Stable N‐Heterocyclic Germylenes of the Type [Fe{(η5‐C5H4)NR}2Ge] and Their Oxidation Reactions with Sulfur, Selenium, and Diphenyl Diselenide

Abstract

Three new N‐heterocyclic germylenes of the type [Fe{(η5‐C5H4)NR}2Ge] (1RGe) containing particularly bulky alkyl [R = 2‐adamantyl (Ad), 1,1,2,2‐tetramethylpropyl (Pr*)] or aryl substituents [R = 2,6‐diisopropylphenyl (Dipp)] were prepared and structurally characterized, in two cases (R = Ad, Dipp), by single‐crystal X‐ray diffraction. Together with the previously described homologues with R = trimethylsilyl (TMS), tert‐butyl (tBu), and mesityl (Mes) their oxidative addition reactions with S8 and Se8 were studied, which afforded compounds of the type [1RGe(μ‐E)]2 (E = S, Se). The low solubility of most of these products severely hampered their purification and characterization. Nevertheless, their structural characterization by single‐crystal X‐ray diffraction was possible in six cases (E = S, R = Ad, Pr*; E = Se, R = Ad, Pr*, Mes, Dipp). No solubility problems were encountered in oxidative addition reactions with diphenyl diselenide, affording products of the type 1RGe(SePh2)2, whose crystal structures could be determined in four cases (R = TMS, tBu, Mes, Dipp). Short intramolecular CH···Se contacts compatible with hydrogen bonds were observed for [1AdGe(μ‐Se)]2, [1Pr*Ge(μ‐Se)]2, and 1tBuGe(SePh2)2.