Easy access to uranium nucleophilic carbene complexes
Résumé
Metathesis reactions of UCl4 with Li2C(Ph2PS)2 in Et2O only afforded the tris-carbene complex [{Li(OEt2)}2U{[double bond, length as m-dash]C(Ph2PS)2}3] (1), while the bis- and mono-carbene compounds [U{[double bond, length as m-dash]C(Ph2PS)2}2(THF)2] (2) and [{Li(THF)2}2U{[double bond, length as m-dash]C(Ph2PS)2}Cl4] (3) were obtained by treatment of UCl4 with Li2C(Ph2PS)2 in a mixture of THF and toluene. The bis-carbene complex 2 was also obtained either from the comproportionation reaction of 1 and UCl4 or protonolysis reaction of U(NEt2)4 with H2C(Ph2PS)2 and was transformed into the mono-carbene complex [U{[double bond, length as m-dash]C(Ph2PS)2}Cl2(THF)2] (4) by further reaction with UCl4. The utility of these complexes as precursors is illustrated by the synthesis of the biscyclopentadienyl derivative [Cp2U{[double bond, length as m-dash]C(Ph2PS)2}] (5) by treatment of 3 with TlCp. The crystal structures of [U{[double bond, length as m-dash]C(Ph2PS)2}2(py)2]·1.5py·0.5THF and 5·toluene are reported.