Preparation of halogenated arene complexes and their dehalogenation for further metallation

79-85Reaction of tris(acetonitrile)molybdenumtricarbonyl [Mo(CO)3(CH)CN)3] and 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), [C6(CH2Br)6Mo(CO)3] (5), [C6H2(CH2Br)4Cr(CO)3] (6) and [C6(CH2Br)6Cr(CO)3] (7) respectively. The halogenated arene complexes (4), (6) and (5) on treatment with Na2[Fe(CO)4] at room temperature form of the complexes [C6H2(CH2)4 { Fe(CO)4}2Mo(CO)3] (8), [C6H2(CH2)4{Fe(CO)4}2Cr(CO)3] (9) and [C6(CH2)6 {Fe(CO)4}3 Mo(CO)3] (10) respectively. The complexes have been characterized by IR, 1H NMR and mass spectral data