The co-ordination of small molecules by manganese(II) phosphine complexes. Part 8. Irreversible oxidation of trimethylphosphinemanganese(II) dihalides, [MnX2(PMe3)](X = Cl, Br, or I), to bis(trimethylphosphine)manganese(III) trihalides, [MnX3(PMe3)2]. X-Ray crystal structure of trans-tri-iodobis-(trimethylphosphine)manganese(III), the first example of a trigonal-bipyramidal manganese(III) tertiary phosphine complex

Abstract

Unlike previously reported complexes [MnX₂(PR₃)](R = alkyl, but not Me) which reversibly bind molecular oxygen, [MnX₂(PMe₃)](X = Cl, Br, or I) react irreversibly with dioxygen either in the solid state or in diethyl ether to give products from which can be sublimed [MnX₃(PMe₃)₂](after sublimation only inorganic products remain). An X-ray crystal-structure determination of [MnI₃(PMe₃)₂] reveals a trigonal-bipyramidal geometry with three equatorial I atoms and two axial P atoms [Mn–I, 2.605(6)–2.635(3)Å; Mn–P, 2.43(1)–2.44(1)Å].