Keto-enol tautomerism, spectral (infrared, Raman and NMR) studies and Normal coordinate analysis of 4-Methyl-2-hydroxyquinoline using quantum mechanical calculations

互变异构体 化学 拉曼光谱 红外线的 计算化学 甲基 化学位移 碳-13核磁共振 物理化学 结晶学 立体化学 群(周期表) 有机化学 光学 物理
作者
Ibrahim A. Shaaban,Mohammed A. Assiri,Tarik E. Ali,Tarek A. Mohamed
出处
期刊:Journal of Molecular Structure [Elsevier BV]
卷期号:1252: 132137-132137 被引量:3
标识
DOI:10.1016/j.molstruc.2021.132137
摘要

The Raman (3500−100 cm−1) and mid-infrared (4000−400 cm−1) spectra of 4-Methyl-2-hydroxyquinoline (MHQ) have been recorded. Owing to the keto-enol tautomerism and rotation of methyl group around C4–C13 single bond, six structures (S1–S6) were hypothetically proposed. Full geometry optimization and frequency calculations were performed for keto (quinolone) and enol (hydroxyquinoline) structures using the DFT methods including B3LYP, ωB97XD and mPW1PW91 with basis sets up to 6–311+G(2d,p). In addition, 1H/13C NMR chemical shifts (δ, ppm) were estimated utilizing GIAO approach and IEF-PCM solvation model. The computational outcomes favor keto tautomer, 4-Methylquinolin-2-one (MQO) while the methyl group is staggered to C4–C5 bond (S5). However, other structures were excluded owing to high energy differences besides having an imaginary wavenumber for the transition state structures S2, S4 and S6. These results agree with the observed/calculated vibrational spectral data along with 1H/13C NMR chemical shifts. Aided by the calculated wavenumbers and normal coordinate analysis, complete assignments for the observed infrared/Raman bands to their corresponding vibration modes were quantitatively reported herein for keto- MQO. Employing B3LYP/6–311+(2d,p) structural parameters, the thermo kinetic parameter F-number (5.3936707 cm−1) is estimated along with V3 barrier (1067±48/1219±62 cm−1, 3.05±0.14/3.48±0.18 kcal/mol) using the calculated/observed methyl torsion at 217/233 cm−1.
最长约 10秒,即可获得该文献文件

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
汉堡包应助哈哈哈大赞采纳,获得10
1秒前
Xixicccccccc发布了新的文献求助10
1秒前
缥缈发布了新的文献求助10
3秒前
3秒前
阁下宛歆完成签到,获得积分10
3秒前
4秒前
4秒前
弯弓丝的小张完成签到,获得积分10
7秒前
orixero应助bottle采纳,获得10
7秒前
8秒前
QI关注了科研通微信公众号
9秒前
英姑应助weijie采纳,获得10
9秒前
年年发布了新的文献求助10
9秒前
10秒前
852应助LLL采纳,获得10
10秒前
frl发布了新的文献求助10
10秒前
10秒前
科研通AI2S应助冥月采纳,获得10
11秒前
所所应助孤独士晋采纳,获得10
11秒前
12秒前
echo发布了新的文献求助20
13秒前
15秒前
Victoria发布了新的文献求助10
15秒前
多情含灵发布了新的文献求助10
16秒前
慕青应助JackeyChen采纳,获得10
17秒前
小马甲应助忧虑的冰姬采纳,获得10
17秒前
17秒前
烟花应助123采纳,获得10
18秒前
cc完成签到,获得积分20
18秒前
18秒前
19秒前
AZUSA完成签到,获得积分20
20秒前
20秒前
在水一方应助猪猪院长采纳,获得10
20秒前
21秒前
朴素烧鹅发布了新的文献求助10
21秒前
superbada完成签到,获得积分10
22秒前
nanween完成签到,获得积分10
22秒前
zhaoyy发布了新的文献求助10
22秒前
22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 3988732
求助须知:如何正确求助?哪些是违规求助? 3531027
关于积分的说明 11252281
捐赠科研通 3269732
什么是DOI,文献DOI怎么找? 1804764
邀请新用户注册赠送积分活动 881869
科研通“疑难数据库(出版商)”最低求助积分说明 809021