Heterogeneous Proton Transfer As an Explanation for the Unusually Thick Cyclic Voltammograms and Unusually Small Second Redox Wave of Para-Quinones in Aprotic Solvents

氧化还原 化学 二聚体 循环伏安法 光化学 单体 玻璃碳 自由基离子 离子 电化学 电极 无机化学 物理化学 有机化学 聚合物
作者
Patrick Andrew Staley,Diane K. Smith
出处
期刊:Meeting abstracts 卷期号:MA2014-01 (22): 990-990
标识
DOI:10.1149/ma2014-01/22/990
摘要

Quinones are well-known to undergo two reversible reductions at glassy carbon electrodes in aprotic solvents, first to a radical anion and then to a dianion, eq 1. Despite 50+ years of voltammetric investigation of this chemistry, two unusual features of quinone voltammetry—that the second redox wave is smaller than the first, and that the area between the two waves is thicker than CV simulations say it should be—was typically ignored until Gupta and Linschitz made note of the difference in height of the redox waves in 1997.1 The current explanation for the unequal wave heights, advanced by Macías-Ruvalcaba and Evans in 2010,2 is that some of the radical anion is trapped in the form of a pi dimer in solution. Macias-Ruvalcaba and Evans hypothesize that this dimer can be reduced at the same potential as the monomer radical anion, but only by 1 e- per dimer, resulting in smaller current than expected. There currently is no explanation in the literature for the thickness between the two waves. In this study, concentration dependence of the CVs of differently substituted quinones showed that radical dimerization cannot be a general explanation for the small second redox wave. In some cases the thickness between the waves appears as its own quasi-reversible wave. Addition of phenols to a quinone solution produces a quasi-reversible wave at the same potential due to hydrogen bonding to the radical anion. The McCreery lab showed that oxide content of the surface of glassy carbon can change its chemistry through the presence of functional groups such as phenols.3 In low concentration duroquinone studies, different surface treatments show that with higher oxide content a new wave grows in that is at the same potential as the wave seen in a 1:1 addition of naphthol to the quinone redox system. This indicates that the odd thickness in quinone CV’s may be due to hydrogen bonding of the quinones to phenolic groups on the glassy carbon surface followed by proton transfer. REFERENCES 1. Gupta, J. ;Linschitz, H. Hydrogen Bonding and Protonation Effects in Electrochemistry of Quinones in Aprotic Solvents. J. Am. Chem. Soc., 1997, 119(27), 6384-6391. 2. Macías-Ruvalcaba, N.; Evans, D. Association Reactions of the Anion Radicals of Some Hydroxyquinones: Evidence for the Formation of π and σ–Dimers As Well As a Neutral-Anion Radical Complex. J. Phys. Chem. C, 2010, 114(2), 1285-1292. 3. Kuo, T.; McCreery, R.L. Surface Chemistry and Electron-Transfer Kinetics of Hydrogen-Modified Glassy Carbon Electrodes. Anal. Chem. 1999, 71, 1553-1560.

科研通智能强力驱动
Strongly Powered by AbleSci AI
更新
PDF的下载单位、IP信息已删除 (2025-6-4)

科研通是完全免费的文献互助平台,具备全网最快的应助速度,最高的求助完成率。 对每一个文献求助,科研通都将尽心尽力,给求助人一个满意的交代。
实时播报
帆帆完成签到,获得积分10
刚刚
2秒前
4秒前
future完成签到 ,获得积分10
4秒前
wwl关闭了wwl文献求助
5秒前
5秒前
5秒前
lzw完成签到,获得积分10
5秒前
帆帆发布了新的文献求助10
5秒前
量子星尘发布了新的文献求助10
5秒前
悦耳冷松完成签到,获得积分10
6秒前
7秒前
7秒前
8秒前
独特乘云发布了新的文献求助10
9秒前
悦耳冷松发布了新的文献求助10
9秒前
9秒前
dian完成签到 ,获得积分10
10秒前
吃饱饱完成签到 ,获得积分10
10秒前
彭于晏应助大力绿柏采纳,获得10
11秒前
11秒前
ri_290完成签到 ,获得积分10
12秒前
贾克斯发布了新的文献求助10
12秒前
何处芳歇发布了新的文献求助10
12秒前
小当家完成签到,获得积分10
12秒前
nightmare发布了新的文献求助10
13秒前
Ava应助独特乘云采纳,获得10
15秒前
义气黄焖排骨完成签到,获得积分10
15秒前
古藤完成签到 ,获得积分10
16秒前
shinian完成签到 ,获得积分10
16秒前
JamesPei应助nightmare采纳,获得10
17秒前
18秒前
19秒前
十年完成签到 ,获得积分10
20秒前
wwl发布了新的文献求助10
22秒前
23秒前
默默千亦完成签到 ,获得积分10
23秒前
贾克斯发布了新的文献求助10
24秒前
撸撸大仙完成签到,获得积分20
25秒前
打我呀发布了新的文献求助10
25秒前
高分求助中
A new approach to the extrapolation of accelerated life test data 1000
ACSM’s Guidelines for Exercise Testing and Prescription, 12th edition 500
‘Unruly’ Children: Historical Fieldnotes and Learning Morality in a Taiwan Village (New Departures in Anthropology) 400
Indomethacinのヒトにおける経皮吸収 400
Phylogenetic study of the order Polydesmida (Myriapoda: Diplopoda) 370
基于可调谐半导体激光吸收光谱技术泄漏气体检测系统的研究 350
Robot-supported joining of reinforcement textiles with one-sided sewing heads 320
热门求助领域 (近24小时)
化学 材料科学 医学 生物 工程类 有机化学 生物化学 物理 内科学 纳米技术 计算机科学 化学工程 复合材料 遗传学 基因 物理化学 催化作用 冶金 细胞生物学 免疫学
热门帖子
关注 科研通微信公众号,转发送积分 3989406
求助须知:如何正确求助?哪些是违规求助? 3531522
关于积分的说明 11254187
捐赠科研通 3270174
什么是DOI,文献DOI怎么找? 1804901
邀请新用户注册赠送积分活动 882105
科研通“疑难数据库(出版商)”最低求助积分说明 809174