Filippov Oleg A, Tsupreva Victoria N, Epstein Lina M, Lledos Agusti, Shubina Elena S
A.N. Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, Vavilov Street 28, 119991 Moscow, Russia.
J Phys Chem A. 2008 Sep 4;112(35):8198-204. doi: 10.1021/jp804303j. Epub 2008 Aug 13.
The results of DFT calculations of harmonic and anharmonic frequencies of the dihydrogen bonded (DHB) complexes H 3EH (-)...HOR (E = B, Al, Ga and HOR = CH 3OH, CF 3CH 2OH) in gas phase and in low polar medium (by CPCM model) in comparison with the partners are presented. Normal coordinate analysis of the low-frequency modes was carried out to assign the new vibrations induced by DHB formation by the potential energy distribution values. Among them, the intermolecular H...H stretching vibrations only have individual modes. The influence of central atom mass and isotope and the strength of the proton donor effects were determined. The systems convenient for IR studies were chosen from the calculation predictions. The spectral investigation was made on the BH 4 (-)/ROH complexes (ROH = CH 2FCH 2OH (MFE), CF 3CH 2OH (TFE), (CF 3) 2CHOH (HFIP)). The results of temperature dependence, isotope substitution, and influence of the proton-donor strength studies agree with the theoretical conclusions. Combination of experimental and theoretical approaches allowed determining for the first time the intermolecular stretching mode characterizing intrinsic DHB vibrations.
本文给出了气相和低极性介质（采用CPCM模型）中双氢键（DHB）配合物H₃EH⁻...HOR（E = B、Al、Ga，HOR = CH₃OH、CF₃CH₂OH）与相关体系相比的谐波和非谐波频率的密度泛函理论（DFT）计算结果。通过势能分布值对低频模式进行了简正坐标分析，以确定由双氢键形成引起的新振动。其中，分子间H...H伸缩振动仅有单独的模式。确定了中心原子质量和同位素以及质子供体效应强度的影响。从计算预测中选择了便于红外研究的体系。对BH₄⁻/ROH配合物（ROH = CH₂FCH₂OH（MFE）、CF₃CH₂OH（TFE）、(CF₃)₂CHOH（HFIP））进行了光谱研究。温度依赖性、同位素取代以及质子供体强度研究的结果与理论结论相符。实验和理论方法的结合首次确定了表征双氢键固有振动的分子间伸缩模式。
