Formation of Novel Tellurium-Containing Anions [(μ-RTe)(μ-CO)Fe2(CO)6-] and Synthesis of Fe/Te Clusters (μ-RTe)(μ-σ,π-PhCCH2)Fe2(CO)6, (μ-RTe)2Fe2(CO)6, and [(μ-RTe)Fe2(CO)6]2(μ-Te−Te-μ). X-ray Crystal Structure of [(μ-PhTe)Fe2(CO)6]2(μ-Te−Te-μ)

Abstract

A series of lithium salts of the anions [(μ-RTe)(μ-CO)Fe2(CO)6-] (R = n-Bu, Ph, o-MeC6H4, p-MeC6H4) were prepared by reaction of organolithium reagents with elemental tellurium, followed by treatment of the intermediates RTeLi with Fe3(CO)12 in THF at room temperature. Further treatment of the lithium salt [(μ-RTe)(μ-CO)Fe2(CO)6-]Li+ (R = n-Bu) in situ with PhC⋮CH at room temperature yielded Fe2Te2 and Fe2Te clusters (μ-n-BuTe)2Fe2(CO)6 (1) and (μ-n-BuTe)(μ-σ,π-PhCCH2)Fe2(CO)6 (2), whereas the lithium salts [(μ-RTe)(μ-CO)Fe2(CO)6-]Li+ (R = n-Bu, Ph, o-MeC6H4, p-MeC6H4) were treated in situ with acid chlorides, such as MeC(O)Cl and p-MeC6H4SO2Cl, to afford Fe2Te2 clusters (μ-RTe)2Fe2(CO)6 (R = n-Bu (1), Ph (4), o-MeC6H4 (6), p-MeC6H4 (8) and double Fe2Te2 clusters [(μ-RTe)Fe2(CO)6]2(μ-Te−Te-μ) (R = n-Bu (3), Ph (5), o-MeC6H4 (7), p-MeC6H4 (9)). In addition, the new single clusters, except 1, were separated into ae and ee (where a = axial and e = equatorial) isomers and characterized individually, whereas the new double clusters were isolated and characterized mostly as isomer mixtures. Possible pathways for the formation of such clusters have been proposed, and the crystal structure of the double cluster 5 was determined by X-ray diffraction analysis.