Spectroscopic study of novel cluster structures created as chemical intermediates in supersonic molecular beams

超音速分子束中作为化学中间体产生的新型簇结构的光谱研究

基本信息

批准号：
20550005
负责人：
MIKAMI Naohiko
金额：
$ 3.24万
依托单位：
Tohoku University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2009
资助国家：
日本
起止时间：
2009 至 2010
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-20550005/
关键词：
分子分光反応中間体構造解析芳香族求核置換反応中間体 σ-complex 分子クラスターベンゼン・メタノールクラスタープロトン付加水クラスターアセトン2量体光イオン化誘起異性化反応 C_6F_6・NH_3クラスターフォルムアミド・水クラスター水素結合形態変化水和メタノールクラスター HCP分子前期解離反応機構レーザー分光気相イオン反応制御

项目摘要

Spectroscopic studies on jet-cooled molecular cluster cations have been carried out for the following systems ;1. IR and electronic spectroscopy of [C_6H_6(NH_3)_n]^+ (n=1 and 2) revealed that their stable forms are of s-complex type, in which the ammonia moiety is covalently bonded to the benzene moiety as expected as the reaction intermediate of nucleophilic substitution of aromatics. The similar structures of [Benzene-(Methanol)_n]^+ (n=2, 3) were also investigated in combination with quantum chemical calculations.2. H-bond network structures of H^+(H_2O)_n (n=20-200) were investigated by IR spectroscopy. It was found that the spectral features of the clusters with increasing cluster size become similar to the characteristic features of water and of ice, indicating the network morphology of the large-size clusters transmutes gradually to those of the bulk systems. It was also found that the spectral feature depends on the internal energy in the species.3.Structures of neutral and cationic clusters of acetone and of acetic acid were investigated by using IR spectroscopy based on vacuum-ultraviolet one-photon ionization detection. It was found that the keto-enol transition is generated after the ionization for many clusters, such as their dimers, whereas their neutrals are of the keto-form. The isomerization mechanism was discussed in relation to their proton affinities and the potential surface of the proton-transfer coordinate.

针对以下系统进行了对喷射冷却分子簇阳离子的光谱研究； 1。 IR和电子光谱[C_6H_6（NH_3）_n]^+（n = 1和2）表明，它们的稳定形式是S-complex类型的，其中氨部分是按预期的，因为氨部分共价粘结到苯科，因为它是预期的。芳香剂的亲核取代的中间体。还研究了[苯 - （甲醇）_n]^+（n = 2，3）的类似结构，并结合量子化学计算2。通过红外光谱研究了H^+（H_2O）_n（n = 20-200）的H键网络结构。发现随着簇尺寸增加的簇的光谱特征与水和冰的特征相似，表明大型簇的网络形态逐渐变速于散装系统。还发现，光谱特征取决于物种中的内部能量。3。丙酮和阳离子簇的结构和乙酸的中性和阳离子簇的结构使用基于真空 - 硫化物的IR光谱法进行了单孔离子化检测研究。发现酮烯醇转变是在许多簇（例如它们的二聚体）的电离之后产生的，而其中性为酮形式。讨论了有关其质子亲和力和质子转移坐标的潜在表面的异构化机制。