烟碱-苹果酸盐制备及晶体结构理论分析

Preparation and crystal structure theoretical analysis of nicotine-malate

以探究烟碱-苹果酸盐晶体结构为目的,采用溶液反应法制备获得烟碱-苹果酸盐,溶液重结晶得到烟碱-苹果酸盐的单晶体。通过单晶X射线衍射分析法解析得到烟碱-苹果酸盐由一个加氢的烟碱阳离子(二价)与一个苹果酸阴离子(二价)组成,其化学计量式为C14H20N2O5,其中烟碱与苹果酸分子以离子键和氢键结合。晶胞参数为:正交晶系,P212121空间群,a=7.629 3(16)?,b=8.160 4(12)?,c=24.030(4)?,α=β=γ=90.00°。相互作用能分析结果表明:在以烟碱为中心,3.8?距离范围内,烟碱分子与周围分子存在12种不同的相互作用能。其中,烟碱分子与最近的苹果酸分子由于形成N2-H2…O2氢键而具有最大的总相互作用能(–23.4 kJ/mol)。能量框架研究结果表明:烟碱-苹果酸盐总体能量框架主要由形如正方体的能量框架单体组合而成,在正方体能量框架单体内部有较小的相互作用能(圆柱体半径较小)连接。该研究制备得到烟碱-苹果酸盐及其单晶体,通过实验与理论分析相结合的方式,系统分析烟碱-苹果酸盐的晶体结构,探究共晶中烟碱与苹果酸分子间的相互作用关系。

The purpose of this study is to analyze the structures of nicotine-malate and its monocrystal which have been prepared by antisolvent diffusion and solution recrystallization,respectively.The result of single crystal X-ray diffraction analysis is that the nicotine-malate structure is composed of a hydrogenated nicotinic cation(divalent)and a malic acid anion(divalent).Its stoichiometric formula is C14H20N2O5,and nicotine binds to malic acid molecules by ionic bond and hydrogen bond.Nicotine-malate structure belongs to orthorhombic crystal system with space group P212121,and the cell parameters are a=7.629 3(16)?,b=8.160 4(12)?,c=24.030(4)?,α=β=γ=90.00°.The analysis of interaction energy shows that there are twelve different interaction energies between nicotine and surrounding molecules in the range of 3.8?with nicotine as the center.Among them,N2-H2…O2 hydrogen bonds formed by nicotine molecules and recent malic acid molecules have the maximum total interaction energy(–23.4 kJ/mol).The research results of energy framework show that the overall energy frame of nicotine-malic acid crystal is mainly composed of energy frame monomers,which are shaped like cubes.Inside the energy frame monomers,there is small interaction energy(cylinders with small radius)connection.In this study,the nicotine-malate and its monocrystal were prepared,and the structure of nicotine-malate was systematically analyzed by combining experimental and theoretical analysis,and the interaction between nicotine and malic acid in eutectic was explored.