Simulation Research Of Chiral Molecular Self-assembly On Surface Driven By Hydrogen-bond In BIC/HA System

Using theoretical simulation method, this paper discusses molecular self-assembly of 5-?benzyloxy?-isophthalic acid derivative ?BIC? and three isomers of heptanol ?HA? on highly oriented pyrolytic graphite?HOPG?, by density functional theory ?DFT?, molecular mechanics ?MM? and molecular dynamics ?MD?. And it also discusses the influence of temperature in BIC/HC system, by adjusting simulation temperature.Firstly, this paper calculates a simplified model of benzoic acid/methanol, which can show compound key feature of BIC/HA system. It also measures bond length and angle of DFT calculation result. Then it optimizes characteristic force field parameters, including key extension and angle bending, in MMFF94 force field. Using the optimized force field ?MMFF941?, as well as MM and MD, it calculates a new BIC/HA system. Compared the new calculation result with the former one, which is calculated by MD in original force field, reasonability of MMFF94 force field can be verified.Secondly, this paper establishes CW/CCW ?closewise/counterclockwise? network structures of BIC and HA, BIC and R-SA, BIC and H-SA. These six structures are marked as HA/CW, HA/CCW, R-HA/CW, R-HA/CCW, S-HA/CW and S-HA/CCW respectively. In room temperature ?test temperature?, using optimized MMFF94₁ force field, MM optimization and MD simulation of the above six systems are calculated. Based on the six MD simulation results, correlational research on forming tendency and stability between hydrogen bond and chiral self-assembly structure is conducted, by making quantitative analysis of characteristic parameters, such as structure of geometry, amount of energy, numbers, length and angle of hydrogen bond, and comparing with the experiment results.Lastly, this paper chooses four two-dimensional network structures HA/CW, HA/CCW, R-HA/CW and S-HA/CCW, which are stable in room temperature, and set test temperatures as 323K,348K,373K. Then it continues MD simulation of molecular self-assembly of the above four structures on HOPG surface in three different temperatures. Temperature influence of BIC and HA self-assembly on HOPG is discussed, by comparing and analyzing variation tendency of energy, geometrical structure and hydrogen bond parameters.