摘要
运用密度泛函B3LYP方法 ,在 6 3 1G 水平上设计优化了丁二酮肟与苯甲酸通过四重氢键构筑的异三聚体超分子 .此异三聚体的总能量比三个单体总能量之和低 14 4 0 816kJ/mol,四重氢键的平均键能约为 3 6 0 2 0 4kJ/mol,属中高强度 ;2 98 15K时吉布斯自由能变化ΔGT=-4 1 70kJ/mol ,显示形成三聚体的反应可自发进行 .在此设想指导下 ,实验合成出相关异三聚体 ,并得到了晶体结构 ,与预测的结构极为相似 .热性能分析显示 ,此三聚体不是三个单体的简单叠加 ,而是一个不同于其单体的全新化合物 .理论计算数据与实验结果的一致性 ,证明了理论计算的预见性 .
A novel quadruple hydrogen bonded heterotrimer supramolecule of benzoic acid and dimethylglyoxime has been designed and completely optimized using density functional theory (DFT) B3LYP/6-31G* method. The calculated results show that the total energy of the heterotrimer is much lower than the sum of energies of three monomers, the average strength of the quadruple hydrogen bonds is about 36.0204 kJ/mol and the change of Gibbs free energy for the aggregation from monomer to the trimer DeltaG(T) = -41.70 kJ/mol at 298.15 K, which implies the spontaneous process of formation of the trimer. Under the guidance of the DFT calculations, the heterotrimer was synthesized successfully and its crystal structure was obtained. The crystal structure resembles closely the predicted structure. Thermal stability analysis indicates that the heterotrimer is a new material and it is not the ordinary superposition of the original monomers. The calculations are in good agreement with the experimental results. It demonstrates the reliability of theoretical calculation as well as the feasibility of construction of supramolecule in laboratory.
出处
《化学学报》
SCIE
CAS
CSCD
北大核心
2004年第14期1265-1271,J001,共8页
Acta Chimica Sinica
基金
国家自然科学基金 (No .50 372 0 2 8)
江苏省高校自然科学研究指导性计划 (No.0 3KJD1 50 0 53)资助项目
关键词
异三聚体
超分子
密度泛函
晶体结构
热性能
氢键
hydrogen bond
heterotrimer
supramolecule
density functional theory
crystal structure
thermal stability
