Synthesis, characterization, reactivity and molecular structure of arene-osmium complexes: A new synthetic entry into (η6-arene)osmium(II) chemistry

A new convenient one-pot procedure for the preparation of the p-cymene-osmium dimer [(η6-p-MeC6H4Pri)OsBr2]2 (1) from potassium osmate K2[OsO2(OH)4] is described. The analogous hexamethylbenzene complex [(η6-C6Me6)OsBr2]2 (2) and a series of new arene-osmium complexes [(η6-p-MeC6H4Pri)OsLBr2] (3–9) (L = CO, PPh3, PEt3, PMePh2, P(OMe)3, P(OBun)3 and P(OPh)3) have been prepared from 1. The complex [(η6-C6Me6)Os(CO)Br2] (10) was obtained from 2. All the complexes were characterized spectroscopically by NMR and IR and by elemental analysis. Single crystal X-ray structures of [(η6-p-MeC6H4Pri)OsBr2]2 (1) and [(η6-p-MeC6H4Pri)Os(PPh3)Br2] (3) are reported. The reactions of some of these complexes with BrMg(CH2)3CHCH2 and MeLi are also described.

Graphical abstractA novel method for the preparation of areneosium complexes from K2[OsO2(OH)4] is described. The characterization and reactivity of these complexes are reported and single crystal X-ray structures of [(η6-p-MeC6H4Pr′)OsBr2]2 and [(η6-p=-MeC6H4Pr′)Os(PPh3)Br2] are resented.Figure optionsDownload full-size imageDownload as PowerPoint slide