Dimethylphosphinato and dimethylarsinato complexes of Sb(III) and Bi(III) and their chemistry

Dioxygen activation by Bi(III) compounds: Air oxidation of thiols to their disulfides

“…Also, it is worth noting that at 10 mol% loading of 3, traces of Me 2 As-SPh were produced in Et 2 O, a little in DMF but significant amounts in CHCl 3 . By IR(KBr), the recovered catalyst was 3 and not the rearranged one 4 [16]. The activity of 10 mol% 3 in acetone for the air oxidation of PhSH remained unchanged (decolorization time: 3.5-4.0 h) in five consecutive runs while its recoveries were very good (83-96%).…”

“…In a previous work [16] it was discovered that in the presence of 3 molar equivalents of thiophenol, the complex Sb(Me 2 AsO 2 ) 3 gave Sb(Me 2 AsO 2 ) 3 (30%), (Me 2 AsO 2 -SbO) x (60%) and nearly equimolar quantities of Me 2 As-SPh and PhSSPh; the complex Bi(Me 2 AsO 2 ) 3 gave (Me 2 AsO 2 -BiO) x (93%), Me 2 As-SPh and PhSSPh (0.6 : 1.0 molar ratio), but the complex (Me 2 AsO 2 ) 2 Bi(NO 3 )·H 2 O 3 gave quantitatively 3 and PhSSPh. In the latter case it was demonstrated that dioxygen was involved in the oxidation of thiophenol to diphenyl disulfide.…”

“…The preparations of bismuth subnitrate monohydrate 2 [15], of the complex (Me 2 AsO 2 ) 2 Bi(NO 3 )·H 2 O 3 [16] and of the rearranged complex (Me 2 AsO 2 ) 2 Bi(NO 3 )·H 2 O 4 [16] have been described. The aliphatic thiols were obtained as described [14] and used as received.…”

“…Finally, the results obtained upon the addition of thiophenol to M(Me 2 AsO 2 ) 3 (M = Sb and Bi) [16], mentioned in the Introduction, can be explained by assuming displacement of cacodylate(s) which are quickly reduced to Me 2 As-SPh and PhSSPh by thiophenol. From the distribution of products it seems that (Me 2 AsO 2 )Bi(SPh) 2 was more reactive than the antimony analogue in binding and activating 3 O 2 .…”

“…Based on the novel results obtained with 3 and thiophenol, in this paper we report on the ability of (Me 2 AsO 2 ) 2 Bi(NO 3 )·H 2 O 3 and its rearranged form 4, both of unknown crystal structure [16], to act as catalysts for autoxidation of a greater variety of aromatic and of bifunctional aliphatic thiols to their disulfides using the simple nitrate Bi(NO 3 ) 3 ·5H 2 O 1 [22,24] as a control. In order to get a better understanding of the process, aliphatic [14,17] and aromatic [15,17] thiolates of Bi(III) were prepared starting from 1 and 2 and the thiols encountered in this work, Figs.…”