Organische Phosphorverbindungen XXXVIII. Darstellung und Eigenschaften von Tris‐(dialkoxyphosphonyl‐methyl)‐, Tris‐(alkoxyphosphinyl‐methyl)‐und Tris‐(oxophosphoranyl‐methyl)‐phosphinsäureestern sowie der entsprechenden Säuren [1]

Tris‐chloromethyl‐phosphine oxide, (ClCH 2)3 PO(I), is obtained by chlorination of (HOCH 2)3 PO with PCl 5 or (C 6 H 5)3 PCl 2 , and also by oxidation of (CICH 2)3 PO and (ClCh 2)2 (CH 3 )PO. High yields of tris‐(dialkyloxyphosphonly‐methyl)‐phosphine oxides, [RO 2 (O)PCH 2]2 PO (II) (RCH 3 , C 2 H 5 , iso ‐C 3 H 7 , n ‐C 4 H 9 , 2‐ ethyl‐hexyl), tris (alkyloxyphosphinyl‐methyl)‐phosphine oxides, [R 2 (O)PCH 2]3 PO(R = C 6 H 5 , CH 3 ) are obtained by heating tris‐chloromethyl‐phosphine oxides, [(RO) (R′) (O)PCH 2]3 PO (R = C 4 H 9 , R′ C 6 H 5 ) and tris‐(oxophosphoranyl‐phosphine oxides with phosphites, phosphonites and phosphinites, respectively, at 170–180°C for several hours. Compounds II possess an extraordinarily high absorption capacity. Thus a warm. 2% solution of II (R = C 2 H 5 ) in benzene solidifies completely on cooling so that no benzene can be poured off. Tris‐dihydroxyphosphonyl‐methyl)‐phosphine oxide, [(HO) 2 (O)PCH 2]3 PO, obtained by hydrolysis of II (R C 2 H 5 ) with refluxing conc. HCl or by thermal decomposition of II (R iso ‐C 3 H 7 ) at 190°, titrates in aqueous solution as a hexabasic acid with breaks at pH = 4,4 (three equivalents) and pH = 10,7 (three equivalents). It forms crystalline salts with amines, alkali and alkaline earth metals, and is an excellent chelating agent. The 1 H‐ and 31− P‐NMR. spectra of all the compounds prepared are discussed.