Electrophilic Functionalization of a Hexaphosphabenzene Ligand in [(Cp*Mo)2(μ,η6 : 6‐P6)]

Abstract

AbstractThe electrophilic functionalization of the triple‐decker sandwich complex [{Cp*Mo}2(μ,η6:6‐P6)] (A) and its mono‐oxidized counterpart [{Cp*Mo}2(μ,η6:6‐P6)][SbF6] (B) with reactive main‐group electrophiles as well as radical scavengers is shown to be a reliable method for the selective functionalization of the hexaphosphabenzene ligand. Depending on the electrophile used, the regioselectivity of the functionalization can be adjusted. Using group 16 electrophiles, the trisubstituted compounds [{Cp*Mo}2{(μ,η3 : 3‐P3)(μ,η1 : 1 : 1 : 1‐1,3‐(SePh)2‐2‐Br‐P3)}][TEF] (1), [{Cp*Mo}2(μ,η3 : 3‐P3)(μ,η1 : 1 : 1 : 1‐1,2,3‐(EPh)3‐P3)][SbF6] (E=S (2), Se (3)) as well as the side product [{Cp*Mo}2(μ,η4:4‐P4)(μ,η1 : 1‐P(SPh)2)][SbF6] (4) are obtained. By switching to phosphenium ions as group 15 electrophiles, the ring‐inserted products [{Cp*Mo}2(μ,η3 : 3 : 2 : 2‐P7R2)][TEF] (R=Cy (5), iPr (6)) are isolated, showing an unprecedented P7R2 structural motif. Furthermore, the reaction with MeOTf yields the dimeric [{Cp*Mo}4(1,4‐Me2‐μ4,η1 : 1 : 1 : 1 : 1 : 1‐P6)(μ,η3 : 3‐P3)2][TEF]2 (7) as the first example of a complex featuring two interconnected cyclo‐P6 middle deck ligands. Finally, by combination of the methylation step with Ph2Se2, the mixed group 14/16 complex [{Cp*Mo}2{(μ,η3 : 3‐P3)(μ,η1 : 1 : 1 : 11,2‐(SePh)2‐3‐Me‐P3)}][OTf] (8) is obtained.