Synthesis and characterization of a series of U(IV) trans-bis(phosphaylide)UX4 (X = Cl, Br, I) adducts

A Metallocene Bis(phosphoranocarbene) of Uranium and a Probe of Its Reactivity with Alcohols

“…Namely, the addition of 2 equiv of the Wittig-type phosphaylide reagents H 2 C�PAr 3 (Ar = Ph; 3,5-di-tertbutylphenyl ( tBu Ar)) to UX 4 (solvent) n (X = Cl, n = 0; X = Br, solvent = THF, n = 2; X = I, solvent = 1,4-dioxane, n = 2), results in the formation of the bis(phosphaylide) adducts UX 4 (CH 2 PAr 3 ) 2 (Ar = Ph, X = Cl, I; Ar = tBu Ar, X = Cl, Br, I), where the phosphaylide ligands adopt a trans geometry. 28 Additionally, we have been exploring the reactivity of these phosphaylides with Cp* 2 UMe 2 . Here we describe, several decades after the original reports of Cp 3 U�C(H)PMe 2 Ph and Cp* 2 U(NPh) 2 , the first unchelated, phosphorano-stabilized uranium bis(carbene) complex Cp* 2 U[C(H)PPh 3 ] 2 (1).…”

“…In our laboratory, we have recently been exploring the coordination chemistry of simple ylide adducts to uranium tetrahalides. Namely, the addition of 2 equiv of the Wittig-type phosphaylide reagents H 2 CPAr 3 (Ar = Ph; 3,5-di- tert -butylphenyl ( t Bu Ar)) to UX 4 (solvent) n (X = Cl, n = 0; X = Br, solvent = THF, n = 2; X = I, solvent = 1,4-dioxane, n = 2), results in the formation of the bis­(phosphaylide) adducts UX 4 (CH 2 PAr 3 ) 2 (Ar = Ph, X = Cl, I; Ar = t Bu Ar, X = Cl, Br, I), where the phosphaylide ligands adopt a trans geometry . Additionally, we have been exploring the reactivity of these phosphaylides with Cp* 2 UMe 2 .…”