Halogenation of the Hexaphosphabenzene Complex [(Cp*Mo)₂(μ,η⁶:η⁶‐P₆)]: Snapshots on the Reaction Progress

Abstract

The oxidation of [(Cp*Mo)2(μ,η6:η6‐P6)] (1) with halogens or halogen sources was investigated. The iodination afforded the ionic complexes [(Cp*Mo)2(μ,η3:η3‐P3)(μ,η1:η1:η1:η1‐P3I3)][X] (X=I3−, I−) (2) and [(Cp*Mo)2(μ,η4:η4‐P4)(μ‐PI2)][I3] (3), while the reaction with PBr5 led to the complexes [(Cp*Mo)2(μ,η3:η3‐P3)(μ‐Br)2][Cp*MoBr4] (4) [(Cp*MoBr)2(μ,η3:η3‐P3)(μ,η1‐P2Br3)] (5) and [(Cp*Mo)2(μ‐PBr2)(μ‐PHBr)(μ‐Br)2] (6). The reaction of 1 with the far stronger oxidizing agent PCl5 was followed via time‐ and temperature‐dependent 31P{1H} NMR spectroscopy. One of the first intermediates detected at 193 K was [(Cp*Mo)2(μ,η3:η3‐P3)(μ‐PCl2)2][PCl6] (8) which rearranges upon warming to [(Cp*Mo)2(μ‐PCl2)2(μ‐Cl)2] (9), [(Cp*MoCl)2(μ,η3:η3‐P3)(μ‐PCl2)] (10) and [(Cp*Mo)2(μ,η4:η4‐P4)(μ‐PCl2)][Cp*MoCl4] (11), which could be isolated at room temperature. All complexes were characterized by single‐crystal X‐ray diffraction, NMR spectroscopy and their electronic structures were elucidated by DFT calculations.