Tetrakis(trimethysilyl)hypophosphate P2O2(OTMS)4: Synthesis, reactivity and application as flame retardant



The preparation of tetrakis(trimethy- silyl)hypophosphate, P2O2(OTMS)4 (TMS = SiMe3), which is easily obtained from cheap starting materials, is reported. Reaction with protic substrates (H2O, alcohols) proceeds under stepwise cleavage of silylethers, ROTMS, and formation of hypophosphoric acid, P2O2(OH)4. Amines in the presence of molecular sieves lead to desilylation and formation of ammonium salts of the [P2O2(OTMS)2(O)2] dianion. On cotton fabrics, P2O2(OTMS)4 hydrolyzes to give P2O2(OH)4 within about 1 h when exposed to air, and this compound acts as an efficient flame retardant (limiting oxygen index >26%) even at low loadings (P content <3%). © 2007 Wiley Periodicals, Inc. Heteroatom Chem 18:721–731, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.20373