f-Element Disiloxanediolates: Novel Si−O-based Inorganic Heterocycles

The preparation and structural characterization of scandium and f‐element complexes derived from the disiloxanediolate dianion, [(Ph2SiO)2O]2−, are reported. Reactions of in situ prepared Ln[N(SiMe3)2]3 (Ln=Eu, Sm, Gd) with (Ph2SiOH)2O in different stoichiometries afforded the lanthanide disiloxanediolates [Eu{[(Ph2SiO)2O]Li(Et2O)}3] (1), [{{(Ph2SiO)2O}Li(dme)}2SmCl(dme)] (2), and [{{(Ph2SiO)2O}Li(thf)2}2GdN(SiMe3)2] (3). In situ formed (Ph2SiOLi)2O reacted with anhydrous NdBr3 (molar ratio 3:1) to give polymeric [{Nd{(Ph2SiO)2O}3{μ‐Li(thf)}2{μ2‐LiBrLi(thf)(Et2O)}}n] (4). Treatment of 3 with Ph2Si(OH)2 in the presence of acetonitrile yielded the dilithium trisiloxanediolate derivative [{Ph2Si(OSiPh2O)2}{Li(MeCN)}2]2 (5), which according to an X‐ray analysis displays an Li4O4 heterocubane structure. The trinuclear scandium complex [{{(Ph2SiO)2O}Sc(acac)2}2Sc(acac)] (6) was obtained by reaction of [(C5Me5)Sc(acac)2] (C5Me5=η5‐pentamethylcyclopentadienyl) with (Ph2SiOH)2O in a 3:2 molar ratio. Selective formation of the colorless uranium(VI) derivative [U{Ph2Si(OSiPh2O)2}2{(Ph2SiO)2O}] (7) was observed when uranocene, U(η8‐C8H8)2, was allowed to react with (Ph2SiOH)2O. An X‐ray diffraction study of the solvated derivative [U{Ph2Si(OSiPh2O)2}2{(Ph2SiO)2O}]⋅Et2O⋅TMEDA (TMEDA=N,N,N′,N′‐tetramethyl‐ethylenediamine) (7 a) revealed the presence of both the original [(Ph2SiO)2O]2− dianion as well as the ring‐enlarged [Ph2Si(OSiPh2O)2]2− ligand in the same molecule. Es wird über die Darstellung und strukturelle Charakterisierung von Scandium‐ und f‐Element‐Komplexen des [(Ph2SiO)2O]2−‐Dianions berichtet. Reaktionen von in situ hergestelltem Ln[N(SiMe3)2]3 (Ln=Eu, Sm, Gd) mit (Ph2SiOH)2O in unterschiedlichen Stöchiometrien liefern die Lanthanoiddisiloxandiolate Eu[{(Ph2SiO)2O}Li(Et2O)]3 (1), [{(Ph2SiO)2O}Li(dme)]2SmCl(dme) (2), und [{(Ph2SiO)2O}Li(thf)2]2GdN(SiMe3)2 (3). In situ gebildetes (Ph2SiOLi)2O reagiert mit wasserfreiem NdBr3 (Molverhältnis 3:1) zum polymeren {μ‐LiBrLi(thf)(Et2O)}[Nd{(Ph2SiO)2O}3{Li(thf)}2]n (4). Die Umsetzung von 3 mit Ph2Si(OH)2 in Gegenwart von Acetonitril führt zum Dilithiumtrisiloxandiolat‐Derivat [{Ph2Si(OSiPh2O)2}{Li(MeCN)}2]2 (5), welches nach der Röntgenstrukturanalyse eine Li4O4‐Heterokubanstruktur besitzt. Der dreikernige Scandiumkomplex [{(Ph2SiO)2O}Sc(acac)2]2Sc(acac) (6) ist durch Reaktion von [(C5Me5)Sc(acac)2] (C5Me5=η5‐Pentamethylcyclopentadienyl) mit (Ph2SiOH)2O im Molverhältnis 3:2 zugänglich. Bei der Reaktion von U(η8‐C8H8)