Preparation of halogenated arene complexes and their dehalogenation for further metallation

Reaction of tris(acetonitrile)molybdenumtricarbonyl [Mo(CO)(3)(CH3CN)(3)] a nd tris(acetonitrile)chromiumtricarbonyl [Cr(CO)(3)(CH3CN)(3)] with 1,2,4,5 -tetrakis (bromomethyl) benzene and 1,2,3,4,5,6-hexakis(bromomethyl)benzene yield complexes [C6H2(CH2Br)(4)Mo(CO)(3)] (4), [C-6(CH2Br)(6)Mo(CO)(3)] (5 ), [C6H2(CH2Br)(4)Cr(CO)(3)] (6) and [C-6(CH2Br)(6)Cr(CO)(3)] (7) respectiv ely. The halogenated arene complexes (4), (6) and (5) on treatment with Na- 2[Fe(CO)(4)] at room temperature form of the complexes [C6H2(CH2)(4)(Fe(CO) (4))(2)Mo(CO)(3)] (8), [C6H2(CH2)(4)(Fe(CO)(4))(2) Cr(CO)(3)](9) and [C-6(C H2)(6) (Fe(CO)(4))(3)Mo(CO)(3)] (10) respectively. The complexes have been characterized by IR, H-1 NMR and mass spectral data.