While attempts to crystallise this species from the reaction mixture resulted in isolation of the starting material, a closely related magnesium analogue has been prepared by Jones and coworkers. During these experiments formation of [Fe(η 5 -C5H5)(CO)2]2 was observed by 1 H NMR spectroscopy. In contrast, the addition of 1 equiv. of 2,2,6,6-tetramethylpyridine 1-oxyl (TEMPO) to 2a under the same conditions led to formation of [Fe(η 5 -C5H5)(CO)2(TEMPO)] (detected by 1 H NMR experiments), and inhibited the formation of [Fe(η 5 -C5H5)(CO)2]2 (Figure ). The EPR measurements and radical trapping experiments support homolysis of the Zn-Fe bond under photolytic conditions, with clear evidence for the formation and trapping of Febased radicals.