Reactions of carbon monoxide with Fe(II) diethyldithiocarbamate and Fe(II) ethylxanthate

Abstract

Reactions of carbon monoxide with iron(II) diethyldithiocarbamate and iron(II) ethylxanthate were followed using solution IR spectroscopy. In DMF and CH 3CN solutions, the only Fe—dithiocarbamate—carbon monoxide complex observed was cis-[Fe(CO) 2(dedtc) 2]. This complex formed rapidly and appeared to be very stable, resisting displacement of the coordinated CO molecules by other ligands. Fe(exa) 2 showed very little coordination of CO in DMF solution, but in CH 3CN solution formed the complex cis-[Fe(CO) 2(exa) 2] rapidly via the monocarbonyl intermediate [Fe(CO)(exa) 2CH 3CN]. In CHCl 3 solution, in the presence of CO and added bases, a series of complexes, [Fe(CO)(exa) 2L], where L = pyridine, pyrrolidine, diethylamine and triphenylphosphine, was formed. However, with the exception of [Fe(CO)(exa) 2(ø 3P)], these monocarbonyl complexes were unstable with respect to disproportionation to cis-[Fe(CO) 2(exa) 2] and [Fe(exa) 2L 2]. No mixed-ligand monocarbonyl complexes were observed with Fe(dedtc) 2.