Complex Fluids Based on the Flexible One-Dimensional Mineral Polymers [K(MPS4)]∞ (M=Ni, Pd): Autofragmentation to Concave, Cyclic (PPh4)3[(NiPS4)3]

A remarkable autofragmentation/rearrangement sequence results in the unprecedented formation of inorganic concave cyclic anion [(NiPS4)3]3− (structure shown on the right) upon dissolving the potassium salt of the charged mineral polymer 1∞[NiPS4]− in DMF; the initial complex fluid has a transient anisotropic texture that can be identified by optical microscopy under polarized light. In contrast, the complex fluid that results upon dissolving 1∞[PdPS4]− is stable up to 323 K as persistent, flexible, charged chains.