Cheng Ruodi, Loire Estelle, Fridgen Travis D
Department of Chemistry, Memorial University, St. John's, NL A1B 3 × 7, Canada.
Laboratoire Chimie Physique - CLIO, Batiment 201, Porte 2, Campus Universite d'Orsay, 91405, France.
Phys Chem Chem Phys. 2019 Jun 7;21(21):11103-11110. doi: 10.1039/c9cp01223k. Epub 2019 May 16.
The structures of alkali metal cation bound 1-methylcytosine (1-mCyt) dimers were explored using vibrational spectroscopy in the form of infrared multiple photon dissociation (IRMPD) spectroscopy and by computational methods. For the smaller alkali metal cations, Li and Na, only non-hydrogen bonded symmetric anti-parallel structures were observed in agreement with the lowest energy computed structures. For K, Rb, and Cs the vibrational spectra in the N-H stretch region showed strong evidence for hydrogen bonding in agreement with the lowest energy structures which contained hydrogen bonding interactions between the amine group of one cytosine and the carbonyl oxygen of the other cytosine. The lowest energy structures for these complexes were compared to previously studied cytosine complexes [(Cyt)M] where M = Li, Na, and K. The calculations are in agreement that only the non-hydrogen bonded structures would be observed for these cytosine complexes.
利用红外多光子解离（IRMPD）光谱形式的振动光谱法并通过计算方法，对碱金属阳离子结合的1-甲基胞嘧啶（1-mCyt）二聚体的结构进行了探索。对于较小的碱金属阳离子锂和钠，仅观察到非氢键结合的对称反平行结构，这与计算出的最低能量结构一致。对于钾、铷和铯，N-H伸缩区域的振动光谱显示出氢键存在的有力证据，这与最低能量结构一致，该结构包含一个胞嘧啶的胺基与另一个胞嘧啶的羰基氧之间的氢键相互作用。将这些配合物的最低能量结构与先前研究的胞嘧啶配合物[（Cyt）M]（其中M = Li、Na和K）进行了比较。计算结果一致表明，对于这些胞嘧啶配合物，只会观察到非氢键结合的结构。
