Constructor Graphs as Useful Tools for the Classification of Hydrogen Bonded Solids: The Case Study of the Cationic (Dimethylphosphoryl)methanaminium (dpmaH+) Tecton

Abstract

Abstract:The structural chemistry of a series of dpmaH (dpmaH = (dimethylphosphoryl)methanaminium) salts has been investigated using constructor graph representations to visualize structural dependencies, covering the majority of known dpmaH salts. It is shown that the structurally related α-aminomethylphosphinic acid can be integrated in the systematology of the dpmaH salts. Those dpmaH salts with counter anions that are weak hydrogen bond acceptors (ClO 4´, SnCl 6 2´, IrCl 6 2´, I´) tend to form head-to-tail hydrogen bonded moieties purely consisting of dpmaH + cations as the primarily structural motif. In structures with weak to very weak hydrogen bonds between the dpmaH + cations and the counter anions, the anions fill the gaps in the structures. In salts with medium to strong hydrogen bond acceptor counter ions (Cl´, NO 3´, PdCl 4 2´) , the predominant structural motif is a double head-to-tail hydrogen bonded (dpmaH + ) 2 dimer. These dimeric units form further NH¨¨¨X hydrogen bonds to neighboring counter anions X, which results in one-dimensional and two-dimensional architectures.

Crystal structure of caffeinium triiodide – caffeine (1/1), C16H21I3N8O4

“…In the course of this study, the new compound caffHI 3 • caff was obtained. The appearance of this compound was expected, as we have already shown that depending on the pH value organic aminium halogenides cocrystals containing the organic aminium cation, the counter anion and one additional equivalent of the neutral organic amine can be easily obtained [11,14,15]. Even though caffeine has been known for many decades, studies on the medical and biological properties are still in progress [16].…”