Insertion of Carbodiimides and Organic Azides into Actinide−Carbon Bonds

Manipulation of steric crowding in organoactinide complexes has been explored by examining the insertion chemistry of carbodiimides, RNCNR, and organic azides, RN3, with actinide alkyl, alkynyl, and aryl complexes. iPrNCNiPr reacts with (C5Me5)2AnMe2 to produce the isomorphous methyl amidinates (C5Me5)2AnMe[(iPr)NC(Me)N(iPr)-κ2N,N′], An = Th, 1; U, 2, in high yield. The reaction of iPrNCNiPr with (C5Me5)2U(CCPh)2 forms a similar insertion product, (C5Me5)2U(CCPh)[(iPr)NC(CCPh)N(iPr)-κ2N,N′], 3. (C5Me5)2U(C6H5)2 does not generate an analogous product with iPrNCNiPr, but forms instead a complex formally derived from carbodiimide insertion into a “(C5Me5)2U(C6H4)” intermediate, (C5Me5)2U[(iPr)NCN(iPr)(C6H4)-κN,κC], 4. Adamantyl azide, AdN3, inserts into the An−Me bonds in the (C5Me5)2AnMe2 complexes to make monomethyl actinide triazenido complexes that differ in the mode of triazenido coordination: (C5Me5)2ThMe[(Me)NNN(Ad)-κ2N1,2], 5, and (C5Me5)2UMe[(Me)NNN(Ad)-κ2N1,3], 6. A κ2N1,3-triazenido complex of thorium was also isolated in a crystal comprised of a mixture of (C5Me5)2ThMe[(Me)NNN(Ad)-κ2N1,3] and (C5Me5)2Th(OH)[(Me)NNN(Ad)-κ2N1,3], 7.