Preparation of halogenated arene complexes and their dehalogenation for further metallation

Abstract

Reaction of <i>tris</i>(acetonitrile)molybdenumtricarbonyl [Mo(CO)₃(CH)CN)₃] and tris(acetonitrile)chromiumtricarbonyl [Cr(CO)₃(CH₃CN)₃] with 1,2,4,5-<i>tetrakis </i>(bromomethyl) benzene and 1,2,3,4,5.6-hexakis(bromomethyl )benzene yield complexes

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