Conformational preferences and isomerization upon excitation/ionization of 2-methoxypyridine and 2-N-methylaminopyridine
文献类型：期刊论文
| 作者 | Cheng, Min2; Zhu, Qihe2; Dai, Wenshuai1,2; Liu, Sheng1,2; Zhang, Zhe1,2; Chi, Xiaoping1,2; Du, Yikui2 |
| 刊名 | PHYSICAL CHEMISTRY CHEMICAL PHYSICS
 |
| 出版日期 | 2018-03-07 |
| 卷号 | 20期号:9页码:6211-6226 |
| ISSN号 | 1463-9076 |
| DOI | 10.1039/c7cp07854d |
| 文献子类 | Article |
| 英文摘要 | Conformers from the rotations of the methyl group and the methoxy or methylamino group, namely staggered (s)/eclipsed (e)-cis/trans 2-methoxypyridine (2MOP) and 2-N-methylaminopyridine (2NMP), are studied using theoretical calculations in combination with one-color resonance-enhanced two-photon ionization (1C-R2PI) and mass-analyzed threshold ionization (MATI) spectroscopies. The calculations predict that, for cis 2MOP, trans 2MOP and trans 2NMP, only the s conformers are stable in the S-0, S-1 and D-0 states. However, for cis 2NMP, the stable conformer is staggered in the S-0 state but eclipsed in the S-1 and D-0 states, indicating an isomerization upon the excitation or ionization from the S-0 state. This is experimentally supported by the 1C-R2PI and MATI spectra of 2NMP. Due to the relative instability, the number density of trans 2MOP is too low in the sample to be detected. All the bands in the 1C-R2PI and MATI spectra of 2MOP are assigned to s-cis 2MOP. The energy differences between cis and trans conformers are derived from excitation and ionization energies, indicating another conformational isomerization: stable trans 2NMP in the S-0 and S-1 states but stable cis 2NMP in the D-0 state. For 2MOP, the so-called syn preference previously found for the S-0 state is also observed in the S-1 and D-0 states. The conformational preference and isomerization are discussed with natural bond orbital calculations and reduced density gradient analysis. For 2MOP, the syn preferences are mainly caused by the exchange repulsion among several s-orbitals of the OCH3 group and the pyridine ring. While the relative stabilities of the s and e conformers of cis 2MOP and cis 2NMP are simultaneously influenced by steric repulsion and orbital interactions. |
| WOS关键词 | THRESHOLD IONIZATION SPECTROSCOPY ; METHYL VINYL ETHER ; CIS-TRANS ISOMERIZATION ; SET MODEL CHEMISTRY ; 1ST EXCITED-STATE ; THEORETICAL CALCULATIONS ; MICROWAVE-SPECTRUM ; INTERNAL-ROTATION ; MATI SPECTROSCOPY ; HYPERCONJUGATION |
| WOS研究方向 | Chemistry ; Physics |
| 语种 | 英语 |
| WOS记录号 | WOS:000429280100022 |
| 出版者 | ROYAL SOC CHEMISTRY |
| 源URL | [http://cas-ir.dicp.ac.cn/handle/321008/169128]  |
| 专题 | 大连化学物理研究所_中国科学院大连化学物理研究所 |
| 通讯作者 | Du, Yikui |
| 作者单位 | 1.Univ Chinese Acad Sci, Beijing 100049, Peoples R China 2.Chinese Acad Sci, Inst Chem, State Key Lab Mol React Dynam, Beijing Natl Lab Mol Sci, Beijing 100190, Peoples R China |
| 推荐引用方式 GB/T 7714 | Cheng, Min,Zhu, Qihe,Dai, Wenshuai,et al. Conformational preferences and isomerization upon excitation/ionization of 2-methoxypyridine and 2-N-methylaminopyridine[J]. PHYSICAL CHEMISTRY CHEMICAL PHYSICS,2018,20(9):6211-6226. |
| APA | Cheng, Min.,Zhu, Qihe.,Dai, Wenshuai.,Liu, Sheng.,Zhang, Zhe.,...&Du, Yikui.(2018).Conformational preferences and isomerization upon excitation/ionization of 2-methoxypyridine and 2-N-methylaminopyridine.PHYSICAL CHEMISTRY CHEMICAL PHYSICS,20(9),6211-6226. |
| MLA | Cheng, Min,et al."Conformational preferences and isomerization upon excitation/ionization of 2-methoxypyridine and 2-N-methylaminopyridine".PHYSICAL CHEMISTRY CHEMICAL PHYSICS 20.9(2018):6211-6226. |
入库方式： OAI收割
来源：大连化学物理研究所
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