Syntheses of cationic tri- and di-carbonyl complexes of manganese(I) with diphosphines from the appropriate neutral bromocarbonyls

Abstract

Reaction of the complexes fac-[MnBr(CO)₃(L–L)][L–L = Ph₂P(CH₂)_nPPh₂, n= 1 (dppm) or 2 (dppe)] with phosphorus-donor ligands, L, leads to the complexes cis,cis-[MnBr(CO)₂(L–L)L]. These neutral dicarbonyls are oxidized by NO₂ or [NO][PF₆] to the unstable cationic species trans-[MnBr(CO)₂(L–L)L]⁺ which may be isolated as hexafluorophosphate salts and which lead to the neutral trans-[MnBr(CO)₂(L–L)L] when reduced by hydrazine. Replacement of the bromo-ligand in either cis,cis- or trans-[MnBr(CO)₂(L–L)L], using TI[PF₆] in the presence of another ligand L′(N or P donor), results in the formation of cis,cis- or trans-[Mn(CO)₂(L–L)LL′][PF₆] respectively, or of mer-[Mn(CO)₃(L–L)L][PF₆] if L′= CO. However, using Ag[CIO₄] as the halogen abstracter, the perchlorate salts of the cis,cis-cationic dicarbonyls (or the mer tricarbonyls) are obtained regardless of the neutral bromocarbonyl isomer used.