Reactions of tris(2,6-dimethoxyphenyl) arsine, tris(2,6-dimethoxyphenyl) stibine and tris(2,6-dimethoxyphenyl) bismuthine and their derivatives

Tris(2,6-dimethoxyphenyl)arsine and tris(2,6-dimethoxyphenyl)stibine (phi(3)M(phi = 2,6-(MeO)(2)C6H3; M = As an Sb)) reacted with common alkyl halides (RX) to give [phi(3)M-R]X, while phi(3)Bi was unreactive in benzene, or it decomposed in hot alcohols. The reactions of (phi(3)M (As,Sb) with butyl bromide in acetonitrile were much faster than that of triphenylphosphine. Treatments of phi(3)M (P,As,Sb) with N-bromosuccinimide (NBS) gave [phi(3)M-OH]Br, while phi(3)Bi decomposed to give 1-bromo-2,6-dimethoxybenzene. [phi(3)M-OH]Br are soluble in water, and the acidity decreased in the order M = P > As > Sb. Treatments of phi(3)M (As,Sb) with aqueous hydrogen peroxide gave the oxides as hydrates, phi(3)MO. xH(2)O (x = 1 for M = As and x = 3 for M = Sb), while phi(3)Bi was unreactive or decomposed. phi(3)PO was brominated by NBS to give phi'3PO.H2O (phi' = 3-Br-2,6-(MeO)(2)C6H2), which did not react with perchloric acid. In contrast, phi(3)MO.xH(2)O (P,As,Sb) reacted with the acid to form the stable hydroxyonium salts [phi(3)M-OH]ClO4. [phi(3)P-OH]ClO4 formed crystals of stable 1:1 adducts with a variety of amines. [phi(3)As-OH]ClO4 formed 1:1 adducts when treated with excess amounts of several amines (triethylamine,diethylamine,isobutylamine and piperidine), but they were unstable to leave amines by recrystallization. [phi(3)Sb-OH]ClO4 formed unstable adducts with these amines, or it did not form. [phi(3)P-SH]ClO4 formed 1:1 adducts with several amines, or it was deprotonated to give phi(3)PS. phi(3)MO.xH(2)O (P,As) reacted with common RX (X = Br or I) to give [phi(3)M-OR]X, but phi(3)SbO.3H(2)O reacted to give [phi(3)Sb-OH]X. [phi(3)P-OR]X decomposed reversibly to give phi(3)PO in solutions, although [phi(3)M-OR]ClO4 (P,As) could be recrystallized.