The reaction of manganese carbonyl with tert-butylisocyanide: Synthesis and characterization of cis- and trans-[Mn I( tBuNC) 4(CN)(CO)

Abstract

The reaction of Mn 2(CO) 10 with tert-butyl isocyanide in the presence of 10 bar of carbon monoxide leads to the formation of cis- and trans-[Mn( tBuNC) 4(CN)(CO)], 1a and 1b, in good yields together with [Mn( tBuNC) 6]CN ( 2), as a minor product. Nevertheless, the reaction pathway highly depends on the reaction conditions. An interesting side-product is obtained, if chloroform is used during the workup procedure. Compound 3 is composed of cationic [Mn( tBuNC) 5(CO)] units as well as dinuclear anionic [Mn( tBuNC) 4(CO)(μ–CN)MnCl 3] moieties. If no additional CO pressure is applied to the system, the organic product N, N′-di- tert-butyl-3,5-bis- tert-butylimino-4-phenyl-cyclopent-1-ene-1,2-diamine ( 4), is formed in considerable amount. Compound 4 most probably is produced via a double benzylic C–H activation of the solvent toluene and the oligomerization of four isocyanide moieties. The reaction of 1b with Co(NO 3) 2 leads to the isolation of the trinuclear cyanide bridged coordination compound {[Mn( tBuNC) 4) (CO) (μ–CN)] 2Co(NO 3) 2}, 5, in which the cobalt atoms are tetrahedrally surrounded by the two cyanide ligands and the η 1-coordinated nitro groups. In contrast to the reaction of 1b, treatment of the dicyano complexes cis- or trans-[Ru( tBuNC) 4(CN) 2] with Co(NO 3) 2 results in the formation of the coordination polymers {[Ru( tBuNC) 4(CN) 2]Co(NO 3) 2} n , 7 ( trans) and 9 ( cis). All new compounds are characterized by X-ray diffraction experiments.