Synthesis of Mn(III)X 3 (X = Cl, Br, I) Compounds with Phosphine (R 3 P) Ligands.

This work details the synthesis and characterization of complexes of the form [Mn III X 3 (PR 3 ) 2 ] (X = Cl, Br, I), which is a rare type of coordination compound. Prior to this work, the only mode of synthesis was oxidizing mixtures of Mn II X 2 and PR 3 with dry air, but these procedures give low yields and variable outcomes. By taking advantage of the starting material [Mn III Cl 3 (OPPh 3 ) 2 ] ( 1 ) and other new strategies, we present robust synthetic protocols for both new and known Mn(III) halido phosphine complexes. In addition to [Mn III X 3 (PR 3 ) 2 ], these include [Mn III Cl 2 (dmpe) 2 ] + salts and [LMn II X 3 ] - manganates (L = phosphine oxide). Furthermore, the full characterization of these [Mn III X 3 (PR 3 ) 2 ] species enabled a definitive revisitation of some controversial chemistry surrounding the compounds and products from the dry air oxidation of certain Mn II X 2 and phosphine ligand mixtures.