Preparation and physico-chemical properties of bis(salicylaldehyde hydrazonato)-iron(III), manganese(III) and chromium(III) iodides

Abstract

Bis(salicytaldehyde hydrazonato)iron(llI) iodide has been prepared by reduction of tris(salicylaldehyde hydrazonato)iron(III) with hydrazine in dimethylformamide solution followed by reaction with methyl iodide. This reaction has been shown to involve an iron(I) chelate intermediate. Reaction of bis(salicylaldehyde hydrazonato)iron(II) with iodine in dimethylformamide solution also leads to formation of bis(salicylaldehyde hydrazonato)iron(III) iodide. The reaction of methyl iodide with a dimethylformamide solution of bis(salicylaldehyde hydrazonato)manganese(II) and hydrazine leads to the formation of bis(salicylaldehyde hydrazonato)- manganese(III) iodide which can also be obtained by reaction of the manganese(II) chelate with iodine. The reduction pathway has been shown to involve the formation of a manganese(O) hydrazine chelate while the use of hydroxylamine, sodium borohydride and sodium dithionite for the reduction of the manganese(II) chelate lead to the formation of a manganese(i) intermediate. Bis(salicylaldehyde hydrazonato)chromium(III) nitrate forms as a result of the reaction of hydrated chromium(III) nitrate with salicylaldehyde hydrazone in dimethylformamide and has been used to prepare the corresponding iodide, chloride, bromide, thiocyanate and cyanide by anion exchange reactions in dimethylformamide. Each product has been characterized by the observation of well resolved ESR spectra.