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运用量子化学从头算方法研究了NH3AlH3与HF,HCl,HBr,H2O和CH3OH形成的双氢键Al—H…H—X(X=F,Cl,Br,O).计算结果表明,在所有体系中,双氢键的形成使得AlH和HX键增长,伸缩振动频率红移.分子间超共轭σ(AlH)σ*(XH)导致了XH键的红移.AlH键红移由两个因素造成:AlH键发生负的重极化与负的重杂化;分子间超共轭导致σ(AlH)成键轨道电子密度减小.
H-X (X = F, Cl, Br, O), a double hydrogen bond formed between NH3AlH3 and HF, HCl, HBr, H2O and CH3OH, has been studied by ab initio method.Results show that in all systems , The formation of double hydrogen bonds leads to the increase of AlH and HX bonds and the shift of the stretching vibration frequency to red shift.The intermolecular hyperconjugation σ (AlH) σ * (XH) leads to the red shift of XH bonds.The red shift of AlH bonds is caused by two factors As a result, negative heavy polarization and negative heavy hybridization occur on the AlH bond, and the intermolecular hyperconjugation leads to the reduction of electron density of the σH bond gate.