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

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 (ClO4−, SnCl62−, IrCl62−,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−, NO3−, PdCl42−), 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.