【作者】 吴俊勇；

【导师】 张敬畅；

【作者基本信息】 北京化工大学 ， 工业催化， 2007， 博士

【摘要】 本论文中，我们选择了几种典型的分子间相互作用体系，围绕分子间相互作用的理论研究方法、分子间相互作用的特征及本质进行了系统的研究。主要内容如下：1、采用超分子方法和对称匹配微扰理论SAPT（Symmetry AdaptedPerturbation Theory）研究了XY（ClF,BrCl，BrF）与HF、H₂O和NH₃分子间存在的稳定的氢键和卤键构型复合物的分子间相互作用的特征及其作用本质。结果表明：卤键型复合物比相应的氢键型复合物更稳定。XY与HF、H₂O、和NH₃形成的氢键复合物或卤键型复合物的分子间相互作用能是按照BrCl<ClF<BrF的顺序增大，这和XY的偶极矩的增大顺序是一致的。SAPT能量分解结果表明：对于氢键复合物，静电和色散能对总的吸引相互作用能占主导地位，诱导能的贡献较小。对于卤键型复合物，是静电能对总的吸引相互作用能占主导地位。对于强的卤键型复合物XY…NH₃，其大的交换排斥能和诱导能说明了它们是一种强的部分共价键的作用。2、通过AIM理论和SAPT能量分析说明了依靠两个带正电荷原子Cl和H间的氢键作用形成的二聚体FCl-HX和依靠两个带正电荷原子Cl和Cl间的卤键作用形成的二聚体FCI-CIF相互作用的本质。对于非传统氢键FCl-HX（HF、HCl和HBr）复合物和非传统卤键复合物FCl-ClF，是诱导能和色散能对总的吸引相互作用能占主导地位。3、在MP2／aug-cc-pVDZ水平上对呋喃与一些不同的氢化物分子H_nX（HF、H₂O、NH₃、HCl、H₂S和PH₃）间可能存在的所有复合物进行了全自由度能量梯度优化，通过在相同水平上的频率验证分析发现了两类稳定的分子间相互作用形式：σ_o-氢键型（Ⅰ）和π-氢键型（Ⅱ）。分子间相互作用能的计算结果表明：呋喃和第一行氢化物（HF、H₂O和NH₃）形成的σ_o-型复合物是最稳定的结构。然而，对于呋喃和第二行氢化物（HCl、H₂S和PH₃）形成的π-氢键型复合物是最稳定的结构。能量分解结果显示：σ_o-型复合物的分子间相互作用中，静电作用占主导地位。在π-氢键型复合物的分子间相互作用中，色散能和静电能对复合物的形成过程中起到了关键作用。当X=F，O是静电作用稍占优势，而当X=N,Cl,S，P时是色散作用稍占优势。4、在MP2／aug-cc-pVDZ水平上，对噻吩和一些不同的氢化物分子H_nX（HF、H₂O、NH₃、HCl、H₂S和PH₃）分子间相互作用的几何构型、相互作用能、电子特性及相互作用本质等进行了理论研究，通过频率验证分析发现在噻吩与氢化物分子H_nX间只形成了一种X-H…π型氢键相互作用。从噻吩的静电势图说明了只形成了π-氢键型复合物的原因，从理论上很好地解释了相关的实验现象。其次，能量分解结果显示：所有的复合物C₄H₄S-HnX（Ⅱ）和C₄H₄O-H_nX（Ⅱ）相似，也是静电能和色散能对总的吸引相互作用能占主导地位，诱导能对总的吸引相互作用能的贡献较小。当X=F，O是静电作用稍占优势，而当X=N，Cl，S，P时是色散作用稍占优势。更多还原

【Abstract】 In this paper, a theoretical study on nature and characteristics such as geometries, interaction energies, and electronic properties for some types of intermolecular interactions have been carried out. The main results are as follows:（1）The nature of the hydrogen-bonded and halogen-bonded complexes between XY（ClF, BrCl, BrF） and H_nX（HF、H₂O and NH₃） were studied by supermolecular （SM） variational or SAPT （Symmetry Adapted Perturbation Theory） methods. The results display that the halogen-bonded complexes are more stable than the corresponding hydrogen-bonded complexes. The interaction energies of hydrogen-bonded and halogen-bonded complexes between XY（ClF, BrCl, BrF） and H_nX（HF、H₂O and NH₃） increase in the order BrCl < ClF < BrF. This order is correlated to the dipole moment of the XY. On the other hand, the energy decomposition shows that electrostatic and dispersion forces play an important role in the hydrogen-bonded complexes. For the halogen-bonded complex, the main interaction energy comes from the electrostatic energy. In the strongest N-X-type complex XY-NH₃, the induction energy is the most important attractive term, followed by the exchange and electrostatic energy. This domination of the induction and exchange terms is the main feature of the strong and partly covalent bonds.（2） The nature of the unusual hydrogen-bonded FCl-HX（HF、HCl和HBr） and halogen-bonded complexes FCl-ClF formed by the interactions between two positively charged atoms of different molecules were studied by Atoms in Molecules （AIM） and SAPT methods. According to the SAPT analysis, induction and the dispersion energy play an important role in determining the equilibrium structure of these special complexes. AIM provides a very sophisticated analysis of the electron desity within a molecular system.（3） The nature of for the intermolecular interactions between furan and various hydrides H_nX（HF、H₂O> NH₃、HCl、H₂S and PH₃） were studied at the MP2/aug-cc-pVDZ level. Two types of geometry are observed in these interactions: theσ_o-type geometry （Ⅰ）, in which an H-O bond formed between a hydrogen atom of H_nX and the furan oxygen atom; Theπ-type geometry （Ⅱ） is characterized by aπ-H bond formed between a hydrogen atom of H_nX and theπ-electron system of the aromatic ring. The calculated interaction energies show that all of theσ_o-type complexes are more stable than the correspondingπ-type complexes for the first-row hydrides （HF、H₂O and NH₃）. However, for the second row hydrides （HCl、H₂S and PH₃）, all of theπ-type complexes are more stable than the correspondingσ_o-type complexes. To study the nature of the intermolecular interactions, an energy decomposition analysis was carried out and the results indicate that theσ_o-type complexes are traditional hydrogen-bonded complexes with electrostatic interactions making the primary contribution to complex formation. In the case of theπ-type complexes, the dispersion and electrostatic forces dominate complexation.（4） Equilibrium geometries, interaction energies and charge transfer for the intermolecular interactions between the thiophene and various hydrides H_nX（HF、H₂O、NH₃、HCl、H₂S and PH₃） were studied at the MP2/aug-cc-pVDZ level. Only one type of geometry is observed in these interactions: theπ-type geometry （Ⅱ）. Although thiophene possesses both aπ-electron system and a non-bonding electron pair （n-pair）, the geometries for all of the thiophene-H_nX complexes obtained in this study appear to be determined by theπ-electron system. By contrast, the furan-H_nX complex geometries were determined by both theπ-electron system and the n-pair. Furan and thiophene are both five-membered heteroaromatic rings with different heteroatoms.The molecular electrostatic potential maps of thiophene and furan, which might provide an insight into the disparity between the results obtained for furan and thiophene. When compared to the electrostatic potential of furan, it is apparent that the relatively weak electronegativity of sulfur confers a strong aromatic character on the thiophene ring. The electrostatic potential of the ring sulfur is insufficient to facilitate complex formation at the site of the S atom. The strongest negative electrostatic potential located at theπ-electron density near center of C₄-C₅. According to the SAPT analysis, the dispersion and electrostatic forces dominate theπ-type complexation.更多还原