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C O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.
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.
出处
《高等学校化学学报》
SCIE
EI
CAS
CSCD
北大核心
2012年第11期2492-2500,共9页
Chemical Journal of Chinese Universities
基金
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)
江苏大学高级专业人才科研启动基金(批准号:08JDG037)资助
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
Density functional theory
Electronic structure
Molecular dynamics simulation
Intermolecularinteraction
Solvent effect
