Electrophilic Functionalization of a Hexaphosphabenzene Ligand in [(Cp*Mo) 2 (μ,η 6 : 6 -P 6 )].

The electrophilic functionalization of the triple-decker sandwich complex [{Cp*Mo} 2 (μ,η 6:6 -P 6 )] (A) and its mono-oxidized counterpart [{Cp*Mo} 2 (μ,η 6:6 -P 6 )][SbF 6 ] (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,η 3 : 3 -P 3 )(μ,η 1 : 1 : 1 : 1 -1,3-(SePh) 2 -2-Br-P 3 )}][TEF] (1), [{Cp*Mo} 2 (μ,η 3 : 3 -P 3 )(μ,η 1 : 1 : 1 : 1 -1,2,3-(EPh) 3 -P 3 )][SbF 6 ] (E=S (2), Se (3)) as well as the side product [{Cp*Mo} 2 (μ,η 4:4 -P 4 )(μ,η 1 : 1 -P(SPh) 2 )][SbF 6 ] (4) are obtained. By switching to phosphenium ions as group 15 electrophiles, the ring-inserted products [{Cp*Mo} 2 (μ,η 3 : 3 : 2 : 2 -P 7 R 2 )][TEF] (R=Cy (5), i Pr (6)) are isolated, showing an unprecedented P 7 R 2 structural motif. Furthermore, the reaction with MeOTf yields the dimeric [{Cp*Mo} 4 (1,4-Me 2 -μ 4 ,η 1 : 1 : 1 : 1 : 1 : 1 -P 6 )(μ,η 3 : 3 -P 3 ) 2 ][TEF] 2 (7) as the first example of a complex featuring two interconnected cyclo-P 6 middle deck ligands. Finally, by combination of the methylation step with Ph 2 Se 2 , the mixed group 14/16 complex [{Cp*Mo} 2 {(μ,η 3 : 3 -P 3 )(μ,η 1 : 1 : 1 : 1 1,2-(SePh) 2 -3-Me-P 3 )}][OTf] (8) is obtained.