Crystal and Electronic Structure of Acetylcholine Halides

The paper investigates the structural and electronic characteristics of biologically active compounds on the example of acetylcholine halides (ACh-Hal, Hal=Cl, Br) using the first-principle methods with consideration of dispersion interactions. Initially, the electrostatic potential distribution map of the ACh molecular form was obtained and analyzed. It helped determine the optimal attachment geometry of halogen atoms at the area of methyl and methylene groups surrounding the nitrogen atom. Also, it further enabled the explanation of the main features of ACh-Hal packing in the crystalline phase (orthorhombic ACh-Cl, P212121, monoclinic ACh-Br, P21). For this case, the optimized geometry parameters and the main characteristics of the electronic structure were obtained, including atom coordinates, valence and torsion angles, energy band structure and gaps, total and projected densities of states, and electron density distribution maps.