Near-Infrared Light-Induced Spin-State Switching Based on Fe(II)-Hg(II) Spin-Crossover Network.

The development of molecular switches with tunable properties has garnered considerable interest over several decades. A novel spin-crossover (SCO) material based on iron(II) complexes incorporating 4-acetylpyridine (4-acpy) and [Hg(SCN)] anions was synthesized and formulated as [Fe(4-acpy)][Hg(μ-SCN)] (1). Compound 1 is crystallized in a three-dimensional network in the non-centrosymmetric orthorhombic space group Pna2 with two octahedral [Fe(4-acpy)(NCS)] entities featuring two distinct Fe centers (Fe1 and Fe2).

Large-scale oxygen order phase transitions and fast ordering kinetics at moderate temperatures in NdNiO electrodes.

Non-stoichiometric 214-nickelates with Ruddlesden-Popper (RP) type frameworks emerged as potential candidates for mixed electronic/ionic conductors in the intermediate temperature range. In this work we investigated structural aspects of the oxygen ion mobility diffusion mechanisms in non-stoichiometric NdNiO nickelates by X-ray (laboratory and synchrotron) as well by neutron diffraction. Temperature dependent synchrotron powder diffraction revealed a phase diagram of unprecedented complexity, involving a series of highly organized, 3D modulated phases related to oxygen ordering below 800 K.