Synthesis and reactivity of new cyclomanganated (eta(6)-arene)tricarbonylchromium complexes

(eta(6)-Arene)tricarbonylchromium complexes derived from N,N-dimethylbenzylamine or from benzyl methyl thioether undergo a cyclomanganation reaction when treated with PhCH(2)-Mn(CO)(5) in boiling heptane. The manganation process is selective and involves solely aromatic C-H bond activation that yields bimetallic and trimetallic compounds, respectively, when compounds such as [(eta(6)-C(6)H(5)CH(2)R)Cr(CO)(3)] (R = N(CH3)(2), SCH3) and the diamine [{eta(6)-C6H4-1,3-[CH2N(CH3)(2)]}Cr(CO)(3)] are reacted. Cases of transmetalation reactions consisting of the transfer of a Mn(CO)(4) moiety froth one aromatic ligand to another are observed with free aromatic ligands and with chromium pi-complexed ligands. Two examples of bimetallic and trimetallic compounds, [(2-eta)-Mn{[eta(6)-3,5-(CH3O)(2)-C6H2-CH2N(CH5)(2)]Cr(CO)(3)}(CO)(4)] (2) and [(4-eta:6-eta)-{Mn(CO)(4)}(2){{eta-C6H2-1,3[CH2N(CH3)(2)](2)}Cr(CO)(3)}] (6a), respectively, were characterized by X-ray diffraction analysis. Both complexes bear distorted Mn(CO)(4) units with the ancillary amino ligand pointing away from the chromium.