Novel manganese(II) complexes formed from the reaction of a coarse-grain, unactivated manganese powder with Pl2(NMe2)3 and Pl2(C6H4SMe-o)3; crystal structure of the dinuclear complex [{Mnl2[P(NMe2)3]}2]

Abstract

The reaction of Pl₂R₃(R = NMe₂ or C₆H₄SMe-o) with manganese metal powder has been studied. In agreement with previous studies, the nature of the products is highly dependent on R, and thus gives further evidence of the subtle nature of the reaction of diiodotriorganophosphorus compounds with metal powders. When R = NMe₂, the dinuclear complex [{Mnl₂[P(NMe₂)₃]}₂] is obtained, whereas when R = C₆H₄SMe-o a monomeric complex is obtained in which the phosphine acts as a chelating ligand. These results are in direct contrast to previously characterised phosphine complexes of this stoichiometry in which a polymeric complex is produced and which reversibly binds dioxygen. The complex [{Mnl₂[P(NMe₂)₃]}₂] has been crystallographically characterised and represents the first example of a dimeric species of this stoichiometry. Conductance and magnetic studies and the Raman spectrum of the complex [Mnl₂{P(C₆H₄SMe-o)₃}] indicate that a monomeric tetrahedral complex is produced in which the phosphorus and one sulfur atom chelate to the manganese centre.