Density functional theory and molecular dynamics investigations on substituted banana-shaped compounds

详细信息    查看全文

• 作者：Ananda Rama Krishnan Selvaraj ; Wolfgang Weissflog and Rudolf Friedemann
• 关键词：Banana ; shaped molecules ; Bending angle ; Order parameters ; Diffusion coefficients
• 刊名：Journal of Molecular Modeling
• 出版年：2007
• 出版时间：August, 2007
• 年：2007
• 卷：13
• 期：8
• 页码：907-917
• 全文大小：621 KB
• 刊物类别：Chemistry and Materials Science
• 刊物主题：Chemistry
  Computer Applications in Chemistry
  Biomedicine
  Molecular Medicine
  Health Informatics and Administration
  Life Sciences
  Computer Application in Life Sciences
  
• 出版者：Springer Berlin / Heidelberg
• ISSN：0948-5023

文摘

Density functional theory (DFT) calculations and molecular dynamics (MD) simulations on the atomic level were performed on three different substituted banana-shaped compounds derived from 1,3-phenylene bis[4-(4-n-hexyloxyphenyliminomethyl)benzoate] (P-6-O-PIMB). The DFT studies were carried out on the isolated molecules, and in the MD simulations clusters were treated with up to 64 monomers. The effect of polar substituents, such as chlorine and the nitro group, on the central 1,3-phenylene unit of banana-shaped compounds was investigated. In particular, flexibility, polarity, electrostatic potential (ESP) group charge distributions, B-factors, bending angles and molecular lengths were considered. The MD results were analysed by trajectories of significant torsion angles as well as order parameters such as radial atom pair distribution functions g(r), orientational correlation functions g(o), diffusion coefficients (D) and root mean square deviations (RMSD) values. The g(r) and g(o) values show that a certain long range order is generated by the introduction of a NO₂ group in the 2-position of the central 1,3-phenylene ring. In contrast, the chlorination at the 4 and 6 positions of the central 1,3-phenylene unit decreases the long range order tendency by its perturbation effect on the conformations in such molecules. Moreover, g(r) and g(o) values, as well as diffusion coefficients, show that in the NO₂ substituted compound the formation of microphase areas is preferred. Finally, the aggregation effect in such compounds was studied in a systematic way by a comparison of the conformational properties of the isolated molecules and the monomers in the clusters.