Deciphering preferred geometries of pyridylmethylamines-based complexes: A robust strategy combining NMR, DFT and X-ray

Abstract

The preparation of pyridylmethylamines (pma)-ZnBr2 and -CoBr2 complexes is described. Accurate structural informations in both solution and solid state have been obtained using an approach combining advanced NMR such as pure shift gradient-encoded selective refocusing (PS-GSERF) and conventional NOESY experiments, DFT calculations and X-ray analysis. The methodology developed has allowed a clear identification and characterization of preferred conformations and configurations at an atomic resolution. Our study has evidenced some key features of the overall 3D structure of pma-Zn and pma-Co complexes which shapes are set by the geometry of the metallacycle, the configuration of the sp3 nitrogen atom, the equatorial position of the benzyl side arm as well as the preferred spatial arrangement of the chiral side arm with respect to the metallacycle.