Institut für Physikalische Chemie, Karlsruhe Institute of Technology (KIT), 76128 Karlsruhe, Germany.
Phys Chem Chem Phys. 2013 May 14;15(18):6640-50. doi: 10.1039/c2cp43808a.
Doubly deprotonated adenosine 5'-diphosphate (ADP-2H) and adenosine 5'-triphosphate (ATP-2H) dianions were investigated using infrared multiple photon dissociation (IR-MPD) and photoelectron spectroscopy. Vibrational spectra acquired in the X-H stretch region (X = C, N, O) and augmented by isotope-labelling were compared to density functional theory (DFT) calculations at the B3LYP/TZVPP level. This suggests that in ATP-2H the two phosphate groups adjacent to the ribose ring are preferentially deprotonated. Photoelectron spectra recorded at 4.66 and 6.42 eV photon energies revealed adiabatic detachment energies of 1.35 eV for ADP-2H and 3.35 eV for ATP-2H. Repulsive Coulomb barriers were estimated at ~2.2 eV for ADP-2H and ~1.9 eV for ATP-2H. Time-dependent DFT calculations have been used to simulate the photoelectron spectra. Photodetachment occurs primarily from lone pair orbitals on oxygen atoms within the phosphate chain.
使用红外多光子解离（IR-MPD）和光电子能谱研究了双去质子化的腺苷 5′-二磷酸（ADP-2H）和腺苷 5′-三磷酸（ATP-2H）二阴离子。在 X-H 伸缩区域（X = C、N、O）中获得的振动光谱，并通过同位素标记进行了比较，与 B3LYP/TZVPP 水平的密度泛函理论（DFT）计算进行了比较。这表明在ATP-2H中，与核糖环相邻的两个磷酸基团优先去质子化。在 4.66 和 6.42 eV 光子能量下记录的光电子能谱揭示了ADP-2H的绝热离解能为 1.35 eV，ATP-2H的绝热离解能为 3.35 eV。估算的排斥库仑势垒约为ADP-2H的 2.2 eV 和ATP-2H的 1.9 eV。已使用时间依赖的 DFT 计算来模拟光电子能谱。光致离解主要发生在磷酸链中氧原子的孤对轨道上。
