Reactivity of the uranium-nitrogen bond: Insertion of isocyanides

Isocyanides react readily with UCp2(NEt2)2 (Cp=cyclopentadienyl) and U(C5Me5)2(NEt2)Cl giving iminoalkylamido insertion compounds. Starting from UCp2(NEt2)2 and an excess of isocyanide or from the monoinserted compound, a second insertion occurs, affording the high symmetrical bisiminoalkylamido compounds. 1H NMR data are indicative of the importance of a ''carbenoid'' resonance hybrid and of the nitrogen lone-pair donation to the ''carbenoid'' carbon atom. (orig.)