Small-Molecule Activation Mediated by [η 5 -1,3-(Me 3 Si) 2 C 5 H 3 ] 2 U(bipy).

The uranium bipyridyl metallocene, [η 5 -1,3-(Me 3 Si) 2 C 5 H 3 ] 2 U(bipy) ( 2 ), is readily accessible in good yield by adding potassium graphite (KC 8 ) to a mixture of [η 5 -1,3-(Me 3 Si) 2 C 5 H 3 ] 2 UCl 2 ( 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 [η 5 -1,3-(Me 3 Si) 2 C 5 H 3 ] 2 U(II) fragment in the presence of Ph 2 E 2 (E = S, Se), alkynes, and a variety of hetero-unsaturated molecules such as diazabutadienes, azine (Ph 2 C═N) 2 , o -benzoquinone, pyridine N -oxide, CS 2 , isothiocyanates, and organic azides. However, upon exposure of 2 to thio-ketone Ph 2 CS, aldehyde p -MePhCHO, ketone Ph 2 CO, imine PhCH═NPh, azine (PhCH═N) 2 , and nitrile PhCN, it may also promote C-C coupling reactions forming [η 5 -1,3-(Me 3 Si) 2 C 5 H 3 ] 2 U[(bipy)(Ph 2 CS)] ( 16 ), [η 5 -1,3-(Me 3 Si) 2 C 5 H 3 ] 2 U[(bipy)( p -MePhCHO)] ( 17 ), [η 5 -1,3-(Me 3 Si) 2 C 5 H 3 ] 2 U[(bipy)(Ph 2 CO)] ( 18 ), [η 5 -1,3-(Me 3 Si) 2 C 5 H 3 ] 2 U[(bipy)(PhCHNPh)] ( 19 ), [η 5 -1,3-(Me 3 Si) 2 C 5 H 3 ] 2 U[(bipy)(PhCHNN═CHPh)] ( 20 ), and [η 5 -1,3-(Me 3 Si) 2 C 5 H 3 ] 2 U[(N 2 C 10 H 7 C(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 [η 5 -1,3-(Me 3 Si) 2 C 5 H 3 ] 2 U(I)(bipy) ( 15 ).