Hydrogen bond network structures based on sulfonated phosphine ligands: the effects of complex geometry, cation substituents and phosphine oxidation on guanidinium sulfonate sheet formation

The interactions between guanidinium cations and the sulfonate groups on the phosphine [PPh2C6H4-m-SO3] are reported in this paper. The robustness of the hydrogen bonded guanidinium sulfonate (GS) network is tested with respect to alteration of the cation substituents, which shows that the sheet structure is tolerant to the loss of one hydrogen bond donor, but not two. The consequences of replacing a phosphine with a phosphine oxide in these network structures shows that that the phosphine oxide group successfully competes with the sulfonate as a hydrogen bond acceptor. Metal incorporation into these networks was also effected and the crystal structure of [C(NH2)3]2{trans-[IrCl(CO)(PPh2C6H4-m-SO3)2]} which showed that both of the sulfonate groups from each complex anion form hydrogen bonds within the same sheet. Solid state characterisation was achieved using X-ray crystallography.