Mononuclear, binuclear, trinuclear and tetranuclear iron complexes of the N(CH2CH2S)33− (NS3) ligand with nitrosyl co-ligands

Abstract

Reaction of [Fe(acac)₃], (NEt₄)OAc and N(CH₂CH₂SH)₃ in MeCN in the presence of NO gives (NEt₄)[Fe(NS₃)(NO)] (1) [where NS₃ = N(CH₂CH₂S)₃]. Complex 1 reacts with metal chloride solvates, giving insoluble compounds of stoichiometry MFe₂(NO)₂(NS₃)₂, probably having the structure [M{Fe(NS₃)(NO)}₂-S,S′] [M = Fe (2), Co (3), Ni (4), Cu (5)], the nitrosyl analogues of known structurally characterised carbonyl compounds. 1 also reacts with HBF₄·Et₂O, giving the tetranuclear complex [{Fe(NO)₂{Fe(NS₃)}-S,S′}₂-S,S′] (6), which adds small molecules, L, giving the binuclear complexes [Fe(NO)₂{Fe(NS₃)(L)}-S,S′] [L = CO (7), CNMe (8), NO (9), CN⁻ (10)]. Complexes 6–9 are more conveniently prepared by treatment of [Fe(NS₃)(L)]⁻ precursors with half an equivalent of [{Fe(NO)₂}₂(μ-I)₂]. Reaction of (NEt₄)[Co(NS₃)(CN)] with half an equivalent of [{Fe(NO)₂}₂(μ-I)₂] gives [Fe(NO)₂{Co(NS₃)(CN)}-S,S′] (11). Treatment of the [Fe(NS₃)L] precursors used to make 7–9 with one equivalent of [{Fe(NO)₂}₂(μ-I)₂] gives another series of complexes, [{Fe(NO)₂I}-S{Fe(NS₃)(L)}-S′,S″{Fe(NO)₂}] [L = CO (12), CNMe (13), NO (14)]. Products were characterised by microanalyses, IR and Mössbauer spectra; X-ray crystal structure determinations were carried out on 1, 6, 7, 9, 10, 13 and 14. Magnetic measurements at room temperature showed evidence of spin pairing in all the polynuclear complexes.