Homoleptic carbonyl cations of palladium(I), palladium(II), platinum(II), and gold(I)—simplified synthetic routes to their fluoroantimonate(V) salts

Abstract

The original synthetic routes to the new noble metal carbonyl cations [Au(CO)2]+ and [M(CO)4]2+, M = Pd or Pt, as [Sb2F11]−salts are multi-step procedures that involve corrosive reagents and require commercially unavailable starting materials. We report here two general simplifications: (i) the sole use of liquid antimony(V) fluoride as reaction medium in a single-step carbonylation process, and (ii) the use of the commercially available chlorides AuCl3 and MCl2, M = Pd or Pt, as starting materials, in addition to the binary fluorosulfates Au(SO3F)3, Pd[Pd(SO3F)6], and Pt(SO3F)4. The simplified routes developed here for [Au(CO)2][Sb2F11] and [M(CO)4][Sb2F11]2, M = Pd or Pt, should make these new reagents more easily available for wider use in synthesis. In addition, these routes are found suitable for the generation of new carbonyl cations of electron-rich metals. Key words: metal carbonyl cations of Au(I), Pd(I), Pd(II), and Pt(II); solvolysis reactions in liquid SbF5, reductive carbonylation in liquid SbF5; carbonylations in strong acidic media.