Infrared spectroscopy of (phenol)(n)(+) (n=2-4) and (phenol-benzene)(+) cluster ions
Infrared spectroscopy of (phenol)(n)(+) (n=2-4) and (phenol-benzene)(+) cluster ions
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DOI：
10.1021/jp961910z
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发表时间：
1997-03-06
影响因子：
2.9
通讯作者：
Mikami, N
中科院分区：
文献类型：
--
作者：
Fujii, A;Iwasaki, A;Mikami, N
采用离解光谱结合离子阱技术，对n = 2 ~ 4的苯酚簇离子（苯酚）(n)（+）的红外光谱和电子光谱进行了观察。OH拉伸区的振动谱表明，二聚体离子具有不对称形式，使得离子部分充当质子供体，三聚体和四聚体离子具有分子间氢键的非环形式。在400 ~ 1600 nm范围内（苯酚）(n)（+）的电子谱中，除了苯酚离子部分局部激发引起的跃迁外，没有发现电荷共振跃迁。结果表明，在这些簇离子中，苯基环之间的电荷离域相互作用不明显。结果表明，三聚体离子中所有的苯基部分都被一条羟基链所束缚。中性三聚体形成了O型氢键，而具有环状氢键的对称构型。还观察到（苯酚-苯）（+）异二聚体离子的OH伸缩振动，其中苯酚离子通过pi型氢键结合在苯环上。发现苯酚离子部分的OH波段有极大的红移和显着的增宽，并就离子团的氢键OH振动的特征进行了讨论。
Infrared and electronic spectra of size-selected phenol cluster ions, (phenol)(n)(+) for n = 2-4, were observed by using dissociation spectroscopy combined with an ion trap technique. Vibrational spectra of the OH stretching region indicate that the dimer ion has an asymmetric form such that the ionic moiety acts as a proton donor and that the trimer and tetramer ions have noncyclic forms with respect to intermolecular hydrogen bonds. In the electronic spectra of (phenol)(n)(+) in the range of 400-1600 nm was found no charge resonance transition except for a transition due to the local excitation of the phenol ion moiety. The result indicates that charge delocalization interaction between phenyl rings is not significant in these cluster ions. It was concluded that all the phenyl moieties in the trimer ion are bound by a linear chain of the OH ... O hydrogen bonds, while a symmetric form with cyclic hydrogen bonds has been established for the neutral trimer. The OH stretching vibration of the hetero dimer ion of (phenol-benzene)(+) was also observed, in which the phenol ion is expected to be bound onto the benzene ring through a pi-type hydrogen-bond. An extremely large red-shift and a substantial broadening of the OH band of the phenol ion moiety were found, and the results were discussed in respect to the characteristic feature of hydrogen-bonded OH vibrations of ionic clusters.