σ-Bonded organotransition-metal ions. Part V. The formation of mono- and di-halogenomethylchromium(III) lons and their reaction with mercuric nitrate

Abstract

Air-stable dihalogenomethylchromium(III) ions are the main products of reduction of chloroform, bromoform, and iodoform with less than two equivalents of chromous perchlorate or fluoroborate. With four or more equivalents of chromous perchlorate the main products are the corresponding air-stable monohalogenomethylchromium(III) ions. Methylchromium(III) ion cannot be detected in the products. These six organochromium(III) ions react with mercuric nitrate; the monochloro- and monobromo-methylchromium(III) ions lead to the corresponding monohalogenomethylmercury(II) ions, in good yield, through attack of mercury(II) on carbon, but in the other four cases the main product is mercurous ion formed after attack of mercury(II) on halogen. The mechanisms of the reduction processes are discussed in relation to the corresponding reductions with chromous sulphate and chloride, from which stable organochromium ions cannot be obtained.