Dynamic Behavior of an N-Metalated β-Enaminoimine Complex − Preparation of N-Phosphanylenamine and β-Enaminoimine Derivatives

Variable‐temperature NMR spectroscopy of the β‐enaminoimine complex 2 showed a dynamic process which was attributed to an internal fluxional aldimido N‐zirconated π‐linear/σ‐bent structure. Such an internal rearrangement has been previously proposed to occur in these systems but never observed. We have prepared a variety of (N‐phosphanyl‐β‐enamino)imine ligands using the hydrozirconation/transmetalation reaction of malonodinitrile compounds RCH(CN)2 (R = H, PPh2). In addition to their potential uses in coordination chemistry, these systems are good tools for the study of intramolecular hydrogen bonding. The X‐ray crystal structure of 14 at 180 K shows an unsymmetrical system with the N(H) proton localized on one of the two chelating nitrogen atoms, consistent with the existence in solution of a low barrier proton transfer process with a double‐well potential. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)