Determination and Recovery of Spin‐States for a High‐Spin and a Spin‐Crossover Complex by Means of X‐Ray Wavefunction Refinement

ABSTRACT In this study, we present the first experimental determination of the spin‐states of a spin‐crossover‐active transition metal complex by using x‐ray wavefunction refinement. Two complexes— and —were investigated using the method with wavefunctions in different spin‐states. The correct spin‐states can be identified by comparing different refinement indicators and resulting residual electron densities. The application of this method to spin‐crossover complexes revealed that the spin‐state can be partially recovered by the refinement method even when initially assumed incorrectly. This work demonstrates the potential for x‐ray wavefunction refinement to be used in order to gain insight not only into the geometric but also into the electronic structure of transition metal complexes.