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. (PrN)-Pr-i=C=(NPr)-Pr-i reacts with (C5Me5)(2)AnMe(2) to produce the isomorphous methyl amidinates (C5Me5)(2)AnMe[(Pr-i)NC(Me)N(Pr-i)-kappa N-2,N'], An = Th, 1; U, 2, in high yield. The reaction of (PrN)-Pr-i=C=(NPr)-Pr-i with (C5Me5)(2)U(C CPh)(2) forms a similar insertion product, (C5Me5)(2)U(C CPh)[(Pr-i)NC-(C=CPh)N(Pr-i)-kappa N-2,N'], 3. (C5Me5)(2)U(C6H5)(2) does not generate an analogous product with (PrN)-Pr-i=C=(NPr)-Pr-i, but forms instead a complex formally derived from carbodiimide insertion into a "(C5Me5)(2)U(C6H4)" intermediate, (C5Me5)(2)U[(Pr-i)NC=N(Pr-i)(C6H4)-kappa N,kappa C], 4. Adamantyl azide, AdN(3), inserts into the An-Me bonds in the (C5Me5)(2)AnMe(2) complexes to make monomethyl actinide triazenido complexes that differ in the mode of triazenido coordination: (C5Me5)(2)ThMe[(Me)NN=N(Ad)-kappa(2) N1,2], 5, and (C5Me5)(2)UMe[(Me)NNN(Ad)-kappa N-2(1,3)], 6. A kappa N-2(1,3)-triazenido complex of thorium was also isolated in a crystal comprised of a mixture Of (C5Me5)(2)ThMe[(Me)NNN(Ad)-kappa N-2(1,3)] and (C5Me5)(2)Th(OH)[(Me)NNN(Ad)-kappa N-2(1,3)], 7.