Cytosine Radical Cations: A Gas-Phase Study Combining IRMPD Spectroscopy, UVPD Spectroscopy, Ion-Molecule Reactions, and Theoretical Calculations
Cytosine Radical Cations: A Gas-Phase Study Combining IRMPD Spectroscopy, UVPD Spectroscopy, Ion-Molecule Reactions, and Theoretical Calculations
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DOI：
10.1002/cphc.201700281
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发表时间：
2017-05-19
期刊：
影响因子：
2.9
通讯作者：
Ryzhov, Victor
中科院分区：
文献类型：
--
作者：
Lesslie, Michael;Lawler, John T.;Ryzhov, Victor
胞嘧啶的自由基阳离子（CytC（+））是由三元Cu-II络合物在气相中解离氧化产生的。自由基阳离子的特征在于红外多光子解离（IRMPD）光谱的指纹区域，紫外/维斯光解离（UVPD）光谱，离子-分子反应，和理论计算（密度泛函理论和从头算）。实验IRMPD光谱特征的诊断频带的两个烯醇氨基和两个酮氨基的CytC（+）的互变异构体，计算出的能量最低的异构体，与以前的研究一致。虽然UVPD作用光谱也可以与四种最低能量互变异构体的组合相匹配，但不能排除非经典二阶自由基阳离子的存在。它的形成，但是，不太可能由于这种异构体和相应的三元铜-II络合物的高能量。气相离子-分子反应表明CytC（+）经历了从1-丙烷乙醚中夺取氢原子、与一氧化氮的自由基复合反应和从二甲基二硫醚中的电子转移。
The radical cation of cytosine (CytC(+)) is generated by dissociative oxidation from a ternary Cu-II complex in the gas phase. The radical cation is characterized by infrared multiple photon dissociation (IRMPD) spectroscopy in the fingerprint region, UV/Vis photodissociation (UVPD) spectroscopy, ion-molecule reactions, and theoretical calculations (density functional theory and ab initio). The experimental IRMPD spectrum features diagnostic bands for two enol-amino and two ketoamino tautomers of CytC(+) that are calculated to be among the lowest energy isomers, in agreement with a previous study. Although the UVPD action spectrum can also be matched to a combination of the four lowest energy tautomers, the presence of a nonclassical distonic radical cation cannot be ruled out. Its formation is, however, unlikely due to the high energy of this isomer and the respective ternary Cu-II complex. Gas-phase ion-molecule reactions showed that CytC(+) undergoes hydrogen-atom abstraction from 1-propanethiol, radical recombination reactions with nitric oxide, and electron transfer from dimethyl disulfide.