Structure and Hydrogen Bonding of Different Isomers of 2-Aminopyridine·NH3 Studied by IR/R2PI Spectroscopy
Structure and Hydrogen Bonding of Different Isomers of 2-Aminopyridine·NH3 Studied by IR/R2PI Spectroscopy
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IR/R2PI光谱研究2-氨基吡啶·NH3不同异构体的结构和氢键
DOI：
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发表时间：
2004
期刊：
影响因子：
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通讯作者：
B. Brutschy
中科院分区：
文献类型：
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作者：
Ronghu Wu;Sascha Vaupel;A. Nachtigall;B. Brutschy
用共振双光子电离（R2 PI）和IR/R2 PI振动光谱测量了2-氨基吡啶（2AP）与氨的1：1团簇的电子光谱和振动光谱。密度泛函理论计算进行了识别结构和分配的振动光谱在NH伸缩区域。已经确定了两种能量最低的异构体。在异构体I中，它是全局最低能量结构，氨与氨基形成强氢键，与芳香氮形成弱氢键。参与这个氢键的基团的振动表现出110 cm-1的红移，对于氨的供体氨基N-H和69 cm-1的红移。氨的两个不对称振动的简并性在簇中被去除，在3438和3406 cm-1处具有相应的带。在异构体II中，氨与远离芳香氮的N-H基团形成H键。该键比异构体I中相应的键弱。伸展运动...
The electronic and vibrational spectra of the 1:1 clusters of 2-aminopyridine (2AP) with ammonia have been measured using resonant two-photon ionization (R2PI) and IR/R2PI vibrational spectroscopy. Density functional theory calculations were performed to identify structures and assign the vibrational spectra in the NH stretch region. The two lowest-energy isomers have been identified. In isomer I, which is the global minimum energy structure, ammonia forms a strong H bond with the amino group and a weak one with the aromatic nitrogen. The vibrations of the groups involved in this H bonding exhibit red shifts of 110 cm-1 for the donating amino N−H and of 69 cm-1 for the donating N−H group of ammonia. The degeneracy of the two asymmetrical vibrations of ammonia is removed in the cluster, with the corresponding bands at 3438 and 3406 cm-1. In isomer II ammonia forms an H bond to the N−H group which points away from the aromatic nitrogen. This bond is weaker than the corresponding one in isomer I. The stretch...