Hydrogen bonding in different pyrimidine-methanol clusters probed by polarized Raman spectroscopy and DFT calculations
Hydrogen bonding in different pyrimidine-methanol clusters probed by polarized Raman spectroscopy and DFT calculations
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DOI：
10.1002/jrs.2744
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发表时间：
2011-04-01
影响因子：
2.5
通讯作者：
Singh, Ranjan K.
中科院分区：
文献类型：
--
作者：
Singh, Dheeraj K.;Mishra, Shivangi;Singh, Ranjan K.
本文报道了嘧啶（Pd）和甲醇（M）之间的氢键作用。嘧啶和甲醇分子之间的氢键以及不同甲醇分子之间的氢键显著影响高稀释度下的光谱特征。选择参比系统Pd的环呼吸模式nu（1）作为标记带，以探测氢键的程度。在970-1020 cm（-1）区域记录了28种不同摩尔分数的（嘧啶+甲醇）二元混合物的偏振拉曼光谱。在所有浓度下的各向同性拉曼线轮廓的拉曼线形分析揭示了三个不同的光谱成分在Pd的摩尔分数低于0.75。这三种组分归因于三种不同的物质：“游离Pd”（Pd）、“低甲醇含量的Pd”（pd 1）和“高甲醇含量的Pd”（pd 2）。后两种物种在氢键的模式和强度上有很大的不同。纯Pd和8个不同甲醇含量的Pd/M配合物的结构和振动光谱的密度泛函理论计算结果支持我们对实验结果的解释。一个很好的光谱结构的相关性，不同的集群子群，类似于早期的结果获得的Pd和水。除了嘧啶与甲醇之间的N中心点H和O中心点H氢键外，高甲醇含量时团簇中甲醇分子之间形成的O中心点H氢键对实验结果的解释也起着至关重要的作用。版权所有（C）2010约翰威利父子有限公司
We report on the hydrogen bonding between pyrimidine (Pd) and methanol (M) as H-donor in this study. Hydrogen bonds between pyrimidine and methanol molecules as well as those between different methanol molecules significantly influence the spectral features at high dilution. The ring-breathing mode nu(1) of the reference system Pd was chosen as a marker band to probe the degree of hydrogen bonding. Polarized Raman spectra in the region 970-1020 cm(-1) for binary mixtures of (pyrimidine + methanol) at 28 different mole fractions were recorded. A Raman line shape analysis of the isotropic Raman line profiles at all concentrations revealed three distinct spectral components at mole fractions of Pd below 0.75. The three components are attributed to three distinct groups of species: 'free Pd' (pd), 'Pd with low methanol content' (pd1) and 'Pd with high-methanol content' (pd2). The two latter species differ considerably in the pattern and the strengths of the hydrogen bonds. The results of density functional theory calculations on structures and vibrational spectra of neat Pd and eight Pd/M complexes with varying methanol content support our interpretations of the experimental results. A nice spectra-structure correlation for the different cluster subgroups was obtained, similar to earlier results obtained for Pd and water. Apart from N center dot center dot center dot H and O center dot center dot center dot H hydrogen bonds between pyrimidine and methanol, O center dot center dot center dot H hydrogen bonds formed among the methanol molecules in the cluster at high methanol content also play a crucial role in the interpretation of the experimental results. Copyright (C) 2010 John Wiley & Sons, Ltd.