高等学校化学学报

高等学校化学学报 ›› 2012, Vol. 33 ›› Issue (11): 2492.doi: 10.7503/cjcu20120559

• 物理化学 • 上一篇    下一篇

有机π共轭配体溶剂化效应与分子间相互作用的理论研究

孟素慈1,2, 殷秀莲1, 马晶3, 谢吉民1   

  1. 1. 江苏大学化学化工学院, 镇江 212013;
    2. 江苏大学材料科学与工程学院, 镇江 212013;
    3. 南京大学化学化工学院, 介观化学教育部重点实验室, 理论与计算化学研究所, 南京 210093
  • 收稿日期:2012-06-08 出版日期:2012-11-10 发布日期:2012-10-15
  • 通讯作者: 谢吉民,男,博士,教授,博士生导师,主要从事新型功能配合物的制备及性能研究.E-mail:xiejm@ujs.edu.cn E-mail:xiejm@ujs.edu.cn
  • 基金资助:

    国家自然科学基金(批准号: 21103073);教育部博士点基金(批准号: 20093227110009);中国博士后科学基金(批准号: 2011M501173)和江苏大学高级专业人才科研启动基金(批准号: 08JDG037)资助.

Theoretical Studies on Solvent Effects and Intermolecular Interactions of Organic π-Conjugated Ligand in Solutions

MENG Su-Ci1,2, YIN Xiu-Lian1, MA Jing3, XIE Ji-Min1   

  1. 1. School of Chemistry and Chemical Engineering, Jiangsu University, Zhenjiang 212013, China;
    2. School of Materials Science and Engineering, Jiangsu University, Zhenjiang 212013, China;
    3. Institute of Theoretical and Computational Chemistry, Key Laboratory of Mesoscopic Chemistry, Ministry of Education, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210093, China
  • Received:2012-06-08 Online:2012-11-10 Published:2012-10-15

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摘要：

采用可极化的连续介质模型(PCM), 运用密度泛函理论(DFT), 在B3LYP/6-31+G**水平下研究了溶剂极性对有机π共轭配体N,N'-Bis-(3-pyridyl)ethylene-bis-urea(BPEBU)中syn-anti构象的分子几何和电子结构的影响, 并借助分子动力学模拟的方法, 采用明确溶剂模型研究了溶质-溶剂分子间的相互作用. 密度泛函理论计算结果表明, 随着溶剂极性的增强, BPEBU中尿素基上的CO键和N-H键以及吡啶环上的C-N键被明显极化, 使羰基氧原子和吡啶氮原子的电负性明显增强, 尿素基的N-H键上氢原子的正电荷也显著增加. 分子动力学模拟统计的结果表明, 在极性较强的乙醇溶液中, 有明确的O…H-O, N…H-O和N-H…O等3种氢键作用存在, 而在丙酮溶液中, 只有N…H-O一种氢键作用存在, 而且与乙醇溶液中的N…H-O作用相比要弱些. 另外, 采用密度泛函理论方法结合连续/明确的混合溶剂模型, 优化得到了溶质-溶剂三聚体的超分子簇结构, 与分子动力学模拟的第一溶剂层中的超分子结构相比, 两者定性一致.

关键词: 密度泛函理论, 电子结构, 分子动力学模拟, 分子间相互作用, 溶剂化效应

Abstract:

The influence of solvent polarity on the molecular geometries and electronic structures of organic π-conjugated ligand, N,N'-bis-(3-pyridyl)ethylene-bis-urea(BPEBU), was theoretically investigated within the framework of the polarized continuum model(PCM) via the density functional theory (DFT) calculations. The solute-solvent intermolecular interactions of BPEBU in acetone and ethanol solutions were studied by adopting the discrete solvent model through molecular dynamics (MD) simulations. It is demonstrated that CO and N-H bonds in urea moiety group and C-N bonds in pyridine rings of BPEBU are polarized and leng-thened with increasing the solvent polarity through DFT calculations. Correspondingly, the magnitudes of ne-gative charges of oxygen atoms and positive charges of hydrogen atoms in urea group are increased significantly. The MD simulations show the specific O…H-O, N…H-O and N-H…O hydrogen bonding interactions between BPEBU and ethanol solvents. Only N…H-O hydrogen bonds are formed in acetone solutions. And the N…H-O intermolecular interaction in acetone solution is weaker than that in ethanol solution. Furthermore, the solute-solvent hydrogen-bonded trimers are optimized by adopting the combined discrete/continuum solvation model through DFT method. The structures of trimers are qualitatively agreement with supramolecular clusters in the first solvation shell from molecular dynamics simulations.

Key words: Density functional theory, Electronic structure, Molecular dynamics simulation, Intermolecular interaction, Solvent effect

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