Ren Zhiyong, Cheng Senxiang, Zhang Guobao, Ma Dezhu, Yang Xiaozhen
8224 Henan Key Laboratory of Fine Chemicals, Zhengzhou 450002, People's Republic of China.
J Phys Chem B. 2008 Feb 21;112(7):1926-34. doi: 10.1021/jp075588b. Epub 2008 Jan 30.
As an extension study, FTIR and molecular simulation methods were combined in the present paper to analyze the H-bond interactions resulting from multiple donors and acceptors that have led to self-assembly based on segmented polyurethane with carboxyl (PUc) and poly(4-vinylpyridine) (P4VP) in our previous work. Of them, FTIR was used to analyze the H-bonding types and interactions as well as their changes before and after self-assembly; molecular mechanics (MM/COMPASS) was used to study the effect of possible conformations on the H-bonds involved and analyze the most probable H-bond patterns; quantum mechanics (QM/B3LYP) was used to help confirm the experimental FTIR band assignments and calculate the H-bond energy. It was found that two types of H-bonds exist, namely, COOH...P4VP (type I) and (OCO)NH...P4VP (type II), based on OH and NH as the strong donors in the interaction between PUc and P4VP. Strong evidence has been obtained for a type II H-bond, which is the specialty in PUc/P4VP assembly. The type I and type II H-bonding energies are -11.293 and -7.150 kcal/mol, respectively. The forming probability of the type I H-bond accounts for 95.87%, while that of the type II H-bond is 4.13%, showing the primary driving force for the assembly based on PUc and P4VP is still the H-bond between COOH and P4VP, yet the H-bonds based on NH and pyridyl in P4VP cannot be ignored.
作为一项拓展研究，本文结合傅里叶变换红外光谱（FTIR）和分子模拟方法，分析了在我们之前的工作中基于含羧基的嵌段聚氨酯（PUc）和聚（4-乙烯基吡啶）（P4VP）发生自组装的过程中，由多个供体和受体导致的氢键相互作用。其中，FTIR用于分析氢键类型、相互作用以及自组装前后的变化；分子力学（MM/COMPASS）用于研究可能的构象对所涉及氢键的影响，并分析最可能的氢键模式；量子力学（QM/B3LYP）用于帮助确认实验FTIR谱带归属并计算氢键能。研究发现，基于PUc与P4VP相互作用中OH和NH作为强供体，存在两种类型的氢键，即COOH...P4VP（I型）和（OCO）NH...P4VP（II型）。已获得II型氢键的有力证据，这是PUc/P4VP组装体的特性。I型和II型氢键能分别为-11.293和-7.150 kcal/mol。I型氢键的形成概率占95.87%，而II型氢键的形成概率为4.13%，这表明基于PUc和P4VP组装的主要驱动力仍然是COOH与P4VP之间形成的氢键，然而基于P4VP中NH和吡啶基形成的氢键也不容忽视。
