The chemistry of iron-tris(dimethylphosphinomethyl)methylsilane complexes: crystal structure of the compound [{Fe((Me 2PCH 2) 3SiMe)} 2(μ-H) 2(μ-CCH 2)] with a vinylidene group which is derived from ethylene

Abstract

The ability of the tri-tertiary-phosphine tris(dimethylphosphinomethyl)methylsilane (tmps) to act as a ligand in a variety of iron compounds has been explored. Tmps reacts with [Fe(η-C 6H 6)(PMe 3) 2] giving [Fe(η 4-C 6H 6)(tmps)]. The η 4-C 6H 6 ligand of this compound is readily displaced by carbon monoxide, cyclopentadiene, cyclohexa-1,3-diene, disubstituted acetylenes or ethylene giving [Fe(tmps)(CO) 2], [Fe(η-C 5H 5)H(η 2-tmps)], [Fe(η-C 6H 8)(tmps)], [Fe(η-RCCR)(tmps)] (R,R′  Ph, Ph; Me, Me; Me, Et; Et, Et or Me 3Si, Me 3Si) or [{Fe(tmps)(μ-H)} 2(μ-CCH 2)], respectively. The formation of the μ-vinylidene compound directly from ethylene is noteworthy. The crystal structure of the μ-vinylidene compound has been determined. The new compounds [Fe(η 5-C 6H 7)(tmps)]PF 6, [Fe(η-C 6H 6)(tmps)][BF 4] 2, [(tmps)Fe(μ-Cl) 3Fe(tmps)]Cl, [(tmps)Fe(μ-Cl) 3Fe(tmps)]BPh 4, [Fe(η-C 5H 5)(tmps)]-PF 6, [Fe(η-C 4H 6)(tmps)], [Fe(η-C 6H 5CH 2CH 2Ph)(tmps)], [Fe(η 5-2-PhCH 2CH 2C 6H 6)(tmps)]PF 6 are also described.