The First Areneosmium(II) Complexes with Diarylcarbenes as Ligands

Using [(η6-mes)Os(κ1-O2CCF3)(κ2-O2CCF3)] (1) and diaryldiazomethanes as the starting materials, the half-sandwich-type carbeneosmium(II) complexes [(η6-mes)Os(κ1-O2CCF3)2(CR2)] (2a−c; R = p-C6H4X with X = H, Me, Cl) were prepared. The dichloro derivatives [(η6-mes)OsCl2(CR2)] (3a,b), obtained from 2a,b and Me3SiCl, react with PPh3 in the presence of AgPF6 to form the cationic compounds [(η6-mes)OsCl(CR2)(PPh3)]PF6 (5a,b); moreover, the π-allyl complex [(η6-mes)OsBr(η3-CH2CHCPh2)] (4) was prepared from 2a and CH2CHMgBr.