Novel condensed thionated bis(phosphonic) acid salts with a rigid naphthalene-1,8-diyl backbone.

New salts of thionated (naphthalene-1,8-diyl)bis(phosphonic) acid monoanhydrides [PPh4+](2)[C10H6PS2(mu-S)PS22-] (2) and [K+](2)[C10H6PS2(mu-S)POS2-]. H2O (3) both containing the C3P2S ring, were prepared in high yields by the reaction of 2,4-(naphthalene-1,8-diyl)-1,3,2,4-dithiadiphosphetane 2,4-disulfide (1) with NaHS and PPh4Cl, or KOH, respectively, in water. The derivative 3, containing a P=O terminal bond as well as P-S-P bridge, undergoes, in acid conditions, a rearrangement reaction leading to the O,S-symmetrically substituted derivative [K+](2)[C10H6PS2(mu-O)PS22-] (4) containing a C3P2O heterocycle. Dipotassium salt 4 was converted into the bis (tetraphenylphosphonium) salt 5 by the treating with PPh4Cl. Hydrolysis of [PyH+][C10H6P(S)(NHMe)(mu-S)PS22-] (15) led to [CH3NH3+][PyH+][C10H6POS(mu-O)POS2-]. 1.5 Py (6), New compounds were characterised by P-31{H-1}-, H-1- and C-13{H-1}-NMR, FT-IR, ES-MS and in the cases 2-6 by X-ray structure determination. The P-31{H-1}-NMR spectra of these mixed O,S-derivatives are briefly discussed.