Gabapentin Coordination Networks: Mechanochemical Synthesis and Behavior under Shelf Conditions

Abstract

Active pharmaceutical ingredients (API) coordination complexes and networks present a promising pathway for developing new bioinspired materials. In the present study, we report several coordination networks of gabapentin with Y­(III), Mn­(II), and several lanthanides (LnCl₃), Ln = La³⁺, Ce³⁺, Nd³⁺, Er³⁺ obtained by mechanosynthesis. To the best of our knowledge, these are among the first coordination networks of pharmaceuticals involving lanthanides. These novel compounds proved to be unstable under shelf conditions, are thermally stable until water release at approximately 80 °C, and decompose above 200–250 °C. The coordination networks obtained present different structural architectures based on mono-, di-, tri-, and hexa-metallic centers (herein called monomers, dimers, trimers, and hexamers), and also a one-dimensional polymeric chain was obtained. Gabapentin chelation modes are the same in most of the networks, adopting three typical geometries: the bidentate coordination – chelation, mode I; the bridge coordination, mode II, and the “bidentate-bridge” coordination, mode III. NMR studies show that the compounds have different behavior in solution, where a single coordination mode seems to be present