Ring-Opening in the Actinide Cyclopropyl Complexes [Cp3U(2,2-Diphenylcyclopropyl)] n- (n=0, 1)

The reaction of [Cp3UCl] with in situ generated 1-lithium-2,2-dipenylcyclopropane results in the formationof [Cp3U(2,2-diphenylcyclopropyl)] (1) ingood yield. Reduction of 1 with KC8, in thepresence of 2.2.2-cryptand, results in the formation of a rare U(III)alkyl complex, [K(2.2.2-cryptand)][Cp3U(2,2-diphenylcyclopropyl)](2). Thermolysis or photolysis of 1 for10 d in toluene results in isomerization to the U(IV) & eta;(1)-allyl complex, [Cp3U(& eta;(1)-3,3-diphenylallyl)](3). Moreover, photolysis of 2 in THF for9 h at room temperature results in isomerization to the U(III) & eta;(1)-allyl complex, [K(2,2,2-cryptand)][Cp3U(& eta;(1)-3,3-diphenylallyl)] (4). Both 3 and 4 were fully characterized. In addition, selectivelabeling of the C-& alpha; positions of 1 and 2 with deuterium revealed that cyclopropyl ring-opening occursvia distal C-C bond cleavage via a hypothesized & eta;(3)-allyl intermediate.