Tri(η-cyclopentadienyl)uranium(IV) silyl and siloxide compounds. Crystal structure of [U(η5-C5H5)3(OSiPh3)]. Insertion of lsocyanide into a uranium–silicon bond

Abstract

The complex [U(η⁵-C₅H₅)₃(SiPh₃)](1) has been synthesized from [U(η⁵-C₅H₅)₃Cl] and Li(SiPh₃) and fully characterized. The direct U–Si bond in (1) is quite reactive towards proton acidicmolecules, moreover it reacts with 2,6-dimethylphenyl isocyanide to give the insertion product [U(η⁵-C₅H₅)₃{C(NC₆H₃Me₂-2,6)SiPh₃}](3), the ¹H n.m.r. and i.r. data for which show that the isocyanide ligand is η²-co-ordinated to the uranium atom. The synthesis of [U(η⁵-C₅H₅)₃(OSiPh₃)](2) by reaction of [U(η⁵-C₅H₅)₃(NEt₂)] with SiPh₃(OH) and its X-ray structural determination are also reported. Compound (2) crystallizes from diethyl ether in the monoclinic space group P2₁/n with a= 15.368(5), b= 17.333(5), c= 10.778(5)Å and β= 106.27(3)° for Z= 4. The main features are the almost linear U–O–Si bond angle of 172.6(6)° and the short U–O distance of 2.135(8)Å.