Dibismuthates as linking units for bis-zwitterions and coordination polymers

Adducts of bismuth trihalides BiX3 (X = Cl, Br, I) and the PS3 ligand (PS3 = P(C6H4-o-CH2SCH3)3) react with HCl to form inorganic/organic hybrids with the general formula HPS3BiX42. On the basis of their solid-state structures determined by single-crystal X-ray diffraction, these compounds exhibit discrete bis-zwitterionic assemblies consisting of two phosphonium units HPS3+ linked to a central dibismuthate core Bi2X82? via S?Bi dative interactions. Remarkably, the phosphorus center of the PS3 ligand undergoes protonation with hydrochloric acid. This is in stark contrast to the protonation of phosphines commonly observed with hydrogen halides resulting in equilibrium. To understand the important factors in this protonation reaction, 31P NMR experiments and DFT computations have been performed. Furthermore, the dibismuthate linker was utilized to obtain the coordination polymer {AgPS3BiCl3(OTf)2(CH3CN)2}?, in which dicationic Ag(PS3)22+ macrocycles containing five-coordinate silver centers connect the dianionic Bi2Cl6(OTf)22? dibismuthate fragments. The bonding situation in these dibismuthates has been investigated by single-crystal X-ray diffraction and DFT calculations (NBO analysis, AIM analysis, charge distribution).