Disproportionation of Diethylarsanyl N,N-Diethyl(3,5-di-tert-butyl-4-hydroxyphenyl)-phosphonamidodithioate

Abstract

S-Organoelement derivatives of four-coordinate phosphorus thioacids containing a P(S)SE fragment (E = P, As) often exhibit low thermal stability. In particular, diorganylphosphanyl N,N-dialkylarylphosphonamidodithioates with the R 2 N3P(S)S3P< fragment, regarded as the products of insertion of monomeric fragments of 2,4-diaryl-1,3,2,4-dithiadiphosphetane 2,4-disulfides into the N3P bond of aminophosphines, transform under heating to the sulfides of the starting aminophosphines and the products of condensation of arylmetadithiophosphonates [1]. We have previously prepared diorganylarsanyl N,N-dial-ÄÄÄÄÄÄÄÄÄÄÄÄ kylarylphosphonamidodithioates containing an R 2 N3 P(S)S3As< fragment by the reactions of 2,4-diaryl-1,3,2,4-dithiadiphosphetane 2,4-disulfides with aminoarsines [2]. We found that, contrary to the compounds with the R 2 N3P(S)SP< fragment, diethylarsanyl N,Ndiethyl(3,5-di-tert-butyl-4-hydroxyphenyl)phosphonamidodithioate I disproportionates at 70oC within 1 h to form crystalline bis(diethylarsanyl) 3,5-di-tert-butyl-4-hydroxyphenylphosphonotrithioate II. The second reaction product, N,N,N`,hydroxyphenylphosphonothiodiamide III, could not be isolated because of its lability [reaction (1)]. 2Ar!P i e S!AsNEt 2 NEt 2 o S %$ Ar!P(SAsEt 2 ) 2 + Ar!P(NEt 2 ) 2 , o S o S I II III 4 R T S Q . c HO Ar = (1) ÄÄÄÄÄÄÄÄÄÄÄÄThe structure of II was comfirmed by an independent synthesis from 2,4-bis(3,5-di-tert-butyl-4-hy-: droxyphenyl)-1,3,2,4-dithiadiphosphetane 2,4-disulfide IV and bis(diethylarsanyl) sulfide V at~20oC for 1 h [reaction (2)].The physicochemical constants and spectral characteristics of samples of II prepared by these two i e S S o S Ar!P e i P!Ar o S + 2(Et 2 As) 2 S %$ 2II, IV V 4 R T S Q .c HO Ar = (2)