CNR and CO insertion reactions of 2,6-xylyl isocyanide with p-chlorobenzylpentacarbonylmanganese

Stirring a solution of (CO)(5)MnCH2C6H4-p-Cl, 1, with 2 equiv of 2,6-xylyl isocyanide in toluene in the presence of a catalytic amount of PdO produced isocyanide insertion products I Ir including the bis(iminoacyl) (CO)(3)(CN -xylyl)Mn[C(=N-xylyl)C(=N-xylyl)CH2C6H4-p-Cl], 3, and the first octahedrall y based tris(iminoacyl) (CO)(4)Mn[C(=N-xylyl)C(=N-xylyl)C(=N-xylyl)-CH2C6H4 -p-Cl], 6. The same reaction in THF afforded the carbonyl insertion product (CO)(3)(xylyl-NC)(2)MnC(O)CH2C6H4-p-Cl, 9. Reaction of 1 with 1 equiv of x ylyl isocyanide in THF without PdO produced, the expected acyl (CO)(4)(CN-x ylyl)MnC(O)CH2C6H4-p-Cl, 11, along with a minor quantity of 3. Exposure of the reaction mixture to CO2 afforded the unique dimanganese species (CO)(4) Mn[C{=CH(C6H4-p-Cl)}N-(xylyl)C(O)OMn(CO)(4)[C(=NH-xylyl)-CH2C6H4-p-Cl], 12, in which the manganese centers are linked through a carbamato bridge. X-ra y structures of 3, 6, and 12 are reported.