13C‐ and 1H‐NMR. Studies on the Configuration of Tricarbonyliron Complexes of Oxa‐ and Aza[4.4.3]propellanes

The configurations of a series of mono‐ and bis‐Fe(CO)3 complexes of 12‐oxa[4.4.3]‐propella‐2,4,7,9‐tetraene (1) and of 11,13‐dioxo‐12‐methyl‐12‐aza[4.4.3]propella‐2,4,7,9‐tetraene (7) as well as of a trienic aza‐propellane complex have been studied in solution by 13C‐ and 1H‐NMR. spectroscopy. Praseodymium‐induced 13C‐shifts of the metalcarbonyl carbon atoms and of the central carbon atom of the complexed diene systems are particularly sensitive and useful to prove exo‐ or endo‐configuration of the tricarbonyliron ligand. In addition, H,H‐ and C,H‐coupling constants of the complexes and parent compounds are reported and discussed.