SiH_4与Na、Mg和Be等金属氢化物分子间反向氢键相互作用

Inverse hydrogen bonds between SiH_4 and hydride of Na,Mg and Be

在B3LYP/6-311++g**、MP2/6-311++g(3df,3pd)及MP2/aug-cc-pvtz水平上分别求得H3SiH…MeHn(Me=Na,Mg,Be;n=1或2)复合物势能面上的3个稳定构型,探讨了以Si-H为电子供体的红移反向氢键相互作用(IHB).经MP2/6-311++g(3df,3pd)水平的计算,在3个复合物中,含基组重叠误差(BSSE)校正的单体间相互作用能分别为-5.98、-8.65和-3.96kJ.mol-1,与MP2/aug-cc-pvtz水平下计算得到的-6.18、-9.12和-4.28kJ·mol-1接近,可见3个反向氢键复合物的相对稳定性顺序为:SiH4...MgH2>SiH4...NaH>SiH4...BeH2.NBO分析及对相关原子化学位移的计算表明,在复合物中,电子流向总体表现为SiH4→MeHn(n=1或2),且直接参与反向氢键形成的H3的化学位移向低场移动.与传统氢键相比,这里Si1-H3既是氢键供体,又是电子供体,从而形成反向氢键相互作用.另外,采用分子中原子理论(AIM)分别对各复合物中相关键鞍点处的电子密度拓扑性质进行了分析,结果表明3个复合物中均存在以静电性质为主的分子间反向氢键弱相互作用.

The optimized geometries of the three complexes between MeHn（Me=Na,Mg,Be;n=1 or 2） and SiH4 have been calculated at the B3LYP/6-311＋＋g＊＊,MP2/6-311＋＋g（3df,3pd） and MP2/aug-cc-pvtz levels,respectively.The red-shift inverse hydrogen bonds based on Si-H,electron donor,were reported.The calculated binding energies with basis set super-position error（BSSE） correction of the three complexes are-5.98,-8.65 and-3.96 kJ.mol-1（MP2/6-311＋＋g（3df,3pd））,respectively,which agree with the results obtained via MP2/aug-cc-pvtz（-6.18,-9.12 and-4.28 kJ.mol-1,respectively）.The relative stabilities of the three complexes in the order：SiH4...MgH2 SiH4...NaH SiH4...BeH2.Natural bond orbital theory（NBO） analysis and the chemical shifts calculation of the related atoms revealed that the charges flow from SiH4 to MeHn and the chemical shifts of the interacting H shift to down field.Here,the Si1-H3 of SiH4 acts as bond hydrogen donor and electron donor simultaneously.So,compared to conventional hydrogen bonds,they formed inverse hydrogen bond（IHB） complexes.Atom in molecule（AIM） theory has also been used to investigate the topological properties of the critical points in the three IHB structures.