Synthesis, some properties and structural features of 1,2-thiaphosphacyclanes

Synthetic routes to 1,2-thiaphosphacyclanes bearing both tri- and tetracoordinate phosphorus atoms, and their reactivity and structural features based on data from X-ray diffraction analysis are discussed. Particular emphasis is placed on the rare case of ring-chain halogenotropic tautomerism in the series of 1,2-thiaphosphacyclanium salts and related compounds.