The reaction of the tertiary phosphine sulfides R_3PS (R = Ph, Me_2N or C_6H_(11)) with X_2(X_2 = I_2, Br_2, IBr or ICl; structural characterisation of the CT complexes (Me_2N)_3)PSI_2 and Ph_3PS(I_(0.89)Br_(0.11)) Br and the ionic compound ({(Me_2N)

摘要

The reactions of the tertiary phosphine sulfides R_3PS (R = Ph, Me_2N or C_6H_(11)) with X_2(X = I, or Br) and IX(X = Br or Cl) have been studied. Reaction of R_3PS with I_2 or IX results in quantitative isolation of the CT complexes R_3PSIX (X = I, Br or Cl) except for Ph_3PS with I_2 which produces the unusual compound (Ph_3PSI_2)_2I_2, which has been crystallographically characterized by earlier workers. The crystal structure of (Me_2N)_3PSI_2 has been determined and compared to Ph_3PSI_2, previously described. The greater d(I-I) for (Me_2N)_3PSI_2, 2.856 (1)A, compared to that of 2.823 (1)A for Ph_3PSI_2 clearly illustrates that d(I-I) in R_3PSI_2 compounds is sensitive to R, although this effect is less pronounced when compared to that of analogous R_3PSeI_2 compounds. The crystal structure of the product from the reaction of Ph_3PS with IBr has also been determined and represents the first example of a tertiary phosphine sulfide interhalogen CT complex. It has the formula Ph_3PS(I_(0.89)Br_(0.11))Br and is isomorphous with Ph_3PSI_2. The reaction of R_3PS with Br_2 is complex. In the case of Ph_3PS, phosphorus-sulfur bond cleavage occurs quantitatively to produce Ph_3PBr_2 and elemental sulfur. Reaction of (Me_2N)_3PS with Br_2 gives, as one product, [{(Me_2N)_3PS}_2S][Br_3]_2 in moderate (ca.30%) yield. this unusual dication is compared to the previously reported [(Mu_3~tPTe)_2Te][SbF_6]_2. Tricyclohexylphosphine sulfide reacts with Br_2 in solvents of low relative permittivity (Et_2O) to produce the 1:1 addition complex (C_6H_(11))_3PSBr_2; however, dissolution of this material in solvents of higher relative permittivity results in phosphorus-sulfur bond cleavage to produce (C_6H_(11))_3PBr_2 and elemental sulfur.