Crown-capped iron(S⁻) porphyrins 1·H₂O and 2·H₂O and their corresponding Ba²⁺ complexes have been prepared as active site analogues of the resting state of cytochrome P450_cam. cw-EPR studies and electronic structure calculations at the density functional theory (DFT) level of model systems suggest a functional role of the water cluster of P450_cam.