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, RN 3, with actinide alkyl, alkynyl, and aryl complexes. i PrN═C═N i Pr reacts with (C 5 Me 5 ) 2 AnMe 2 to produce the isomorphous methyl amidinates (C 5 Me 5 ) 2 AnMe[( i Pr)NC(Me)N( i Pr)-κ 2 N,N′], An = Th, 1; U, 2, in high yield. The reaction of i PrN═C═N i Pr with (C 5 Me 5 ) 2 U(C≡CPh) 2 forms a similar insertion product, (C 5 Me 5 ) 2 U(C≡CPh)[( i Pr)NC(C≡CPh)N( i Pr)-κ 2 N,N′], 3 . (C 5 Me 5 ) 2 U(C 6 H 5 ) 2 does not generate an analogous product with i PrN═C═N i Pr, but forms instead a complex formally derived from carbodiimide insertion into a “(C 5 Me 5 ) 2 U(C 6 H 4 )” intermediate, (C 5 Me 5 ) 2 U[( i Pr)NC═N( i Pr)(C 6 H 4 )-κN,κC], 4 . Adamantyl azide, AdN 3, inserts into the An−Me bonds in the (C 5 Me 5 ) 2 AnMe 2 complexes to make monomethyl actinide triazenido complexes that differ in the mode of triazenido coordination: (C 5 Me 5 ) 2 ThMe[(Me)NN═N(Ad) - κ 2 N 1,2 ], 5, and (C 5 Me 5 ) 2 UMe[(Me)NNN(Ad) -κ 2 N 1,3 ], 6 . A κ 2 N 1,3 -triazenido complex of thorium was also isolated in a crystal comprised of a mixture of (C 5 Me 5 ) 2 ThMe[(Me)NNN(Ad) - κ 2 N 1,3 ] and (C 5 Me 5 ) 2 Th(OH)[(Me)NNN(Ad) - κ 2 N 1,3 ], 7 .