Synthesis of Mn(III)X₃ (X = Cl, Br, I) Compounds with Phosphine (R₃P) Ligands

This work details the synthesis and characterization of complexes of the form [MnIIIX3(PR3)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 MnIIX2 and PR3 with dry air, but these procedures give low yields and variable outcomes. By taking advantage of the starting material [MnIIICl3(OPPh3)2] (1) and other new strategies, we present robust synthetic protocols for both new and known Mn­(III) halido phosphine complexes. In addition to [MnIIIX3(PR3)2], these include [MnIIICl2(dmpe)2]+ salts and [LMnIIX3]− manganates (L = phosphine oxide). Furthermore, the full characterization of these [MnIIIX3(PR3)2] species enabled a definitive revisitation of some controversial chemistry surrounding the compounds and products from the dry air oxidation of certain MnIIX2 and phosphine ligand mixtures.