A new class of eight-membered Sn2P2O4 heterocycles. Crystal structure and electrolytic dissociation in solution of cyclo-[R2Sn(OPPh2O)2SnR2](O3SCF3)2(R=Me, t-Bu)

The syntheses of <i>cyclo</i>-[R₂Sn(OPPh₂O)₂SnR₂](O₃SCF₃)₂ (R = Me (<b>1</b>), <i>t</i>-Bu (<b>2</b>)) by the consecutive reaction of R₂SnO (R = Me, <i>t</i>-Bu) with triflic acid and diphenylphosphinic acid are presented. In the solid state, <b>1</b> and <b>2</b> were investigated by ¹¹⁹Sn MAS and ³¹P MAS NMR spectroscopy as well as X-ray crystallography and appear to exist as ion pairs of <i>cyclo-</i>[R₂Sn(OPPh₂O)₂SnR₂]²⁺ dications and triflate anions. In solution, <b>1</b> and <b>2</b> are involved in extensive equilibria processes featuring cationic diorganotin(IV) species with Sn-O-P linkages, as evidenced by ¹¹⁹Sn and ³¹P NMR spectroscopy, electrospray mass spectrometry, and conductivity measurements. <br />