Small-Molecule Activation Mediated by [η5-1,3-(Me3Si)2C5H3]2U(bipy).

ABSTRACT

The uranium bipyridyl metallocene, [η5-1,3-(Me3Si)2C5H3]2U(bipy) (2), is readily accessible in good yield by adding potassium graphite (KC8) to a mixture of [η5-1,3-(Me3Si)2C5H3]2UCl2 (1) and 2,2'-bipyridine. Compound 2 was fully characterized and employed for small-molecule activation. It has been demonstrated that 2 may serve as a synthon for [η5-1,3-(Me3Si)2C5H3]2U(II) fragment in the presence of Ph2E2 (E = S, Se), alkynes, and a variety of hetero-unsaturated molecules such as diazabutadienes, azine (Ph2C═N)2, o-benzoquinone, pyridine N-oxide, CS2, isothiocyanates, and organic azides. However, upon exposure of 2 to thio-ketone Ph2CS, aldehyde p-MePhCHO, ketone Ph2CO, imine PhCH═NPh, azine (PhCH═N)2, and nitrile PhCN, it may also promote C-C coupling reactions forming [η5-1,3-(Me3Si)2C5H3]2U[(bipy)(Ph2CS)] (16), [η5-1,3-(Me3Si)2C5H3]2U[(bipy)(p-MePhCHO)] (17), [η5-1,3-(Me3Si)2C5H3]2U[(bipy)(Ph2CO)] (18), [η5-1,3-(Me3Si)2C5H3]2U[(bipy)(PhCHNPh)] (19), [η5-1,3-(Me3Si)2C5H3]2U[(bipy)(PhCHNN═CHPh)] (20), and [η5-1,3-(Me3Si)2C5H3]2U[(N2C10H7C(Ph)NH)] (22), respectively, in quantitative conversion. Furthermore, in the presence of CuI, a single-electron transfer (SET) process is observed to yield the uranium(III) iodide complex [η5-1,3-(Me3Si)2C5H3]2U(I)(bipy) (15).