Synthesis, Structure, and Reactivity of the Uranium Bipyridyl Complex [{η5-1,2,4-(Me3Si)3C5H2}2U(bipy)]

Reduction of [{eta(5)-1,2,4-(Me3Si)(3)C5H2}(2)UCl2] (1) using potassium graphite (KC8) in the presence of 2,2'-bipyridine forms the uranium bipyridyl metallocene [{eta(5)-1,2,4-(Me3Si)(3)C5H2}(2)U(bipy)] (2) in good yield, which was studied by various techniques. Complex 2 constitutes an excellent starting material for further reactions with small molecules for which two dominant reaction patterns emerge: (a) in the presence of Cul, Ph2E2 (E = S, Se), organic azides, diazenes, diazoalkanes, and CS2, complex 2 delivers a {eta(5)-1,2,4-(Me3Si)(3)C5H2}(2)U-(II) fragment. (b) In contrast, C-C bond coupling occurs when 2 is exposed to the thio-ketone Ph2CS, the aldehyde p-MePhCHO, the ketones Ph2CO and (CH2)(5)CO, and the seleno-ketone (p-MeOPh)(2)CSe to yield [{eta(5)-1,2,4-(Me3Si)(3)C5H2}(2)U{(bipy)(Ph2CS)}] (12), [{eta(5)-1,2,4-(Me3Si)(3)C5H2}(2)U{(bipy)(p-MePhCHO)}] (13), [{eta(5)-1,2,4-(Me3Si)(3)C5H2}(2)U{(bipy)(Ph2CO)}] (14), [{eta(5)-1,2,4-(Me3Si)(3)C5H2}(2)U{(biPy){(CH2)(5)CO}}] (15), and [{eta(5)-1,2,4-(Me3Si)(3)C5H2}(2)U{(biPY){(P MeOPh)(2)CSe}}] (16), respectively. On the contrary, the imido complex [{eta(5)-1,2,4-(Me3Si)(3)C5H2}(2)U=NCHPh(C10H7N2)] (17) is isolated from the reaction of 2 with PhCN.