PROBING HYDROGEN-BONDING IN BENZENE-(WATER)(N) CLUSTERS USING RESONANT ION-DIP IR SPECTROSCOPY
PROBING HYDROGEN-BONDING IN BENZENE-(WATER)(N) CLUSTERS USING RESONANT ION-DIP IR SPECTROSCOPY
复制标题
DOI：
10.1039/fd9949700229
复制
发表时间：
1994-01-01
影响因子：
3.4
通讯作者：
ZWIER, TS
中科院分区：
文献类型：
--
作者：
PRIBBLE, RN;ZWIER, TS
在C-H和O-H拉伸区(2900-4000 cm(-1))，用共振离子浸渍红外光谱(RIDIRS)记录了n=1-7的C6H6-(H2O)(N)(Bwn)团簇的团簇尺寸光谱。在C-H拉伸区，苯的费米三重态特性几乎没有变化，但添加了多达七个水分子。相比之下，O-H拉伸谱显示出对团簇大小的显著依赖关系。在C6H6-H2O中，由于络合物中H2O的内部旋转，O-H伸缩转变因额外的结构而变得复杂。在C6H6-(H2O)(2)中，O-H伸缩光谱与自由水二聚体的伸缩光谱十分相似。对于n=3-5的团簇，由于自由O-H(3715 cm(-1))、pi H成键O-H(3650 cm(-1))和单施主O-H伸展，光谱可以大致分为三类，这与由环状W-n团簇组成的BWN结构一致，其中一个自由O-H基团用于与苯的pi氢键。当n=6时，在3500-3600 cm(-1)区域有明显的新跃迁。通过与W-n从头计算的预测相比较，这些新的跃迁被指定为与W-6中形成更紧密的冰状结构有关的双施主O-H伸缩。向双施主水的转变在BW7中继续发展，在双施主O-H拉伸区出现额外的跃迁，以牺牲自由O-H跃迁强度为代价。
Resonant ion-dip infrared spectroscopy (RIDIRS) is used to record cluster-size-specific spectra of C6H6-(H2O)(n) (BWn) clusters with n=1-7 in the C-H and O-H stretch regions (2900-4000 cm(-1)). The Fermi triad characteristic of benzene in the C-H stretch region is virtually unchanged by addition of as many as seven water molecules. By contrast, the O-H stretch spectra show a dramatic dependence on cluster size. In C6H6-H2O, the O-H stretch transitions are complicated by additional structure due to internal rotation of H2O in the complex. In C6H6-(H2O)(2), the O-H stretch spectrum closely mimics that of the free water dimer. For the n=3-5 clusters, the spectra can be divided roughly into three categories, due to free O-H (3715 cm(-1)), pi H-bonded O-H (3650 cm(-1)), and single donor O-H stretches, consistent with a BWn structure composed of a cyclic W-n cluster in which one of the free O-H groups is used in pi hydrogen bonding with benzene. At n=6, the spectra show distinct new transitions in the 3500-3600 cm(-1) region. By comparing with the predictions of ab initio calculations of W-n, these new transitions are assigned to double donor O-H stretches associated with the formation of a more compact, ice-like structure in W-6. The transformation to double-donating waters continues to develop in BW7, where additional transitions in the double-donor O-H stretch region appear at the expense of free O-H transition intensity.