摘要
利用密度泛函理论,对6种氨基酸阴离子和不同链长咪唑阳离子形成的离子液体的结构、阴阳离子间相互作用以及碱性进行理论研究。优化得到5种稳定构型,并且阴阳离子间存在2种氢键。利用分子中的原子理论(AIM)、非共价键相互作用理论(NCI)及自然键轨道理论(NBO)进行分析,结果显示阴离子羰基中的O与H(C2)能形成更强的氢键且具有一定的共价性质。利用最负表面静电势(V_(s.ming))和平均局部离域化能(I_(s.ming)),在微观水平上对氨基酸离子液体的碱性进行分析,发现当引入氨基或羟基到阴离子中时,离子液体的碱性变强。
Density functional theory (DFT ) calculations were carried out to study the structures, intermolecular interactions, and basicity of ionic liquids formed by six amino acid-based anions and the imidazolium cations with different side chain lengths. Five locally stable conformers of the ion pairs were located,and two kinds of hydrogen bonds were obtained by optimization. The atoms in molecules (AIM ) , noncovalent interaction (NCI) ,and natural bond orbital (NBO) analysis were undertaken. Hydrogen bonds between the carbonyl O in the anions and H (C2) are much stronger in strength and have some covalent character. Final ly, the basicity of these ionic liquids was analyzed at the microscopic level, using the surface electrostatic potential (V s,min) and the lowest surface average local ionization energy (I s,min). The basicity of these ionic liquids could be enhanced with the introduction of an amine or hydroxyl group into the anion.
出处
《华东理工大学学报(自然科学版)》
CAS
CSCD
北大核心
2016年第5期587-593,652,共8页
Journal of East China University of Science and Technology
基金
国家重点基础研究发展计划项目(2015CB251401)
国家自然科学基金(21473054,21136004)
中央高校基本科研业务费专项资金(222201313001)
关键词
氨基酸离子液体
氢键
碱性
静电
amino acid ionic liquids
hydrogen bonds
basicity
electrostatics