Unraveling the Synthesis of SbCl(C3N6H4): A Metal-Melaminate Obtained through Deprotonation of Melamine with Antimony(III)Chloride

Abstract

The discovery of melamine by Justus von Liebig was fundamental for the development of several fields of chemistry. The vast majority of compounds with melamine or melamine derivatives appear as adducts. Herein, we focus on the development of novel compounds containing anionic melamine species, namely the melaminates. For this purpose, we analyze the reaction of SbCl3 with melamine by differential scanning calorimetry (DSC). The whole study includes the synthesis and characterization of three antimony compounds that are obtained during the deprotonation process of melamine to melaminate with the reaction sequence from SbCl4(C9N18H19) (1) via (SbCl4(C6N12H13))2 (2) to SbCl(C3N6H4) (3). Compounds are characterized by single-crystal X-ray diffraction (SXRD), powder X-ray diffraction (PXRD), and infrared spectroscopy (IR). The results give an insight into the mechanism of deprotonation of melamine, with the replacement of one, two, or eventually three hydrogen atoms from the three amino groups of melamine. The structure of (3) suggests that metal melaminates are likely to form supramolecular structures or metal-organic frameworks (MOFs).