Application, structure, salts and complexes of lidocaine: a review. Part IV. Structure of bis(lidocaine) tetrachloroferrate(III) chloride

Abstract

The review focuses on lidocaine (2-(diethylamino)-N-(2,6-dimethylphenyl)acetamide): in the first part, its use in various branches of medicine, as well as the structure of lidocaine, its salts and molecular complexes was discussed; in the second part the use of lidocaine in the composition of deep-eutectic solvents (DES), DES-microemulsions and complexes of lidocaine with zinc, copper, cobalt, platinum and iron was considered; the third part described the structure of bis(lidocaine) tetrachloridozincate(II). The forth part examines the structure of bis(lidocaine) tetrachloro-ferrate(III) chloride, which crystallizes in the monoclinic space group P21/c with a = 11.0597(1), b = 23.0083(2), c = 14.6629(2) Å, β = 109.378(2)°, V = 3519.82(8) Å3, Z = 4, and Dc = 1.328 Mg/m3 (CCDC Deposition Number 2109673),and consists of the [FeCl4]– slightly distorted tetrahedral anion, chlorine anion Cl– and two protonated cations of lidocaine LidH+ in an outer coordination sphere. H-bonds form a “bridge” connecting two lidocaine molecules of neighboring complexes with the formation of molecular dimers. “Bridges” are located in the center and in all eight corners of the unit cell, half of the ligands of the complex form dimers, the other half stacks with the metal group and chlorine anions. The dimers form a chain lying in the ac plane and on the diagonal passing through the origin at an angle of 54.69° (0.5β) to the a and c axes; the chains form layers lying in the ac plane with an interlayer distance of 11.5 Å (0.5b), and layers containing anions and cations not involved in the formation of dimers are arranged between the dimer layers.