Realizing the magneto-structural correlation of a highly anisotropic Fe(III) porphyrin complex through ab-initio approaches

A mononuclear pentacoordinate Fe(III)-porphyrin-NCS complex has been synthesized and characterized by single-crystal X-ray diffraction, magnetic, electrochemical, spectroscopic, and theoretical studies. Single crystal X-ray diffraction studies show a planar porphyrin moiety with an axial NCS coordinated to the Fe(III) centre. Electrochemical and spectroelectrochemical studies in solution depict clear changes in the system during oxidation and reduction processes. Mössbauer spectroscopic analysis at different temperatures also supported the observation of a high-spin state of the Fe(III)-porphyrin complex that was further backed by DFT calculations. Attempts to understand the origin of high magnetic anisotropy in the ground state as determined by DC magnetic measurements was undertaken by detailed CASSCF/QD-NEVPT2 calculations.