Structure and stability of electronsprayed cytidine_nCu²⁺ and cytidine_nH⁺ (n = 1-4) compounds in the gas phase

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• 作者：Shuqin Zhang ; Junguo Dong ; Li Xu ; Ping Cheng ; Zhen Zhou ; Jiamo Fu
• 关键词：Cytidinen-Cu2+ complex ; Protonated cytidinen ; DFT calculation ; Zero-point energy
• 刊名：International Journal of Mass Spectrometry
• 出版年：2013
• 出版时间：1 October, 2013
• 年：2013
• 卷：351
• 期：Complete
• 页码：5-11
• 全文大小：1844 K

文摘

[CuL_n]²⁺ and [L_nH]⁺ (L = cytidine) with high relative intensity were observed in the gas phase via electronspray of water and methanol solution of Cu(NO₃)₂ and cytidine. The possible structures and zero-point energies for the most of these complexes were calculated with DFT methods. The results show that coordination is the main interaction between the L and Cu(II) for [CuL_n]²⁺ (n = 1-4), and the hydrogen-bond between the Ls for [L_nH]⁺ (n = 1-4); the structures for [CuL_n]²⁺ are that the Cu(II) coordinate mostly 4 ligands forming the primary order sphere and other ligands just bind loosely with the primary sphere forming the secondary or outer sphere, and [L_nH]⁺ are that the protonated L dimer composes the primary sphere, and the others binding the dimer loosely form the outer sphere; the calculated stability orders are [CuL₂]²⁺ > [CuL]²⁺ > [CuL₄]²⁺ > [CuL₃]²⁺ and [L₂H]⁺ > [LH]⁺ > [L₃H]⁺ > [L₄H]⁺ which are luckily consistent quite well with the peak intensity distribution in the mass spectrum.