C_4H_6O,C_4H_6S与HX(X=F,Cl,Br)分子间氢键的理论研究

Theoretical Studies on the Hydrogen-bonding Interactions of C_4H_6O,C_4H_6S and HX(X=F,Cl,Br)

运用MP2/aug-cc-pVDZ对C4H6O,C4H6S与HX(X=F,Cl,Br)之间的氢键作用进行了理论研究,发现2,5-二氢呋喃、2,5-二氢噻吩与HX之间不仅存在n…HX型氢键,C C双键与卤化氢分子亦可形成π型氢键.氢键键能ΔE、氢键键鞍点处的电子密度ρ(rc)以及从电子给体到受体之间的电子转移数Δq(HX)均表明,n型氢键比π型氢键更容易形成,与实验结果一致;C4H6O…HX(n),C4H6S…HX(n)(X=Cl,Br)中的氢键作用介于离子键和共价键之间;而对于其他氢键复合物,电子供体和受体之间的作用为闭壳层相互作用,即静电作用.形成氢键后,电子从C4H6O,C4H6S转移到HX使卤化氢分子的积分性质发生了变化,氢原子能量增加,偶极矩减小,体积减小.

Theoretical studies on the hydrogen-bonding interactions of C4H6O,C4H6S and HX（X=F,Cl,Br） have been investigated at the MP2/augcc-pVDZ level.Results show that both n-type and π-type hydrogen-bonded complexes can be formed between C4H6O,C4H6S and HX.The interaction energies,electron densities at the hydrogen bond critical point,and the charge transfer amount indicate that the n-type hydrogen bonds are stronger than the π-type hydrogen bond,which are consistent with the experimental results.The interactions of C4H6O…HX（n）,C4H6S…HX（n）（X=Cl,Br） are between covalent and ionic,the other hydrogen-bonded interactions belong to ＂closed-shell＂ interactions.The formation of hydrogen bonds results in the changes of the integration over the atom basin.The energies of hydrogen atom increase,the dipole moments and the volumes of hydrogen atom decrease upon complex formation.