On the Preparation and Properties of a Thiodi-Phosphorus (IV)-Acid Betaine

Abstract

On heating phosphorusi(v) sulfide in anhydrous pyridine the pentathiodiphosphorus(V) acid-P,P′-bis(pyrididium betaine), (C₅H₅N)₂P₂S_B (1), is formed (1,2). In 1 the P atoms are linked via an S atom. The nucleophilic degradation of the sultid P₄S_T by pyridine yields the new tetrathiodiphosphorus(IV) acid-P,P′-bis(pyrididium betaine), (C₅H₅N)₂P₂S₄ (2, which contains a direct P-P bond. 2 is already formed at room temperature on shaking ot P₄S_T with anhydrous pyridine for several days, resulting as a microcrystalline yellow solid in almost 50% yield. As has been proven by means of ³¹P NMH spectroscopy, P₄S_a is a further product of this reaction.