Department of Chemistry, University of Gdańsk, Wita Stwosza 63, 80-952 Gdańsk, Poland.
J Chem Phys. 2013 Aug 21;139(7):075101. doi: 10.1063/1.4817779.
The intact (parent) 2'-deoxycytidine homodimer anion, (dC)2 (●-), was generated in the gas phase (in vacuo) using an infrared desorption∕photoemission source and its photoelectron spectrum was recorded using a pulsed, magnetic bottle photoelectron spectrometer. The photoelectron spectrum (PES) revealed a broad peak with the maximum at an electron binding energy between 1.6 and 1.9 eV and with a threshold at ∼1.2 eV. The relative energies and vertical detachment energies of possible anion radicals were calculated at the B3LYP/6-31++G(∗∗) level of theory. The most stable anion radicals are the complexes involving combinations of the sugar[middle dot][middle dot][middle dot]base and base[middle dot][middle dot][middle dot]base interactions. The calculated adiabatic electron affinities and vertical detachment energies of the most stable (dC)2 (●-) anions agree with the experimental values. In contrast with previous experimental-computational studies on the anionic complexes involving nucleobases with various proton-donors, the electron-induced proton transferred structures of (dC)2 (●-) are not responsible for the shape of PES.
完整的（母体）2'-脱氧胞嘧啶同二聚体阴离子（dC）2（●-）在气相（真空中）中使用红外解吸/光电发射源生成，并使用脉冲磁瓶光电电子能谱仪记录其光电子能谱（PES）。光电子能谱（PES）显示出一个具有最大电子结合能在 1.6 和 1.9 eV 之间的宽峰，且阈值约为 1.2 eV。可能的阴离子自由基的相对能量和垂直离解能是在 B3LYP/6-31++G（∗∗）理论水平上计算的。最稳定的阴离子自由基是涉及糖[点线][点线][点线]碱基和碱基[点线][点线][点线]碱基相互作用组合的复合物。最稳定的（dC）2（●-）阴离子的计算绝热电子亲和能和垂直离解能与实验值相符。与之前涉及具有各种质子供体的碱基的阴离子复合物的实验-计算研究相反，电子诱导的质子转移结构（dC）2（●-）不是 PES 形状的原因。
