The combination of EPR and Mossbauer spectroscopy along with IR, Diffuse Reflectance UV-visible, and XRD techniques proved to be a powerful tool for identifying and characterizing the mol. and electronic structure of various Fe complexes formed inside the supercages of zeolite-Y. Esp. interesting is the identification of encapsulated trans-[(cyclam)Fe(N3)2]+@NaY, as a potent precursor for the synthesis of catalytically active Fe(V) nitrido species. [on SciFinder (R)]