Reduction of [{η 5 -1,2,4-(Me 3 Si) 3 C 5 H 2 } 2 UCl 2 ] (1) using potassium graphite (KC 8 ) in the presence of 2,2′-bipyridine forms the uranium bipyridyl metallocene [{η 5 -1,2,4-(Me 3 Si) 3 C 5 H 2 } 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 CuI, Ph 2 E 2 (E = S, Se), organic azides, diazenes, diazoalkanes, and CS 2 , complex 2 delivers a {η 5 -1,2,4-(Me 3 Si) 3 C 5 H 2 } 2 U-(II) fragment. (b) In contrast, C−C bond coupling occurs when 2 is exposed to the thio-ketone Ph 2 CS, the aldehyde p-MePhCHO, the ketones Ph 2 CO and (CH 2 ) 5 CO, and the seleno-ketone (p-MeOPh) 2 CSe to yield 15), and [{η 5 -1,2,4-(Me 3 Si) 3 C 5 H 2 } 2 U{(bipy){(p-MeOPh) 2 CSe}}] (16), respectively. On the contrary, the imido complex [{η 5 -1,2,4-(Me 3 Si) 3 C 5 H 2 } 2 UNCHPh(C 10 H 7 N 2 )] ( 17) is isolated from the reaction of 2 with PhCN.

A Lewis base supported terminal uranium phosphinidene, [η5-1,3-(Me3C)2C5H3]2U­(P-2,4,6- t Bu3C6H2)­(OPMe3) (5), is isolated from the reaction of the uranium methyl chloride [η5-1,3-(Me3C)2C5H3]2U­(Cl)­Me (4) with 2,4,6-(Me3C)3C6H2PHK in toluene in the presence of Me3PO. Moreover, the reactivity of uranium phospinidene 5 toward a series of small molecules was comprehensively explored. While no reactivity of 5 with internal alkynes is observed attributed to steric hindrance, it readily reacts in good yields with various small molecules including isothiocyanates, aldehydes, imines, diazenes, carbodiimides, nitriles, isonitriles, and organic azides, yielding uranium sulfidos, oxidos, metallaheterocycles, and imido complexes.

This paper describes the synthesis and reactivity of [5-1,3-(Me3Si)2C5H3]2U(=P-2,4,6-iPr3C6H2)(OPMe3) (6) which is accessible from a ligand exchange reaction between [5-1,3-(Me3Si)2C5H3]2U(=P-2,4,6-iPr3C6H2)(OPPh3) (2) and Me3PO at ambient temperature. Phosphinidene 6 exhibits no...

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 Noxide, 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- 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).

The Lewis base supported terminal uranium phosphinidene metallocene [5-1,3-(Me3C)2C5H3]2U(=P-2,4,6-iPr3C6H2)(OPMe3) (2) could be isolated from a salt metathesis reaction in toluene at ambient temperature between [5-1,3-(Me3C)2C5H3]2U(Cl)Me (1) and 2,4,6-iPr3C6H2PHK in the...