明，体系的氧化还原电位受氢键形成的熵驱动稳定化控制，所得结果对进一步探讨生物醌作为电荷分离剂的作用具有重要意义。

项目成果

奥村典子, 宇野文二: "電解により生成した有機二価イオンの分子間相互作用と分子化合物生成能"日本化学会誌. 2002(3). 289-300 (2002)

Noriko Okumura，Bunji Uno：“电解产生的有机二价离子的分子间相互作用和形成分子化合物的能力”日本化学学会杂志 2002(3) (2002)。

Bunji Uno., and Yoshiaki Kato.: "Amperometric Detection of Endocrine Disruptive Alkylphenolic Compounds Based upon the Redox Recyclization on an Alkyl Chain-Coated Electrode."Chem. Lett.. 2002, (7). 652-653 (2002)

Bunji Uno. 和 Yoshiaki Kato.：“基于烷基链涂层电极上的氧化还原再循环对内分泌干扰性烷基酚化合物的电流检测。”Chem。