Entropy-driven rearrangement of the water network at the hydrated amide group of the trans-formanilide-water cluster in the gas phase
Entropy-driven rearrangement of the water network at the hydrated amide group of the trans-formanilide-water cluster in the gas phase
复制标题
气相中反式苯胺-水簇的水合酰胺基团的水网络的熵驱动重排
DOI：
10.1039/c0cp02836c
复制
发表时间：
2011
期刊：
影响因子：
--
通讯作者：
H.Sekiya
中科院分区：
文献类型：
--
作者：
K.Sakota;Y.Shimazaki;H.Sekiya
用红外光谱和量子化学计算研究了反式甲酰苯胺1 ∶4簇合物FA-（H_2O）_4中光电离诱导的水网络重排。 FA-（H_2O）_4在S_0态的红外光谱表明，所观察到的簇合物具有环状氢键结构，其中FA的CO基团和NH基团与四个水分子桥接，与文献报道的结构一致[E. G. Robertson，Chem. Phys. Lett.，2000，325，299]。然而，在[FA-（H2O）4]+的D 0态中的相应环状氢键结构是通过FA-（H2O）4的S1-S 0起源的光电离产生的次要产物。主要产物具有扩展的氢键结构，其中水分子的OH基团的氢与CO基团之间的分子间氢键解离。这是第一次观察到光电离诱导的水网络在[FA-（H2O）4]+的重排。通过密度泛函理论计算，我们得出结论，重排发生由于熵效应。
Photoionization-induced rearrangement of the water network in the trans-formanilide 1 ∶ 4 cluster, FA–(H2O)4, has been investigated by using IR-photodissociation spectroscopy and quantum chemical calculations. The IR spectrum of FA–(H2O)4 in the S0 state shows that the observed cluster has a cyclic hydrogen-bonded structure where the CO group and the NH group of FA are bridged with four water molecules, consistent with the reported structure [E. G. Robertson, Chem. Phys. Lett., 2000, 325, 299]. However, the corresponding cyclic hydrogen-bonded structure in the D0 state of [FA–(H2O)4]+ is a minor product arising from photoionization via the S1–S0 origin of FA–(H2O)4. The dominant product has an extended H-bonded structure, where the intermolecular hydrogen bond between the hydrogen of the OH group of a water molecule and the CO group is dissociated. This is the first observation of a photoionization-induced rearrangement of the water network in [FA–(H2O)4]+. Through DFT calculations, we conclude that the rearrangement occurs due to entropic effects.