Large negative cubic hyperpolarizability for the spin-crossover compound cis-bis(thiocyanato)bis[N-(2-pyridylmethylene)aminobiph enyl]iron(ii)

The first example of a spin-crossover iron(II) compound with a large negative third-order polarizability, associated with an instantaneous electronic response, is reported; magnetic measurements show that this compound, cis-bis(thio-cyanato)bis[N-(2-pyridylmethylene)aminobip henyl]iron(II), characterized by X-ray structural data is in the high-spin form at room temperature.